JP2001315352A - Ink-jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the non-ejection state of a nozzle efficiently and certainly in a short time, and to cut back wasteful ink consumption amount in the case a nozzle is in the non-ejection state. SOLUTION: In the case the non-ejection state of a nozzle is detected, after executing a recovery process, detecting operation of the non-ejection state is executed again only for the nozzle with the non-ejection state detected.

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 forming an image using a recording head having a plurality of nozzles for discharging ink droplets, and more particularly to detecting a non-discharge state of the plurality of nozzles. In addition, the present invention relates to an ink jet recording apparatus that performs a recovery process on a recording head according to a result of the detection.

[0002]

2. Description of the Related Art A recording apparatus having functions such as a printer, a copying machine, and a facsimile, or a recording apparatus used as an output device of a multifunction machine or a workstation including a computer, a word processor, etc., is based on image information.
An image is recorded on a recording sheet such as a sheet of paper or a plastic thin plate (for example, a sheet used for OHP). Such a recording apparatus is classified into a recording method such as an ink jet type, a wire dot type, a thermal type, a thermal transfer type, and a laser beam type according to a recording method of a recording unit to be used.

[0003] Among these recording methods, an ink jet recording apparatus performs recording by ejecting ink onto a recording medium such as a recording sheet from an ink jet recording head (hereinafter also referred to as a recording head) as recording means. The recording means can be easily made compact, high-definition images can be recorded at high speed, and furthermore, recording can be performed on plain paper without requiring special processing, so running costs are low, and The non-impact method has advantages such as low noise at the time of a printing operation and easy printing of a color image using multicolor inks.

There are several methods in such an ink jet recording system. One of them is to provide a heating element for applying thermal energy to ink in a nozzle, and to generate heat in the nozzle by the heat of the heating element. There is a bubble jet (registered trademark) recording method in which ink is ejected from a nozzle using foaming energy generated when a bubble is generated in the ink.

However, this type of recording apparatus has a drawback in that bubbles are gradually generated in the ink discharge nozzles with the passage of time, and the bubbles do not discharge ink at the time of image recording, resulting in poor recording. are doing.

In addition, there is a disadvantage that the ink staying in the nozzle adheres to the nozzle with the passage of time and causes non-ejection of ink during image recording.

In order to overcome these drawbacks, in this type of ink jet recording apparatus, several types of recovery processing are performed in order to eliminate the above-described ink ejection failure.

The recovery processing includes, for example, preliminary discharge, wiping, and suction recovery.

[0009] Preliminary ejection means that, out of a plurality of nozzles of the head, a volatile component in the ink is partially evaporated from an orifice at the tip of a nozzle that has not been used for a while, resulting in insufficient ejection performance and recording quality. This is a method of maintaining the recording quality by performing an ink discharging operation toward an object other than the recording medium in order to eliminate the ink that has become a nozzle.

[0010] Wiping is a process in which the direction of ink ejection changes due to ink droplets or paper dust adhering to the surface of the head where a plurality of orifices in a row are opened, and furthermore, non-ejection occurs. In order to prevent this, the head surface is wiped with an elastic wiper (wiping member) to remove them. After the wiping operation, the above-described preliminary ejection is usually performed in order to discharge the thickened ink or the like pushed into the orifice (ejection port) by the wiping to make a state in which normal ejection and image formation can be performed. is there.

[0011] Suction recovery refers to a case where air bubbles enter the nozzle or clogging occurs in the nozzle due to thickened ink generated by evaporation of a volatile component in the ink in the nozzle, and the nozzle cannot be recovered by preliminary ejection. When the ink runs out from the common liquid chamber to which the nozzles and the plurality of ink flow paths communicate, the cap member covers the print head surface at the position where the cap member and the print head face each other, and then the suction is performed. The inside of a nozzle is filled with ink suitable for recording by a method such as suctioning ink through a cap member by a pump. After such suction recovery processing, preliminary ejection is generally performed. The preliminary ejection at this time is mainly performed for the following purpose.

That is, at the time of the suction recovery process, a part of the color ink mixed in the cap member remains on the discharge port surface, and is drawn into the nozzle again by the capillary force, and mixed with the color ink inside. This will contaminate it. Therefore, when the printing operation is started from this state,
As a result, the contaminated and mixed color ink is ejected onto the print medium, so that color printing of the correct color cannot be performed. Therefore, the preliminary ejection is performed immediately after the suction by the cap member described above.

The recovery process is performed when a predetermined event occurs, such as when the power is turned on or when the ink tank is replaced, or at predetermined time intervals by measuring the elapsed time from the previous recovery operation with a timer. Or every time a predetermined number of dots are printed.

On the other hand, one of the important points for performing stable printing or the like is the presence or absence of ink at the time of printing in the common liquid chamber in the head or in each nozzle. In other words, when the amount of ink in the ink tank is low, or when air is mixed into the nozzle from the nozzle tip or when bubbles generated in the common liquid chamber move to the nozzle, the ink becomes stable. And it becomes difficult to discharge the recording paper, which may degrade the recording quality. For example, when a situation occurs in which it is difficult to stably eject ink only to a specific nozzle among a plurality of nozzles provided in an ink jet recording head and the nozzle becomes a defective nozzle, recording by the defective nozzle is performed. Is not performed, a portion where the recording is not performed in the recorded image occurs in a stripe shape. In addition, when the amount of ink in the common liquid chamber becomes low, ink may be supplied to only some of the nozzles. Similarly, the recording quality is degraded.

In order to detect such a state in which a defective nozzle causes partial non-ejection of ink, conventionally,
There has been proposed a method for detecting the state of ink in a common liquid chamber or a nozzle, particularly the presence or absence of ink.

In addition, since a large amount of ink is discharged when the above-described recovery processing is performed, the recovery processing should be reduced as much as possible from the viewpoint of suppressing wasteful ink consumption.

Therefore, there has been proposed a method in which non-ejection of a nozzle is detected and a recovery process is performed only when non-ejection of a nozzle is detected.

Japanese Patent Application Laid-Open No. Sho 61-123545 shows such a prior art. This conventional technique directly detects ink droplets ejected from a nozzle,
According to this conventional technique, an output signal when an ink droplet sequentially ejected from each nozzle collides with a channel error detector after a lapse of a certain time by sequentially driving each nozzle at a certain time interval is provided. There is described a technique for determining whether or not a channel error (non-ejection) has occurred by detection. According to this conventional technique, when a channel error has occurred, the non-ejection state due to a contract or the like is eliminated by simultaneously purging (suctioning) the ink flow paths of the print head. .

[0019]

In the above prior art, when a channel error is detected, a recovery operation is performed. However, even if the recovery operation is performed, there is no guarantee that the ink discharge failure can always be eliminated. Absent.

In order to solve this problem, the detection of the ink discharge failure may be performed again after the recovery processing. At this time, the detection of the ink discharge failure is performed for all the nozzles as in the above-mentioned prior art. Is performed, and ink droplets are ejected from each nozzle each time, so that a large amount of extra time is spent for ink detection, and a large amount of ink is wasted. As a result, printing speed decreases,
This leads to an increase in running costs.

The present invention has been made in view of such circumstances, and detects a non-discharge state of a nozzle of an ink jet recording head efficiently and reliably in a short time. It is an object of the present invention to provide an ink jet recording apparatus capable of returning to a normal state without causing useless ink as much as possible.

[0022]

According to the first aspect of the present invention, there is provided an ink jet recording apparatus for forming an image using a recording head having a plurality of nozzles for discharging ink droplets, wherein each of the nozzles of the recording head is provided. Detecting means for detecting a non-discharge state of the recording head, recovery means for recovering the nozzle to an ink discharge state by sucking ink in each nozzle of the recording head, and detecting a non-discharge state of the nozzle by the detecting means After the recovery process is performed by the recovery unit, a control unit that performs the non-discharge state detection by the detection unit again only for the nozzles that have detected the non-discharge state is provided.

According to the present invention, when the non-discharge state of the nozzle is detected, after performing the recovery processing by the recovery means,
Since the detection of the non-discharge state by the detection unit is performed again only for the nozzles that have detected the non-discharge state, no extra time is required for detecting the ink state,
Efficient detection can be achieved. In addition, if the ink is detected when the ink state is detected, consumption of excess ink can be suppressed.

In another aspect of the present invention, a plurality of recording elements for supplying thermal energy to a recording head substrate of the recording head and the plurality of recording elements are driven, respectively. A plurality of drive elements, and a detection electrode for detecting a change in voltage generated between the print element and the drive element according to the presence or absence of ink in a nozzle when the print element is driven. The detecting means sequentially detects non-ejection states of the plurality of nozzles based on detection outputs of the detection electrodes.

The detecting means may apply a power capable of discharging ink to the drive element when detecting a non-discharge state using the detection electrode, so that the preliminary discharge processing after the suction recovery processing is performed. Will be done.

The detecting means may apply a small amount of electric power to the drive element to prevent the ink from being ejected when detecting the non-ejection state using the detection electrode. Consumption can be further reduced.

According to a seventh aspect of the present invention, there is provided an ink jet recording apparatus for forming an image using a recording head having a plurality of nozzles for discharging ink droplets, wherein each nozzle of the recording head is in a non-discharge state. Detecting means for sequentially detecting the nozzles, recovery means for recovering the nozzles to an ink discharge state by sucking ink in each nozzle of the recording head, and recovering when the discharge failure state of the nozzles is detected by the detection means. After performing the recovery process by the means, the control means performs the re-detection of the non-discharge state by the detection means and the preliminary discharge processing only for the nozzles which have detected the non-discharge state.

According to the present invention, when the ejection failure state of the nozzle is detected, after the recovery processing by the recovery means is performed,
Since the re-detection of the non-discharge state and the preliminary discharge process by the detection unit are performed only for the nozzles that have detected the non-discharge state, no extra time is spent for detecting the ink state and performing the preliminary discharge. In addition, efficient detection can be performed, and ink consumption due to preliminary ejection can be reduced.

[0029]

Embodiments of the present invention will be described below with reference to the drawings.

(Configuration for Non-ejection Detection) First, as a method for detecting non-ejection of ink applicable to the present invention, a method in which an electrode for non-ejection detection is provided on a silicon substrate constituting a recording head will be described.

FIG. 1 is a diagram showing a basic configuration of a recording head substrate.

In FIG. 1, a heating element 101 as a recording element for applying thermal energy for ink ejection to ink is arranged on an element substrate 100 which is a substrate for a recording head. A power transistor (driver) 102 for driving each heating element 101 is provided for a plurality of heating elements (printing elements) 101 arranged in parallel. Further, on the element substrate 100, a shift register 104, a latch circuit 103, and a plurality of AND gates 115 are formed. Shift register 104
Receives serially image data from the outside via a terminal 106, and inputs a serial clock synchronized with the image data from a terminal 105 to hold image data for one line. The latch circuit 103 latches one line of image data output in parallel from the shift register 104 in synchronization with a latch clock (latch signal) input via a terminal 107, and To be transferred in parallel. Multiple AND gates 11
5 is provided corresponding to the power transistor 102, and applies an output signal of the latch circuit 103 to the power transistor 102 in response to an external enable signal. 108 is a power transistor 1 as a driving element
02 is a drive pulse signal input (heat pulse) terminal for controlling the ON time of 02, that is, the time for driving the heating element 101 by supplying a current from outside the recording head unit. 1
Reference numeral 09 denotes a terminal for inputting drive power (5 V) for a logic circuit such as the latch circuit 103 and the shift register 104. Further, in addition to the ground terminal 110, a terminal 112 for driving and monitoring the sensor 114 and the like are provided. Thus, the terminals 105 to 112 formed on the substrate 100
Is an input terminal for inputting image data and various signals from the outside.

Further, a sensor 114 such as a temperature sensor for measuring the temperature of the element substrate 100 or a resistance sensor for measuring the resistance value of each heating element 101 is formed on the element substrate 100.

Further, the element substrate 100 is provided with a detection electrode 118 for detecting a non-ejection nozzle. The detection electrode 118 is formed on the protective film 40 as described later.
5, AC-coupled to the drive circuit of the heater 101 via the anti-cavitation film 205 and the ink in the nozzles. Reference numeral 116 in FIG. 1 denotes the AC coupling portion, which forms an equivalent circuit as a capacitor as shown in FIG. A portion surrounded by a two-dot chain line B in FIG. 6 is a portion in the nozzle where the electric resistance changes according to the amount of ink, as described later, and D in FIG. Represents the drive signal from the controller.

In such a configuration, image data input as a serial signal is converted into a parallel signal by the shift register 104 and is held in the latch circuit 103 in synchronization with a latch clock. In this state, when a drive pulse signal (enable signal for the AND gate 115) of the heating element 101 is input via the input terminal 107, the power transistor 102 is turned on in accordance with image data, and the corresponding heating element 10
A current flows through 1 to generate heat energy. A top plate is joined to the element substrate 100 to form a liquid flow path (also referred to as a nozzle) for discharging ink and a common liquid chamber communicating with the liquid flow path. With this configuration, the ink stored in the ink tank (also referred to as an ink storage unit) is supplied to each nozzle via the common liquid chamber, and stable supply of the ink is achieved. As described above, the ink in the liquid flow path (nozzle) is heated by the thermal energy generated by driving the heating element, and the ink is ejected as droplets from the ejection port at the tip of the nozzle.

FIG. 2 is a plan view showing a schematic configuration of the substrate for an ink jet recording head shown in FIG. 1, and shows a schematic layout of elements, electrodes, terminals and the like provided on the substrate. FIG. 3 is a schematic perspective view showing a state in which a top plate for forming discharge ports and nozzles is joined to the inkjet recording head substrate shown in FIGS. 1 and 2. Also,
FIG. 4 is a cross-sectional view showing the configuration of the substrate and the nozzles in a state where the top plate is bonded to the substrate for the inkjet recording head. FIG. 4 is a cross-sectional view along the line aa in FIG. FIG. 5 is a diagram showing the state of the voltage of each part on the substrate for an ink jet print head when a heating element as a print element is driven.

Reference numeral 101 shown in FIG. 2 denotes a heating element (hereinafter, referred to as a heater) used as a printing element, which is driven by a driver 102 as a driving element. 203 is
Wiring for connecting one end of the heater 101 and the driver 102 is provided, and 111 is a wiring for supplying a power supply voltage to the other end of the heater 101. Also, the heater 101
On the top, as shown in FIG.
5 (protective layer) is formed, and the cavitation-resistant film 205 is provided above the heater 101 via the protective film 405.
Is arranged. It should be noted that in FIG.
1, illustration of the protective film 405 is omitted to explain the arrangement of the driver 102 and the like. In addition, the ink jet recording head described in the present embodiment generates bubbles in the ink in the nozzles by thermal energy generated when the heater 101 is driven, and discharges the ink by the growth pressure of the bubbles to discharge the ink to the ejection port 310 (see FIG. 3 and FIG. 4), which is a so-called bubble jet method. The above-described anti-cavitation film 205 is provided to play a role of suppressing an impact generated when a bubble generated when the ink is ejected is contracted from being transmitted to the heater 101 and the protective film 405. It is formed of a high melting point metal. Reference numeral 118 denotes an electrode wiring provided for detecting ink, and reference numeral 117 denotes an external terminal provided at an end of the electrode wiring 118 to electrically connect the electrode wiring 118 to the outside of the substrate.

The characteristic structure of the recording head substrate is as follows.
As shown in FIG. 2, a configuration in which the anti-cavitation film 205 is divided and arranged for each heater (printing element) 101,
The detection electrode 118 is separated from the driver 102 and the heater 1
The layout is arranged at a position distant from the wiring 203 between the driver 01 and the driver 102. The detection electrode 118 can be formed as a wiring pattern.

How to detect the presence or absence of ink in the nozzles in the configuration of the ink jet recording head substrate shown in FIG. 2 will be described in detail with reference to FIGS. 3 and 4.

As described above, FIG. 3 is a schematic perspective view showing a state in which the top plate 314 is joined to the substrate 100 for the ink jet recording head, and the nozzle portion 408 is formed by joining the top plate 314 and the substrate 100. (See FIG. 4) and a common liquid chamber 311 are configured. In FIG. 3, the configuration of the wall member above the top plate 314 is indicated by a dotted line in order to explain the configuration of the nozzle unit 408 and the common liquid chamber 311. Further, as shown in FIG. 2, reference numeral 205 denotes a cavitation-resistant film. Further, as described above, the heater 101 as the recording element is provided with the cavitation-resistant film 205.
The heater 101 is not shown in FIG. 3 since the insulating protective film 405 is formed above the heater 101 and above the heater 101. The same applies to the driver 102 for driving the heater 101.
It is also not shown in FIG.

In the present invention, the heater 101 (not shown in FIG. 3) including the cavitation-resistant film 205 separately provided for each nozzle, and the driver 102
(Not shown in FIG. 3), the nozzle portion 408 formed by the nozzle wall 312, and the detection electrode 118 for detecting ink.
And the relationship becomes important.

In FIG. 4, the power supply unit 111
Is supplied to the heater 101 in accordance with switching by the driver 102 to generate thermal energy. Bubbles are generated in the nozzles by the heat energy, and ink is ejected from the ejection ports 310.

Here, before the heater 101 is driven by the switching of the driver 102, that is, at the time when the driver 102 is turned off, the heater 10
1, the potential of the wiring 203 between the heater 101 and the driver 102, and the potential of a part of the wiring on the driver 102 (the part on the heater 101 side from the portion of the driver 102 that functions as a switch) Power supply wiring 1
11 is the same as the potential. In addition, the ink (generally conductive because of the presence of ions in the ink components) is electrically floating, that is, the ink is in a DC high impedance state with respect to GND. In some cases, the protective film 405 becomes an electrically insulating film.
The potential of the upper anti-cavitation film 205 is in an electrically floating state like ink, that is, in a DC high impedance state with respect to GND (ground). Similarly, the potential of the detection electrode 118 is basically in an electrically floating state, and the potential is substantially determined by the input impedance of a device connected to detect the potential of the detection electrode 118. In the case of this example, in order to detect the potential of the detection electrode 118, the voltage monitors M and 1M to 10M are connected between the detection electrode 118 and GND as shown in FIG.
MΩ resistors were connected in parallel. Therefore, the heater 10
At the stage before the driving of No. 1, the detection potential becomes 0V.

On the other hand, when the heater 101 is driven, that is, when the driver 102 switches (ON) so as to connect the wiring 203 to GND, a current naturally flows through the heater 101. At this time, the potential of the heater 101 decreases as it approaches the driver 102 side, and the wiring 203 between the heater 10 and the driver 102 and the driver 102
The potential of the upper partial wiring rapidly drops to almost the GND level. In FIG. 4, a portion surrounded by a dotted line A is
This shows a portion where the voltage drops sharply when the heater 101 is driven. When the voltage drops as described above, the protective film 405, which has worked as an insulating film in terms of direct current, functions as a dielectric film of the capacitor, so that the protective film 405 is provided from the heater 101 to the driver 102 via the protective film 405. It has been found that a potential change is transmitted to the anti-cavitation film 205 and the ink positioned thereon in an alternating manner. Therefore, the ink is supplied to the nozzle section 408 and the common liquid chamber section 31.
When it is at 1, the potential change is transmitted to the detection electrode 118. Further, the nozzle portion 408 and / or
Or, when there is no ink in the common liquid chamber 311,
Although a potential change is transmitted to the portion of the anti-cavitation film 205, the electrical resistance in the nozzle portion 408 and / or the common liquid chamber portion 311 between the portion and the detection electrode 118 is significantly increased. , The change in potential transmitted to the detection electrode 118 becomes extremely small,
Alternatively, the change in potential is not transmitted to the detection electrode 118. As described above, the potential change of the detection electrode 118 varies depending on the amount of ink present in the nozzle portion 408 and the common liquid chamber portion 311, and extremely depending on the presence or absence of ink. It is possible to detect the amount of ink present between the electrode 118 and the presence of ink.

In FIGS. 2 and 4, a portion surrounded by a dotted line B indicates a portion where the electric resistance changes depending on the amount of the ink, that is, a portion which has a great influence on a change in the potential of the detection electrode 118. Further, a portion surrounded by a dotted line 116 in FIG. 2 corresponds to an AC coupling portion in FIGS.

FIG. 5 is a timing chart for explaining an ink detecting operation utilizing the above-described detection principle. Reference numeral 701 denotes an enable signal for determining a timing for driving the heater 101 and a driving time. Heater 1
01 is sequentially driven individually in synchronization with an enable signal based on a driver drive control signal (not shown).
Reference numeral 703 denotes the potential of the wiring 203 between the heater 101 and the driver 102, and similarly to the change in the potential 703, the potential of the heater 101 near the driver 102 and the partial wiring on the driver 102 (driver The electric potential of the portion in the heater 102 (the portion on the heater 101 side) also changes. The portion where the voltage changes, including these portions, is also called a voltage change region. The heater 10
On 1, the amplitude of the change in the potential differs depending on the position, and becomes larger as the position is closer to the driver 102. Further, it is considered that the surface potential of the insulating protective film 405 is almost the same as the potential of the voltage change region thereunder. 70
4 and 705 are ink detection signals obtained by a change in the potential of the detection electrode 118, and the detection signal 704 is
The detection signal and the detection signal 705 when there is ink in the portion B in FIG. 4 are detection signals when there is no ink in the portion B. When there is ink in the portion B, the electric resistance of the portion B is small, so that the change in the potential detected by the detection electrode 118 and the change in the detection signal 704 are large. On the other hand, when there is no ink in the portion B, since the electrical resistance of the portion B is large, the change in the potential detected by the detection electrode 118 and the change in the detection signal 704 are small. Thus, it can be seen that the detection signal detected by the detection electrode 118 changes depending on whether or not there is ink in the portion B. Of course, the detection signal detected by the detection electrode 118 changes according to the amount of ink present in the portion B.

The detection signal from the detection electrode 118 is time-divided according to the driving timing of the heater 101, so that the presence or absence of ink or the amount of ink can be detected for each driving nozzle. The detection signal 704 in FIG. 7 is a detection signal when ink is present in all of the driving nozzles. Similarly, the detection signal 704 in FIG.
Reference numeral 5 denotes a detection signal when there is no ink in all of the driving nozzles. Therefore, for example, when there is no ink in one driving nozzle, only the detection signal corresponding to that driving nozzle appears as a detection signal 705 having a small change, and the detection signals corresponding to the other driving nozzles are detection signals having a large change. It will appear as signal 705.

Since the anti-cavitation film 205 is separated corresponding to the heater 101, it is possible to reliably detect a potential change of each nozzle according to the presence or absence of ink without being affected by an adjacent nozzle. Can be. Further, as described above, the anti-cavitation film 205 is
01 and the electrode 11 on the detection side.
8 is commonly used for all nozzles, and the presence or absence of ink in each of a plurality of arranged nozzles is detected by a detection signal from one detection electrode 118 by sequentially driving each nozzle in a time division manner. Can be.

As a signal source of the ink detection signal,
Since the heater 101 itself can be used, the presence / absence of ink for each nozzle can be detected by using a logic circuit provided in a print head to constitute a shift register or the like, and the structure is complicated. It is possible to detect the presence / absence of ink with a very simple configuration without making the configuration.

(Overall Configuration) FIG. 7 is a schematic view of an ink jet recording apparatus IJRA to which the present invention can be applied.

In the figure, a lead screw 84 is
The forward / reverse rotation of the drive motor 81 causes the drive force transmission gear 8
The rotation is reversed through 2,83. The carriage HC has a pin (not shown) that engages with the spiral groove of the lead screw 84, and is reciprocated in the directions of arrows a and b in the drawing according to the rotation direction of the lead screw 84. A head cartridge IJ comprising an ink jet recording head 85 and an ink tank 86 is provided on the carriage HC.
H is mounted. The ink jet recording apparatus IJRA shown in FIG. 7 is a recording apparatus generally called a serial printer, and performs main scanning of the carriage HC in the directions of arrows a and b and sub-scanning of a recording sheet 87 as a recording medium. By repeating the scanning, the printing operation on the entire surface of the printing sheet 87 is performed.

At the left end of the movable area of the carriage HC, a suction recovery system unit 88 is provided so as to face each ink ejection port of the recording head 85 on the carriage HC. The suction recovery system unit 80 includes a cap member 8 for capping the face surface of the recording head 85.
9, a wiper blade 90 for wiping the face surface of the recording head 85, and a pump (not shown) for sucking ink from each nozzle through the ink path from the cap.
And so on. The suction recovery system unit 88 performs a suction recovery operation for maintaining a good ink discharge state of the recording head 85.

A pre-discharge ink receiver (not shown) for receiving ink to be discharged at the time of pre-discharge, which will be described later, is provided near the cap member.

FIG. 8 is a block diagram showing a configuration of a main part of a control unit for executing printing control of the printing apparatus shown in FIG.

In FIG. 8, reference numeral 1000 denotes a control circuit;
Reference numeral 00 denotes an interface for inputting a recording signal. The interface 1100 receives data transferred from a host device or the like connected to the outside of the recording apparatus IJRA. 1001 is an MPU, 1002 is a program ROM for storing a control program executed by the MPU 1001,
A dynamic RAM 1003 stores various data (such as the above-described recording signal and recording data supplied to the head). 1004 is a head cartridge IJH
Is a gate array that controls supply of recording data to the interface 1100, the MPU 1001,
Data transfer control between M1003 is also performed. 1009 is
Carriage HC with head cartridge IJH
Carrier motor for scanning (FIG. 7), 1008
Is a transport motor for transporting the recording paper 87 as a recording medium. Reference numerals 1006 and 1007 denote motor drivers for driving the transport motor 1008 and the carrier motor 1009, respectively.

Reference numeral 1117 denotes a terminal 117 shown in FIGS.
, And via a terminal 117 thereof,
Detection electrode 11 of inkjet recording head substrate 100
8 is electrically connected. At the time of detecting ink, a voltage change corresponding to the amount of ink (the presence or absence of ink) is transmitted from a terminal 117 via a signal line 1117 to a control circuit 1000 of the apparatus main body.
Is input to Reference numeral 1012 denotes a heater 10 as a printing element.
1 is a signal line for outputting various signals including an enable signal for driving the clock signal 1, a clock signal input to a logic circuit on the element substrate 100, and a latch signal. Reference numeral 1016 denotes a heater 10 as a recording element from a power supply unit (not shown) to the head cartridge IJH.
1 is a signal line for supplying driving power for driving the driving circuit 1.
Reference numeral 1017 denotes a signal line for supplying power to the logic circuit of the printhead element substrate 100 mounted on the head cartridge IJH.

In such a configuration of the control unit, the heater 101 is driven at an arbitrary timing, and a detection signal obtained by the detection electrode 118 on the element substrate 100 is input via the signal line 1117 and the terminal 117. hand,
By monitoring this, the presence or absence of ink in the nozzle can be detected. The timing for detecting the presence or absence of such ink is determined, for example, by sequentially driving each nozzle when the recording operation is not performed on the recording medium, thereby determining whether the presence or absence of ink for each nozzle is present. Can be detected. In general, in an inkjet recording apparatus, in order to recover the ejection state of an inkjet recording head, it is known that a preliminary ejection operation for preliminary ejection of ink, that is, only ejection without suctioning ink, is performed. By utilizing the timing of the ejection operation, it is possible to individually detect the state of each nozzle regarding the presence or absence of ink. Of course, it is also possible to detect the ink during the recording operation.

The monitoring of the signal obtained by the detection electrode 118 is performed by a control means M provided on the control circuit.
This can be performed by the PU 1001. In addition, by associating the driven heater 101 with the change in the potential of the detection electrode 118, the presence or absence of ink is detected for each of the arranged nozzles, and a state in which ink is exhausted and ink cannot be ejected occurs. Nozzles, or nozzles with the possibility of non-ejection of ink, can be specified.

(First Embodiment) Next, a first embodiment of the ink non-discharge detection and recovery operation will be described with reference to FIG. This flowchart shows an operation procedure in the control circuit 1000 in FIG.

First, the count value N of the number of recovery processes is set to 0 (step S201).

Next, the non-ejection of ink is detected simultaneously with the preliminary ejection (step S202). As described above, the preliminary ejection is performed in order to prevent non-ejection due to viscosity increase due to evaporation of a volatile component of the ink, and usually, several tens to several hundreds ejections are performed for one nozzle.

If it is determined that there is no non-ejection nozzle in the ink non-ejection detection (step S20)
3) Then, the process ends.

If it is determined that there is a non-ejection nozzle (step S203), it is determined whether or not the count value N is a predetermined number of times (in this case, three times) (step S204).

If the count value N is not 3, the procedure moves to step S205.

In step S205, the suction recovery system unit 88 is operated to perform suction recovery processing. The count N is incremented by one.

Next, in step S206, preliminary ejection is performed on only the nozzles determined to have no ink in the detection in step 202, and at the same time, non-ink ejection is detected.

If there is a non-ejection nozzle even after the above recovery processing (step 203), steps 204 to 204 are repeated.
Step 206 is repeated.

As described above, even if the suction recovery process and the preliminary ejection process for only the nozzles without ink are performed a plurality of times (three times in this case), if there is a non-ejection nozzle,
Since the determination in step S204 is YES, the process is abnormally terminated.

In the abnormal termination, the user is notified that there is a nozzle having no ink, or the dot to be recorded by the nozzle without ink is recorded by another nozzle having ink based on the information of the nozzle without ink. Processing.

As described above, in the first embodiment, since the preliminary ejection and the detection of the absence of ink are performed only for the nozzles having no ink, the time required for the ink detection and the preliminary ejection is shortened as compared with the related art. It is also possible to shorten the recording time. Further, since the preliminary ejection is not performed for all the nozzles, the consumption of ink can be suppressed.

(Second Embodiment) Next, a second embodiment of the ink non-discharge detection and recovery operation will be described with reference to FIG. This flowchart also shows the operation procedure in the control circuit 1000 in FIG.

First, the count value N of the number of recovery processes is set to 0 (step S301).

Next, the non-ejection of ink is detected at the same time as the preliminary ejection is performed (step S302).

If it is determined that there is no non-ejection nozzle in the ink non-ejection detection (step S30).
3) Then, the process ends.

If it is determined that there is a non-ejection nozzle (step S303), it is determined whether or not the count value N is a predetermined number of times (in this case, two times) (step 304).

If the count value N is not 2, the procedure moves to step S305.

In step S305, the suction recovery system unit 88 is operated to perform suction recovery processing. The count N is incremented by one.

Next, in step S306, no ink is detected only for the nozzles determined to be out of ink in the detection in step 202. At the time of the detection of the absence of the ink, electric power that does not cause the ink to be ejected is applied to the recording element 101 in the nozzle determined to be the absence of the ink.

If there is a non-ejection nozzle even after the above recovery processing (step 303), the processing of steps 304 to 306 is repeated again.

In this way, even if the suction recovery process is performed a plurality of times (in this case, twice), if there is a non-ejection nozzle, the determination in step S304 becomes YES, and the process is abnormally terminated.

In the abnormal termination, as described above, the user is notified that there is a nozzle having no ink, or the dot to be recorded by the nozzle having no ink is determined based on the information of the nozzle having no ink. Or to perform recording.

As described above, in the second embodiment, only the nozzles having no ink are applied to the recording element with such an amount of power that ink is not ejected, and the absence of ink is detected. Ink consumption due to ejection can be suppressed. Further, since the detection of the absence of ink is not performed for all the nozzles, the time required for the detection of the absence of ink can be reduced, and the recording time can be reduced.

The configuration for detecting whether or not ejection has occurred for each nozzle is not limited to the configuration described above, and various known techniques can be employed. As a configuration for detecting the occurrence of an ejection failure for each nozzle, for example, a test pattern is printed on a recording medium such as paper, and the occurrence of the ejection failure is determined based on the result of a user visually checking the recorded pattern. There are known a method of inputting information about nozzles, a method of reading a recorded pattern by an optical sensor, and detecting a nozzle having a discharge failure. In the present invention, such a method can be appropriately adopted.

However, in the method of visually checking the test pattern by the user, it is conceivable that a check error by the user, an error when the user inputs information on a non-ejection nozzle, or the like may occur. In a configuration in which a recorded pattern is detected by a sensor, the accuracy of the sensor is required in order to read the pattern corresponding to each nozzle, and the position where a non-ejection occurs and the nozzle are accurately associated. There is a problem that it is difficult.

The present invention employs the principle of detection described with reference to FIGS. 1 to 6 to detect a state in which non-ejection has occurred for each of a plurality of nozzles provided in a print head. This makes it possible to accurately detect the state in which non-ejection has occurred for each nozzle, and to control the recovery processing according to the detection result, thereby enabling the recovery processing to be performed efficiently and effectively reducing the ink consumption. is there.

In the above-described embodiment, the bubble jet recording method in which ink is ejected using a heating element as a recording element has been described as an example. However, it is possible to detect a change in the voltage that occurs when the printing element is driven via the ink in another printing method. Therefore, the present invention can be widely applied not only to the bubble jet recording method but also to other recording methods using a piezoelectric element, for example.

(Others) It should be noted that the present invention includes a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for ink ejection, particularly in an ink jet recording system. An excellent effect is obtained in a recording head and a recording apparatus of a type in which the state of ink is changed by the thermal energy. This is because according to such a method, it is possible to achieve higher density and higher definition of recording.

The typical configuration and principle are described, for example, in 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 is a so-called on-demand type,
Although it can be applied to any type of continuous type, in particular, in the case of the on-demand type, it can be applied to a sheet holding liquid (ink) or an electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recorded information and giving a rapid temperature rise exceeding the nucleate boiling, heat energy is generated in the electrothermal transducer, and film boiling occurs on the heat acting surface of the recording head. Liquid (ink) corresponding to this drive signal on a one-to-one basis.
This is effective because air bubbles inside can be formed. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble 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 a liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition to the combination of the discharge port, the liquid path, and the electrothermal converter (linear liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned specifications, U.S. Pat. Nos. 4,558,333 and 44, which disclose a configuration in which a heat acting portion is arranged in a bending region.
A configuration using the specification of Japanese Patent No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Application Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an aperture for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration is based on JP-A-59-138461, which discloses a configuration corresponding to a discharge unit. That is, according to the present invention, recording can be reliably and efficiently performed regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium on which a recording apparatus can record. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads, or a configuration as one integrally formed recording head.

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

Further, it is preferable to add ejection recovery means for the recording head, preliminary auxiliary means, and the like as the constitution of the recording apparatus of the present invention since the effects of the present invention can be further stabilized. If these are specifically mentioned, the recording head is heated using capping means, cleaning means, pressurizing or suction means, an electrothermal transducer, another heating element or a combination thereof. Pre-heating means for performing the pre-heating and pre-discharging means for performing the discharging other than the recording can be used.

Further, the types and the number of recording heads to be mounted are, for example, not only those provided for one color ink but also plural inks having different recording colors and densities. A plurality may be provided. That is, for example, the printing mode of the printing apparatus is not limited to a printing mode of only a mainstream color such as black, but may be any of integrally forming a printing head or a combination of a plurality of printing heads. The present invention is also very effective for an apparatus provided with at least one of the recording modes of full color by color mixture.

In addition, in the embodiments of the present invention described above, the ink is described as a liquid. However, an ink which solidifies at room temperature or lower and which softens or liquefies at room temperature may be used. In general, the ink jet method generally controls the temperature of the ink itself 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. Sometimes, the ink may be in a liquid state. In addition, in order to positively prevent temperature rise due to thermal energy by using it as energy for changing the state of the ink from a solid state to a liquid state, or to prevent evaporation of the ink, the ink is solidified in a standing state and heated. May be used. In any case, the application of heat energy causes the ink to be liquefied by the 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, the ink
JP-A-54-56847 or JP-A-60-7
As described in Japanese Patent Publication No. 1260, a form may be adopted in which the liquid sheet or the solid substance is held as a liquid or solid substance in the concave portion or through hole of the porous sheet and faces the electrothermal converter. 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, the form of the ink jet recording apparatus of the present invention is not only used as an image output terminal of an information processing apparatus such as a computer, but also for a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function. It may take a form.

[0096]

As described above, according to the present invention, when there is an inkless nozzle, after performing a recovery process,
Since no-ink detection is performed again only for the nozzles that have been detected as having no ink, efficient detection can be performed without spending extra time for detecting the ink state. Further, if the ink is ejected at the time of detecting the ink state, it is possible to suppress consumption of excess ink.

Further, according to the present invention, when there is an inkless nozzle, after performing recovery processing, preliminary ejection and ink state detection are performed only for the nozzles that have been detected as having no ink. The state detection and the preliminary ejection can be efficiently performed, and the consumption of the ink by the preliminary ejection can be suppressed. In addition, if the detection of the absence of the ink is performed by applying a power to the recording element to such an extent that the ink is not ejected, the consumption of the ink can be further reduced.

[Brief description of the drawings]

FIG. 1 is a plan view for explaining an electrical schematic configuration of a substrate for an inkjet recording head.

FIG. 2 is a plan view illustrating a schematic configuration of a main part of the substrate for an inkjet recording head illustrated in FIG. 1;

3 is a schematic perspective view showing a state in which a top plate is joined to the substrate for an ink jet recording head of FIG. 1 to form a nozzle.

FIG. 4 is a cross-sectional view of a portion around a nozzle taken along the line aa in FIG. 3;

FIG. 5 is a time chart for explaining an operation of detecting the presence or absence of ink in a nozzle.

FIG. 6 is an equivalent circuit diagram corresponding to a configuration around an ink detection electrode of an inkjet recording head substrate.

FIG. 7 is a perspective view illustrating a schematic configuration of an inkjet recording apparatus to which the present invention can be applied.

8 is a block diagram illustrating a control system of the inkjet recording apparatus illustrated in FIG.

FIG. 9 is a flowchart illustrating a first embodiment of the present invention.

FIG. 10 is a flowchart illustrating a second embodiment of the present invention.

[Explanation of symbols]

 85 recording head 86 ink tank 88 suction recovery system unit 89 cap member 90 wiper blade 100 substrate for ink jet recording head (element substrate) 101 recording element (heating element) 102 driving element (driver) 103 latch circuit 104 shift register 116 AC coupling Unit 118 detection electrode 203 wiring unit 205 anti-cavitation film 310 discharge port 311 common liquid chamber 312 nozzle wall 314 top plate 405 protective film (insulating protective film) 408 nozzle unit 1000 control circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomonori Sato 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor ▲ Taka ▼ Bashi Katsuhiko 3-30-2 Shimomaruko, Ota-ku, Tokyo No. within Canon Inc. (72) Kenichi Saito, Inventor 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Kentaro Yano 3-30-2, Shimomaruko, Ota-ku, Tokyo Canon Stock Inside the company (72) Inventor Toshiharu Inai 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masao Kato 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F Terms (reference) 2C056 EA14 EA25 EA29 EB08 EB27 EB39 EB40 EB51 EC08 EC24 EC39 EC42 EC54 EC57 FA03 HA05 JC20 JC23 KD06 2C057 AF72 AF75 AG46 AK10 AL13 AL17 AM31 BA03 BA 13

Claims (7)

[Claims] 1. An ink jet recording apparatus for forming an image using a recording head having a plurality of nozzles for discharging ink droplets, comprising: a detecting unit for detecting a non-discharging state of each nozzle of the recording head; Recovery means for recovering the nozzle to an ink discharge state by sucking ink in each nozzle of the recording head; and when the detection means detects a non-discharge state of the nozzle,
An ink jet recording apparatus comprising: a control unit configured to perform re-detection of a non-discharge state by the detection unit only for a nozzle that has detected the non-discharge state after performing the recovery process by the recovery unit. . 2. The ink jet recording apparatus according to claim 1, wherein the control unit executes the recovery process by the recovery unit again when the non-discharge state of the nozzle is detected again by the detection unit detecting the non-discharge state again. apparatus. 3. A plurality of printing elements for supplying thermal energy to a printing head substrate of the printing head, a plurality of driving elements for driving the plurality of printing elements, respectively, and when the printing elements are driven. A detecting electrode for detecting a change in voltage generated between the recording element and the driving element in accordance with the presence or absence of ink in the nozzle, wherein the detecting unit is configured to detect a change in voltage based on a detection output of the detecting electrode. 2. The ink jet recording apparatus according to claim 1, wherein non-ejection states of the plurality of nozzles are sequentially detected. 4. The ink jet recording apparatus according to claim 3, wherein the detecting unit applies power capable of discharging ink to the driving element when detecting a non-discharge state using the detection electrode. apparatus. 5. The apparatus according to claim 3, wherein said detecting means applies a small amount of electric power to the driving element such that ink cannot be ejected when the non-ejection state is detected using the detecting electrode. The inkjet recording apparatus according to any one of the preceding claims. 6. The control device according to claim 3, wherein when the non-ejection state is re-detected by the detection device, the control device applies a small amount of electric power to the driving element such that ink cannot be ejected. 3. The ink jet recording apparatus according to claim 1. 7. An ink jet recording apparatus for forming an image using a recording head having a plurality of nozzles for discharging ink droplets, comprising: a detecting unit for sequentially detecting a non-discharging state of each nozzle of the recording head. A recovery unit that recovers the nozzle to an ink discharge state by sucking ink in each nozzle of the recording head; and when a non-discharge state of the nozzle is detected by the detection unit,
After performing the recovery process by the recovery unit, the control unit performs re-detection of the non-discharge state and the preliminary discharge process by the detection unit only for the nozzles that have detected the non-discharge state. Inkjet recording device.