JP2002127458A - Method of detecting presence or absence of ink ejection and recorder using the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of detecting presence or absence of ejection of ink by each ink ejection nozzle on a recording head in a simple structure, and a recorder using the method. SOLUTION: An electrode 101 is provided in the vicinity of each ink ejection nozzle of the recording head 1113 and an electrode 102 is provided on the external section of the recording head 1113. The conductivity between the two electrodes is detected in synchronism with the ejecting operation of ink and then the presence or absence of the ejection of ink is judged based on the detected result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting the presence or absence of ink ejection and a recording apparatus therefor, and more particularly, to the method for detecting the presence or absence of ink ejection when performing recording using, for example, an ink jet recording head that uses thermal energy to eject ink. The present invention relates to a method and a recording device thereof.

[0002]

2. Description of the Related Art With the spread of information processing equipment such as copying apparatuses, word processors, computers, etc., as one of output (recording) apparatuses of such equipment, a recording apparatus (inkjet) which performs recording using an ink jet recording head. Recording devices) are rapidly spreading. In general, an inkjet recording apparatus includes a carriage on which a recording head and an ink tank are mounted, a transport mechanism for transporting the recording medium, and a control circuit for controlling these.

[0003] In the conventional ink jet recording apparatus, there is a case where a recording failure occurs due to ink exhaustion during recording. For example, if the ink runs out during printing while feeding continuous paper, the printing time after the ink runs out is wasted. Also,
If printing of an unclear image is continued in a so-called “faint printing” state that occurs immediately before the ink runs out, a large number of printing media are wasted. Further, if such printing is continued, a load is applied to the print head, and the print head itself may be destroyed.

Therefore, in order to avoid such a problem, various non-discharge detection methods for ink have been proposed. For example, a light emitting unit and a light receiving unit are provided, and when irradiating light from the light emitting unit to the light receiving unit, ink droplets are ejected between the light emitting unit and the light receiving unit so as to block the optical path, and the light receiving unit An optical ink presence / absence detection method of detecting a change in the amount of received light and performing ink non-discharge detection is a typical method.

FIG. 13 is a block diagram showing a schematic configuration of a conventional ink jet recording apparatus.

In FIG. 13, reference numeral 1101 denotes a CPU 1101A and a ROM 1101 for controlling the entire recording apparatus.
B, a control unit including a RAM 1101C. CPU1
101A reads various control programs stored in ROM 1101B, and executes the programs using a work area provided in RAM 1101C for temporarily storing data and the like to control the recording apparatus.

Reference numeral 1102 denotes a CPU bus for connecting the control unit 1101 to peripheral control units to be described later.
3 is a part of the image data received from the external device, or
An image buffer 1104 for temporarily storing the entire image is an external interface (I / F) unit for receiving image data and commands from an external device. Reference numeral 1105 denotes a connection cable for connecting the external device to an external interface (I / F) unit, and reference numeral 1106 denotes a host computer (hereinafter, referred to as a host) which is a typical external device for generating commands and image data. .

Reference numeral 1107 denotes a motor control unit for driving a suction cap drive motor, a suction pump, and a carriage motor, which will be described later. Reference numeral 1108 denotes a suction cap which is pressed by an ink discharge port of the print head and sucks ink in the print head. A suction cap motor 1110 for vertically moving the suction cap 1108 to press it against the head ejection port
Reference numeral 1111 denotes a suction pump that suctions ink in the print head via the head discharge port and the suction cap 1108, and 1111 denotes a carriage motor that reciprocates the print head in a predetermined direction (main scanning direction).

Further, 1112 converts the image data sent from the host 1106 into a format suitable for the recording head, and performs recording by controlling the recording head in synchronization with the reciprocation of the recording head in the main scanning direction. The printhead controller 1113 prints one or more dots of image data transferred from the printhead controller 1112 in a direction (sub-scanning direction) orthogonal to the main scanning direction, and prints while reciprocating in the main scanning direction. Is a cleaning plate that cleans the ink ejection port surface of the recording head by moving the recording head 1113 thereon.

Further, reference numeral 107 denotes a recording head control unit 1
Ink droplets ejected from the recording head 1113 under the control of 112, a light emitting unit 1201 for emitting predetermined light,
Reference numeral 202 denotes a light receiving unit that receives light emitted from the light emitting unit 1201, and reference numeral 1153 denotes an optical element control unit that controls operations of the light emitting unit 1201 and the light receiving unit 1202. And the light emitting unit 1
201, light receiving unit 1202, and optical element control unit 115
3 constitutes an ink presence / absence detection sensor.

In the above-described configuration, the conventional ink jet recording apparatus checks the presence or absence of ink before starting the recording operation.

First, the recording head 1113 is moved by the carriage motor 1111 under the control of the motor control unit 1107, and is moved to a position right above the position where the light emitting unit 1201 and the light receiving unit 1202 are provided.

Next, a print head controller 1112 controls the print head 1113 to eject ink droplets 107. The ejected ink droplet 107 passes between the light emitting unit 1201 and the light receiving unit 1202, that is, so as to block the optical path of the light emitted from the light emitting unit 1201. Here, the optical element control unit 1153 inputs the electric signal converted according to the light receiving intensity of the light received by the light receiving unit 1202. This electric signal is sent to the CPU 1101A via the CPU bus 1102, and a digital value represented by the electric signal is compared with a predetermined threshold.

FIGS. 14 and 15 are views showing a state when an ink discharging operation is performed from a recording head on a test basis to determine the presence or absence of ink. In these figures, FIG.
4 shows a state when there is ink, and FIG. 15 shows a state when there is no ink. In these figures, reference numeral 105 denotes an electrothermal conversion element (heater) provided in a plurality of ink ejection nozzles of the print head 1113;
106 is an ink ejection port, 108 is an ejection pulse for applying ink to the electrothermal transducer to heat the ink to cause ink ejection, and 1203A and 1203B are electric signals (ink presence / absence detection waveform) output from the light receiving unit 1202. It is a waveform of.

[0015] As shown in FIG.
If the ink droplet 107 is detected from the
Interrupts the optical path of the light emitted from the light receiving unit 1201 to the light receiving unit 1202, so that the amount of light received by the light receiving unit 1202 decreases. Therefore, the level 1203A of the electric signal converted according to the received light intensity also decreases. On the other hand, as shown in FIG. 15, when the ink droplet 107 is not ejected from the ink ejection port 106 or the ejection amount is small, the light irradiated from the light receiving unit 1201 to the light receiving unit 1202 is The ink does not block. As a result, the amount of light received by the light receiving unit 1202 decreases. Therefore, the level 1203 of the electric signal converted according to the received light intensity
B does not decrease much.

For this reason, a comparison between a digital value obtained by A / D conversion of an electric signal obtained from the light receiving unit 1202 and a predetermined threshold value (indicated by a broken line 1204 in FIGS. 14 to 15). As a result, if the digital value is equal to or less than the threshold value, the light between the light emitting unit 1201 and the light receiving unit 1202 is blocked by the ink droplet 107, so that it is determined that there is ink. On the other hand, if the digital value is larger than the threshold value, it is determined that the ink droplet 107 has not blocked light, and it is determined that there is no ink.

If it is determined that there is no ink, the recording head 1113 is moved to a position facing the absorption cap 1108 by the carriage motor 1111, and the suction cap 1108 is moved by the suction cap motor 1109.
The ink ejection port of the print head is pressed against the print head 108, and the ink in the print head is sucked by the suction pump 1110. In addition, the ink ejection openings are cleaned by moving the recording head 1113 to a position where the cleaning plate 1114 is provided by the carriage motor 1111 as necessary. Thereafter, the above-described ink presence / absence detection operation is performed again. As a result, if it is determined that there is no ink again, a message of “ink out” is displayed on the display unit (for example, L
CD) to prompt the user to fill the ink,
If it is determined that “ink is present”, recording is started.

Incidentally, the recording operation is normally executed as follows.

First, under the control of the control unit 1101, the connection cable 1105, the external interface (I / F) unit 1
A part or all of the image data sent from the host 1106 is received via the
03.

Next, the image data stored in the image buffer 1103 is sent to the printhead control unit 1112 via the CPU bus 1102 under the control of the control unit 1101 so that the printhead 1113 performs printing. After being converted into a suitable format, it is transferred to the recording head 1113.

In synchronization with this data transfer, the recording head 1
Reference numeral 113 performs recording by discharging ink while being reciprocated in the main scanning direction by the carriage motor 1111. The recording paper is transported by a recording paper transport motor (not shown) every time one scan of printing in the main scanning direction is performed.

By repeating the above operation, the recording of one page of the recording paper is completed.

[0023]

However, in the above conventional example, in order for the ink droplet to pass through the optical path from the light emitting portion to the light receiving portion and to detect a change in the amount of received light at the light receiving portion, a plurality of ink droplets are required. It is necessary to eject, that is, simultaneously eject a plurality of ink droplets from a plurality of ink ejection ports, and thus there is a disadvantage that it is not possible to detect the presence or absence of ink ejection for each ink ejection port.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and has an ink discharge detection method and a recording apparatus capable of detecting the presence or absence of ink discharge for each ink discharge port of a recording head with a simple structure. It is intended to provide.

[0025]

In order to achieve the above object, a method for detecting the presence or absence of ink ejection according to the present invention comprises the following steps.

In other words, there is provided a method for detecting the presence or absence of ink ejection in ink jet recording in which an image is recorded by ejecting ink droplets onto a recording medium using an ink jet recording head having a plurality of ink ejection nozzles. In synchronization with the ink ejection operation,
An application step of applying a voltage pulse to a first electrode provided in the vicinity of each ink ejection port of the plurality of ink ejection nozzles, and a second electrode provided at a location where ink droplets are ejected from the inkjet recording head A detecting step of detecting whether there is continuity between the first electrode and the second electrode according to the application of the voltage pulse;
A determination step of determining whether or not ink has been discharged from the inkjet recording head according to the detection result in the detection step.

According to another aspect of the present invention, there is provided a recording apparatus for recording an image by ejecting ink droplets onto a recording medium using an ink jet recording head having a plurality of ink ejection nozzles. A first electrode provided near each ink discharge port of a discharge nozzle, a second electrode provided at a location where ink droplets outside the ink jet recording head are discharged, and an ink discharge operation from the ink jet recording head. Applying means for applying a voltage pulse to the first electrode in synchronization with the application of the voltage pulse, and detecting whether or not there is conduction between the first electrode and the second electrode in response to the application of the voltage pulse; Detecting means for determining whether or not ink has been ejected from the ink jet recording head according to the detection result of the detecting means. A recording apparatus according to claim.

Here, each of the plurality of ink discharge nozzles of the ink jet recording head is provided with an electrothermal converter for generating thermal energy given to the ink in order to discharge the ink using thermal energy. Is preferred. In this case, the first electrode and the electrothermal transducer are shared, and the voltage pulse applied to the first electrode is a pulse applied to the electrothermal transducer in order to eject ink from the ink ejection port. You may do it.

The judging means judges that there is ink ejection when there is conduction between the first and second electrodes, and judges that there is no conduction between the first and second electrodes. It is good to judge that there is no ink ejection.

Further, a cleaning means for cleaning the surface of the ink jet recording head provided with the ink discharge ports, and a cap for sucking and recovering the ink jet recording head, such as a cap for covering the surface provided with the ink discharge ports, It is desirable to provide suction recovery means including a suction pump for sucking the inside of the ink discharge nozzle of the ink jet recording head. Still further, a preliminary continuity test in which the application unit and the detection unit are operated to perform preliminary inspection of continuity between the first and second electrodes without performing the ink ejection operation from the ink jet recording head. Preferably, means are provided. In this case, it is preferable to provide a recovery control unit that controls the cleaning unit and / or the suction recovery unit to operate according to the preliminary conduction inspection result.

The second electrode may be configured to be included in the cap. At this time, the second electrode can be brought into contact with the surface of the ink jet recording head where the ink ejection port is provided, and at that time, the pressing force of the second electrode on the surface where the ink ejection port is provided changes. It is desirable to be made.

In this case, before performing the ink discharge operation from the ink jet recording head, the cap may be pressed against the surface provided with the ink discharge ports, and the suction pump may be operated to perform the suction operation. After the ink ejection presence / absence detection by the application unit, the detection unit, and the determination unit, the cap may be controlled to be suctioned.

Regarding the potential difference between the first electrode and the second electrode, the first electrode side may be set to a higher potential than the second electrode side, and the first electrode side may be set to the second potential. The potential may be lower than the electrode side.

Further, it is preferable that the operation by the application unit and the detection unit is controlled so as to be continuously executed over each of the plurality of ink ejection nozzles, and the storage unit for storing the detection result by the detection unit is further provided. Is preferred.

With the above arrangement, according to the present invention, a first electrode is provided in the vicinity of each ink ejection port of an ink jet recording head, and a second electrode is provided outside the recording head. The conduction between these two electrodes is detected, and the presence or absence of ink ejection is determined according to the detection result.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <Schematic Description of Apparatus Main Body> FIG.
1 is an external perspective view illustrating an outline of a configuration of an inkjet printer IJRA according to a representative embodiment of the present invention. In the apparatus components shown in FIG. 1, the same components as those already described in the conventional example are denoted by the same reference numerals.

In FIG. 1, the carriage motor 1111
Transmission gears 5009 to 501 in conjunction with forward and reverse rotation of
The carriage HC that engages with the spiral groove 5004 of the lead screw 5005 that rotates through 1 has a pin (not shown), and is supported by the guide rail 5003 and reciprocates in the directions of arrows a and b. On the carriage HC, an integrated ink jet cartridge IJC containing a recording head 1113 and an ink tank IT is mounted.
A paper pressing plate 5002 presses the recording paper P against the platen 5000 in the moving direction of the carriage HC. Reference numerals 5007 and 5008 denote home position detectors for confirming the presence of the carriage lever 5006 in this region and switching the rotation direction of the carriage motor 1111.

A member 5016 supports a suction cap 1108 for capping the front surface of the recording head 1113.
Reference numeral 110 denotes a suction pump that suctions the inside of the cap, and performs suction recovery of the recording head through the opening 5023 in the cap. Reference numeral 1114 denotes a cleaning plate. Reference numeral 5019 denotes a member that enables the cleaning plate to move in the front-rear direction.
These are supported. It goes without saying that the cleaning plate 1114 is not limited to this form, and a well-known cleaning blade can be applied to the present embodiment. Reference numeral 5021 denotes a lever for starting suction for recovery of suction, which moves with the movement of the cam 5020 which engages with the carriage, and the driving force from the driving motor is controlled by a known transmission mechanism such as a clutch switch. Is done.

The capping, cleaning, and suction recovery are configured so that desired operations can be performed at the corresponding positions by the action of the lead screw 5005 when the carriage comes to the area on the home position side. If a desired operation is performed at the timing, any of the embodiments can be applied.

As described above, the ink tank IT and the recording head 1113 may be integrally formed to constitute a replaceable ink cartridge IJC. However, the ink tank IT and the recording head 1113 are separated. It can be configured so that the ink tank IT
May be exchangeable.

FIG. 2 is an external perspective view showing the structure of an ink cartridge IJC in which an ink tank and a recording head can be separated. In the ink cartridge IJC, as shown in FIG. 2, the ink tank IT and the recording head 1113 can be separated at the position of the boundary line K. Ink cartridge IJ
C is provided with an electrode (not shown) for receiving an electric signal supplied from the carriage HC when it is mounted on the carriage HC, and the electric signal drives the recording head 1113 as described above. Then, the ink is ejected.

In FIG. 2, reference numeral 500 denotes an ink ejection port array. The ink tank IT is provided with a fibrous or porous ink absorber for holding ink, and the ink is held by the ink absorber.

<Description of Control Structure> Next, a control structure for executing the recording control of the above-described apparatus will be described.

FIG. 3 is a block diagram including the configuration of the control circuit of the ink jet printer IJRA. Note that FIG.
Here, the same components as those described in the conventional example are denoted by the same reference numerals, and description thereof will be omitted. Here, only the configuration characteristic of this embodiment will be described.

Reference numeral 101 denotes an electrode provided near the ink discharge port of the recording head 1113, 102 denotes an electrode provided near the suction cap 1108 at a position where ink droplets are discharged from the recording head 1113, and 103 denotes an electric electrode. A conduction detecting unit that controls a series of operations for detecting conduction between the electrode 101 and the electrode 102 when the ink droplet 107 is ejected based on the ejection pulse 108 input to the heat conversion element 105. is there. With such a configuration, the continuity detecting unit 103 detects continuity due to the ink droplet between the electrode 101 and the electrode 102 in synchronization with the ejection of the ink droplet from the recording head 1113.

The electrode 102 is a conductive ink absorber, and it goes without saying that the distance between the electrode 102 and the ink discharge port 106 is shorter than the length of the ink droplet to be discharged.

FIG. 4 is a diagram showing in detail how to detect the presence or absence of ink ejection.

This figure particularly shows whether or not there is ink ejection from one ink ejection port. FIG.
In the figure, reference numeral 104 denotes a conduction detection pulse detected by the conduction detection unit 103, and 1113N denotes one recording element of the recording head 1113 including one electrothermal conversion element 105 and one ink ejection port 106. One dot is recorded by this one recording element.

FIG. 4A shows a state when the ink droplet 107 is ejected and the conduction detection pulse 104 between the electrode 101 and the electrode 102 is detected.
(B) shows a state when the ink droplet 107 is not ejected and the conduction detection pulse 104 is not detected.

In such a configuration, in order to detect the presence / absence of ink ejection, the recording head 1113 is moved over the electrode 102, and thereafter, an ejection pulse 108 is applied to the electrothermal transducer 105 so that the ink droplet 107 is ejected. Discharge port 10
Discharge from 6. In synchronization with this ejection, a conduction detection pulse 104 is applied to the electrode 101 and the electrodes 101 and 102
The continuity detecting unit 103 detects whether or not the continuity is established via the ink droplet 107 between the two. FIG. 4 shows the derived detection pulse 104 as a pulse-like waveform.
If a long-time charge is applied and the ink is not electrolyzed, a DC potential may be applied.

FIG. 5 is a diagram showing a detailed configuration of the conduction detecting unit 103.

In FIG. 5, B indicates a signal input to the conduction detection unit 103 via the electrode 102, and C indicates a signal output from the conduction detection unit 103. Further, as shown in FIG. 5, the conduction detecting unit 103 includes a flip-flop circuit.

Further, as can be seen from FIG.
The second side has a low potential, and the electrode 101 side has a supply voltage level. Therefore, if the ink droplet 107 is ejected and there is conduction, the signal B becomes high level and the detection result indicates “HIGH”. If no ink droplet is ejected and there is no conduction, the signal B becomes low level and the detection result becomes “high”. LOW ”
Is shown.

The printing apparatus having the above configuration checks whether or not ink has been ejected before starting the printing operation.

Next, the ink ejection presence / absence detection processing will be described with reference to the flowchart shown in FIG.

First, in step S10, the recording head 11
13 is moved above the electrode 102 by driving the carriage motor 1111 under the control of the motor control unit 1107. Next, in step S20, the recording head controller 11
The ejection pulse 108 is controlled by the recording head 11 under the control of
13, the ink droplet 107 is ejected onto the electrode 102, and the conduction detection pulse 104 is applied to the electrode 101 in synchronization with the ejection operation.

In step S30, it is determined whether or not the conduction detection pulse 104 applied to the electrode 101 reaches the electrode 102 through the ink droplet 107.
Check based on the level of the signal output from.

Here, if the signal level is "HIGH", the process proceeds to step S40, where "ink present"
If the signal level is "LOW", the process proceeds to step S50, and determines that "ink is out".

Next, in step S60, the carriage motor 1111 is driven to move the recording head 1113 to a position facing the suction cap 1108, and in step S70, the suction cap 1108 is moved by the suction cap motor 1109 to the ink discharge port. 106, the suction pump 1110 is operated, and the recording head 11
The 13 ink ejection nozzles are sucked. In this way,
Suction recovery is performed by removing the cause of the ejection failure such as bubbles. Further, if necessary, the carriage motor 1111 is driven to move the recording head 1113, and the surface of the recording head having the ink discharge ports is cleaned by the cleaning plate 1114, and the ink fixed to the ink discharge ports 106 is cleaned. You may do it. Thereafter, the process proceeds to step S80.

In step S80, step S2 is executed again.
The detection of the presence / absence of ink ejection similar to 0 is performed, and the level of the signal output from the conduction detection unit 103 is checked in step S90. Here, the signal level is “HIG”.
If the signal level is "H", the process proceeds to step S40. If the signal level is "LOW", the process proceeds to step S10.
0, judge that there is no ink,
Is displayed as a message on a display unit (not shown) of the recording apparatus composed of the above. Thereafter, the process ends.

On the other hand, after it is determined in step S40 that "ink is present", the process proceeds to a normal printing operation.

Therefore, according to the embodiment described above, 2
Since the conduction between the two electrodes is controlled by the presence or absence of ink between them, one electrode is provided for each of the plurality of ink ejection ports of the recording head, and the other electrode is used as a common electrode at an ink ejection position outside the recording head. With this arrangement, it is possible to detect whether or not ink has been ejected for each ink ejection port.

Prior to the above-described process of detecting the presence or absence of ink ejection, preliminary conduction detection between the electrode 101 and the electrode 102 may be performed before the ink droplet 107 is detected on the electrode 102. If the conduction between the electrode 101 and the electrode 102 is detected before the ejection operation of the ink droplet 107 is performed by such preliminary conduction detection, it is determined that the area around the ink ejection port 106 is dirty. Then, the recording head 1113 is moved onto the cleaning plate 1114 to clean the periphery of the ink discharge port 106, and preliminary conduction is detected again. When conduction is detected again, it is possible that the ink discharge operation is not performed. Of the electrode 101 and the electrode 1 for some other reason.
Since 02 is electrically connected, a message indicating that the device needs to be checked may be displayed on the display unit to alert the user of the device. Again,
If the conduction is not detected in the preliminary conduction detection, it is assumed that the apparatus has returned to a normal state, and the above-described processing from step S20 may be executed.

The electrode 102 is connected to the suction cap 1108.
At this time, after the recording head 1113 is moved onto the suction cap 1108, the above-described step S
The processing described in 20, S30, S80, and S90 is performed. When the suction cap also serves as the electrode 102, the suction pump 1110 is driven and the suction cap 1108 is driven before the suction cap 1108 is pressed against the recording head 1113 in order to perform the above-described ink ejection presence / absence detection processing.
A part of the ink contained in the absorber may be sucked to make it easy to absorb the ink ejected at the time of detecting the presence or absence of ink ejection.
After canceling the pressing of 08, the suction cap 1108 may be sucked again to suck the ink detected by the detection process.

FIG. 7 shows that the suction cap 1108 is
FIG. 7 is a diagram illustrating a positional relationship between the absorber of the suction cap and the ink discharge port 106 when the above function is also performed.

In FIG. 7, (a) shows a state in which the suction cap 1108 made of an absorber comes into contact with the ink discharge port 106, and (b) shows a state in which the suction cap 1108 made of the absorber discharges the ink. The state when the ink droplet 107 is ejected in a state of being in contact with the outlet 106 is shown.

As shown in FIG. 7A, when the suction cap 1108 formed of an absorber comes into contact with the ink discharge port 106, the ink around the ink discharge port 106 is absorbed by the suction cap 1108 and has no ink. 106A is generated, and the state between the electrode 101 and the electrode 102 becomes non-conductive. Here, by ejecting the ink droplet 107, the presence or absence of ink ejection is detected as described above.

However, depending on the difference in the structure of the ink ejection port 106 of the recording head 1113, the space 106A completely free of ink around the ink ejection port 106 can be obtained only by bringing the suction cap 1108 into contact with the ink ejection port 106. Is not always formed. Therefore, when the suction cap 1108 is pressed against the ink ejection port of the recording head 1113, the pressing force may be changed so that the ink-free space 106A is reliably formed.

FIG. 8 is a diagram showing a state when the pressing force of the suction cap 1108 against the recording head 1113 is changed. 8A shows a state in which the pressing force of the suction cap 1109 on the ink ejection port 106 is increased.
(B) has shown the state returned to normal contact. As shown in FIG. 8, the pressing force on the ejection port 106 of the suction cap 1108 is increased once (FIG. 8A), the ink around the ink ejection port 106 is absorbed, and then the pressing force is increased. (FIG. 8B), a space 106A completely free of ink is reliably formed around the ink ejection port 106.

[0070]

[Other Embodiments] In the above embodiment, the discharge pulse 108 applied to the electrothermal transducer 105 and the conduction detection pulse 104 input to the electrode 101 are described as separate pulses. Then, the ejection pulse 10
An example in which the conduction detection pulse 104 is also used in FIG.

FIG. 9 shows the state of detecting the presence or absence of ink ejection by using the ejection pulse and the conduction detection pulse in common, and the conduction detection unit 10.
3 is a diagram showing the configuration of FIG. 3 in detail.

In this case, as shown in FIG. 9A, a discharge pulse 108 is applied to both the electrothermal transducer 105 and the electrode 101. This application is shown in detail by the circuit configuration shown in FIG.

FIG. 10 is a time chart of various signals used when the operation of detecting the presence or absence of ink discharge is performed using the discharge pulse 108. In FIG. 10, (a) shows a timing chart of one ink ejection detection operation.
(B) shows a timing chart when the ink ejection presence / absence detection operation is continuously performed.

In FIG. 10, A represents the ink droplet 10.
7 shows a state in which conduction between the electrode 101 and the electrode 102 is performed while the recording head 7 is ejected from the recording head 1113 toward the electrode 102, B indicates a signal input to the conduction detection unit 103 via the electrode 102, C indicates a signal output from the conduction detecting unit 103, and D indicates a case where the operation of detecting the presence or absence of ink ejection is continuously performed, and the detection result is converted from serial data to parallel data and continuously stored in the RAM 1101C. 3 shows a signal waveform.

In this embodiment, similarly to the above-described embodiment, when the ink droplet 107 is ejected by the ejection pulse 108 applied to the electrothermal transducer 105, FIG.
As shown in A of FIG. 0 (a) and A of FIG. 10 (b), the ink droplet 107 moves from the ink discharge port 106 to the electrode 102, and a section shown by a hatched portion in the middle, between the electrode 101 and the electrode 102, Conduct. In this conduction section, a potential is generated by the load resistance of the conduction detection unit 103, and B in FIG.
A signal as indicated by B in (b) is output to the conduction detection unit 103.

Here, if the ink droplet 107 is actually ejected and the two electrodes are electrically connected, C in FIG.
The level of the signal indicated by C of 0 (b) indicates “HIGH”, and if the ink droplet 107 is not ejected and there is no conduction between the two electrodes, the signal level indicates “LOW”.

The above-described operation is continuously performed on each electrothermal conversion element, the detection result is converted from serial to parallel, and stored continuously in the RAM 1101C, and the information is processed in the idle time of the CPU 1101A. By doing
It is possible to efficiently detect the presence or absence of ink ejection for each electrothermal conversion element (each recording element).

Further, by modifying the configuration of the conduction detecting section 103, the potential levels of the electrodes 101 and 102 may be changed as shown in FIG.

FIG. 11A is a diagram showing an example in which the electrode 102 is set to a high potential and the electrode 101 is set to the ground level. In this case, if ink droplets are ejected and there is continuity between the two electrodes, the signal B becomes low level and the detection result is "ink present". It becomes a high level, and the detection result becomes “no ink”. FIG. 11B is a diagram showing an example in which the electrode 102 side is set to a low potential and the electrode 101 side is set to a supply voltage level of the ejection pulse 108. In this case, if an ink droplet is ejected and there is continuity between the two electrodes, the signal B becomes high level and the detection result is “ink present”. It becomes low level, and the detection result becomes "no ink".

The conduction detection pulse 104 is generated by the ejection pulse 108.
In addition to the above, the apparatus may be configured such that the electrothermal conversion element 105 also serves as the electrode 101 as shown in FIG. In such a configuration, as shown in FIG.
When the ejection pulse 108 is applied to the electrothermal transducer 105, a current flows from the lower part to the upper part of the figure,
Becomes high potential on the ink ejection port 106 side. By detecting this potential with the electrode 102 or the suction cap 1108 via the ink droplet 107, the presence or absence of ink ejection can be detected.

Here, the ink does not necessarily have to be DC conductive, and if it is AC conductive, the AC component of the applied pulse or the change component when the ink droplet is conducted becomes:
Information on the presence or absence of ink ejection can be extracted.

In the above embodiment, the description has been made assuming that the droplets ejected from the recording head are ink, and that the liquid stored in the ink tank is ink. It is not limited. For example, an ink tank may contain a processing liquid discharged to a recording medium in order to improve the fixability and water resistance of the recorded image or to improve the image quality.

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 ejecting ink 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 the 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. 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 driving 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.

The configuration of the recording head is not limited 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 printhead, 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 a recording mode of only a mainstream color such as black, and may be a recording head integrally formed or a combination of a plurality of 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, the ink that softens or liquefies at room temperature is used. 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 the solid state to the 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.

[0093] 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.

The present invention can be applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), but can be applied to a single device (for example, a copying machine, a facsimile machine). Etc.).

Further, an 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 an 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.

Examples of a storage medium for supplying the program code include a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, and 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 on a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instruction 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.

[0100]

As described above, according to the present invention, a first electrode is provided in the vicinity of each ink ejection port of an ink jet recording head, and a second electrode is provided outside the recording head, and the ink ejection operation is performed. In synchronization with this, the conduction between these two electrodes is detected, and the presence or absence of ink ejection is determined according to the detection result. Therefore, it is possible to detect the presence or absence of ink ejection for each ink ejection nozzle with a very simple structure. There is an effect that can be.

According to the present invention, for example, compared with the conventional method of optically detecting the presence or absence of ink, it is not necessary to discharge a large amount of ink to the extent that a sufficient change in the amount of light can be detected in the optical element. There is also an advantage that the amount of ink consumed for detecting the presence or absence of ink can be reduced as much as possible.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing an outline of a configuration of an ink jet printer IJRA which is a typical embodiment of the present invention.

FIG. 2 is an external perspective view illustrating a configuration of an ink cartridge IJC in which an ink tank and a recording head are separable.

FIG. 3 is a block diagram including a configuration of a control circuit of the inkjet printer IJRA.

FIG. 4 is a diagram showing in detail how to detect the presence or absence of ink ejection.

FIG. 5 is a diagram illustrating a detailed configuration of a conduction detecting unit 103;

FIG. 6 is a flowchart illustrating an ink ejection presence / absence detection process.

FIG. 7 shows the structure of the suction cap absorber and the ink ejection port when the suction cap 1108 also serves as the electrode 102;
FIG. 3 is a diagram showing a positional relationship with the data.

FIG. 8 is a diagram illustrating a state in which the pressing force of the suction cap 1108 against the recording head 1113 is changed.

FIG. 9 is a diagram showing in detail the state of detecting the presence / absence of ink ejection using a common ejection pulse and conduction detection pulse, and the configuration of the conduction detection unit 103.

FIG. 10 is a time chart of various signals used when performing an ink ejection presence / absence detection operation using an ejection pulse.

FIG. 11 is a diagram showing a relationship between potential levels of an electrode 101 and an electrode 102.

FIG. 12 is a diagram showing a configuration in which an electrothermal conversion element 105 also serves as an electrode 101.

FIG. 13 is a block diagram illustrating a schematic configuration of a conventional inkjet recording apparatus.

FIG. 14 is a diagram illustrating a state in which an ink discharge operation is performed from a recording head on a test basis to determine the presence or absence of ink.

FIG. 15 is a diagram illustrating a state in which an ink discharge operation is performed from a print head on a test basis to determine the presence or absence of ink.

[Explanation of symbols]

 101 electrode 102 electrode 103 continuity detection unit 104 continuity detection pulse 105 electrothermal converter 106 ink discharge port 107 ink droplet 108 discharge pulse 1101 control unit 1101A CPU 1101B ROM 1101C RAM 1102 CPU bus 1103 image buffer 1104 external interface (I / F) Unit 1105 Connection cable 1106 Host computer 1107 Motor control unit 1108 Suction cap 1109 Suction motor 1110 Suction pump 1111 Carriage motor 1112 Recording head control unit 1113 Head 1114 Cleaning plate 1151 Optical element control unit 1201 Light emitting unit 1202 Light receiving unit

Claims (18)

[Claims] 1. A method for detecting the presence or absence of ink ejection in ink jet recording, in which an image is recorded by ejecting ink droplets onto a recording medium using an ink jet recording head having a plurality of ink ejection nozzles, the method comprising: An application step of applying a voltage pulse to a first electrode provided in the vicinity of each ink ejection port of the plurality of ink ejection nozzles in synchronization with an ink ejection operation; and a place where ink droplets are ejected from the inkjet recording head. A detecting step of detecting whether there is continuity between the first electrode and the second electrode in response to the application of the voltage pulse in the second electrode provided in the detecting step; A determining step of determining whether ink has been ejected from the inkjet recording head according to the detection result. A method for detecting the presence or absence of ink ejection. 2. A recording apparatus for recording an image by ejecting ink droplets onto a recording medium using an ink jet recording head having a plurality of ink ejection nozzles, wherein each ink ejection port of the plurality of ink ejection nozzles is provided. A first electrode provided in the vicinity, a second electrode provided at a location where ink droplets outside the inkjet recording head are ejected, and the first electrode synchronized with an ink ejection operation from the inkjet recording head. Application means for applying a voltage pulse to the electrodes; detection means for detecting whether there is continuity between the first electrode and the second electrode in response to the application of the voltage pulse; Determining means for determining whether or not ink has been ejected from the inkjet recording head in accordance with a detection result by the means. . 3. Each of the plurality of ink discharge nozzles of the ink jet recording head includes an electrothermal converter for generating thermal energy to be applied to the ink in order to discharge the ink using thermal energy. 3. The recording apparatus according to claim 2, wherein: 4. The first electrode and the electrothermal transducer are commonly used, and the voltage pulse applied to the first electrode is used to discharge ink from the ink ejection port. The recording apparatus according to claim 3, wherein the pulse is a pulse applied to the recording apparatus. 5. The method according to claim 1, wherein the determining unit determines that there is ink ejection when there is conduction between the first electrode and the second electrode, and determines whether the first electrode and the second electrode are present. 3. The recording apparatus according to claim 2, wherein it is determined that there is no ink ejection when there is no conduction between the recording apparatus and the recording apparatus. 6. The ink jet recording head according to claim 2, further comprising: a cleaning unit for cleaning a surface of the ink jet recording head provided with the ink discharge ports; and a suction recovery unit for suction recovering the ink jet recording head. Recording device. 7. The method according to claim 1, further comprising: operating the application unit and the detection unit without performing an ink discharge operation from the ink jet recording head to preliminarily establish conduction between the first electrode and the second electrode. 7. The recording apparatus according to claim 6, further comprising a preliminary continuity inspection unit for controlling to perform the inspection. 8. The recording apparatus according to claim 7, further comprising a recovery control unit that controls the cleaning unit and / or the suction recovery unit to operate according to a result of the inspection performed by the preliminary conduction inspection unit. . 9. The ink-jet recording head according to claim 6, wherein the suction recovery unit includes a cap that covers a surface provided with the ink discharge port, and a suction pump that suctions the inside of the ink discharge nozzle of the inkjet recording head.
The recording device according to claim 1. 10. The recording apparatus according to claim 9, wherein the second electrode is included in the cap. 11. The recording apparatus according to claim 10, wherein the second electrode is in contact with a surface of the ink jet recording head on which the ink ejection ports are provided. 12. The recording apparatus according to claim 11, wherein a pressing force when the second electrode comes into contact with a surface provided with the ink ejection port is changed. 13. Before performing an ink discharge operation from the ink jet recording head, the cap is pressed against a surface provided with the ink discharge ports, and the suction pump is operated to perform a suction operation. The recording apparatus according to claim 10, further comprising a preliminary suction control unit. 14. The control device according to claim 13, wherein the preliminary suction control unit controls to suction the cap after detecting the presence or absence of ink ejection by the application unit, the detection unit, and the determination unit. The recording device according to claim 1. 15. The recording apparatus according to claim 2, wherein a potential of the first electrode is higher than a potential of the second electrode. 16. The recording apparatus according to claim 2, wherein the potential of the first electrode is lower than that of the second electrode. 17. The apparatus according to claim 2, further comprising an ink ejection presence / absence detection control unit that controls the operation by the application unit and the detection unit to be continuously performed over each of the plurality of ink ejection nozzles. The recording device according to any one of the preceding claims. 18. The storage device according to claim 2, further comprising storage means for storing a detection result by said detection means.