JP2925760B2 - Ink jet recording apparatus and ink jet recording method - Google Patents

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 and an ink jet recording method, and more particularly, to an improvement in the performance of a wiping process for cleaning a surface of a recording head provided with ink discharge ports (a discharge port forming surface). It is about.

[0002]

2. Description of the Related Art In recent years, devices such as computers, word processors, facsimile machines, and copiers have become widespread, and many recording devices used in these devices adopt various recording methods. Above all, the ink jet recording apparatus has excellent features that it is easy to achieve high definition compared to other recording methods, and that it is excellent in high-speed recording and quietness and inexpensive.

In an ink jet recording apparatus, when unnecessary ink droplets or foreign matter such as paper powder adheres to the discharge port forming surface of a recording head, the ink discharge direction is deflected, and the image quality may deteriorate. That is, in the ink jet recording method, ink is ejected from a recording head to a recording medium such as paper or an OHP film to perform recording. (Ink mist) or rebound of the ink discharged to the recording medium. As shown in FIG. 12, due to these factors, ink adheres to the ejection port forming surface 1 of the recording head, and if a large amount of ink gathers around the ejection port 12, ejection is hindered and ejection in an unexpected direction ( In some cases, such a problem may occur that the ink may not be ejected (non-ejection).

In order to eliminate such inconveniences caused by using a liquid ink as a recording agent, an ink jet recording apparatus has a unique configuration not found in other recording apparatuses, and is a means for improving a discharge state. Recovery means may be provided. Then, as a means for refreshing the ejection port forming surface to prevent deflection of the ejection direction,
There is a type in which a wiping member is provided to be in contact with the discharge port forming surface, and ink droplets and the like are removed (wiping) by relatively moving the two.

Unnecessary ink droplets adhering to the discharge port forming surface are formed by ink mist generated at the time of ink discharge accompanying recording and rebound of ink from paper. It is considered that the paper adheres when moving relatively close to the paper. for that reason,
Generally, the recording operation is interrupted or after the recording is completed, it is removed by the wiping means.

[0006]

On the other hand, in an ink jet recording apparatus, the ink in the liquid path may thicken due to evaporation of moisture or the like, and the ink may not be ejected even if energy for causing the ink to be ejected is applied. Means for refreshing the ink in the liquid path by forcibly discharging the ink unsuitable for ejection by applying a suction force by a pump, for example, may be provided as one form of the recovery means. In connection with such processing, ink discharged at the time of forcible discharge of ink from a liquid path by a pump or the like may adhere. The amount of ink adhered after the suction may be larger than the amount of the ink adhered during the recording, and if the suction recovery operation is performed frequently, the load on the wiping unit may be increased, resulting in an increase in unwiped residue or discharge. There is also an adverse effect that ink processing becomes difficult.

[0007] Most of the ink droplets remaining on the discharge port forming surface and foreign matters such as paper dust remaining on the discharge port forming surface remain after the wiping is completed. If the ink or the like is left on the discharge port forming surface, the ink itself will thicken due to the evaporation of the water in the ink, and the foreign matter such as paper powder will also adhere and deposit strongly, and after leaving. In some cases, it cannot be easily removed by wiping. In addition, when a pigment or an auxiliary solvent that easily thickens or crystallizes is contained as a component of the ink, a phenomenon in which the thickened ink swells near the ejection port due to evaporation of the ink from the ejection port (hereinafter also referred to as a flower blooming phenomenon). ) Occurs, and the ejection openings may be blocked by the thickened ink, resulting in ejection failure. The thickened ink remaining on the discharge port forming surface as described above, or the thickened ink that has swelled at the discharge port due to the flowering phenomenon cannot be completely removed only by the normal wiping operation and the preliminary discharge, and the ink is removed before the preliminary discharge. In many cases, no improvement is observed even if the ink is heated to the same temperature as that used for printing, and the forced discharge of the ink from the ejection port such as suction recovery is performed. However, when recovery is performed by forcibly discharging ink by suction or the like, problems such as an increase in the size of the receiving means for discharged ink and a reduction in the effective use amount of ink occur according to the discharged amount.

The present invention has been made in view of the above problems, and has as its object to improve wiping performance. That is,
The present invention stabilizes the ejection of the recording head by efficiently removing or reducing the ejection failure factors such as the thickened ink present on the ejection port forming surface and the ejection port itself, thereby achieving good recording over a long period of time. The purpose is to be able to maintain.

[0009]

According to a first aspect of the present invention, there is provided an ink jet recording apparatus for performing recording on a recording medium by using a recording head which discharges ink from a discharge port. A wiping unit capable of rubbing the surface provided with the discharge port, a heating unit capable of heating the vicinity of the discharge port of the recording head, and the heating unit during recording by the recording head. Control means for keeping the recording head warm while heating the recording head at a temperature higher than the warming temperature by the heating means prior to rubbing by the wiping means. According to a second aspect of the present invention, there is provided an ink jet recording apparatus for performing recording on a recording medium using a recording head which discharges ink from a discharge port, wherein the discharge port of the recording head is provided. Wiping means capable of rubbing the recording head, heating means capable of heating the vicinity of the discharge port of the recording head, and preliminary heating of the recording head by the heating means prior to preliminary discharge by the recording head. On the other hand, there is provided control means for performing heating at a temperature higher than the preheating temperature by the heating means prior to rubbing by the wiping means. In the first or second embodiment of the present invention, the recording head has, as an element for generating energy used for discharging ink, an electrothermal converter capable of generating heat energy for causing film boiling of the ink. May be. In this case, the control means can use the electrothermal transducer as the heating means and can drive the heating element to such an extent that ink is not ejected.

[0010]

According to a third aspect of the present invention, there is provided an ink jet recording method for performing recording on a recording medium by using a recording head for discharging ink from a discharge port. And a step of heating the recording head at a temperature higher than a recording temperature of the recording head prior to rubbing the surface of the recording head on which the ejection openings are provided. It is assumed that. According to a fourth aspect of the present invention, there is provided an ink jet recording method for performing recording on a recording medium using a recording head which discharges ink from a discharge port, wherein prior to performing preliminary discharge by the recording head,
Performing preheating of the recording head, and heating the recording head at a temperature higher than the preheating temperature of the recording head before rubbing the surface of the recording head on which the discharge ports are provided. It is characterized by having. In the third or fourth embodiment of the present invention, the recording head has, as an element for generating energy used for ejecting ink, an electrothermal converter capable of generating heat energy for causing film boiling of the ink. May be. In this case, the recording head can be heated by driving the electrothermal transducer to such an extent that ink is not ejected.

[0012]

[0013]

[0014]

In the first embodiment of the present invention, the control means activates the heating means at the time of recording by the recording head to keep the temperature in the vicinity of the discharge port of the recording head, and the ink is smoothly discharged from the discharge port at the time of recording. Make sure it is ejected. Further, prior to the rubbing by the wiping unit, the control unit operates the heating unit to heat the vicinity of the discharge port of the recording head at a temperature higher than the heat retaining temperature, and the ink adhered to the surface provided with the discharge port. Is softened, so that it is surely wiped by the wiping means. In the second embodiment of the present invention, prior to the preliminary ejection by the recording head, the control means activates the heating means to preheat the vicinity of the ejection port of the recording head so that the ink is ejected smoothly from the ejection port. I do. Further, prior to rubbing the surface of the recording head provided with the ejection ports with the wiping means, heating near the ejection ports of the recording head was performed at a temperature higher than the preliminary heating temperature for the recording head, and the ejection ports were provided. By softening the ink adhering to the surface, it is surely wiped by the wiping means.

[0015]

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

(Outline of Apparatus) FIG. 1 is a schematic view of an ink jet recording apparatus to which the present invention is applied. Here, C is an ink jet cartridge, which has an ink tank unit in the upper part of the figure and a recording head in the lower part, and a connector for receiving signals for driving the recording head and the like. Is provided. The recording head according to the present example has a plurality of ejection ports on the bottom side in the drawing, and an element that generates energy used for ink ejection is disposed in a liquid path portion communicating with the ejection ports. Each liquid passage communicates with a common liquid chamber, and the common liquid chamber receives ink supplied from the ink tank unit. Note that it is preferable to use an electrothermal conversion element as the above element because the discharge ports or liquid paths can be highly integrated.

Reference numeral 2 denotes a carriage, and four cartridges C (C1, C2, C3, C4; corresponding to inks of different colors, for example, yellow, magenta,
(Cyan, Black, etc.) are positioned and mounted, and a connector holder for transmitting a signal for driving the recording head and the like is provided so as to be electrically connected to the recording head. Absorbers are provided at the bottom of the carriage 2 so as to be located on both sides of each recording head as described later.

A scanning rail 11 extends in the main scanning direction of the carriage 2 and slidably supports the carriage 2.
Reference numeral 2 denotes a drive belt for transmitting a driving force for reciprocating the carriage 2. The transport roller pairs 15 and 16 and the transport roller pairs 17 and 18 are arranged before and after the recording position by the recording head, and perform the nipping and transporting of the recording medium. P
Is a recording medium such as paper, and is pressed against a platen (not shown) for regulating the recording surface of the recording medium P flat. Inkjet cartridge C mounted on carriage 2
The recording head portion protrudes downward from the carriage 2 in the drawing and is located between the recording medium transport rollers 16 and 18, and the ejection port forming surface of the recording head portion is a recording medium pressed against a guide surface of a platen (not shown). It faces in parallel with P.

In the ink jet recording apparatus of this embodiment, a recovery system unit 200 as recovery means is disposed on the home position side on the left side of FIG. In the recovery system unit 200, reference numeral 300 denotes a cap unit provided corresponding to each of the plurality of ink jet cartridges C having a recording head. The cap unit 300 is slidable in the horizontal direction in FIG. Can be moved up and down. When the carriage is at the home position, the carriage is joined to the recording head and capped, thereby preventing the ink in the ejection openings of the recording head from evaporating and thickening and sticking, thereby preventing ejection failure.

In the recovery unit, reference numeral 500 denotes a pump unit which communicates with the cap unit 300. In the event of a discharge failure in the print head, a suction recovery process is performed by joining the cap unit 300 and the print head. At this time, it is used to generate a negative pressure. Further, in the recovery system unit, reference numeral 401 denotes a blade as a wiping member formed of an elastic member such as rubber, and 402 denotes a blade holder for holding the blade 401. In this example, the blade 401 supported by the blade holder 402 by a blade lifting mechanism (not shown) driven by the movement of the carriage 2.
Denotes a position (wiping position) at which the ink adhered to the ejection port forming surface of the recording head is protruded (upward) to wipe the ink.
And a position (standby position) that is retracted (downward) so as not to interfere with the ejection opening surface of the recording head.

Further, in this embodiment, the carriage 2 is moved from the left side in the figure (the home position side where the recovery unit is located).
Only when moving from right to right, the wiping by the blade 401 is performed. This is blade 4
Since the position 01 is located between the cap unit 300 and the transport system for transporting the recording medium P, when the wiping is performed when moving from the right side to the left side in the drawing, the wiping is performed by the elastic force of the blade 401. This is because there is a risk that the ink is scattered around the conveyance section of the recording medium P and the recording medium is inadvertently stained. However, if there is no such adverse effect, wiping may be performed in both directions.

As described above, the execution and release of capping by sliding or elevating the cap unit 300,
Wiping by raising and lowering the blade 401 and regulating the wiping direction are described in, for example, Japanese Patent Application No. 2-126655 (Japanese Patent Application No. 1-12) filed by the present applicant.
No. 2878 (National priority claim application). Further, the present invention is not limited to this, and can be performed by a combination of a driving member such as a motor and a solenoid for raising and lowering the cap unit 300 and the blade 401 and a control means for controlling the same.

FIG. 2 shows a view (a) of the carriage 2 viewed from the bottom side and a view (b) of the carriage 2 viewed from the front side. Here, 1 is a discharge port forming surface, and 12 is a discharge port for discharging ink droplets. Reference numeral 3 denotes an absorber provided as a cleaning means for cleaning the blade 401, and is formed of a porous absorbent member having corrosion resistance to ink and high absorbency. The blade cleaning absorber 3 is provided on both sides of the ejection port forming surface 1 of each recording head. Further, as shown in FIG. 2B, the blade cleaning absorber 3 is slightly smaller than the ejection port forming surface 1 of the recording head projecting below the carriage 2 in order to prevent rubbing at the time of recording with the recording medium P. It is arranged so as to be located at the place where it is retracted. Further, in order to surely prevent the rubbing, it is preferable to use a member which does not swell even by liquid absorption.

(Wiping) By the way, generally, when a recording head ejects ink to record an image as described above, a so-called wetting state occurs as shown in FIG. When a large amount of ink droplets adhere around the discharge port, the discharge is hindered, causing a phenomenon (discharge) of discharging in an unexpected direction or a phenomenon of not discharging the ink droplet (non-discharge). For this reason, it is preferable to periodically wipe the discharge port surface 1 with the blade 401 before the adverse effect on the discharge is caused.

Here, the wiping operation in this embodiment will be described with reference to FIGS.

FIG. 3 shows the overall operation of the blade 401 during wiping, and FIG. 4 shows that part in an enlarged manner. As described above, the wiping operation is performed only when necessary in the direction of moving from the home position (left side in FIGS. 1 and 3) to the recording medium transport system side (right side in FIGS. 1 and 3).

FIG. 3A shows a state immediately before the wiping operation is performed. First, the blade 401 rises from the standby position in the direction of arrow Y, and is fixed at a position (wiping position) where the amount of intrusion is optimal for wiping the recording head. Next, as shown in FIGS. 3B and 3C, when the carriage 2 on which the cartridge C is mounted moves horizontally from left to right, the blade 401 is attached to each of the blade cleaning absorbers disposed at the bottom of the carriage 2. The ink is sequentially removed from the ejection port forming surface 1 while alternately contacting the ejection port surface 1 of the recording head protruding from the carriage 2 and is also cleaned by the absorber 3 (FIG. 4).
(See (a) and (b)). When all the blade cleaning absorbers 3 have come into contact with the discharge port forming surface 1, the blade 4
01 descends in the direction of arrow Y 'and waits at the standby position.
By providing the blade cleaning absorber 3 on both sides of the recording head, the ink swept from the ejection port forming surface is absorbed by the blade cleaning absorber 3, so that the amount of ink remaining on the blade 401 is reduced. In addition, when wiping the discharge port forming surface 1 of the next recording head, a great effect is exhibited in preventing color mixture from occurring.

Regarding the wiping speed, the unevenness of the blade contact surface (the discharge port forming surface 1 and the absorber 3 surface), the resilience of the elastic blade 401 (the ability to follow the contact surface), and the like. Determined in consideration of. In other words, as the speed increases, the wiping effect decreases due to slip-through due to a delay in following the blade, or the effect of removing foreign matter such as ink tends to decrease.Thus, the wiping speed is preferably low, The applicant is 30
It was confirmed that no significant problem would occur if it was 0 mm / sec or less. (Configuration of Control System) FIG. 5 shows a configuration example of the control system of the present embodiment.

Here, reference numeral 800 denotes a controller constituting a main control unit, for example, a CPU 801 in the form of a microcomputer for executing the procedures shown in FIGS. 6 to 11, and an R which stores programs corresponding to the procedures and other fixed data.
An OM 803 and a RAM 805 provided with an area for developing image data, a work area, and the like are provided. The controller 800 includes a timer group 807 used to perform appropriate recovery processing according to time in the course of the conventional processing.
have. Reference numeral 810 denotes a host device (which may be a reader or the like) serving as a supply source of image data. Image data and other commands and status signals are transmitted to and received from the controller via an interface (I / F) 812.

Reference numeral 820 denotes a switch group for receiving an instruction input by an operator, such as a power switch 822, a copy switch 824 for instructing the start of recording (copy), a recovery switch 826 for instructing the start of recovery, and the like. 83
Reference numeral 0 denotes a sensor group for detecting the state of the apparatus, such as a sensor 832 for detecting the position of the carriage 2 such as a home position and a start position, and a sensor 834 for detecting the position of a suction pump.

840 is the recording head 8 of the cartridge C
6 is a head driver for driving an element (in this example, an electrothermal converter) that generates energy used for ink ejection. Reference numeral 850 is a main scanning motor for moving the carriage 2 in the main scanning direction (the left-right direction in FIG. 1), and 852 is its driver. A sub-scanning motor 860 is used to convey (sub-scan) a recording medium. Reference numeral 862 denotes the driver.

Reference numeral 870 denotes a heater for keeping the head warm, which is provided integrally with the recording head or formed on the substrate provided with the electrothermal converter in the same process as that for forming the electrothermal converter. can do. Further, it may be provided on the carriage 2, but in this case, it is preferably provided at a position where it can come into contact with the recording head 86 when the head cartridge is mounted to perform effective heat transfer.

(Recovery Mode) Next, various recovery modes employed in the present embodiment will be described.

(A) Recovery Mode by Recovery Switch 826 The purpose of this recovery mode is to perform normal ejection of the head despite the fact that the recovery mode in the sequence in the apparatus of this embodiment is being performed. If this happens,
When the recovery switch 826 is pressed by the operator, the ejection of the head is restored to a normal state. It is not usually used, but if used, it is more powerful than other recovery modes to ensure recovery.

In this mode, suction is performed by the pump 500 to remove bubbles in the common liquid chamber or the liquid path and to remove thickened ink. Further, simultaneously with the suction, the electrothermal transducer is driven to perform a discharge operation, and a negative pressure generated only by suction is applied with an instantaneous negative pressure at the time of discharge, so that bubbles in the liquid chamber or liquid path are formed. Removal is easy. Further, since the electrothermal transducer is driven as a means for generating bubbles at the time of ejection, the ink temperature in each liquid path rises and the viscosity decreases, and the surface tension decreases. The resistance is smaller and the removal of air bubbles is easier. The value to be set for suction varies depending on the number of discharge ports, dimensions of each part, ink viscosity, etc. In this example, the suction pressure is the maximum pressure of the pump, and the suction holding time is 2.5 seconds. The amount is about 0.17 g. After the suction, the orifice surface of the head is wiped with a rubber blade, and then the idle discharge is performed. (B) Recovery mode using timer suction The purpose of this recovery mode is that if the suction recovery operation is not performed for a long time, the ink in the liquid chamber of the head thickens, and air bubbles are formed in the liquid chamber of the head. In some cases, normal ejection cannot be performed due to the occurrence and increase of the pressure. For this reason, for example, a time provided by a timer provided in the controller is measured from the last suction, and the recovery operation in this mode is performed after a predetermined time has elapsed.

In this mode, air bubbles in the liquid chamber are removed by suctioning with a pump, and the thickened ink is eliminated.

After the suction, the ejection port forming surface of the head is wiped by the blade 401, and then the idle ejection is performed. (C) Suction recovery mode using a counter The purpose of this recovery mode is that if recording continues for a long time without suction recovery operation, the ink in the liquid chamber of the head thickens, and Normal ejection may not be possible due to the generation and increase of bubbles. Therefore, the number of recording sheets is counted by the counter from the last suction, and the recovery operation in this mode performed after recording the predetermined number of sheets is performed.

This mode is a recovery operation similar to the timer suction recovery described above. In this mode, air bubbles in the liquid chamber are removed by suctioning with a pump, thickened ink is eliminated, and after suction, the blade 401 is used to remove the head. Wiping is performed on the discharge port forming surface, and then idle discharge is performed. Therefore, the timer and the counter are reset when either the timer suction or the counter suction in this mode is performed. (D) Pre-ejection (A) mode In this pre-ejection mode, ink is ejected from all ejection ports before the printing operation, when the printing operation is interrupted, during standby, and after wiping. In order to obtain a stable discharge state without increasing the temperature of the liquid path, for example, the maximum drive frequency of 4
The discharge frequency is 1 KHz with respect to KHz.

(E) Preliminary ejection (B) mode In this preliminary ejection, ink is ejected from all ejection ports simultaneously with suction. In this mode, the maximum drive frequency is used to increase the temperature of the liquid path, reduce the viscosity of the thickened ink, and increase the flow rate in the liquid path by using the ejection energy to increase the suction performance. Of 4 KHz.

(F) Pre-discharge (C) mode This pre-discharge is performed when the thickened ink is generated on the discharge port forming surface or in the vicinity of the discharge ports. Is driven at the maximum drive frequency to perform ejection. In this mode, the maximum driving frequency was set to 4 KHz in order to increase the temperature of the electrothermal transducer and promote the viscosity reduction of the thickened ink to facilitate the ejection.

(G) Heating mode of print head In the heat mode of print head, the print head 86 is maintained at a temperature suitable for ink discharge by using a heater 870 provided separately from the electrothermal transducer (heater for discharge). This is performed during recording and in a predetermined standby state.

(H) Preheating (A) Mode This preheating is performed prior to the predischarge performed when left for a predetermined time, and the discharge heater generates heat with such energy that discharge does not occur. By doing so, the temperature of the ink in the liquid path is adjusted to a temperature suitable for ejection. The reason why the ejection heater is used is that the ink can be efficiently and quickly heated because it is in direct contact with the ink in the liquid path, but a separately provided heater 870 may be used.
Basically, the temperature is controlled so as to be equal to the recording head heat retaining temperature.

(I) Pre-heating (B) mode This pre-heating is performed prior to a wiping operation or a pre-discharge (C) mode which is carried out after being left for a predetermined time. The ink in the liquid path is heated to a temperature suitable for discharge by generating heat with a small amount of energy. The reason for using the heater for ejection is to heat the ink efficiently and quickly because it is in direct contact with the ink in the liquid path. However, a heater 870 provided separately may be used.

(Recovery Control Procedure of Recording Apparatus) Next, a recovery control process using the above-described modes and the like as appropriate will be described.

FIG. 6 shows an example of the main control procedure of the ink jet recording apparatus, which is simplified for the sake of explanation, particularly focusing on the operation of the recovery system.

When the power is turned on, the ink jet recording apparatus of this embodiment firstly performs an initial check of the recording apparatus itself as the ROM 803 and the RAM 8 of the recording apparatus.
05 and other necessary parts are checked (step S1).

Next, after performing a necessary recovery operation in a timer recovery process described later with reference to FIG.
3), the preliminary ejection (A) is executed (step S)
5). In the timer recovery process, the aforementioned timer suction or the thickened ink removal process may be performed.

After step S5, a recording command is awaited (step S9) through a wiping + capping process (step S7) described later with reference to FIG. While waiting for the recording command (in the case of a negative determination in step S), it is determined whether or not the recovery switch 826 has been operated (step S1).
1) If the determination is negative, the standby process (step S13) described later with reference to FIG. 9 is executed, and if the determination is affirmative, the forced recovery process (step S15) described later with reference to FIG. 10 is executed.

On the other hand, if a recording command is detected in step S9, it is determined whether or not the cap is closed (ON) (step S17). If the determination is affirmative, the timer recovery process (step S19; FIG. 7) is performed prior to the recording operation.
Is performed, and if the cap is closed (on), the cap is opened (off) (steps S21 and S2).
Perform 3). After the wiping (step S25) and the preliminary ejection (A) (step S27), the process proceeds to step S29.

If it is determined in step S17 that the cap is open, the flow advances to step S31 to determine whether a predetermined time (for example, 12 seconds) has elapsed from the time when the cap was opened. . If the determination is negative here, the process immediately proceeds to step S29. If the determination is affirmative, after performing the preliminary ejection (A) (step S33), whether a predetermined time (for example, 60 seconds) has elapsed from the above time point? It is determined whether or not it is (step S35). If a negative determination is made here, wiping (step S37) is performed immediately if an affirmative determination is made, and then the process proceeds to step S29.

In step S29, a timer for measuring a predetermined time (four hours) (hereinafter referred to as a 4h timer) is one of the recovery processing timers used to execute an appropriate recovery processing according to the time. Is reset, and a required recording operation is performed (step S39). After that, a counter recovery process (step S41) described later with reference to FIG. 11 is performed, and the process returns to step S9 to wait for a recording command. In the counter recovery process, the aforementioned counter suction mode may be performed.

FIG. 7 shows an example of the timer recovery procedure called in steps S3 and S19. First, step S
Reference numeral 51 denotes a timer for measuring a relatively long predetermined time (for example, 72 hours), which is one of recovery processing timers (hereinafter referred to as 7)
2h timer) to determine whether 72 hours have elapsed since the last suction recovery. If a negative determination is made here, the process proceeds to step S53, and it is determined by the 4h timer whether four hours have elapsed since the last preliminary discharge and wiping. If the determination is negative, the process immediately returns. If the determination is affirmative, the cap is turned off (steps S55 and S57), and the following thickened ink removal processing is performed after step S59.

As described above, when foreign matters such as ink droplets and paper dust remaining on the discharge port forming surface without being wiped completely are left on the discharge port formation surface, the water content of the ink evaporates. As a result, the ink itself thickens,
In some cases, foreign matter such as paper powder is also strongly adhered and deposited, and may not be easily removed by wiping after standing. In addition, when a pigment or an auxiliary solvent that easily thickens or crystallizes is contained as a component of the ink, a phenomenon (referred to as a flower blooming phenomenon) occurs in which the thickened ink swells at the ejection port due to evaporation of the ink from the ejection port. The ejection opening may be blocked by the thickened ink, resulting in ejection failure.

The thickened ink remaining on the discharge port forming surface or the thickened ink raised at the discharge port due to the flower blooming phenomenon cannot be completely removed only by the normal wiping operation and the preliminary discharge. In many cases, ink cannot be ejected even if the ink is heated to the same optimal ejection temperature as at the time of recording, and forcible ejection of ink from the ejection port such as suction recovery is performed.

On the other hand, in the present invention, the thickened ink is efficiently removed without causing a large amount of ink consumption due to forced ejection. In the present embodiment, when a long time (72 hours) has not elapsed since the previous suction (4 to 72)
Time), the wiping operation (step S61)
To deal with. Prior to this, preliminary heating (B) is operated as a heating means for heating the discharge portion of the print head including the discharge port forming surface (step S59).

The ink whose viscosity has been increased by standing or the like rises in temperature by preheating (B), has a low viscosity, and is easily moved by wiping. The thickened ink that swells at the ejection port due to the flowering phenomenon is gradually reduced in viscosity from the nozzle side by preheating (B), and even if all the flowering inks are not reduced in viscosity, they are separated from the portion that has been reduced in viscosity by wiping. It becomes easy to move. Most of the ink that has been thickened by wiping after preheating is removed from the ejection port forming surface.However, if the flower bloom is too large to be removed by one wiping, In some cases, the thickened ink may remain on the ejection port forming surface or the ejection port. Therefore, in this embodiment, (preheating (B) + wiping) is repeated n times (step S6).
3). Note that only wiping may be repeatedly performed.

A portion of the thickened ink removed from the ejection port forming surface by wiping after preheating may be applied to the ejection port, and normal ejection cannot be performed as it is. Therefore, in the present embodiment, the preheating (B) and the predischarge (C) processes are further performed (steps S65 and S67; these may be repeated), and the 4h timer is reset (step S69). It returns to the main routine (FIG. 6).

It is easy to wipe the thickened ink,
The preliminary heating (B) for facilitating the ejection is intended to lower the viscosity of the ink obtained by evaporating and drying some components of the ink. The temperature is set higher than the preheating (A).

In this embodiment, the necessity of performing heating prior to the wiping means is determined based on the standing time. That is, the power supply O is controlled using a 4h timer that counts the time elapsed since the last preliminary discharge and wiping.
This is performed when N hours or four hours or more have elapsed at the start of recording. Therefore, this operation is not performed when recording is performed intermittently, so that time is not wasted. However, since it is also effective in removing ink adhering to the ejection port forming surface during printing, it may be performed prior to the wiping operation after the printing operation. In such a case, it is considered that the viscosity of the attached ink is not so much increased, so that it is good to make a contrivance such as setting the preheating temperature to be slightly lower.

Referring again to FIG. 7, in step S51, in the present embodiment, when at least 72 hours have elapsed since the last suction recovery at the time of power-on or before the start of printing, timer suction recovery is performed (step S73). However, also in this case, the preliminary heating (B) and the wiping are performed prior to the suction operation to facilitate removal of the thickened ink (step S71). This is also effective as an auxiliary means for suction recovery and can reduce the suction amount, so that it may be performed also during the counter recovery processing (FIG. 10) and the forced recovery (FIG. 11). In any case, in the present embodiment, the foreign matter such as the thickened ink can be efficiently removed, so that the ejection of the recording head can be stabilized for a long time.

After step S73, step S7 is performed.
5, reset each timer in S77, execute wiping (step S79), and return to the main routine.

Preheating may be performed before wiping in step S79, and after wiping, step S6 is performed.
5, the same processing as S67 may be added.

FIG. 8 shows an example of the wiping + capping processing procedure shown in step S7 of FIG. Here, first, in step S81, a timer (hereinafter referred to as 0.5) for measuring a predetermined time (for example, 0.5 hour) from the time when the cap is turned on.
After resetting the “h timer” and executing wiping in step S83, capping (cap on) is performed in step S85, and the process returns to the main routine.

FIG. 9 shows an example of a standby processing procedure for waiting for a recording command. Here, it is first determined in step S91 whether or not the cap is on. If the determination is affirmative, it is determined in step S93 whether or not the above 72 hours has elapsed with the cap on. If the determination is affirmative, the process returns to the main routine. In this case, the suction recovery is performed in the timer recovery process before the subsequent recording operation. If a negative determination is made in step S93, step S is executed.
Proceeding to 95, it is determined whether 0.5 h has elapsed since the cap-on time. If a negative determination is made here, the process returns to the main routine. In the case of an affirmative determination, the preliminary ejection (C) is performed, but also in this case, the preliminary heating (B) is performed prior to the preliminary ejection as described above (steps S97 and S9).
9). Then, in step S101, the 0.5h timer is reset, and the process returns to the main routine.

On the other hand, if it is determined in step S91 that the cap is open, it is determined whether the cap has been left open for a predetermined time (for example, 5 seconds) or more (step S103). If there is, the process returns to the main routine via wiping + capping processing (step S105; see FIG. 8).

FIG. 10 shows an example of a forced recovery processing procedure started when the recovery switch 826 is operated.

First, in step S111, preliminary ejection (B) is performed while performing suction as described above, and step S113 is performed.
After performing the preliminary heating (B), the wiping (step S115) and the preliminary ejection (A) (step S117)
Execute These processes may be appropriately repeated a plurality of times (step S119).

As described above, for example, preheating (B) and wiping may be performed prior to step S111. Further, for example, preheating (A) may be performed prior to step S117.

FIG. 11 shows an example of the counter recovery processing procedure.

First, in step S121, it is determined whether or not a predetermined number of sheets (for example, 10 sheets) have been recorded after the previous suction recovery. If the determination is affirmative, suction recovery is performed in the same manner as in step S73 (preliminary heating and wiping may be performed prior to this), and the timer of each unit is reset (step S125).

After the processing of step S125, or if a negative determination is made in step S121, step S12
7, the preliminary heating (B) and the wiping (step S1)
29), and after performing the preliminary ejection (A) (step S131), the process returns to the main routine.

In the above, each mode, its operating conditions, the time measured by the timer, and the like are merely examples, and it is needless to say that they can be appropriately selected as needed.

(Verification of Specific Effects) A durability test was performed on the stability of image quality in the ink jet recording apparatus of the present embodiment described above. Here, various conditions in this embodiment are shown below as specific numerical values.

Blade: thickness 0.7 mm ± 0.1 width 12.0 mm ± 0.1 free length 8.0 mm ± 0.1 penetrating amount at wiping (to discharge surface) 1.5 mm ± 0.5 at blade cleaning Penetration amount (to cleaner edge) 4.0 mm ± 0.5 Carriage moving speed: 200 mm / sec ± 30 (during wiping) 100 mm / sec ± 30 (during cleaning) Recording head used: 400 dpi 128 nozzles Wiping operation sequence: A4 Sequence of timer suction operation: After 72 hours Counter printing operation sequence: After every 10 sheets printing Thickening ink removal sequence: After 4 hours Recording temperature: 38 ° C Preheating (A): 35 -40 ° C Preheating (B): 50 ° C or higher Test environment: High temperature / low humidity (35 ° C / 10%) The test environment has a large discharge rate Wetting amount of ink was also carried out at high temperature and severe that dried easily evaporated humidity environmental conditions. Under the above conditions, the wetting amount was maximized by solid black recording at a recording ratio of 100%, and an endurance test of 5,000 sheets of A4 size (500 sheets / day for 10 days, and the standing time per day was 12
As a result, no ejection failure such as twisting or non-ejection occurred. However, when the above-described preheating (B) was excluded, ejection failure sometimes occurred in the initial printing after the standing, and the effect of the present invention was confirmed.

(Modification Example Regarding Wiping Direction and Timer Control of Preheating) In the embodiment described above, the relative movement direction between blade 401 and the discharge port forming surface during the wiping operation is relative to the arrangement direction of the discharge ports. Although the direction is a right angle, the wiping may be performed in the arrangement direction of the discharge ports.

As a recording head used in an ink jet recording apparatus, in order to avoid an end effect of a liquid path array (for example, a subtle difference in ejection characteristics due to a difference in the influence of ink vibration during ejection at the end). In some cases, liquid paths called dummy nozzles that are not actually used for discharge for printing are provided on both sides of the discharge port array.

Another effect can be obtained when the dummy nozzle is wiped in the discharge port arrangement direction as in the present modification.
When ink or the like adheres to the ejection port forming surface, the ink may be applied to the ejection port by wiping, but in the wiping direction of this modification, the ink between the ejection ports affects the adjacent ejection port. Also, such foreign matter is trapped by the dummy nozzles at the end ejection port, so that it is less susceptible to the effect of thickened ink on the ejection port forming surface as compared with the above embodiment. However, since the dummy nozzles only exchange ink at the time of suction recovery, the ink in the nozzles tends to increase in viscosity as compared with the ejection openings used for recording, and the flowering phenomenon described above tends to occur.

In this modified example, taking into account such thickening of the dummy nozzle, a timer II (corresponding to a 4h timer in the above example) for judging the necessity of the above (preheating + wiping) and a suction recovery The timer I (which corresponds to the 72h timer in the above example) for determining whether or not the execution is necessary is associated with the timer I. That is, it is possible to gradually shorten the determination time of the (preliminary heating + wiping) timer according to the elapsed time after the suction recovery. For example, (timer II determination time) = 4 × 72 / (72−timer I elapsed time)
It can be.

(Modification Example of Control of Preheating Temperature) In the above-described embodiment, the heating temperature of the preheating prior to the wiping operation is fixed, but the correlation between the standing time and the increase in the viscosity of the ink is used. Thus, the preheating temperature can be controlled. In this modification, as described above, an energy that does not lead to discharge is given for a predetermined time by using a discharge heater, that is, a pulse width of a heat pulse is made shorter than that in normal discharge to give a predetermined number of pulses. Thus, preheating is performed. Therefore, a control table of the number of pulses of the preheating (B) is set so that the number of pulses of the preheating (B) is positively correlated with the standing time and the number of pulses of the preheating (B) with the number of pulses of the preheating (A) being the minimum value.

Similarly, the remaining amount of ink relating to the ambient temperature, the water head pressure at the ejection port, the recording amount before leaving (the number of ejections) relating to the amount of ink attached to the ejection port forming surface, and the ease of wiping In accordance with various other factors, such as the use state of the print head (the number of prints, etc.) related to the water-repellent state of the ejection port forming surface, the efficient removal sequence of the thickened ink after leaving, for example, The holding time of the heating (B), the number of times of wiping, the preliminary discharge condition after wiping, the combined use with suction recovery, and the like may be controlled.

(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 discharging ink, 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 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 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 respective specifications, U.S. Pat. No. 4,558,333 and U.S. Pat. No. 44,558 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 is attached to 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.

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

Further, the form of the ink jet recording apparatus of the present invention is not limited to the one used as an image output terminal of an information processing apparatus such as a computer, a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmitting / receiving function. It may take a form.

[0088]

As described above, according to the present invention,
Wiping means for slidingly removing foreign substances adhering to the discharge port forming surface by relatively moving in pressure contact with the discharge port forming surface of the recording head, and heating for heating the discharge section of the recording head including the discharge port forming surface Means for operating the heating means prior to operating the wiping means so that foreign substances such as thickened ink can be efficiently removed, thereby stabilizing the ejection of the recording head for a long period of time. In particular, it is possible to improve the ejection when printing is resumed after a pause due to the use of a liquid ink as a recording material, thereby maintaining image quality.

Further, by making the heating temperature by the above-mentioned heating means higher than the heat retention temperature, the above removal becomes more effective.

Further, since the heating prior to the wiping is performed as required according to time, control flow, and the like, the efficiency of cleaning by wiping can be further improved.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view illustrating a configuration example of an inkjet recording apparatus to which the present invention can be applied.

FIGS. 2A and 2B are a bottom view and a front view of the vicinity of a carriage on which the recording head shown in FIG. 1 is mounted.

FIGS. 3A to 3C are explanatory diagrams of the wiping operation of FIG. 1;

FIGS. 4A and 4B are enlarged explanatory views of the same. FIG.

FIG. 5 is a block diagram illustrating an example of a control system of the present example apparatus.

FIG. 6 is a flowchart illustrating an example of a recording control procedure of the apparatus according to the present embodiment.

FIG. 7 is a flowchart illustrating an example of a timer recovery processing procedure in the procedure of FIG. 6;

FIG. 8 is a flowchart showing an example of a wiping and capping processing procedure.

FIG. 9 is a flowchart illustrating an example of a standby processing procedure.

FIG. 10 is a flowchart showing an example of a forced recovery processing procedure.

FIG. 11 is a flowchart illustrating an example of a counter recovery processing procedure.

FIG. 12 is an explanatory diagram illustrating a state of attachment of foreign substances such as ink on a discharge port forming surface of a recording head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Discharge port formation surface 2 Carriage 3 Absorber 12 Discharge port 86 Recording head 200 Recovery system unit 300 Cap unit 401 Blade 500 Pump unit 800 Controller 801 CPU 804 Timer group C Cartridge P Recording medium

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Jin Sugimoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Miyuki Matsubara 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inside (72) Inventor Kiichiro Takahashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Within Canon Inc. (56) References JP-A-1-157607 (JP, A) JP-A-63-89350 (JP) , A) (58) Field surveyed (Int. Cl. ⁶ , DB name) B41J 2/165

Claims (8)

(57) [Claims] 1. An ink jet recording apparatus for performing recording on a recording medium using a recording head that discharges ink from a discharge port, wherein a surface of the recording head on which the discharge port is provided is rubbed. A wiping means capable of heating, a heating means capable of heating the vicinity of the ejection port of the recording head, and a heating means for keeping the temperature of the recording head by the wiping means during recording by the recording head. An ink jet recording apparatus comprising: a control unit for performing heating at a temperature higher than the heat retaining temperature by the heating unit before rubbing. 2. A recording head for discharging ink from a discharge port.
For printing on a printing medium using
A recording head, wherein a surface of the recording head on which the discharge port is provided can be rubbed.
Wiping means and heating capable of heating the vicinity of the discharge port of the recording head
Means and the heating means prior to preliminary ejection by the recording head
The preheating of the recording head is performed by
Prior to rubbing by the ping means,
Control means for heating at a temperature higher than the preheating temperature;
An ink jet recording apparatus comprising: 3. The recording head according to claim 1, wherein the recording head includes an electrothermal transducer capable of generating heat energy for causing film boiling of the ink, as an element for generating energy used for discharging the ink. The ink jet recording apparatus according to claim 1 or 2 . 4. The ink jet recording apparatus according to claim 3 , wherein the control unit uses the electrothermal transducer as the heating unit and drives the electrothermal converter to such an extent that ink is not ejected. 5. An ink jet recording method for performing recording on a recording medium using a recording head that discharges ink from a discharge port, wherein the recording head is kept warm during recording by the recording head. Heating the recording head at a temperature higher than the heat retaining temperature of the recording head prior to rubbing the surface of the recording head on which the discharge ports are provided. 6. A recording head for discharging ink from a discharge port.
Inkjet recording that records on a recording medium using
A recording method , wherein prior to performing preliminary ejection by the recording head,
Performing preheating of the recording head, and rubbing the surface of the recording head on which the discharge ports are provided.
Prior to the pre-heating temperature of the recording head.
That comprises the steps of heating the recording head in degrees
An inkjet recording method characterized by the above-mentioned. Wherein said recording head, according to claim, characterized in that it comprises as elements for generating energy used for ejecting ink, the ink can generate heat energy to cause film boiling on a electrothermal transducer The inkjet recording method according to claim 5 or 6. 8. The ink jet recording method according to claim 7, characterized in that the pressurized heat of the recording head by driving to such an extent that the discharge of ink the electrothermal transducer does not occur.