JP2005246640A - Liquid discharging head and its controlling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent liquid discharging failures of liquid discharging nozzles formed at a nozzle face by cleaning the nozzle face of a liquid discharging head of a liquid discharging apparatus. <P>SOLUTION: In an inkjet printer equipped with a printing head 2 for discharging liquid droplets from a plurality of ink discharging nozzles 18 formed at the nozzle face 17, a bubble removing means 23 for removing bubbles mixed with ink by discharging the ink in the printing head 2, and a cap member 11 for storing inside a cleaning member formed cylindrically by a material with an elasticity and also for protecting the nozzle face 17 of the printing head 2, the ink within the ink discharging nozzles 18 is sucked by moving the cleaning member with the outer circumferential face in contact with the nozzle face 17 by keeping the cap member 11 open after the bubbles collected in a common passage 20 of the printing head 2 are removed by the bubble removing means 23. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a liquid ejecting apparatus such as an ink jet printer and a control method thereof, and more specifically, after discharging liquid from the liquid ejecting head of the liquid ejecting apparatus and removing bubbles contained in the liquid, the liquid ejecting apparatus. The present invention relates to a liquid ejection apparatus and a control method therefor that prevent a liquid ejection failure of a liquid ejection nozzle formed on the nozzle surface by cleaning a nozzle surface of a head.

  Conventionally, various techniques have been proposed in order to prevent deterioration in print quality of a print image formed by an ink jet printer. As one of such techniques, there is a method of removing the dirt on the nozzle surface of the print head and the adhered ink droplets by wiping, and stabilizing the ejection recovery and ejection performance. For example, when dirt is attached to the nozzle surface of the print head, or when an ink pool is formed on the nozzle surface, the print quality of the print image may deteriorate. In particular, in the case of a color ink jet printer, when an ink reservoir having a color different from a predetermined ink enters from a nozzle, a color mixture occurs with the ink, and the color mixture ink is ejected at the time of printing, thereby degrading the image quality. For this reason, it is necessary to remove dirt and ink reservoirs from the liquid ejection surface of the nozzle sheet by wiping. This wiping is a technique in which the surface of the nozzle surface of the print head is rubbed with a rubber blade or the like to wipe off dirt around the nozzle and attached ink droplets. In recent years, a technique for wiping the nozzle surface of a nozzle sheet with a cleaning member such as a rubber blade or a cleaning roller to wipe off dirt around the nozzle and an ink reservoir attached to the nozzle sheet is known.

Specifically, by rotating a cleaning roller made of a porous elastic body in contact with the nozzle surface of the print head, the capillary force generated in the cells of the porous body is used to absorb the ink while absorbing the ink. Inkjet printers that improve the cleaning effect by wiping off and foreign matter are disclosed (for example, see Patent Document 1).
According to this ink jet printer, when the cleaning roller is elastically deformed and returns, a capillary force is generated in each cell of the porous body, so that dirt and foreign matter are wiped off while absorbing ink in the nozzle. can do. The cleaning effect can be improved by preventing reattachment of ink and foreign matters and scattering into the printer head.

  As another technique, the ink quality is reduced by sucking ink from the nozzle surface side of the print head by means of negative pressure generating means and discharging dust and bubbles contained in the ink in the print head together with the ink. There are ways to prevent it. That is, if bubbles are contained in the ink, the bubbles are carried to the print head and remain in the ink liquid chamber. As a result, ejection failure such as non-ejection or incomplete ejection of ink occurs, and print quality deteriorates. Therefore, it is necessary to remove bubbles contained in the ink as appropriate. Therefore, for example, by using a negative pressure generating means to suck ink from the liquid ejection surface side of the printer head, bubbles and dust in the ink liquid chamber are discharged together with the ink.

Specifically, an ink jet printer that includes a head cap that serves as a nozzle closing member and an ink pump and sucks ink with the ink pump is disclosed (for example, see Patent Document 2).
According to this ink jet printer, the nozzle face of the print head is covered with a head cap to be in an airtight state, and ink and ink are sucked from all the nozzles by using an ink pump, thereby forcibly discharging bubbles and dust together with the ink. it can. Therefore, bubbles and the like that cause ejection failure can be removed from the printer head.

  Furthermore, the print quality is also degraded by nozzle clogging and the presence of impurities in the nozzle. Therefore, it is necessary to prevent clogging of nozzles that are not frequently used or to discharge impurities in the nozzles. Therefore, preliminary ejection that ejects ink completely at a predetermined time interval and ejects ink completely independent of printing by ejecting ink that is not intended for printing or by pressing the recovery button etc. by the user as necessary. The technology is known. In general, the preliminary ejection is performed in combination with the above-described bubble removal and cleaning when the power is turned on or during the printing operation, thereby further stabilizing ink ejection.

Furthermore, with regard to the timing for performing cleaning and preliminary ejection, for example, a technology configured to execute an optimal cleaning operation according to, for example, the ink tank loading mode and the elapsed time after performing the recovery operation of the printer head (For example, refer to Patent Document 3) and a technique (for example, refer to Patent Document 4) that enables various maintenance of a printer head at a timing requested by a user.
JP-A-4-185450 JP 2000-85153 A JP 2001-239679 A JP 7-125225 A

  However, when the above-described cleaning method is applied to a line head type ink jet printer, the nozzle surface of the print head cannot be sufficiently cleaned, and the print quality may deteriorate due to poor liquid ejection. For example, when the technique described in Patent Document 2 is applied, it is necessary to seal the periphery of the nozzle with a head cap so that ink containing bubbles can be sucked from each nozzle formed on the nozzle surface. Therefore, there is a problem that the structure is complicated and productivity and economy are deteriorated. Further, if the sealed state by the head cap is insufficient, there is a problem that ink leaks to the outside.

In particular, in the case of a line head type printer that forms a line corresponding to the print width, the nozzle formation range is very wide compared to a serial type printer that performs printing by moving the head. For this reason, the head cap serving as a nozzle closing member is enlarged, which not only increases structural problems, but it is actually very difficult to seal the periphery of the nozzle surface so that ink leakage does not occur.
Even if the periphery of the nozzle surface can be sealed with the head cap, in the case of a line head in which a large number of nozzles are formed on the nozzle surface, the difference in flow path resistance becomes very large depending on the presence or absence of bubbles. There arises a problem that suction cannot be performed with uniform pressure. That is, for the air bubbles that have entered each ink chamber in the print head before the ink suction operation, the flow path resistance in the ink chamber increases, and the ink flow due to the suction cannot be taken. There was a stagnation. For this reason, there is a problem that ejection failure occurs because the air bubbles in each nozzle are not removed and all the nozzles cannot be filled with ink.

Furthermore, in order to stably eject ink and prevent deterioration in print quality, it is effective to combine the various techniques described above. However, in the technique described in Patent Document 2, a head cap is used. Since the nozzle surface of the print head is covered, the cleaning technique as described in Patent Document 1 and the preliminary ejection technique cannot be smoothly combined.
Furthermore, the head cap may get in the way when cleaning or the like is performed at the timing described in Patent Document 3 and Patent Document 4 described above.

  In addition, the applicant of the present application has disclosed a plurality of directions for ejecting ink droplets ejected from the nozzle according to Japanese Patent Application Nos. 2003-37343, 2002-360408, and 2003-55236, which are undisclosed prior application technologies. We have already proposed a technology that enables high-quality printing by making it variable. As described above, when using a technique for positively changing the ejection direction of the ink droplets ejected from the nozzle, it is particularly required that the ejection stability of the ink droplets be excellent.

In addition, the present applicant generates negative pressure in the ink flow path according to Japanese Patent Application Nos. 2003-364939, 2003-364940, 2003-364944, and 2003-364944, which are undisclosed prior application technologies. In addition, there has already been proposed a technique for removing bubbles contained in ink while preventing ink leakage from the nozzles during circulation by circulating ink in the ink flow path between the ink tanks.
However, air bubbles that have entered the ink liquid chamber before ink circulation are removed by stagnating in the ink liquid chamber because the flow path resistance in the ink liquid chamber is large and the side wall of the ink liquid chamber becomes an obstacle. There are also things you can't do. Therefore, there is room for further improvement in order to prevent a decrease in print quality.

  Therefore, the present invention addresses such problems, and after discharging the liquid from the liquid discharge head of the liquid discharge apparatus and removing bubbles contained in the liquid, the nozzle surface of the liquid discharge head is cleaned. Accordingly, an object of the present invention is to provide a liquid ejection apparatus and a control method therefor that prevent a liquid ejection failure of a liquid ejection nozzle formed on the nozzle surface.

  In order to achieve the above object, a liquid ejection apparatus according to the present invention includes a plurality of liquid ejection nozzles arranged side by side on a nozzle surface, and liquid ejection means in each liquid chamber provided corresponding to each liquid ejection nozzle. A liquid discharge head that replenishes liquid into each liquid chamber from a common flow path serving as a predetermined liquid supply path, drives the liquid discharge means to discharge liquid droplets from the liquid discharge nozzle, and the liquid Connected to the common flow path of the discharge head and formed in a cylindrical shape with an elastic material and bubble removing means for removing bubbles mixed in the liquid from the common flow path by discharging the liquid in the common flow path A cleaning member, a moving means for relatively moving the cleaning member in a state where the outer peripheral surface of the cleaning member is in contact with the nozzle surface of the liquid discharge head, and a drive control for controlling the driving of the moving means In the liquid ejection apparatus comprising the step, after the bubbles accumulated in the common flow path of the liquid ejection head are removed by the bubble removal means, the moving means is driven under the control of the drive control means, The liquid in the liquid discharge nozzle is sucked by moving the outer peripheral surface of the cleaning member in contact with the nozzle surface.

  With such a configuration, after the bubbles accumulated in the common flow path of the liquid discharge head are removed by the bubble removing means, the moving means is driven by the control of the drive control means, and the outer periphery of the cleaning member The liquid in the liquid discharge nozzle is sucked by moving the surface in contact with the nozzle surface.

  Further, another liquid discharge apparatus according to the present invention includes a plurality of liquid discharge nozzles formed side by side on a nozzle surface, and includes liquid discharge means in each liquid chamber provided corresponding to each liquid discharge nozzle, A liquid discharge head that replenishes liquid into each of the liquid chambers from a common flow path serving as a liquid supply path and drives the liquid discharge means to discharge liquid droplets from the liquid discharge nozzle. A bubble removing means connected to the flow path to remove bubbles mixed in the liquid by discharging the liquid in the common flow path, and a cleaning member formed in a cylindrical shape with an elastic material A cap member that houses the cleaning member and protects the nozzle surface of the liquid ejection head, and opens and closes the cap member and opens the cap member as described above. A liquid comprising: a cap opening / closing means for relatively moving the outer peripheral surface of the leaning member in contact with the nozzle surface of the liquid discharge head; and a drive control means for controlling the drive of the cap opening / closing means. In the ejection device, after the bubbles accumulated in the common flow path of the liquid ejection head are removed by the bubble removal means, the cap opening / closing means is driven by the control of the drive control means to open the cap member. Sometimes, the liquid in the liquid discharge nozzle is sucked by moving the outer peripheral surface of the cleaning member in contact with the nozzle surface.

  With such a configuration, after the bubbles accumulated in the common flow path of the liquid discharge head are removed by the bubble removing means, the cap opening / closing means is driven under the control of the drive control means to open the cap member. However, the liquid in the liquid discharge nozzle is sucked by moving the outer peripheral surface of the cleaning member in contact with the nozzle surface.

  The control method of the liquid discharge apparatus according to the present invention includes a plurality of liquid discharge nozzles formed side by side on the nozzle surface, and liquid discharge means provided in each liquid chamber provided corresponding to each liquid discharge nozzle, A liquid discharge head that replenishes liquid into each liquid chamber from a common flow path serving as a predetermined liquid supply path, drives the liquid discharge means to discharge liquid droplets from the liquid discharge nozzle, and the liquid discharge head of the liquid discharge head A bubble removing means connected to the common channel and removing the bubbles mixed in the liquid by discharging the liquid in the common channel, and a cleaning formed in a cylindrical shape with an elastic material A member, a moving unit that relatively moves the outer peripheral surface of the cleaning member in contact with the nozzle surface of the liquid discharge head, and a drive control unit that controls the driving of the moving unit. In the control method of the liquid ejection device for ejecting liquid droplets from the liquid ejection nozzle of the liquid ejection head, the drive control is performed after the bubbles accumulated in the common flow path of the liquid ejection head are removed by the bubble removal means. The moving means is driven under the control of the means, and the outer peripheral surface of the cleaning member is brought into contact with the nozzle surface and moved so as to suck the liquid in the liquid discharge nozzle.

  By carrying out such a method, after the bubbles accumulated in the common flow path of the liquid discharge head are removed by the bubble removing means, the moving means is driven under the control of the drive control means, and the cleaning member The liquid in the liquid discharge nozzle is sucked by moving the outer peripheral surface of the liquid in contact with the nozzle surface.

  In another liquid ejection apparatus control method according to the present invention, a plurality of liquid ejection nozzles are formed side by side on a nozzle surface, and liquid ejection means is provided in each liquid chamber provided corresponding to each liquid ejection nozzle. A liquid discharge head that replenishes liquid into each liquid chamber from a common flow path serving as a predetermined liquid supply path, drives the liquid discharge means to discharge liquid droplets from the liquid discharge nozzle, and the liquid discharge head It is connected to the common flow path of the head, and is formed in a cylindrical shape with an elastic material and bubble removing means for removing bubbles mixed in the liquid from the common flow path by discharging the liquid in the common flow path. A cleaning member, a cap member that houses the cleaning member and protects the nozzle surface of the liquid discharge head, and an operation for opening and closing the cap member and opening the cap member Accordingly, a cap opening / closing means for relatively moving the cleaning member in a state where the outer peripheral surface of the cleaning member is in contact with the nozzle surface of the liquid discharge head, and a drive control means for controlling the drive of the cap opening / closing means. And a control method of a liquid discharge apparatus that discharges liquid droplets from a liquid discharge nozzle of the liquid discharge head, and the drive control is performed after air bubbles accumulated in the common flow path of the liquid discharge head are removed by the bubble removing means. Under the control of the means, the cap opening / closing means is driven to open the cap member, and at this time, the outer peripheral surface of the cleaning member is brought into contact with the nozzle surface and moved to suck the liquid in the liquid discharge nozzle. To control.

  By carrying out such a method, after the bubbles accumulated in the common flow path of the liquid discharge head are removed by the bubble removing means, the cap opening / closing means is driven by the control of the drive control means, and the cap member By moving the outer peripheral surface of the cleaning member in contact with the nozzle surface while opening the liquid, the liquid in the liquid discharge nozzle is sucked.

  According to the liquid ejecting apparatus of the first aspect, the bubbles accumulated in the liquid ejecting head are first removed by the bubble removing means for discharging the liquid in the liquid ejecting head, and then the outer peripheral surface of the cleaning member is placed on the liquid surface. The moving member that relatively moves both of them in contact with the nozzle surface of the discharge head is driven, and the liquid in the liquid discharge nozzle can be sucked by the cleaning member. Thereby, it is possible to remove bubbles contained in the liquid in the liquid discharge head and prevent the discharge failure of the liquid discharge nozzle. Therefore, the ejection failure of the liquid ejection head can be eliminated and the image quality can be improved. Further, since the bubbles in the liquid in the liquid discharge head are discharged by the bubble removing means, the bubbles can be removed without flowing out the liquid from the liquid discharge nozzle, and the nozzle surface is not contaminated with the liquid. be able to. Furthermore, the mechanism for sucking the negative pressure of the liquid in the liquid discharge head can have a simple configuration, and the size of the entire apparatus can be prevented from being increased.

  According to the second aspect of the present invention, the cleaning member rotates in contact with the nozzle surface of the liquid discharge head and cleans the nozzle surface while sucking deposits. Thus, the nozzle surface can be cleaned while sucking the deposits on the nozzle surface of the liquid discharge head. Therefore, the ejection failure of the liquid ejection head can be eliminated and the image quality can be improved.

  According to the invention of claim 3, the cleaning member is formed of a liquid absorbent material impregnated with a surfactant solution, so that the cleaning member can be impregnated with the surfactant solution. it can. Therefore, by moving the outer peripheral surface of the cleaning member in contact with the nozzle surface, it is possible to form a surfactant film on the nozzle surface and clean the nozzle surface.

  Further, according to the invention according to claim 4, the bubble removing means is provided on the circulation flow path for circulating the liquid discharged from the common flow path of the liquid discharge head, whereby the liquid discharge head of the liquid discharge head is provided. The liquid discharged from the common flow path can be circulated and reused. Thereby, wasteful consumption of the liquid in the liquid discharge head can be suppressed, and bubbles accumulated in the common flow path of the liquid discharge head can be appropriately removed. Therefore, it is possible to greatly improve the reliability of liquid ejection.

  Furthermore, according to the invention of claim 5, the bubble removing means applies a pressure smaller than the capillary pressure of the meniscus to the liquid meniscus in the liquid discharge nozzle formed on the nozzle surface of the liquid discharge head. When the operation of removing bubbles contained in the liquid in the liquid discharge head is performed, the liquid discharge in the common flow path of the liquid discharge head is performed. It is possible to prevent air bubbles from being mixed into the common flow path by sucking air from the nozzle. Therefore, it is possible to reliably remove bubbles in the liquid in the liquid discharge head and prevent discharge failure of the liquid discharge nozzle.

  According to the invention of claim 6, the liquid discharge head drives the liquid discharge means separately from the liquid discharge to the discharge target, and preliminarily discharges the liquid droplets from the liquid discharge nozzle, The liquid discharge stability of the liquid discharge nozzle can be improved.

  According to another liquid ejecting apparatus of the present invention, the air bubbles accumulated in the liquid ejecting head are first removed by the air bubble removing means for discharging the liquid in the liquid ejecting head, and then the cap opening / closing means is installed. By driving and moving the outer peripheral surface of the cleaning member in contact with the nozzle surface while opening the cap member, the liquid in the liquid discharge nozzle can be sucked. Thereby, it is possible to remove bubbles contained in the liquid in the liquid discharge head and prevent the discharge failure of the liquid discharge nozzle. Therefore, the ejection failure of the liquid ejection head can be eliminated and the image quality can be improved. Further, since the bubbles in the liquid in the liquid discharge head are discharged by the bubble removing means, the bubbles can be removed without flowing out the liquid from the liquid discharge nozzle, and the nozzle surface is not contaminated with the liquid. be able to. Furthermore, the mechanism for sucking the negative pressure of the liquid in the liquid discharge head can have a simple configuration, and the size of the entire apparatus can be prevented from being increased. Furthermore, since the nozzle surface is cleaned by the cleaning member while opening the cap member after the bubble removing operation by the bubble removing means, the ink adhering to the cap member does not reattach to the nozzle surface, and liquid Since the exposure time of the discharge nozzle is minimized, clogging and sticking due to drying and deterioration of the liquid can be reduced.

  According to the invention of claim 8, the cleaning member rotates in contact with the nozzle surface of the liquid discharge head, and cleans the nozzle surface while sucking deposits. Thus, the nozzle surface can be cleaned while sucking the deposits on the nozzle surface of the liquid discharge head. Therefore, the ejection failure of the liquid ejection head can be eliminated and the image quality can be improved.

  According to a ninth aspect of the present invention, the cleaning member is made of a liquid absorbent material impregnated with a surfactant solution, so that the cleaning member can be impregnated with the surfactant solution. it can. Therefore, by moving the outer peripheral surface of the cleaning member in contact with the nozzle surface, it is possible to form a surfactant film on the nozzle surface and clean the nozzle surface.

  Further, according to the invention of claim 10, the bubble removing means is provided on the circulation flow path for circulating the liquid discharged from the common flow path of the liquid discharge head. The liquid discharged from the common flow path can be circulated and reused. Thereby, wasteful consumption of the liquid in the liquid discharge head can be suppressed, and bubbles accumulated in the common flow path of the liquid discharge head can be appropriately removed. Therefore, it is possible to greatly improve the reliability of liquid ejection.

  According to the eleventh aspect of the present invention, the bubble removing means applies a pressure smaller than the capillary pressure of the meniscus to the liquid meniscus in the liquid discharge nozzle formed on the nozzle surface of the liquid discharge head. When the operation of removing bubbles contained in the liquid in the liquid discharge head is performed, the liquid discharge in the common flow path of the liquid discharge head is performed. It is possible to prevent air bubbles from being mixed into the common flow path by sucking air from the nozzle. Therefore, it is possible to reliably remove bubbles in the liquid in the liquid discharge head and prevent discharge failure of the liquid discharge nozzle.

  According to the invention of claim 12, the liquid discharge head drives the liquid discharge means separately from the liquid discharge to the discharge target, and preliminarily discharges the liquid droplets from the liquid discharge nozzle, The liquid discharge stability of the liquid discharge nozzle can be improved.

  According to the control method of the liquid ejection device according to the thirteenth aspect, first, the bubbles accumulated in the liquid ejection head are removed by the bubble removing means for discharging the liquid in the liquid ejection head, and then the outer periphery of the cleaning member is removed. The liquid in the liquid discharge nozzle can be sucked by the cleaning member by driving a moving means that relatively moves both surfaces in contact with the nozzle surface of the liquid discharge head. Thereby, it is possible to remove bubbles contained in the liquid in the liquid discharge head and prevent the discharge failure of the liquid discharge nozzle. Therefore, the ejection failure of the liquid ejection head can be eliminated and the image quality can be improved. Further, since the bubbles in the liquid in the liquid discharge head are discharged by the bubble removing means, the bubbles can be removed without flowing out the liquid from the liquid discharge nozzle, and the nozzle surface is not contaminated with the liquid. be able to.

  According to the invention of claim 14, the cleaning member rotates in contact with the nozzle surface of the liquid discharge head, and cleans the nozzle surface while sucking deposits. Thus, the nozzle surface can be cleaned while sucking the deposits on the nozzle surface of the liquid discharge head. Therefore, the ejection failure of the liquid ejection head can be eliminated and the image quality can be improved.

  According to the invention of claim 15, the cleaning member is made of a liquid absorbent material impregnated with a surfactant solution, so that the cleaning member can be impregnated with the surfactant solution. it can. Therefore, by moving the outer peripheral surface of the cleaning member in contact with the nozzle surface, it is possible to form a surfactant film on the nozzle surface and clean the nozzle surface.

  According to the sixteenth aspect of the present invention, the bubble removing means is provided on the circulation flow path for circulating the liquid discharged from the common flow path of the liquid discharge head. The liquid discharged from the common flow path can be circulated and reused. Thereby, wasteful consumption of the liquid in the liquid discharge head can be suppressed, and bubbles accumulated in the common flow path of the liquid discharge head can be appropriately removed. Therefore, it is possible to greatly improve the reliability of liquid ejection.

  Further, according to the invention of claim 17, the bubble removing means applies a pressure smaller than the capillary pressure of the meniscus to the liquid meniscus in the liquid discharge nozzle formed on the nozzle surface of the liquid discharge head. When the operation of removing bubbles contained in the liquid in the liquid discharge head is performed, the liquid discharge in the common flow path of the liquid discharge head is performed. It is possible to prevent air bubbles from being mixed into the common flow path by sucking air from the nozzle. Therefore, it is possible to reliably remove bubbles in the liquid in the liquid discharge head and prevent discharge failure of the liquid discharge nozzle.

  According to the invention of claim 18, the liquid discharge head drives the liquid discharge means separately from the liquid discharge to the discharge target, and preliminarily discharges the liquid droplets from the liquid discharge nozzle, The liquid discharge stability of the liquid discharge nozzle can be improved.

  According to another control method for a liquid ejection apparatus according to claim 19, first, the bubbles accumulated in the liquid ejection head are removed by the bubble removal means for discharging the liquid in the liquid ejection head, and then the cap is removed. The liquid in the liquid discharge nozzle can be sucked by driving the opening / closing means and moving the outer peripheral surface of the cleaning member in contact with the nozzle surface while opening the cap member. Thereby, it is possible to remove bubbles contained in the liquid in the liquid discharge head and prevent the discharge failure of the liquid discharge nozzle. Therefore, the ejection failure of the liquid ejection head can be eliminated and the image quality can be improved. Further, since the bubbles in the liquid in the liquid discharge head are discharged by the bubble removing means, the bubbles can be removed without flowing out the liquid from the liquid discharge nozzle, and the nozzle surface is not contaminated with the liquid. be able to. Furthermore, the mechanism for sucking the negative pressure of the liquid in the liquid discharge head can have a simple configuration, and the size of the entire apparatus can be prevented from being increased. Furthermore, since the nozzle surface is cleaned by the cleaning member while opening the cap member after the bubble removing operation by the bubble removing means, the ink adhering to the cap member does not reattach to the nozzle surface, and liquid Since the exposure time of the discharge nozzle is minimized, clogging and sticking due to drying and deterioration of the liquid can be reduced.

  According to the twentieth aspect of the present invention, the cleaning member rotates in contact with the nozzle surface of the liquid ejection head and cleans the nozzle surface while sucking deposits. Thus, the nozzle surface can be cleaned while sucking the deposits on the nozzle surface of the liquid discharge head. Therefore, the ejection failure of the liquid ejection head can be eliminated and the image quality can be improved.

  According to the invention of claim 21, the cleaning member is made of a liquid absorbent material impregnated with a surfactant solution, so that the cleaning member can be impregnated with the surfactant solution. it can. Therefore, by moving the outer peripheral surface of the cleaning member in contact with the nozzle surface, it is possible to form a surfactant film on the nozzle surface and clean the nozzle surface.

  According to a twenty-second aspect of the present invention, the bubble removing means is provided on the circulation flow path for circulating the liquid discharged from the common flow path of the liquid discharge head. The liquid discharged from the common flow path can be circulated and reused. Thereby, wasteful consumption of the liquid in the liquid discharge head can be suppressed, and bubbles accumulated in the common flow path of the liquid discharge head can be appropriately removed. Therefore, it is possible to greatly improve the reliability of liquid ejection.

  Further, according to the invention of claim 23, the bubble removing means applies a pressure smaller than the capillary pressure of the meniscus to the liquid meniscus in the liquid discharge nozzle formed on the nozzle surface of the liquid discharge head. When the operation of removing bubbles contained in the liquid in the liquid discharge head is performed, the liquid discharge in the common flow path of the liquid discharge head is performed. It is possible to prevent air bubbles from being mixed into the common flow path by sucking air from the nozzle. Therefore, it is possible to reliably remove bubbles in the liquid in the liquid discharge head and prevent discharge failure of the liquid discharge nozzle.

  According to the invention of claim 24, the liquid discharge head drives the liquid discharge means separately from the liquid discharge to the discharge target, and preliminarily discharges the liquid droplets from the liquid discharge nozzle, The liquid discharge stability of the liquid discharge nozzle can be improved.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing an embodiment of an ink jet printer as an example of liquid ejection according to the present invention. This ink jet printer includes a line type print head 2 in which, for example, ink discharge nozzles corresponding to the print width are formed inside the printer main body 1, and is compatible with A4 size color. As shown in FIG. 1, the print head 2 is provided with an ink tank 4 for containing ink, and ink tanks 4y, 4m, 4c, four colors of yellow, cyan, magenta, and black corresponding to color printing. 4k is detachable to it.

  Here, the print head 2 ejects four colors of ink from the ink ejection nozzles. That is, as shown in FIG. 2, a plurality of head chips 19 are arranged on the inner surface of the nozzle sheet 17, and ink is supplied from the four ink tanks 4. Each ink tank 4 is filled with ink of four colors, Y (yellow), M (magenta), C (cyan), and K (black). To a head chip through a liquid flow path (not shown). Each ink tank 4 is detachable from the print head 2.

  Further, a head cap unit 11 (corresponding to a cap member of the present invention) is attached to the print head 2. The head cap unit 11 is disposed outside the nozzle sheet 17 to protect the nozzle surface that ejects ink, and has a shallow box shape with an upper surface opened. And it moves to the left-right direction of FIG. 1 and a direction parallel to the nozzle sheet | seat 17 by moving means, such as a motor, and when moving to the left direction of FIG. 1, the nozzle surface of the nozzle sheet | seat 17 is protected. The head cap unit 11 can be detached from the print head 2 while moving in the right direction in FIG. 1, and is attached to the print head 2 again in the state returned in the left direction in FIG.

  In order to print with the ink jet printer of this embodiment shown in FIG. 1, first, the head cap unit 11 is moved in the right direction of FIG. 1 to open the nozzle surface of the nozzle sheet 17. Then, the printing paper is conveyed from the paper feed tray. Subsequently, based on the printing information, ink droplets of four colors are appropriately ejected from the nozzles of the nozzle sheet 17 while precisely feeding the printing paper below the print head 2. Then, characters, images and the like are printed in color on the photographic paper.

  On the other hand, while the ink jet printer is stopped, the head cap unit 11 moves to the left in FIG. 1 and closes so as to cover the entire nozzle surface of the nozzle sheet 17. As a result, the nozzle surface of the nozzle sheet 17 is protected, dust is not attached or scratched, and the nozzle is prevented from being dried or clogged.

  Further, a cleaning roller 31 (corresponding to the cleaning member of the present invention) is accommodated in the head cap unit 11 (see FIG. 1B). The cleaning roller 31 is made of a porous body (for example, urethane-based or polyethylene-based sponge) having a circular cross section and capable of elastic deformation, and is attached in parallel to the longitudinal direction of the nozzle sheet 17. When the head cap unit 11 moves to the right in FIG. 1 to open the nozzle surface of the nozzle sheet 17, the cleaning roller 31 rotates while being in contact with the nozzle surface of the nozzle sheet 17 with an appropriate pressure. Therefore, the ink and dirt adhering to the nozzle sheet 17 are wiped and removed by the cleaning roller 31.

  If the cleaning roller 31 is impregnated with a surfactant, the ink becomes familiar and easily absorbed, so the cleaning effect is further improved. Further, the cleaning roller 31 may be fixed to the head cap unit 11 so as not to rotate, or may be rotated while being restricted by a brake mechanism or the like and rubbing the nozzle sheet 17.

  As described above, in the print head 2 of the ink jet printer shown in FIG. 1, the cleaning roller 31 is accommodated in the head cap unit 11, and this constitutes a cleaning means. The head cap unit 11 prevents dust from adhering to the nozzle surface of the nozzle sheet 17 and scratches, and the cleaning roller 31 in the head cap unit 11 wipes and removes ink and dirt adhering to the nozzle sheet 17. .

  FIG. 2 is an exploded perspective view of the print head 2 of the ink jet printer shown in FIG. 1, and is a view seen from the front side of the printer body 1 (the right side of FIG. 1). As shown in FIG. 2, the print head 2 is formed by arranging a plurality of head chips 19 side by side in a staggered manner and bonding the lower portions of these head chips 19 to the inner surface side of one nozzle sheet 17. The Here, each ink discharge nozzle 18 formed on the nozzle sheet 17 is in a position corresponding to each ink liquid chamber (not shown) of all the head chips 19, and the interval between each ink discharge nozzle 18 is All are evenly spaced, including the staggered adjacent parts.

  Further, there are four rows of head chips 19 arranged in a staggered pattern, and each row is arranged inside the accommodating space 16 a of the head frame 16. A common flow path member (not shown) is attached to each of the rows in the receiving space 16a of the head frame 16 on the back surface of the head chip 19, and four ink tanks 4 (see FIG. 1). Thus, different colors of ink are supplied to each column of the head chips 19.

  Here, the head frame 16 is a support member attached to the upper surface of the nozzle sheet 17, and gives rigidity to the wide nozzle sheet 17 corresponding to the A4 size. The head frame 16 has a thickness of about 5 mm and a size corresponding to the nozzle sheet 17. The length of each storage space 16 a in each row of each head chip 19 is the A4 size horizontal width (about 21 cm). To match. A head cap unit 11 that covers the entire nozzle surface of the nozzle sheet 17 is disposed below the nozzle sheet 17 and reciprocates in the direction of the arrow.

  As described above, in the print head 2 shown in FIG. 2, each ink liquid chamber in each row of the head chips 19 corresponds to each ink discharge nozzle 18 formed in one nozzle sheet 17. Then, the ink in each ink liquid chamber is ejected from the respective ink ejection nozzles 18 as ink droplets by the heating resistors arranged in the head chip 19, and characters, images, etc. are printed in color on A4 size photographic paper. The

  3 is an enlarged view of the periphery of the ink chamber 12 of the print head 2 shown in FIG. 2, FIG. 3 (a) is a perspective view thereof, and FIG. 3 (b) is a sectional view thereof. As shown in FIG. 3, on the substrate of the head chip 19, a plurality of heating resistors 13 are arranged in one direction at regular intervals. In addition, ink discharge nozzles 18 are formed on the nozzle sheet 17 at positions corresponding to the respective heating resistors 13. A barrier layer 15 is laminated between the head chip 19 and the nozzle sheet 17.

  Here, the substrate constituting the head chip 19 is a semiconductor substrate made of silicon, glass, ceramics or the like. The heating resistor 13 is deposited on one surface of the substrate using a fine processing technique for manufacturing semiconductors and electronic devices. The heating resistor 13 is electrically connected to an external circuit through a conductor portion (not shown) formed on the substrate.

  The barrier layer 15 is formed on the side of the heating resistor 13 of the substrate constituting the head chip 19. That is, the barrier layer 15 has a wavelength of radiation that is optimal for exposing the photosensitive resin through a photomask in which a photosensitive resin is applied to the entire upper surface of the substrate and a pattern having an appropriate shape is drawn. After the exposure by the exposure machine, the exposed photosensitive resin layer is developed with a predetermined developer, and the unexposed portion is removed to form a pattern on the substrate excluding the periphery of the heating resistor 13.

  Further, the nozzle sheet 17 is formed by, for example, an electroforming technique using Ni (nickel), and a plurality of ink discharge nozzles 18 are arranged side by side on the nozzle sheet 17. As shown in FIG. 3, the head chip 19 having the barrier layer 15 stacked thereon is arranged so that the position of each ink discharge nozzle 18 matches the position of each heating resistor 13, that is, each ink discharge nozzle 18 has each Positioning is made precisely so as to face the heating resistor 13, and it is arranged on the nozzle sheet 17 with the barrier layer 15 facing down.

  Therefore, as shown in FIG. 3A, the ink liquid chamber 12 is composed of the substrate of the head chip 19, the barrier layer 15, and the nozzle sheet 17 so as to surround the heating resistor 13 as the liquid discharge means. The That is, the substrate of the head chip 19 and the heating resistor 13 constitute the upper wall of the ink liquid chamber 12 in FIG. 3A, and the barrier layer 15 constitutes the three lateral walls of the ink liquid chamber 12, and the nozzle The sheet 17 constitutes the lower wall of the ink liquid chamber 12.

  In addition, the ink liquid chamber 12 has an opening region in the lower right direction in FIG. 3A, and this opening region communicates with the common ink flow path 21. That is, as shown in FIG. 3B, a common flow path member 20 is disposed on the upper side of the head chip 19, and the common ink flow path 21 formed by the common flow path member 20 is used for all ink liquids. It communicates with the chamber 12. Therefore, the ink in the ink tank (not shown) flows through the common ink flow path 21 and is supplied to all the ink liquid chambers 12.

  When the ink liquid chamber 12 is filled with ink and a pulse current is passed through the heating resistor 13 for a short time, for example, 1 to 3 μsec, according to a command from a control means (not shown), the heating resistance The body 13 is heated rapidly. As a result, a gas phase ink bubble is generated at a portion in contact with the heating resistor 13, and a predetermined volume of ink is pushed away by the expansion of the ink bubble (the ink boils). Then, this becomes a discharge pressure, and a very small amount (for example, several picoliters) of ink equivalent to the pushed-off ink is discharged from the ink discharge nozzle 18 as ink droplets and landed on the photographic paper.

  Since the print head 2 of the inkjet printer described above is compatible with A4 size full color, the ink liquid chamber 12, the heating resistor 13, and the ink discharge nozzle 18 correspond to the A4 size print width for each color. There are as many as you want. However, all the ink liquid chambers 12 containing the same color ink communicate with each other through a common ink channel 21 (corresponding to the common channel of the present invention) formed by the common channel member 20.

  FIG. 4 is a perspective view showing a state in which bubbles b and inks of different colors are mixed around the ink liquid chamber 12 shown in FIG. As described above, the ink is supplied from the ink flow path 21 to the ink liquid chamber 12. If the ink in the ink flow path 21 includes the bubble b, the bubble b is an opening region of the ink liquid chamber 12. Or may enter the ink liquid chamber 12. In addition, fine ink mist scattered inside the printer main body 1 (see FIG. 1), ink overflowing from the ink discharge nozzles 18 and ink mist accumulate and adhere to the back surface of the nozzle sheet 17, thereby forming an ink pool. Then, an ink reservoir may enter the ink liquid chamber 12 from the ink discharge nozzle 18 while the ink jet printer is waiting or being left.

  As shown in FIG. 4, if the bubbles b stay in the opening area of the ink liquid chamber 12, the ink flow may be obstructed. For this reason, ink is insufficiently supplied in the ink liquid chamber 12, or the bubbles b become dampers against the discharge pressure. Then, even if the ink pool adhering to the nozzle sheet 17 is removed by the cleaning roller 31, ejection failure such as non-ejection or incomplete ejection of ink occurs.

  Further, in the case of the color-compatible print head 2, when an ink pool having a color different from that of the existing ink enters the ink liquid chamber 12, color mixing occurs with the existing ink, and the color ink is diffused to the ink flow path 21. There are things to do. When printing is performed in such a state, mixed color inks are ejected, which causes a decrease in image quality such as density change, hue shift, and stripe unevenness.

  Therefore, it is necessary to provide a bubble removing means for discharging the ink in the ink flow path 21 of the print head 2 to remove the bubbles b mixed in the ink from the ink flow path and preventing ejection failure. Further, it is necessary to have a cleaning means for removing the mixed color ink in the ink liquid chamber 12 and preventing the image quality from deteriorating. Therefore, hereinafter, the bubble removing means is operated by the control means, the ink containing the bubbles b in the ink flow path 21 is discharged, and after the bubbles b in the ink flow path 21 are removed, the cleaning means is operated and the ink is removed. The ink jet printer according to the present embodiment in which the mixed color ink in the liquid chamber 12 can be absorbed by the cleaning roller 31 will be described.

  FIG. 5 is a conceptual diagram showing bubble removing means for removing bubbles in the print head of the ink jet printer according to the present embodiment. As shown in FIG. 5, a common flow path member 20 is disposed above the nozzle sheet 17 on which the ink discharge nozzles 18 are formed, and a common ink flow path 21 formed by the common flow path member 20 is formed. It communicates with all the ink liquid chambers 12 (see FIGS. 3 and 4) of the head chip. The central portion of the common flow path member 20 is connected to the supply port 42 of the ink tank 4. Accordingly, the ink in the ink tank 4 enters the common flow path member 20 from the supply port 42, flows through the ink flow path 21, and is supplied to each ink liquid chamber 12 (see FIGS. 3 and 4). The ink is ejected from the ink ejection nozzle 18. The head cap unit 11 is disposed below the nozzle sheet 17.

  Here, bubble suction ports 22 for discharging the bubbles b accumulated in the ink flow channel 21 together with the ink are provided at both ends of the common flow channel member 20, and the suction ports 24 of the pump 23 that sucks the ink. Connected with resin tube. The discharge port 25 of the pump 23 is connected to the circulation port 43 of the ink tank 4 by a resin tube. Therefore, in the inkjet printer shown in FIG. 5, the circulation channel 26 is between the bubble suction port 22 of the common channel member 20, the suction port 24 and the discharge port 25 of the pump 23, and the circulation port 43 of the ink tank 4. Connected, this constitutes the bubble removing means.

  Moreover, the control means 27 operates the pump 23 which comprises a bubble removal means. The control means 27 also controls the movement of the head cap unit 11 constituting the cleaning means and the heating of the heating resistor 13 (see FIG. 3). That is, the control means 27 relates to all of the removal of the bubbles b in the print head 2, the wiping of the nozzle surface of the print head 2, and the ejection of ink droplets, and is based on a predetermined execution timing based on a predetermined algorithm. Then, the pump 23 is operated, the head cap unit 11 is opened and closed, and the heating resistor 13 is heated.

  Next, FIG. 6 is a perspective view showing an operation of performing cleaning by wiping the cleaning roller 31 constituting the cleaning unit after the bubble b is removed by the bubble removing unit of the ink jet printer shown in FIG. That is, FIG. 6A shows a state in which the bubble removing unit is in operation, and FIG. 6B shows a state in which the cleaning unit is in operation. The state before bubble removal and cleaning is as shown in FIG. 4, and the series of cleaning operations shown in FIGS. 4 and 6 is based on the flowchart of FIG. 7 described later.

  In the state shown in FIG. 4, as shown in FIG. 5, when the pump 23 constituting the bubble removing unit is first operated, ink containing bubbles in the ink flow path 21 is sucked and discharged from the bubble suction port 22. . Then, as shown in FIG. 6A, the ink flows as indicated by the arrows, and the bubbles b are removed from the ink flow path 21 along the ink flow. At the same time, the mixed color ink in the ink flow path 21 is also removed.

  Here, as shown in FIG. 5, the ink containing the bubble b discharged from the bubble suction port 22 flows through the circulation channel 26 and is returned to the ink tank 4 by the pump 23, and the bubble rises upward. The ink supplied to the ink flow path 21 again no longer includes the bubble b. Further, since the mixed color ink is diluted, there is no substantial influence even if it is returned to the ink tank 4. Such ink circulation also causes ink recycling, and wasteful consumption of ink is suppressed.

  However, the bubble b that has entered the ink liquid chamber 12 before the ink is sucked is hindered in the ink liquid chamber 12 because the side wall of the ink liquid chamber 12 becomes an obstacle as shown in FIG. It may not be removed. Similarly, the mixed color ink in the ink liquid chamber 12 may not be completely removed. For this reason, the bubbles b and the mixed color ink in the ink liquid chamber 12 are removed from the ink discharge nozzle 18 by the cleaning unit together with the ink reservoir adhering to the nozzle sheet 17.

  In order to remove the ink pool adhering to the nozzle sheet 17, the head cap unit 11 (see FIG. 1) is moved, and as shown in FIG. 6B, the cleaning roller that is in contact with the nozzle surface of the nozzle sheet 17 31 is driven to rotate. Then, the nozzle surface is wiped as indicated by an arrow by the cleaning roller 31. Further, since the cleaning roller 31 is made of a porous body that can be elastically deformed, a capillary force is generated in each cell of the porous body by driven rotation, and the ink in the ink discharge nozzles 18 is absorbed. Then, the mixed color ink and the bubbles b in the ink liquid chamber 12 are removed through the ink discharge nozzle 18. Therefore, as shown in FIG. 6B, both the inner and outer surfaces of the nozzle sheet 17 are refreshed, and non-ejection of ink and mixed color ink are prevented.

  Note that when the ink is sucked as shown in FIG. 6A, it is necessary to prevent the meniscus of the ink discharge nozzle 18 from being broken and entraining air. Therefore, the negative pressure generated by the pump 23 (see FIG. 5) for ink suction is set within a range in which the meniscus of the ink formed in the ink discharge nozzle 18 is maintained. That is, if the pressure applied to the ink meniscus in the ink discharge nozzle 18 is made smaller than the capillary pressure of the meniscus, the meniscus in the ink discharge nozzle 18 will not be destroyed, and the ink discharge nozzle 18 Conversely, the bubbles b can be prevented from being mixed.

  Thus, according to the ink jet printer of the present embodiment, as shown in FIG. 5, the ink is sucked by the pump 23 and the ink containing the bubbles b is discharged from the bubble suction port 22 of the common flow path member 20. it can. Further, at that time, as shown in FIG. 6A, the bubbles b can be removed without blocking the ink discharge nozzles 18, so that cleaning is performed following the removal of bubbles as shown in FIG. 6B. It can be carried out. Therefore, the operation of removing the bubbles b and the cleaning operation can be smoothly combined.

  In addition, when there is a large amount of mixed color ink or bubbles b in the ink liquid chamber 12, it may be considered that the removal by the cleaning means is insufficient. In such a case, preliminary ink ejection is performed. That is, after wiping by the cleaning roller 31, preliminary ejection of ink completely different from the printing is performed, and the mixed color ink and the bubbles b in the ink liquid chamber 12 are discharged. If the head cap unit 11 (see FIG. 1) is closed during preliminary ejection, the head cap unit 11 serves as a tray for the pre-ejected ink.

  FIG. 7 shows a state in which the outer peripheral surface of the cleaning member 11 is brought into contact with the nozzle surface of the nozzle sheet 17 and moved after the bubbles b accumulated in the common flow path 21 of the print head are removed by the bubble removing means. FIG. 5 is a diagram showing an example of a flowchart for performing cleaning by sucking ink in the ink discharge ink discharge nozzle 18 and preliminarily discharging ink. In the flowchart shown in FIG. 7, the control means 27 (see FIG. 5) first activates the bubble removing means at a timing other than when the printing operation is started, subsequently activates the cleaning means, and then further reserves the ink. The discharge is performed.

  Hereinafter, a method for controlling the liquid ejection apparatus that performs the above-described series of cleaning operations at the timing when the power of the inkjet printer is turned on will be described with reference to FIG. According to the flowchart shown in FIG. 7, when the power of the inkjet printer is turned on, the cleaning operation is started. Specifically, the control means 27 (see FIG. 5) functions to check the mounting of the ink tank 4 (see FIG. 1) (step S1). Here, if the ink tank 4 is not correctly mounted, the process proceeds to “No” and a warning is displayed (step S2). If the ink tank 4 is correctly mounted, step S1 proceeds to the “Yes” side, and the amount of ink in the ink tank 4 is confirmed. If it is determined in step S3 that the amount of ink is not greater than or equal to the reference value, the process proceeds to “No” and a warning is displayed (step S4).

  If it is determined that the amount of ink is equal to or greater than the reference value, step S3 proceeds to the “Yes” side, and the bubbles in the print head 2 are removed by the bubble removing means. At this time, the pump 23 (see FIG. 5) is operated to start the removal of bubbles (step S5), and the operation of the pump 23 is controlled while measuring the amount of bubbles b contained in the ink. It operates until it falls below the reference value, and stops when it falls below the reference value. That is, until the amount of bubbles discharged from the print head 2 becomes equal to or less than the reference value, step S6 advances to “No” and the pump 23 continues to operate (step S5). When the amount of bubbles becomes equal to or less than the reference value, step S6 proceeds to “Yes”, and the operation of the pump 23 is stopped (step S7). The operation from the confirmation operation (step S1) for mounting the ink tank 4 to the stop operation (step S7) for the pump 23 is the bubble suction sequence. At this time, as shown in FIG. The mixed color ink in 21 is also removed.

  Thus, after the bubble 23 is removed by operating the pump 23, the cleaning operation by the cleaning means is performed. That is, the head cap unit 11 (see FIG. 1) is opened (step S8), and the nozzle surface is wiped by the cleaning roller 31 as shown in FIG. 6B (step S9). As a result, the ink reservoir is removed, and even if there is mixed color ink or bubbles b remaining in the ink liquid chamber 12, it is removed.

  Further, after the nozzle surface is wiped by the cleaning roller 31, preliminary ink discharge is further performed (step S10), and the mixed color ink and the bubbles b in the ink liquid chamber 12 are completely discharged to increase the refresh effect. . By this preliminary discharge, the subsequent discharge stability is improved. Since a small amount of ink is consumed by the preliminary ejection, the amount of ink is checked again. If the amount of ink is not equal to or greater than the reference value in step S11, the process proceeds to “No” and a warning is given. Display is performed (step S12). In step S11, if the amount of ink is equal to or greater than the reference value, the process proceeds to “Yes”, and a series of cleaning operations is completed.

  As described above, according to the flowchart shown in FIG. 7, the bubble b is first removed, then the nozzle surface is cleaned, and preliminary ejection is further performed to start a series of cleaning operations. Through a series of these cleaning operations, the amount of bubbles b in the ink liquid chamber 12 (see FIG. 6) formed in the print head 2 can be reduced to a reference value or less, and as a result, ejection defects are eliminated. Can do. Further, the mixed color ink is eliminated, and the discharge of the mixed color ink is prevented. Since the bubble removal and cleaning are performed before the start of printing, the image quality does not deteriorate. This series of cleaning operations is not limited to when the ink jet printer is turned on, for example, when the ink cartridge or the ink tank 4 is replaced, or when a paper jam (paper jam) generated during printing is removed. Done at the timing.

  FIG. 8 is a perspective view showing a process of performing the cleaning operation first by the cleaning roller 31 constituting the cleaning means and then removing the bubbles b by the bubble removing means, contrary to FIG. That is, FIG. 6A shows a state in which the cleaning unit is operating, and FIG. 6B shows a state in which the bubble removing unit is operating. In addition, the state before cleaning and bubble removal is as shown in FIG.

  As shown in FIG. 8A, when the nozzle surface of the nozzle sheet 17 is wiped by the cleaning roller 31, an ink reservoir (not shown) or the like attached to the nozzle sheet 17 is removed. Further, the ink in the ink discharge nozzle 18 is absorbed, and the mixed color ink and the bubbles b in the ink liquid chamber 12 are removed through the ink discharge nozzle 18.

  However, when the ink in the ink flow path 21 contains a large amount of bubbles b or when the mixed color ink has diffused to the ink flow path 21, the ink is discharged from the ink discharge nozzle 18 by the cleaning roller 31. When sucked, bubbles b and mixed color ink existing in the ink flow path 21 around the ink liquid chamber 12 may be drawn into the ink liquid chamber 12. Then, the bubble b and the mixed color ink which have entered the ink liquid chamber 12 in this way are then used to remove the ink containing the bubbles b in the ink flow path 21 by the bubble removing means, as shown in FIG. 8B. Even if the ink is sucked, the side wall of the ink liquid chamber 12 may become an obstacle, and may stay in the ink liquid chamber 12 and cannot be removed.

  Therefore, as shown in FIGS. 6 and 7, the order relationship between the operation for removing the bubble b and the cleaning operation is preferably the order in which the cleaning operation is performed after the bubble removing operation is performed first. However, even in the reverse order as shown in FIG. 8, if the bubbles b and the mixed color ink remain in the ink liquid chamber 12, the bubbles b and the mixed color ink are finally performed by performing preliminary discharge. Can be discharged. Therefore, it is preferable that the preliminary ejection is performed after the bubble removing operation and the cleaning operation.

  As described above, according to the ink jet printer of the present embodiment, the ink including the bubbles b in the ink flow path and the mixed color ink are discharged by the bubble removing unit, which hinders the ejection of ink droplets from the nozzles. The bubble b is removed, and the mixed-color ink that causes the deterioration of the image quality is removed. In addition, the ink reservoir attached to the nozzle sheet is removed by the cleaning unit, and the mixed color ink and the bubbles b are also removed. Furthermore, the pre-discharge of ink completely removes the mixed color ink and the bubbles b.

  Therefore, the ink jet printer according to the present embodiment automatically starts the removal of the bubbles b and the mixed color ink before the start of printing, and is always refreshed at the start of printing. That is, the ink jet printer tends to deteriorate the image quality and the discharge environment as the number of prints, the operation time, the standing time, etc. become longer, but the ink jet printer of this embodiment always has a high image quality. You can print with

  Further, in the ink jet printer of the present embodiment, the head cap unit 11 is opened after the removal of the bubbles b, so that the ink attached to the head cap unit 11 does not have the possibility of reattaching to the nozzle sheet 17. Furthermore, since the exposure time of the nozzle is minimized, it is possible to prevent clogging due to drying and deterioration of the ink.

  Note that the present invention is not limited to the above-described embodiment, and various modifications such as the following are possible. That is, in the embodiment described above, a color-compatible ink jet printer is used, but the present invention is not limited to this, and can be applied to monochrome. Moreover, even if it corresponds to a color, it is not restricted to a 4 color integrated type, It can apply also to the thing of the structure which became independent for each color. Furthermore, in this embodiment, a line-type inkjet printer in which a large number of heads are arranged side by side in the width direction of the recording medium and a print head corresponding to the print width is formed, but the head is moved in the width direction of the recording medium. The present invention can also be applied to a serial system that performs printing.

  In the above description, the present embodiment is a thermal method using a heating resistor as an energy generating element, but the present invention is not limited to this, and instead of a heating element such as a heating resistor, a diaphragm and , Two electrodes through the air layer are provided on the lower side of this diaphragm, and after applying a voltage between both electrodes to deflect the diaphragm, the electrostatic force is released and the diaphragm is returned to its original position. The present invention can also be applied to an electrostatic discharge method in which ink droplets are discharged using the elastic force at that time. Further, the present invention can also be applied to a piezo method in which a laminated body of piezoelectric elements having electrodes on both surfaces and a diaphragm is used, and the diaphragm is deformed by the piezoelectric effect to eject ink droplets.

  Further, in the above description, in the present embodiment, when the head cap unit constituting the cleaning unit is opened, the nozzle surface of the nozzle sheet is wiped by the cleaning roller, but the present invention is not limited to this, Conversely, the nozzle surface may be wiped when the head cap unit is closed.

  The liquid ejection apparatus and the control method for the liquid ejection apparatus of the present invention are particularly suitable when applied to an ink jet printer. However, as an industrial applicability of the present invention, the recording medium is limited to photographic paper. For example, the present invention can be applied to, for example, a medical liquid ejecting apparatus that ejects liquid onto a film, or a liquid ejecting apparatus that ejects dye to a dyed product. Further, the present invention can be applied to a liquid ejection device that ejects a DNA-containing solution for detecting a biological sample.

It is sectional drawing which shows the inkjet printer as an example of the liquid discharge apparatus by this invention. FIG. 2 is an exploded perspective view of a print head of the ink jet printer shown in FIG. 1. FIG. 3 is an enlarged perspective view and a cross-sectional view showing the vicinity of an ink liquid chamber of the print head shown in FIG. 2. FIG. 4 is a perspective view showing a state where air bubbles and inks of different colors are mixed around the ink liquid chamber shown in FIG. 3. It is a conceptual diagram which shows the bubble removal means which removes the bubble in the print head of the inkjet printer shown in FIG. FIG. 6 is a perspective view illustrating a cleaning operation in which wiping is performed by a cleaning roller after bubbles in the print head illustrated in FIG. 5 are removed by a bubble removing unit. 5 is a flowchart illustrating a control method of the liquid ejection apparatus according to the present invention, and is a diagram illustrating a control method for performing preliminary cleaning of ink while performing cleaning after removing bubbles. FIG. FIG. 7 is a perspective view showing a cleaning operation for removing bubbles by bubble removing means after wiping the nozzle surface of the print head with a cleaning roller, contrary to FIG. 6.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Printer main body 2 ... Print head 11 ... Head cap unit (cap member)
12 ... Ink liquid chamber (liquid chamber)
13. Heating resistor (energy generating element)
15 ... Liquid chamber forming member (barrier layer)
DESCRIPTION OF SYMBOLS 17 ... Nozzle sheet 18 ... Ink discharge nozzle 19 ... Head chip 20 ... Common flow path member 21 ... Ink flow path (liquid flow path)
23 ... Pump (bubble removing means)
26. Circulation channel (bubble removing means)
31 ... Cleaning roller (cleaning member)

Claims (24)

A plurality of liquid discharge nozzles are formed side by side on the nozzle surface, liquid discharge means are provided in each liquid chamber provided corresponding to each liquid discharge nozzle, and the above-described common flow path serving as a predetermined liquid supply path A liquid discharge head for replenishing each liquid chamber with liquid, driving the liquid discharge means to discharge liquid droplets from the liquid discharge nozzle;
A bubble removing means connected to the common flow path of the liquid discharge head, for removing bubbles mixed in the liquid from the common flow path by discharging the liquid in the common flow path;
A cleaning member formed into a cylindrical shape with a material having elasticity;
Moving means for relatively moving the cleaning member in a state in which the outer peripheral surface of the cleaning member is in contact with the nozzle surface of the liquid discharge head;
Drive control means for controlling the drive of the moving means;
In a liquid ejection device comprising:
After removing bubbles accumulated in the common flow path of the liquid discharge head by the bubble removing means, the moving means is driven under the control of the drive control means to bring the outer peripheral surface of the cleaning member into contact with the nozzle surface. A liquid ejecting apparatus for sucking the liquid in the liquid ejecting nozzle by moving it.   2. The liquid ejection apparatus according to claim 1, wherein the cleaning member rotates in contact with the nozzle surface of the liquid ejection head and performs cleaning of the nozzle surface while sucking adhering matter.   The liquid ejecting apparatus according to claim 1, wherein the cleaning member is formed of a liquid absorbent material impregnated with a surfactant solution.   2. The liquid ejection apparatus according to claim 1, wherein the bubble removing means is provided on a circulation channel for circulating the liquid discharged from the common channel of the liquid ejection head.   The bubble removing means is configured to apply a pressure smaller than the capillary pressure of the meniscus to the liquid meniscus in the liquid discharge nozzle formed on the nozzle surface of the liquid discharge head. 2. The liquid discharge apparatus according to claim 1, wherein the liquid in the passage is discharged.   2. The liquid ejection apparatus according to claim 1, wherein the liquid ejection head preliminarily ejects liquid droplets from the liquid ejection nozzle by driving the liquid ejection means separately from the liquid ejection to the ejection target. A plurality of liquid discharge nozzles are formed side by side on the nozzle surface, liquid discharge means are provided in each liquid chamber provided corresponding to each liquid discharge nozzle, and the above-described common flow path serving as a predetermined liquid supply path A liquid discharge head for replenishing each liquid chamber with liquid, driving the liquid discharge means to discharge liquid droplets from the liquid discharge nozzle;
A bubble removing means connected to the common flow path of the liquid discharge head, for removing bubbles mixed in the liquid from the common flow path by discharging the liquid in the common flow path;
A cleaning member formed into a cylindrical shape with a material having elasticity;
A cap member that houses the cleaning member and protects the nozzle surface of the liquid ejection head;
A cap opening and closing means for opening and closing the cap member and relatively moving the outer peripheral surface of the cleaning member in contact with the nozzle surface of the liquid ejection head as the cap member opens.
Drive control means for controlling the drive of the cap opening and closing means;
In a liquid ejection device comprising:
After the bubbles accumulated in the common flow path of the liquid discharge head are removed by the bubble removing means, the cap opening / closing means is driven to open the cap member under the control of the drive control means, and the cleaning is performed at that time. A liquid discharge apparatus for sucking the liquid in the liquid discharge nozzle by moving the outer peripheral surface of the member in contact with the nozzle surface.   8. The liquid ejecting apparatus according to claim 7, wherein the cleaning member rotates in contact with the nozzle surface of the liquid ejecting head and cleans the nozzle surface while sucking an adhering substance.   8. The liquid ejection apparatus according to claim 7, wherein the cleaning member is formed of a liquid absorbent material impregnated with a surfactant solution.   8. The liquid ejection apparatus according to claim 7, wherein the bubble removing means is provided on a circulation channel for circulating the liquid discharged from the common channel of the liquid ejection head.   The bubble removing means is configured to apply a pressure smaller than the capillary pressure of the meniscus to the liquid meniscus in the liquid discharge nozzle formed on the nozzle surface of the liquid discharge head. 8. The liquid discharge apparatus according to claim 7, wherein the liquid in the passage is discharged.   8. The liquid discharge apparatus according to claim 7, wherein the liquid discharge head drives the liquid discharge unit to preliminarily discharge liquid droplets from the liquid discharge nozzle separately from the liquid discharge to the discharge target. A plurality of liquid discharge nozzles are formed side by side on the nozzle surface, liquid discharge means are provided in each liquid chamber provided corresponding to each liquid discharge nozzle, and the above-described common flow path serving as a predetermined liquid supply path A liquid discharge head for replenishing each liquid chamber with liquid, driving the liquid discharge means to discharge liquid droplets from the liquid discharge nozzle;
A bubble removing means connected to the common flow path of the liquid discharge head, for removing bubbles mixed in the liquid from the common flow path by discharging the liquid in the common flow path;
A cleaning member formed into a cylindrical shape with a material having elasticity;
Moving means for relatively moving the cleaning member in a state in which the outer peripheral surface of the cleaning member is in contact with the nozzle surface of the liquid discharge head;
Drive control means for controlling the drive of the moving means;
In a method for controlling a liquid ejection apparatus that ejects liquid droplets from a liquid ejection nozzle of the liquid ejection head,
After removing bubbles accumulated in the common flow path of the liquid discharge head by the bubble removing means, the moving means is driven under the control of the drive control means to bring the outer peripheral surface of the cleaning member into contact with the nozzle surface. A control method for the liquid discharge apparatus, wherein the liquid discharge nozzle is controlled so as to suck the liquid in the liquid discharge nozzle.   14. The method of controlling a liquid ejection apparatus according to claim 13, wherein the cleaning member rotates in contact with the nozzle surface of the liquid ejection head and performs cleaning of the nozzle surface while sucking an adhering substance.   The cleaning member is formed of a liquid absorbent material impregnated with a surfactant solution, and moves the outer peripheral surface of the cleaning member in contact with the nozzle surface to form a surfactant film on the nozzle surface. The method of controlling a liquid ejection apparatus according to claim 13, wherein the nozzle surface is cleaned.   The bubble removing means is provided on a circulation flow path for circulating the liquid discharged from the common flow path of the liquid discharge head, and circulates and reuses the liquid discharged from the common flow path. The method of controlling a liquid ejection device according to claim 13.   The bubble removing means is configured to apply a pressure smaller than the capillary pressure of the meniscus to the liquid meniscus in the liquid discharge nozzle formed on the nozzle surface of the liquid discharge head. 14. The method for controlling a liquid ejection apparatus according to claim 13, wherein the liquid in the passage is discharged.   14. The control of a liquid discharge apparatus according to claim 13, wherein the liquid discharge head drives the liquid discharge means and preliminarily discharges the liquid droplets from the liquid discharge nozzle separately from the liquid discharge to the discharge target. Method. A plurality of liquid discharge nozzles are formed side by side on the nozzle surface, liquid discharge means are provided in each liquid chamber provided corresponding to each liquid discharge nozzle, and the above-described common flow path serving as a predetermined liquid supply path A liquid discharge head for replenishing each liquid chamber with liquid, driving the liquid discharge means to discharge liquid droplets from the liquid discharge nozzle;
A bubble removing means connected to the common flow path of the liquid discharge head, for removing bubbles mixed in the liquid from the common flow path by discharging the liquid in the common flow path;
A cleaning member formed into a cylindrical shape with a material having elasticity;
A cap member that houses the cleaning member and protects the nozzle surface of the liquid ejection head;
A cap opening and closing means for opening and closing the cap member and relatively moving the outer peripheral surface of the cleaning member in contact with the nozzle surface of the liquid ejection head as the cap member opens.
Drive control means for controlling the drive of the cap opening and closing means;
In a method for controlling a liquid ejection apparatus that ejects liquid droplets from a liquid ejection nozzle of the liquid ejection head,
After the bubbles accumulated in the common flow path of the liquid discharge head are removed by the bubble removing means, the cap opening / closing means is driven to open the cap member under the control of the drive control means, and the cleaning is performed at that time. A control method for a liquid discharge apparatus, wherein the liquid discharge nozzle is controlled to be sucked by moving the outer peripheral surface of the member in contact with the nozzle surface.   20. The method of controlling a liquid ejection apparatus according to claim 19, wherein the cleaning member rotates in contact with the nozzle surface of the liquid ejection head and performs cleaning of the nozzle surface while sucking deposits.   The cleaning member is formed of a liquid absorbent material impregnated with a surfactant solution, and moves the outer peripheral surface of the cleaning member in contact with the nozzle surface to form a surfactant film on the nozzle surface. 20. The method for controlling a liquid ejection apparatus according to claim 19, wherein the nozzle surface is cleaned.   The bubble removing means is provided on a circulation flow path for circulating the liquid discharged from the common flow path of the liquid discharge head, and circulates and reuses the liquid discharged from the common flow path. The control method of the liquid discharge apparatus of Claim 19.   The bubble removing means is configured to apply a pressure smaller than the capillary pressure of the meniscus to the liquid meniscus in the liquid discharge nozzle formed on the nozzle surface of the liquid discharge head. The liquid ejection apparatus control method according to claim 19, wherein the liquid in the passage is discharged.   20. The control of a liquid discharge apparatus according to claim 19, wherein the liquid discharge head drives the liquid discharge means to preliminarily discharge liquid droplets from the liquid discharge nozzle separately from the liquid discharge to the discharge target. Method.

Images