JP4986550B2 - Ink jet recording apparatus and recovery method of ink jet recording apparatus - Google Patents

Description

  The present invention relates to an inkjet recording apparatus provided with an ejection recovery means for stabilizing the ejection state of an inkjet recording apparatus equipped with a recording head having a plurality of nozzles for ejecting ink.

  The ink jet recording apparatus has advantages such as easy miniaturization, low noise, and low cost, and is used in various printing apparatuses including computer output apparatuses. This ink jet recording apparatus includes a recording head having a plurality of nozzles capable of ejecting ink with an electric signal. Then, while the recording head is mounted on the carriage and reciprocatingly moved, each nozzle is selectively driven to discharge droplet-like ink from the corresponding nozzle. Thereby, ink droplets are selectively landed on the recording medium, and a desired image can be formed. Further, the recording head has a plurality of nozzles for ejecting ink arranged in a line to form an ejection unit. By providing a plurality of the ejection units in the same recording head, color printing can be performed by supplying different types of ink, for example, different colors, to the ejection units.

  In such an ink jet recording apparatus, in the ink that accompanies the permeation and intrusion of air through the material forming them in the nozzle for discharging the ink or the ink flow path for supplying the ink to the nozzle. The generation and mixing of bubbles may occur. In some cases, the viscosity of the ink increases due to evaporation from an ejection port provided at the nozzle tip. As a result, the ink is not normally ejected from the nozzles in the form of droplets, that is, ejection failure occurs. This does not cause regular ink droplets to land on the recording medium, leading to a reduction in the quality of the formed image.

  In order to prevent this deterioration in image quality, an ink discharge state recovery process (discharge recovery process) is generally performed in an ink jet recording apparatus for the purpose of avoiding or improving discharge defects. Typical examples of the discharge recovery process include a process for forcibly discharging ink from a nozzle and a process for wiping off stains due to adhesion of ink, paper dust, and the like in the discharge unit.

  In the former case, the ink is forced to flow by depressurizing the space formed by closely attaching the cap having the opening to the ejection part, or by pressurizing the ink flow path, so that the ink flows from the nozzle. This is a process of discharging. As a result, ink with increased viscosity and bubbles in the ink are discharged simultaneously with normal liquid ink. This process of forcibly flowing the ink and discharging the ink from the nozzles is called “forced flow recovery”.

  Furthermore, in the former process, ink that is not related to image formation is ejected immediately before or during the start of recording in an area outside the recording medium, and ink whose viscosity has been increased by evaporation at the nozzle outlet portion. There is also a process of discharging. In particular, this ink discharge process by discharge is referred to as “preliminary discharge”.

  The latter is made of rubber, etc., which is caused by fine ink mist generated by ink ejection or ink wetting caused by ink rebounding from the recording medium when ink droplets are landed or paper dust adhering to it. This is a process of wiping with a wiper blade. This process is called “wiping”.

  Among these, the “suction recovery” mechanism is often incorporated in recent ink jet recording apparatuses in order to cope with the problems of the above-described increase in viscosity of ink and mixing of bubbles into the ink. “Suction recovery” means that a cap having an opening covering the discharge part is brought into contact with the discharge part, the inside of the space formed by the discharge part and the cap opening is depressurized, and the pressure difference generated is used to generate a nozzle. The ink filled in the recording head is sucked and discharged. A device that performs a “suction recovery” operation is referred to as a “suction recovery device”.

  The suction recovery works very effectively in order to avoid a discharge failure, but has a disadvantage. Since the suction recovery is performed independently of the ink discharge operation from each nozzle for the purpose of image formation, the ink discharge must be interrupted during the suction recovery. That is, image formation on the recording medium cannot be performed while this suction recovery operation is being performed. This causes the inconvenience that the time from the intended recording to the finishing is substantially increased.

  Furthermore, since the ink is forcibly discharged from the nozzles in the suction recovery, ink consumption that does not contribute to image formation is involved. Therefore, there arises a disadvantage that increases the cost required for recording. In addition, since the discharged ink cannot normally be reused, there arises a disadvantage that it is necessary to store the ink as waste ink.

  In view of the above disadvantages, it is desirable that the suction recovery is limited to a small number of operations. Therefore, the suction recovery is generally performed only when necessary in terms of quality by automatically operating after a lapse of a certain time, and unnecessary suction recovery is not performed as much as possible. One method for performing automatic suction recovery is “timer suction”. “Timer suction” means that an ink jet recording apparatus is provided with a timer for which a predetermined time is set in advance, and the elapsed time after suction recovery is measured together with the timer. Then, referring to the elapsed time and the set value of the timer, the suction recovery is automatically executed when the elapsed time exceeds the set value of the timer.

  The time setting in normal timer suction is based on the time until the amount of bubbles generated and growing in the nozzle and the ink flow path reaches a state where ejection failure can be caused. This time is obtained as a characteristic of the ink jet recording apparatus to be used, and is set as a timer.

  By the way, the cause of the generation and growth of bubbles in the ink in the nozzle and the ink flow path is that air passes through the joints of the members constituting the recording head and the ink flow path and the member itself and enters the ink. The case of entering. Further, there is a case where air is taken in from the ejection port by repeating ink ejection. Furthermore, in recording heads that use thermal energy to instantaneously heat and foam ink to form ejected droplets, there are residual bubbles when defoaming after ejection, which accumulates in the ink. There is also a case.

  In general, it is known that the relationship between the gas permeability and temperature in a member follows the Arrhenius equation, and the amount of gas transmission increases exponentially with temperature. When the gas permeates through a member having substantially no holes, the gas molecules are condensed on the wall surface of the member on the high concentration side (the gas pressure is high), and then the gas is dissolved in the member. Subsequently, the dissolved gas molecules are diffused toward the low concentration side of the gas molecules using the concentration gradient difference of the gas molecules between the two sides of the member as the driving force, and are evaporated and released from the opposite side of the member. Arises from that.

  When this is applied to the ink flow path, first, gas molecules in the air agglomerate and dissolve in the member on the outer wall surface of the member constituting the ink flow path, that is, the wall surface on the air side. To go. The surface of the member constituting the ink channel opposite to the wall surface, that is, the inner wall surface in contact with the ink has almost no air, so the gas molecules dissolved in the previous member are on the ink channel inner wall side. Will diffuse towards the surface and then be released into the ink. For this reason, the difference in gas concentration on both wall surfaces of the members constituting the ink flow path acts and gas permeation continues while ink is present in the ink flow path. At the same time, the amount of gas accumulated in the ink flow path increases.

  For this reason, as the timer suction, the time is set with the characteristics at the maximum temperature within the temperature environment range that guarantees the operation of the ink jet recording apparatus to be used. Originally, the temperature change while the inkjet recording device is in use is sequentially detected, the amount of gas that has permeated and accumulated in the ink is derived from the temperature change history, and an appropriate suction recovery operation is performed based on that amount It is preferable to determine the timing. However, in order to detect the temperature change while recording is paused, including when the inkjet recording device is not turned on, and to store the history, the temperature detection sensor is always operated. It is necessary to keep. For this reason, the ink jet recording apparatus is difficult in practical use because it must always be energized for sensor driving and sensor output processing.

  Therefore, in order to guarantee the operation of the ink jet recording apparatus, it is necessary to set the timer time based on the gas permeation characteristic at the highest temperature in actual use, and to perform timer suction according to the time setting.

  For this reason, depending on the actual use environment of the ink jet recording apparatus, even when the time set by the timer is reached, satisfactory ink ejection may be possible without performing suction recovery. In other words, unnecessary ink discharge may be performed.

In order to prevent such unnecessary ink discharge, it is preferable to have a configuration in which the set value of the timer can be changed. As a configuration for changing the setting value of the timer, for example, Patent Document 1 discloses increasing or decreasing the setting value of the suction timer according to the type of the recording medium. That is, a configuration is disclosed in which the standard setting value is +12 hours for plain paper, and -10 hours for glossy paper that requires high quality. Also, in Patent Document 2, in a device in which a cartridge storing liquid is detachable, the first determination reference time from the cartridge mounting to the specified number of times is shortened, and the second determination reference time after the specified number of times is It is disclosed to set a long time.
JP 2001-260370 A (page 6, FIG. 3-4) Japanese Unexamined Patent Publication No. 2004-136502 (page 5-6, FIG. 10)

  However, Patent Literature 1 changes the timer setting with the image quality required according to the recording medium used when recording. In other words, when high image quality is required using an expensive recording medium, an image formation failure should not occur. Therefore, an unexpected discharge failure is caused by performing a suction recovery operation even before the set time of the timer. The idea is not to cause Therefore, it does not consider the bubble growth in the ink and is different from the viewpoint in the present application.

  Patent Document 2 depends on the configuration of a cartridge that stores ink. Even after the liquid introduction needle provided on the head side is inserted into the needle insertion port of the cartridge and ink filling is completed, the bubbles in the needle cannot be completely removed, so it is necessary to set a short timer until the specified suction is completed. It is an invention that was made because it was not obtained. For this reason, after the bubbles in the needle are removed, a constant timer setting is maintained, and the characteristics of bubble growth in the ink over time are not taken into consideration. Rather, there are a lot of bubbles remaining immediately after the cartridge is mounted, thereby avoiding ejection failure due to this, and the initial timer setting is short. Therefore, each time the cartridge is mounted, the timer setting returns to a short time and is not appropriate for the purpose of reducing the suction frequency.

  Further, in the timer suction in the conventional ink jet recording apparatus, the time setting is experimentally obtained, and suction recovery based on the setting is performed uniformly only with the elapsed time.

  The present invention has been made in view of the characteristics of bubbles generated and grown in the nozzle and the ink flow path, and does not wastefully perform the recovery process, and is stable with the minimum frequency of the recovery process. The purpose is to set the time during timer suction so that the discharge can be maintained.

  As a result of intensive studies by the present inventors, the following could be confirmed.

  The ink jet recording apparatus in the form of a head cartridge having an ink tank that can be attached to and detached from the recording head has a state in which the ink flow path of the recording head is not filled with ink when the head cartridge is replaced or when the ink in the ink tank is used up. There is a case. In such a case, the head cartridge and the ink tank are replaced and the ink flow path is filled with ink. At this time, in particular, bubbles are easily mixed in the ink, and an early recovery process is required.

  However, after replacing the head cartridge and the ink tank and filling the ink flow path with ink, it was found that the generation and growth of bubbles slowed with time.

This invention is completed in order to achieve the said objective based on the said knowledge. Specifically, a carriage in which a recording head having a plurality of nozzles for ejecting ink and an ink tank for storing ink supplied to the recording head are detachably provided;
Recovery means for performing recovery operation of the recording head;
A recovery control means for causing the recovery means to perform a next recovery operation when an elapsed time from the previous recovery operation is equal to or greater than a threshold ;
Detecting means for detecting a remaining amount of ink in the ink tank in order to perform an ink tank replacement operation in a state where ink remains in the ink tank;
With
The recovery control means includes
In the ink jet recording apparatus, the threshold value is increased in accordance with the cumulative number of recovery operations, and the elapsed time is not initialized even when the ink tank is replaced.

According to another aspect of the invention for achieving the above object, there is provided a carriage in which a recording head having a plurality of nozzles for ejecting ink and an ink tank for storing ink supplied to the recording head are detachable; A recovery method for an ink jet recording apparatus comprising recovery means for performing a recovery operation,
A step of causing the recovery means to perform a next recovery operation when an elapsed time from the previous recovery operation is equal to or greater than a threshold;
A detection step of detecting a remaining amount of ink in the ink tank in order to perform an ink tank replacement operation in a state where ink remains in the ink tank;
A step of increasing the threshold in accordance with the accumulated number of the recovery operation,
And a step of not initializing the elapsed time even if the ink tank is replaced.

  According to the present invention, since the behavior of residual bubbles on the inner wall of the nozzle and the ink flow path where the ink is in contact with the ink after filling with ink is taken into consideration, the timer suction is executed by appropriately changing to an appropriate time setting. Recovery processing is not performed in a short time as necessary. Accordingly, the consumption of extra ink is eliminated, and in addition, the time required for substantial recording is increased and the running cost is suppressed.

  In this specification, “recording” not only forms significant information such as characters and graphics, but also forms images, patterns, patterns, etc. on a wide variety of recording media, regardless of significance, or It also represents the case where the medium is processed. It does not matter whether it has been made obvious so that humans can perceive it visually.

  “Recording medium” refers not only to paper used in general recording apparatuses but also widely to cloth, plastic film, metal plate, glass, ceramics, wood, leather, and the like that can accept ink. Shall.

  Further, “ink” should be interpreted widely as the definition of “recording (printing)” above, and when applied to a recording medium, it forms an image, a pattern, a pattern, etc. or processes the recording medium. Or a liquid that can be subjected to ink processing. Further, as an example that can be used for ink processing, there is coagulation or insolubilization of the colorant in the ink applied to the recording medium.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  First, the configuration of an example of an ink jet recording apparatus (hereinafter abbreviated as “recording apparatus”) to which the present invention is applied will be described with reference to FIGS. 4 and 5. FIG. 4 shows a schematic configuration of the external appearance of the recording apparatus. The outer shell of the recording apparatus main body 1000 includes an outer member including a lower case 1001, an upper case 1002, an access cover 1003, and a discharge tray 1004. In these exterior members, a recording apparatus unit 2000 including a chassis 2001 shown in FIG. 5 is housed. The chassis 2001 is constituted by a plurality of plate-like metal members having a predetermined rigidity, forms a skeleton of the recording apparatus, and holds each recording operation mechanism described later.

  Further, the lower case 1001 forms a substantially lower half part of the exterior of the apparatus main body 1000, and the upper case 1002 forms a substantially upper half part of the exterior of the apparatus main body 1000, respectively. A hollow body structure having a storage space for storing the mechanism is formed. Openings for feeding and discharging the recording medium are formed in the upper surface portion and the front surface portion of the apparatus main body 1000, respectively.

  Further, one end of the discharge tray 1004 is rotatably held by the lower case 1001 so that the opening formed on the front surface of the lower case 1001 can be opened and closed by the rotation. For this reason, when performing the recording operation, by rotating the discharge tray 1004 to the front side and taking out the opening, the recording medium can be discharged from here and the discharged recording media can be sequentially stacked. It is like that. The discharge tray 1004 accommodates two auxiliary trays 1004a and 1004b, and the support area of the recording medium can be expanded or reduced in three stages by pulling each tray forward as necessary. It has become.

  One end of the access cover 1003 is rotatably held by the upper case 1002 so that an opening formed on the upper surface can be opened and closed. By opening the access cover 1003, the head cartridge or ink tank housed in the main body can be replaced. This head cartridge is composed of a head cartridge body having an ink tank mounting portion in the recording head portion and an ink tank, and details of the configuration will be described later. Although not particularly shown here, when the access cover 1003 is opened and closed, a protrusion formed on the back surface rotates the cover opening and closing lever. The open / closed state of the access cover can be detected by detecting the rotation position of the lever with a micro switch or the like.

  In addition, a power key 3001 and a resume key 3002 are provided on the upper surface of the rear portion of the upper case 1002 such that the power key 3001 and the resume key 3002 can be pressed, and a light emitting unit 3003 including LEDs is provided. When the power key 3001 is pressed, the light emitting unit 3003 is turned on to inform the user that recording is possible. In addition, the light emitting unit 3003 has various display functions such as notifying the user of an abnormality of the recording apparatus or the like by the blinking method or the change in the light emission color. In addition, a buzzer can be leveled. When the abnormality is resolved, the recording is resumed by pressing the resume key 3002.

  Next, the recording operation mechanism of the recording apparatus unit 2000 housed in the apparatus main body 1000 will be described with reference to FIG. The recording operation mechanism in this embodiment includes an automatic feeding unit 2002 that automatically feeds a recording medium into the apparatus main body. In addition, the recording medium that is sent one by one from the automatic feeding unit 2002 is guided to a predetermined recording position, and the conveyance unit 2003 guides the recording medium from the recording position to the discharge unit 2004. Furthermore, a recording unit that performs desired recording on the recording medium conveyed to the recording position, and an ejection recovery device unit 2200 that performs ejection recovery processing on the recording unit and the like are provided.

  Here, the recording unit includes a carriage 2100 movably supported by a carriage shaft 2103 and a head cartridge 4000 (see FIG. 6) that is detachably mounted on the carriage 2100. The carriage 2100 is reciprocated in the main scanning direction indicated by the arrow S via the transmission mechanism 2104 by the driving force of the carriage motor 3020 as a driving source.

  6 and 7 show a configuration example of the head cartridge 4000, and FIG. 6 shows a perspective view showing a state where an ink tank 4100 for storing ink is attached to the head cartridge main body 4001. FIG. FIG. 7 is a perspective view showing a state in which the ink tank 4100 is detached from the head cartridge main body 4001, with the top and bottom reversed from FIG. In this example, the head cartridge main body 4001 is detachably mounted on the carriage 2100 described above. In the head cartridge 4000 shown here, for example, black, light cyan, light magenta, cyan, magenta, and yellow ink tanks 4100 are prepared as ink tanks in order to enable high-quality color recording with a photographic tone. ing. Each of them is detachable from the head cartridge main body 4001 having the ejection part 4002.

  FIG. 8 is an exploded perspective view of the head cartridge body 4001. The head cartridge main body 4001 of this example includes a recording element substrate 4010, a first plate 4020, an electric wiring board 4030, a second plate 4040, a tank holder 4050, an ink flow path forming member 4060, a filter 4070, and a seal rubber 4080. ing.

  In the recording element base 4010, a plurality of recording elements for ejecting ink to one surface of a silicon substrate and electrode wirings such as aluminum for supplying power to each recording element are formed by a film forming technique. A plurality of ink flow paths corresponding to the recording element and a plurality of nozzles having ejection openings 4011 are formed by photolithography, and an ink supply port for supplying ink to the plurality of ink flow paths is provided on the back surface. It is formed to open. The recording element ejects ink using thermal energy and includes an electrothermal converter that generates the thermal energy. In other words, film boiling occurs in the ink due to the heat energy generated from the electrothermal transducer, and the ink is ejected from the ejection port using the pressure change caused by the growth and contraction of bubbles in the ink. The electrothermal converter is provided corresponding to each of the plurality of discharge ports 4011.

  FIG. 9A is a schematic plan view showing the configuration of the recording element and electrode wiring on the recording element substrate 4010, and FIG. 9B is a schematic cross-sectional view of the AA ′ portion. For manufacturing the recording element base 4010, a silicon substrate or a silicon substrate in which a driving IC has already been formed is used. In the case of a silicon substrate, a heat storage layer made of silicon dioxide is formed by a thermal oxidation method, a sputtering method, a CVD method, and the like. Form it. In FIG. 9B, 4012 corresponds to a heat storage layer made of silicon dioxide and has a film thickness of less than 2 μm.

  Next, a first aluminum electrode layer (not shown) is formed as a common electrode wiring to a thickness of 0.55 μm by sputtering, a wiring pattern is formed by photolithography, and reactive ion etching is performed. Etching is performed. Next, an interlayer insulating film 4013 made of silicon nitride, silicon dioxide or the like is formed by 1.4 μm by sputtering, CVD, or the like. Next, a TaSiN layer 4014 as a heater is formed to a thickness of 0.018 μm, and a second aluminum electrode layer 4015 as an electrode wiring is formed to a thickness of 0.2 μm by a sputtering method or a reactive sputtering method, respectively. Next, a wiring pattern is formed using a photolithography method, and etching is continuously performed with aluminum and TaSiN by a reactive ion etching method. Again, the aluminum layer is removed by wet etching in order to expose the heat generating portion as indicated by reference numeral 4016 in FIG. 9 by photolithography. Next, an insulating film made of silicon nitride, silicon dioxide, or the like is formed as the first protective film 4017 to a thickness of 0.3 μm by sputtering, plasma CVD, or the like. A tantalum layer as the second protective film 4018 is formed thereon with a thickness of 0.23 μm while performing a patterning process as necessary.

  Turning again to FIG. The recording element base 4010 manufactured in this way is bonded and fixed to the first plate 4020, and an ink supply port 4021 for supplying ink to the recording element base 4010 is formed here. Further, a second plate 4040 having an opening is bonded and fixed to the first plate 4020, and the electric wiring board 4030 is electrically connected to the recording element base 4010 via the second plate 4040. Is held to be connected. The electric wiring board 4030 mainly applies an electric signal for ejecting ink to the recording element substrate 4010. It has an electrical wiring corresponding to the recording element base 4010 and an external signal input / output terminal 4031 for receiving an electrical signal from the main body located at the end of the electrical wiring. Are fixedly positioned on the back side of the tank holder 4050.

  The head cartridge main body 4001 stores necessary information about the recording element base 4010, that is, information for defining a driving condition corresponding to the heat generating portion 4016, and means for presenting the information when the head cartridge main body 4001 is attached to the apparatus main body. Is provided. As the means, for example, a nonvolatile memory such as an EEPROM or a fuse ROM mounted on the electric wiring board 4030 can be used. Further, the head cartridge main body 4001 or the recording element substrate 4010 can be provided with a temperature sensor for detecting the temperature and presenting the information. The presentation information can be transmitted to the recording apparatus main body control unit via the external signal input / output terminal 4031.

  On the other hand, an ink flow path forming member 4060 is bonded and fixed to the tank holder 4050 that detachably holds the ink tank 4100 by ultrasonic welding or the like, and the ink flow path extending from the ink tank 4100 to the first plate 4020. 4051 is formed. A filter 4070 is provided at the end of the ink flow path 4051 that engages with the ink tank 4100 on the ink tank side so as to prevent dust from entering from the outside. Further, a seal rubber 4080 is attached to the engaging portion with the ink tank 4100 so that ink can be prevented from evaporating from the engaging portion.

  Further, the tank holder portion is composed of a tank holder 4050, a flow path forming member 4060, a filter 4070, and a seal rubber 4080. The recording element section includes a recording element substrate 4010, a first plate 4020, an electric wiring board 4030, and a second plate 4040. Then, the head cartridge main body 4001 is configured by bonding the tank holder portion and the recording element portion by bonding or the like.

  Next, the carriage 2100 on which the head cartridge 4000 having the above-described configuration is mounted will be described with reference to FIG. 5 again. The carriage 2100 is provided with a carriage cover 2101 that engages with the carriage 2100 and guides the head cartridge body 4001 to a predetermined mounting position on the carriage 2100. The carriage 2100 is provided with a head set lever 2102 that engages with the tank holder 4050 of the head cartridge main body 4001 and presses the head cartridge main body 4001 to be set at a predetermined mounting position.

  That is, the head set lever 2102 is provided on the upper portion of the carriage 2100 so as to be rotatable with respect to the head set lever shaft, and a spring-set head set plate (not shown) is engaged with the engaging portion with the head cartridge main body 4001. ) Is provided. The head cartridge main body 4001 is pressed by this spring force and is mounted on the carriage 2100.

  Further, a contact flexible recording cable 3011 is provided at another engagement portion of the carriage 2100 with the head cartridge body 4001. Then, the contact portion 3010 on the contact flexible recording cable 3011 and the contact portion (external signal input terminal) 4031 provided on the head cartridge main body 4001 are in electrical contact. Thereby, various information for recording and the like are exchanged and power is supplied to the head cartridge main body 4001.

  Here, an elastic member such as rubber (not shown) is provided between the contact portion of the contact flexible recording cable 3011 and the carriage 2100. The contact portion 3010 on the contact flexible recording cable 3011 and the contact portion 4031 of the head cartridge main body 4001 can be reliably contacted by the elastic force of the elastic member and the pressing force by the head set lever spring. . Further, the contact flexible recording cable 3011 is connected to a carriage substrate (not shown) mounted on the back surface of the carriage 2100.

  The carriage 2100 having such a configuration is connected to a part of a driving belt 2105 that is a transmission mechanism for transmitting the driving force of the carriage motor 3020 and is guided along the carriage shaft 2103 in the main scanning direction indicated by an arrow S. Has been. The carriage 2100 reciprocates along the carriage shaft 2103 by forward and reverse rotations of the carriage motor 3020. Reference numeral 2106 denotes a scale indicating the absolute position of the arrow S of the carriage 2100 in the main scanning direction. As the scale 2106 of this example, a transparent PET film on which black bars with a predetermined pitch are printed is used, one end of which is fixed to the chassis 2001, and the other end is not shown. It is supported by the leaf spring.

  In the recording apparatus 1000 of this example, a platen (not shown) is provided so as to face the ejection unit 4002 of the head cartridge 4000 (lower part of the transport unit 2003). Then, the carriage 2100 on which the head cartridge 4000 is mounted is reciprocated in the main scanning direction by the driving force of the carriage motor 3020. At the same time, ink is ejected from the head cartridge 4000 based on the recording signal, thereby recording in the width direction of the recording medium conveyed on the platen.

  Next, the discharge recovery unit in this example will be described with reference to FIGS. FIG. 10 is a perspective view showing one side portion of the discharge recovery portion, and FIG. 11 is a perspective view showing opposite side portions of FIG. 10 with respect to the same discharge recovery portion. The ejection recovery unit is disposed outside the range in which the carriage 2100 on which the head cartridge 4000 is mounted reciprocates for the recording operation, that is, outside the recording area, so that the ejection state of the head cartridge 4000 is maintained well. Recovery processing. The arrangement position is set to a desired position outside the recording area, such as a position corresponding to the home position of the carriage 2100 and the head cartridge 4000, for example. Furthermore, in this example, it is comprised by the discharge recovery apparatus 2200 which can be attached or detached independently with respect to the apparatus main body 1000. FIG. The ejection recovery device 2200 includes wiping means for removing foreign matter adhering to the recording element substrate 4010 of the head cartridge 4000. Further, a suction recovery means is provided for normalizing ink supply in the ink flow path from the ink tank 4100 to the recording element substrate 4010 of the head cartridge 4000.

  The wiping means includes three wiper blades 2201, 2202, 2203, a wiper holder 2204 that supports them, and a groove 2205a formed in a spiral shape to reciprocate the wiper blade 2204 in the direction of arrow C in the figure. A screw 2205 is used.

  The suction recovery means includes a cap 2206 formed of rubber or the like so as to cover the recording element substrate 4010 of the head cartridge 4000. An absorber 2207 provided inside the cap 2206 and an arm 2208 for operating the cap 2206 with respect to the head cartridge 4000 in the direction B in the drawing to contact and separate.

  The cap 2206 is supported by a holder configured separately from the arm 2208, and the holder is supported by the arm 2208. The cap 2206 is connected to the pump 2210 by a tube 2209 and is configured to suck ink from the head cartridge 4000 covered by the cap 2206 by operating the pump 2210. In the middle of the cap 2206 and the pump 2210, another tube 2211 provided with an air communication valve 2212 is provided.

  The atmospheric communication valve 2212 is made of a rubber material or the like, and an atmospheric communication valve arm 2213 that can be brought into contact with and separated from the valve is provided around the shaft 2214 so as to be rotatable in the direction D in the drawing. When the air communication valve arm 2213 is brought into contact with the air communication valve 2212 and the pump 2210 is operated, ink is sucked from the head cartridge 4000. When the pump 2210 is operated with the air communication valve arm 2213 removed, even if the cap 2206 and the head cartridge 4000 are in contact with each other, ink is not sucked from the head cartridge 4000 and only the ink existing in the cap 2206 is present. Is sucked.

  The operations of these wiping means and suction recovery means in the discharge recovery device 2200 are performed by the PG motor 3022 and a predetermined drive switching means. Further, the air communication valve arm 2213 is operated by being transmitted from a discharge roller (not shown) via a conveyance motor 3021 and a predetermined gear train.

  Further, as a suction recovery means in the discharge recovery device 2200, a configuration that can be controlled to perform various suction methods by changing the operating condition of the pump 2210 is adopted. In this example, there are three types of suction modes. The first type is suction for recovery of discharge. The second type is ink tank replacement suction that causes the ink stored in the ink tank to continue with the ink in the ink flow path when the ink tank 4100 is remounted (replaced) on the head cartridge. . The third type is ink-filled suction that fills the interior of the carriage 2100 with a new head cartridge that is not filled with ink in the nozzles and ink flow path for the first time. In each of these modes, the amount of suction is changed by changing the suction operation time of the pump 2210 for suction. Note that the suction amount in each mode is set with a double suction amount for ink tank replacement suction and a triple suction amount for ink filling suction with reference to suction for ejection recovery.

  Next, FIG. 12 shows a block diagram of a control system in the recording apparatus 1000 of the present invention. Here, the control unit 100 includes a microprocessor unit (MPU) 101, a ROM 102 that stores a control program including processing procedures to be described later and various parameters, and a RAM 103 that temporarily stores recorded image data. In addition, a timer 104 and an input / output port 105 are provided for measuring the elapsed time since the suction pump installed in the suction means in the discharge recovery device 2200 is operated. Furthermore, a timer driving battery 106 for operating the timer 104 and a nonvolatile memory 107 (NVRAM) such as EPROM, EEPROM, FeRAM, etc. are provided for storing values measured by the timer 104. Since the timer 104 is backed up by the timer driving battery 106, the time is always measured regardless of whether the recording apparatus 1000 is turned on. The timer 104 is reset and started at a predetermined timing as will be described later, and measures the elapsed time since it is reset to 0 at that time.

  Also, recorded image data is input via the interface circuit 200 from a host computer (not shown) for generating an image signal to be sent to the recording apparatus 1000. The recording apparatus 1000 of this embodiment can be controlled not only through the host computer but also through the operation panel 300. Further, the presence / absence of a recording medium, the home position of the carriage 2100, the presence / absence of the head cartridge 4000, and the like are detected by various sensors 400. The power supply unit 500 supplies power to each unit. The ejection recovery device 2200 for the head cartridge 4000 performs capping and suction recovery for the ejection unit 4002 as described above. This suction recovery is performed when ink ejection from a plurality of nozzles in the head cartridge 4000 occurs. For example, the periphery of the plurality of ejection ports 4011 (see FIG. 8) is sealed by abutting the cap 2206 against the recording element substrate 4010 in the ejection unit 4002 provided in the head cartridge 4000. Then, by applying a negative pressure in the sealed space, the ink is sucked and discharged, and at the same time, the bubbles in the nozzle and the ink flow path and the dust adhering to the discharge periphery are removed.

  Next, a flow of suction operation control in the discharge recovery device 2200 mounted on the recording apparatus 1000 will be described.

  The recording apparatus 1000 to which the present invention is applied has a configuration in which the head cartridge 4000 can be replaced. Normally, when replacing the head cartridge 4000, the head cartridge mounted so far is removed from the carriage 2100, and then a new head cartridge is mounted on the carriage 2100. Therefore, when the head cartridge 4000 is replaced, there is no ink in the nozzle and the ink flow path, so it is necessary to first fill them with ink. As described above, the replacement of the head cartridge 4000 is performed by opening and closing the access cover 1003 in FIG. 4 and can detect the open / closed state in the recording apparatus 1000. However, the access cover 1003 is also opened and closed when the ink tank 4100 is replaced. For this reason, in order to recognize that the head cartridge 4000 has been replaced, it is necessary to detect whether or not the electrical connection between the carriage 2100 and the head cartridge 4000 has been disconnected simultaneously with the detection of the open / closed state. When these two detections are made, it is recognized that the head cartridge 4000 has been replaced.

  These operations will be described with reference to FIG. First, when the access cover 1003 is opened by the recording apparatus 1000 and it is detected that the access cover 1003 is opened by the operation of a micro switch (not shown), the sequence proceeds to the sequence shown in FIG. Here, the process first proceeds to step S101, and the contact state of the electrical contacts provided in each of the head cartridge 4000 and the carriage 2100 is investigated. For this purpose, the contact state between the contact portion 3010 on the contact flexible recording cable 3011 and the external signal input / output terminal 4031 of the head cartridge main body 4001 is checked. If the normal contact state is recognized, the process proceeds to step S104. If the non-contact state, that is, the electrical connection between both is recognized, the process proceeds to step S102.

  The state recognized as a normal contact state between the head cartridge 4000 and the carriage 2100 in the previous step S101 remains the head cartridge 4000 mounted on the carriage 2100 even when the access cover 1003 is opened. Therefore, in the next step S104, it is determined whether or not the access cover 1003 is closed. Here, when it is recognized that the access cover 1003 is not closed, that is, the access cover 1003 remains open, replacement of the head cartridge 4000 or the ink tank 4100 is scheduled after that point. It will be. Therefore, the process returns to step S101. Therefore, while the access cover 1003 is simply opened, it circulates between step S101 and step S104 and waits until the next operation is performed.

  On the other hand, after it is recognized that the electrical connection between the head cartridge 4000 and the carriage 2100 has been disconnected in step S101, that is, the head cartridge 4000 has been removed from the carriage 2100, and the process proceeds to step S102, the value of the variable N Set to 0. Here, the variable N is a variable indicating the timer suction execution history of the head cartridge 4000, and is incremented by 1 each time suction is performed, as will be described later. The value of the variable N is stored in the nonvolatile memory 107 every time it is updated. In the steps so far, the head cartridge 4000 is just removed from the carriage 2100, so that a new head cartridge is to be mounted after that. Therefore, after this, the process proceeds to step S103.

  In step S103, the contact state of the electrical contacts provided in each of the head cartridge 4000 and the carriage 2100 is checked again. If it is not touched, mounting of a new head cartridge is incomplete, so the process returns to step S102 and circulates between step S102 and step S103 until the contact state is recognized. If the contact of the electrical contact is recognized in step S103, it means that a new head cartridge has been attached, and the process proceeds to step S104. The contents in step S104 are as described above, and the process waits until the access cover 1003 is closed.

  In step S104, after it is recognized that the access cover 1003 is closed by the operation of a micro switch (not shown), the process proceeds to step S105. In order to return the recording apparatus 1000 to the normal state, the carriage 2100 is returned to the home position, and the process proceeds to step S106.

  In step S106, the variable N indicating the timer suction execution history of the head cartridge 4000 described above is referred to. Here, if N = 0, it means that the head cartridge has just been replaced with a new one, and the process proceeds to step S107 to perform ink filling suction. On the other hand, if N = 0 does not hold and a numerical value of 1 or more is stored, the recording head has not been replaced by opening / closing the access cover 1003, and the ink tank has been replaced. In S108, ink tank replacement suction is performed. Since any of these steps S107 and S108 is immediately after the suction operation, the process proceeds to step S109, and the value of T representing the elapsed time since the suction is performed is set to zero. Up to this point, the head cartridge is in a dischargeable state, and thus a series of processing ends. The contents of ink filling suction and ink tank replacement suction are the settings described in the explanation of the discharge recovery device. 1 is performed only when the access cover 1003 is opened. When the access cover 1003 is not opened, the above operation is not performed.

  Hereinafter, suction operation control by timer suction will be described. This control is based on the background described below.

  Until the recording device is used for the first image formation, the inner walls of the nozzle and the ink flow path may be scattered in a small amount of substances other than those constituent components. . Examples of the adhering substance include a small amount of residual ink after the inspection ink is filled after the recording head is manufactured and the ejection state is inspected and the inspection ink is removed. Furthermore, the substance which consists of solid content in the test ink which adhered after the volatile component in the residual test ink evaporated, or other impurities etc. are mentioned. When the ink is filled in the nozzle and the ink flow path in order to use the recording apparatus, it may be difficult to make the inside completely filled with ink due to the presence of these adhering substances.

  In particular, this is the case where the recording head portion is configured separately from the ink tank, such as the head cartridge main body 4001 of this example, and is replaceable on the carriage. Is more likely to occur. In this case, if the nozzle and ink flow path of the replacement head cartridge main body are filled with ink or a liquid similar thereto, and if the packaging form of the head cartridge main body is very highly sealed, the ink will be perfectly It is thought that filling is also possible. However, it is difficult to form the liquid filled in the head cartridge so that it does not evaporate at all inside the packaging material, and the cost is high, so the reality is very low.

  Further, in configuring the nozzle and the ink flow path, the members in which the nozzle and the ink flow path groove are formed are bonded, welded, or the like as in the joining form of the tank holder 4050 and the flow path forming member 4060 in this example. There is also a method in which the groove is formed into a tubular shape by joining together. In such a configuration, it is necessary to provide a portion for escaping and retaining the flow of excess adhesive or molten material on each joint surface of the members to be joined. Is heterogeneous. Accordingly, there may be a slight gap at the joint when viewed over the entire inner wall surface of the ink flow path. When the ink is filled, the gap has a high flow resistance, so that the ink does not sufficiently enter and can be a gas space.

  The above-described ink filling is usually performed by causing ink to flow by suction from an ejection port or pressurization from an ink storage unit. At that time, the inner wall portions of the nozzle and the ink flow path have a lower ink flow velocity than the vicinity of the center of the cross section in the ink flow direction of the nozzle and the ink flow path, that is, the so-called inside. Therefore, on the inner wall portion, there are places where the adhering substance hinders the ink from being sufficiently filled with ink, or places where air does not enter and remains in the gap between the joint portions. Although these portions are in a very minute range, the presence of a so-called ink-free portion also leads to minute bubbles remaining on the inner wall portion.

  In order to eliminate the ink-free portion at the time of filling the ink, it is conceivable to increase the flow velocity of the ink in the vicinity of the inner wall by increasing the pressure at the time of suction or pressurization. However, in this case, air may be taken in simultaneously with the ink from the ink storage side, so that the pressure cannot be raised excessively. Accordingly, there is an appropriate range for the pressure at the time of ink filling, and this can be said similarly as the suction pressure condition at the time of suction recovery.

  For this reason, in the initial stage of use of the recording apparatus, it is difficult to create a state in which the presence of bubbles is completely eliminated in the nozzles and ink flow paths, and it is inevitable that minute bubbles remain.

  However, even in the state in which such fine bubbles remain, with the passage of time thereafter, a part of the remaining bubbles dissolves in the ink, the remaining bubbles merge with each other, Phenomena such as coalescence with the permeated gas gradually occur. Moreover, if time passes in the state which the solid and the liquid contacted, the wettability of the liquid will improve in the interface. This also occurs on the inner walls of the nozzle and the ink flow path, and the bubbles remaining on the inner wall gradually become easier to separate from the inner wall as the wettability is improved.

  In any case, with the passage of time, a group of minute bubbles initially scattered on the inner wall becomes larger and further shifts to a state where it is easily separated from the inner wall. If the ink is forcibly discharged by suction recovery from such a state, it becomes easy to discharge the internal bubbles together with the ink. Therefore, if the ink is discharged after a certain period of time has elapsed since the ink was filled, the remaining bubbles are extremely less than when the ink was filled.

  From the above phenomenon, it is difficult to remove bubbles even after repeated suction recovery immediately after ink filling, but after a certain amount of time has passed, it is easy to remove bubbles even with a single suction recovery operation. I can say that. Furthermore, it was also found that after almost removing bubbles, the bubble growth rate in the ink thereafter tends to be very slow compared to the first time. That is, the timer suction time setting can be extended. In other words, after the suction recovery, the microbubbles that become the core of bubble growth almost disappear from the nozzles and the ink flow path. The time will be longer. The present invention utilizes these phenomena.

  Hereinafter, the suction operation control by the timer suction will be specifically described. As described above, the tendency that minute bubble groups remain on the nozzles in the head cartridge 4000 and the inner wall of the ink flow path gradually decreases as time passes and ink is discharged when suction is performed thereafter. Therefore, the threshold value of the set time in the timer suction can be increased according to the number of times of timer suction. That is, it is possible to lengthen the set time of the timer according to the number of times of timer suction. A method for controlling the operation of the suction recovery means provided in the discharge recovery device 2200 mounted on the recording apparatus 1000 based on such characteristics will be described. FIG. 2 shows a flowchart for explaining this control flow, and FIG. 3 shows a table to be referred to when the control is performed.

  When a recording image signal is sent to the recording apparatus 1000, the sequence proceeds to the sequence shown in FIG. 2 before ink ejection by the head cartridge 4000. Here, the process first proceeds to step S <b> 301, and the elapsed time T from the previous suction operation to the current time is acquired from the value stored in the nonvolatile memory 107. Thereafter, the process proceeds to step S302, where the previously acquired T value is compared with the timer suction set time TM. In this example, the initial setting value of timer suction is set to 120 hours, and this value is stored in the nonvolatile memory 107 as T0.

  If it is determined in step S302 that the value of T is smaller than the value of TM, it is determined that it is not necessary to perform suction during the current elapsed time, so this control is terminated and the normal recording operation is performed. On the other hand, when the value of T is the same as or exceeds the value of TM, bubble growth proceeds in the nozzle and ink flow path of the head cartridge 4000 over time, and normal ejection cannot be continued as it is. There is a need to perform suction recovery. Accordingly, the process proceeds to step S303, and the suction recovery operation is performed by sending an operation command to the pump 2210 for performing the suction operation. After the suction recovery operation is completed, the process proceeds to step S304.

  At this point, since it is immediately after the suction recovery is performed, it is necessary to update the value of N indicating the cumulative number of suction recovery and reset the elapsed time from the suction recovery. In step S304, first, the current value of N is acquired from the nonvolatile memory 107. In step S305, the obtained N value is updated by adding 1, and the updated N value is stored in the nonvolatile memory 107 again. Subsequently, the process proceeds to step S306, the elapsed time T after the suction recovery operation is performed is set to 0, and after storing in the nonvolatile memory 107, the process proceeds to step S307.

  In step S307, the table shown in FIG. 3 is referred to, and an increment DT with respect to the initial set time is obtained corresponding to the value of the cumulative number N of timer suctions updated in the previous step S305. For example, when N = 0, DT = 0 hours, when N = 8, DT = 72 hours, and when N = 30, DT = 120 hours. Then, after obtaining the DT, the process proceeds to step S308, and the value obtained by adding the determined DT value to the initial value of the timer suction setting time T0 (120 hours in this example) is newly updated as TM, and this control is performed. Exit.

  By performing such control, when the head cartridge 4000 is in an initial use state, the bubble growth in the nozzle and the ink flow path is relatively fast, so the timer suction time setting is relatively short. However, for the state where the use of the recording apparatus 1000 is continued and the bubble growth in the nozzle and the ink flow path is gradually slowing, it is appropriate according to the use history of the head cartridge 4000 until then. It is possible to set the time for a simple timer suction.

  In this embodiment, the remaining amount of ink in the ink tank is detected so that the ink in the ink flow path is always filled, and the ink tank can be replaced before the ink tank is completely emptied. An ink jet recording apparatus provided with ink remaining amount detecting means was used. For this reason, even if the ink tank in which the stored ink is consumed is replaced with a new ink tank, the state of the inner wall of the nozzle and the ink flow path does not change, so the above characteristics are maintained. Therefore, it is not necessary to return the timer suction time setting to the original value every time the ink tank is replaced.

  Further, the behavior of these bubbles can be directly confirmed by observing the inside of the nozzle and the ink flow path by using an X-ray CT apparatus.

  In the above-described embodiment, the recording apparatus has a configuration in which each nozzle row that discharges a plurality of colors of ink in one recording head is used as one discharge unit, and the one discharge unit is sucked using an integral cap. The example has been described. However, the present invention is not limited to this mode, and there are various types of recording apparatuses depending on the configuration of the recording head.

  When one recording head is configured to supply a plurality of ink types therein, an ink flow path corresponding to each ink is formed in a limited region within the configuration of the recording head. For this reason, the cross-sectional shape and length are often different for each ink flow path. In this way, if the cross-sectional shape and length differ for each ink flow path, the state of gas permeation and penetration into the ink filled in each ink flow path can change. Therefore, it is most preferable to set the time for timer suction for each ink flow path.

  In the recording apparatus configured to perform the suction recovery operation independently by contacting the cap with the corresponding area for each nozzle row having different ink, the nozzle can be used for the time extension change for the timer suction. Each column can be controlled independently. And since the setting of the first and second threshold values in this case, the setting of the increment with respect to the cumulative number of times of timer suction can be controlled independently for each nozzle row, by performing finer time setting, Unnecessary ink discharge and increase in recording time can be further prevented.

  In addition, using a recording head divided into two or more ejection parts for each color of ink to be ejected in one recording head, and further having a suction recovery cap for each ejection part, the suction recovery There is a recording apparatus configured to perform the operation independently for each discharge unit. In such a recording apparatus, it is possible to independently set a time setting for timer suction in each discharge unit. Therefore, it is possible to control each discharge unit independently for the time extension change for the timer suction. In this case, the setting of the first and second threshold values, the setting of the increment with respect to the cumulative number of times of timer suction, and the like can be controlled independently for each discharge unit. Even in this case, it is possible to set a fine time.

  On the other hand, when mounting a monochromatic recording head, it goes without saying that the present invention can be applied in the form of the above-described embodiment.

  Further, as a form of the recording head, the description has been given in the form of a cartridge that can be exchanged on the carriage. However, the present invention is not limited to this. Are applicable as well.

  In addition, in the above embodiment, a timer driving battery is incorporated in order to keep the timer operating in the recording device, but this time measurement is not limited to this method. The present invention can also be applied to a system that uses bidirectional communication between a recording apparatus and a host computer, reads the time of a clock built in the host computer, and stores it in a nonvolatile memory in the recording apparatus. The timing for reading the time of the clock built in the host computer includes when a recording signal is sent to the recording device, when timer suction is executed, and the like. If this method is used, the elapsed time is calculated from two values: the time when the recording signal is read and the time when the previous timer suction stored in the nonvolatile memory is executed. be able to. Further, according to this method, there is no need to measure the time in the recording apparatus, and there is an advantage that a battery for driving the timer is not necessary.

  In the above example, the explanation has been made in the case of the suction recovery operation as the forced flow recovery. However, the pressure recovery operation in which the ink is discharged by pressurizing the path for supplying the ink to the nozzle is applied. The present invention can be applied to an inkjet recording apparatus in the same manner.

  Furthermore, the present invention includes a recording apparatus of a type that includes means (for example, an electrothermal converter) that generates thermal energy as energy used to perform ink ejection, and causes a change in the state of ink by the thermal energy. It is preferable that This is because by using such a so-called thermal recording apparatus, it is possible to achieve higher recording density and higher definition. However, the present invention is not limited to a thermal recording apparatus.

  Further, as a form of the recording apparatus according to the present invention, a copying apparatus combined with a reader or the like, as well as a facsimile apparatus having a transmission / reception function, as an image output terminal of an information processing device such as a computer, are provided integrally or separately. It may take the form of

It is a flowchart which shows the process after detecting the presence or absence of replacement | exchange of the head cartridge of this invention. It is a flowchart which shows the attraction | suction operation control by the timer attraction | suction of this invention. It is a table referred in the Example of this invention. 1 is a perspective view illustrating an external configuration of an ink jet recording apparatus according to an embodiment of the present invention. It is a perspective view which shows the state which removed the exterior member of the recording device shown in FIG. It is a perspective view which shows the state which assembled the head cartridge used for the Example of this invention. FIG. 7 is a perspective view showing a state in which the ink tank in FIG. 6 is removed from the head cartridge body, with the top and bottom being reversed from FIG. 6. FIG. 7 is an exploded perspective view of the head cartridge in FIG. 6. FIG. 9 is a schematic plan view and a schematic cross-sectional view showing configurations of a recording element and an electrode wiring on the recording element substrate in FIG. 8. It is a perspective view which shows the one side part of the discharge recovery apparatus in the Example of this invention. It is a perspective view which shows the other side part of the discharge recovery apparatus shown in FIG. It is a block diagram of a control system in an ink jet recording apparatus to which the present invention is applied.

Explanation of symbols

100 Control Unit 101 Microprocessor Unit 102 ROM
103 RAM
104 Timer 105 Input / Output Port 106 Battery for Driving Timer 107 Nonvolatile Memory 200 Interface Circuit 300 Operation Panel 400 Sensor 500 Power Supply Unit 1000 Recording Device Main Body 2000 Recording Device Unit 2100 Carriage 2200 Discharge Recovery Device Unit 4000 Head Cartridge

Claims (4)

A carriage in which a recording head having a plurality of nozzles for ejecting ink and an ink tank for storing ink supplied to the recording head are detachably provided;
Recovery means for performing recovery operation of the recording head;
A recovery control means for causing the recovery means to perform a next recovery operation when an elapsed time from the previous recovery operation is equal to or greater than a threshold ;
Detecting means for detecting a remaining amount of ink in the ink tank in order to perform an ink tank replacement operation in a state where ink remains in the ink tank;
With
The recovery control means includes
An ink jet recording apparatus, wherein the threshold value is increased in accordance with the cumulative number of recovery operations, and the elapsed time is not initialized even when the ink tank is replaced. The recovery control means includes
If the recording head is replaced, the ink jet recording apparatus according to claim 1, characterized in that initializing the cumulative number. The recovery control means includes
Wherein when the recording head is replaced, in claim 1 or 2, characterized in that to perform suction a large amount of recovery operation than the recovery operation of when the elapsed time is equal to or greater than the threshold value to said recovery means The ink jet recording apparatus described. Inkjet recording apparatus comprising a carriage in which a recording head having a plurality of nozzles for ejecting ink, an ink tank for storing ink supplied to the recording head is detachable, and recovery means for performing recovery operation of the recording head Recovery method,
A step of causing the recovery means to perform a next recovery operation when an elapsed time from the previous recovery operation is equal to or greater than a threshold;
A detection step of detecting a remaining amount of ink in the ink tank in order to perform an ink tank replacement operation in a state where ink remains in the ink tank;
A step of increasing the threshold in accordance with the accumulated number of the recovery operation,
And a step of not initializing the elapsed time even if the ink tank is replaced.

Images