JP2007022036A - Recording head and ink jet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform a suction recovery which is sufficient but not excessive in each passage corresponding to each output port in suction recovery processing of a recording head equipped with output ports having different opening areas in an ink jet printer, and prevent an excessive quantity of the ink from being discharged by the suction. <P>SOLUTION: Ink tanks 102Bk, 102Y with a large total opening area respectively arranged in the outermost part to a head chip 104A, and the passage lengths of those passages 103Bk, 103Y are longer than the length of the passages 103C, 103M, 103LC, 103LM. The amount of suction of the suction recovery is set to a suction force or an amount of suction enabling ejection of all the ink in the passages C, M, LC, LM having small opening areas among the discharge port group. At this time, even if the lengths of the passage 103Bk, 103Y of the inks Bk, Y are larger, at least all the ink in the passages can be ejected. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a recording head that ejects ink and an ink jet recording apparatus that performs suction recovery processing on the recording head, and more specifically, a flow for supplying ink from an ink tank to a recording head for each of a plurality of types of ink. It relates to the relationship between the length of the road and the volume.

  In addition, “record” described in this specification is not only for forming significant information such as characters and figures, but also manifested so that human beings can perceive visually regardless of significance. Regardless of whether or not it is an object, it also includes a case where an image, a pattern, a pattern or the like is widely formed on a print medium, or a print medium such as etching is processed.

  The “recording medium” is not only a piece of paper used in a general printing apparatus, but also can accept inks such as fabric, resin film, metal plate, glass, ceramics, wood, leather, and the like in sheet form. Also includes three-dimensional solids other than objects, such as spheres and cylinders.

  In an inkjet recording apparatus such as an inkjet printer, ejection failure may occur when the entire apparatus is not used for a long period of time or when the ejection frequency of a specific ejection port is low due to recording data among a large number of ejection ports. This is because the water in the ink in the ink path connected to the discharge port or the discharge port evaporates and the ink is thickened. In addition, ink droplets, water droplets, dust, or the like adheres to the ejection surface of the recording head provided with the ejection openings, and the ejected droplets are pulled by these adhered materials, resulting in ejection failure such as deflection of the ejection direction. Sometimes. The same applies not only to the ink ejected from the recording head, but also to the treatment liquid that insolubilizes the dye in the ink.

  In order to prevent such a discharge failure, it is also known that a so-called discharge recovery process is performed. For example, before or during the recording operation, the ink is ejected to a predetermined ink receiver to discharge the ink that has been thickened, and the ink is discharged from the ink path or the channel communicating with the ink path through the ink ejection port. There are known suction recovery by discharging thickened ink and bubbles in the ink by suction, and capping for preventing evaporation of ink moisture from the ejection port.

  Among these, the suction recovery can discharge not only the ink path in the vicinity of the ejection port of the recording head but also the ink in the flow path that is the ink supply path from the ink tank to the ink path of the recording head. A powerful recovery can be done. In the suction recovery process, generally, a cap is brought into contact with the ejection port surface on which the ejection ports of the recording head are arranged, and ink is discharged from each ejection port by driving the pump to make the inside of the cap have a negative pressure.

  By the way, an inkjet printer for printing a color image is known in which a plurality of ejection port groups for, for example, black, yellow, magenta, and cyan inks are provided on one head chip (Patent Document 1). In this configuration, individual ink tanks and ink flow paths correspond to the plurality of ejection port groups, respectively, whereas the cap for the recovery process is often shared by these ejection port groups. In this case, the recovery process is performed by bringing one common cap into contact with the discharge port surface provided with a plurality of discharge port groups.

  In addition, in this type of ink jet printer, there is also a recording head provided with ejection openings having different diameters for each ink color. For example, the diameter of the black ink ejection port for obtaining a dot diameter suitable for recording text characters differs from the diameter of other color ink ejection ports for obtaining a dot diameter suitable for photographic image quality recording. A recording head may be used. Accordingly, it is possible to realize a printer that performs recording in accordance with various uses such as recording of text and recording of images. In addition, even with the same color ink, the nozzle diameter is reduced to reduce graininess in photographic images, or conversely, ink colors that do not make dots appear conspicuous on the paper surface, or are not used within a range where graininess is noticeable in images. Increasing the nozzle diameter is also performed. Furthermore, there may be provided a plurality of nozzles of different sizes that are used in accordance with the image to be recorded even with the same color.

JP 2004-106522 A JP 2003-266740 A

  However, when a plurality of discharge ports having different diameters as described above are provided in the above-described one head chip, an unnecessary amount of ink is discharged in the suction recovery process, or conversely, recovery is insufficient. There are problems such as.

  That is, when the recovery process is performed by bringing a common cap into contact with the discharge port surface of a recording head provided with a plurality of discharge ports having different diameters (that is, the opening areas of the discharge ports) The same suction force (negative pressure by the pump) acts on the outlet. At this time, the resistance received when ejecting ink differs depending on the difference in the opening area, and the amount of ink that is sucked and ejected varies accordingly. In this case, for suction recovery, it is desirable to perform sufficient ink suction from all ink color channels. In general, for sufficient recovery, it is desirable to discharge an amount of ink that is equal to or greater than the volume of each flow path from the ink tank to the discharge section where each discharge port of the recording head exists. From this point, conventionally, a suction force or a suction amount that can secure a suction amount of a flow path corresponding to a discharge port with a small opening area that has a small discharge amount, that is, a large resistance when discharging ink is set.

  However, in this case, the suction force or the suction amount may be excessive for the flow path corresponding to the discharge port having a larger opening area. That is, since the discharge port with a large opening area has a smaller resistance to ink discharge, more ink is sucked and discharged accordingly. If the volume of the flow path corresponding to the discharge port with the larger opening area is equal to or less than the volume of the flow path corresponding to the small discharge port for which the suction force is set, the volume of the flow path Excess ink is discharged.

  In addition, when the suction force or the suction amount is set corresponding to the discharge port having a small opening area as described above, the volume of the flow channel corresponding to the discharge port having a larger opening area sets the suction force. If it is larger than the volume of the flow path corresponding to the small discharge port, the discharge amount may not be sufficient. That is, although the amount of ink discharged from a discharge port having a larger opening area is large, the recovery is insufficient when the volume is larger than that. That is, in this case, it is necessary to set the suction force or the suction amount corresponding to the discharge port having a large flow path volume. In this case, the discharge amount of the smaller discharge port becomes excessive.

  As described above, in the above configuration, there is a problem that excess ink is discharged by the recovery process regardless of how the suction force or the suction amount is set. Then, since such an excessive amount of ink is discharged, not only is the ink consumed unnecessarily, but also problems such as the configuration for processing the sucked ink becomes more difficult. For example, a material such as an absorber that absorbs sucked ink needs to be made larger. As this absorber increases, the size of the printer itself needs to increase.

  By the way, Japanese Patent Application Laid-Open No. H10-228561 describes a structure for sucking and recovering a recording head that supplies ink of the same color from a common ink tank to a plurality of ejection portions having different opening areas of ejection ports via a branch supply path. . Here, in suction recovery using a common cap, the cross-sectional area (and hence the volume) of the branch supply path communicating with the discharge port group with the larger opening area is communicated with the discharge port group with the smaller opening area. It is smaller than the cross-sectional area of the branch supply path. With this configuration, the amount of ink discharged by the recovery process from each ejection port group is made substantially the same.

  However, the configuration described in Patent Document 2 is intended to make the suction and discharge amounts of the discharge port groups having different opening areas the same. That is, in the configuration described in Patent Document 2, since it is not premised on discharging an amount of ink equal to or greater than the total volume of each flow path leading to the discharge portion where each discharge port exists, It is not possible to perform recovery without excess or deficiency in each of the supply passages corresponding to the discharge ports, that is, the flow passages, and to prevent an excessive amount of ink from being discharged.

  The present invention has been made in order to solve the above-described conventional problems, and an object of the present invention is to perform suction recovery without excess or deficiency in each flow path corresponding to a discharge port having a different opening area. Another object of the present invention is to provide a recording head and an ink jet recording apparatus that can prevent an excessive amount of ink from being discharged by the suction.

  For this purpose, the present invention includes a discharge portion provided with a plurality of discharge ports having different opening areas, and a plurality of flow paths for supplying ink corresponding to the plurality of different discharge ports of the discharge portion, respectively. In the recording head, the plurality of flow paths include a relationship in which a volume of the flow path corresponding to the discharge opening having the larger opening area is larger than a volume of the flow path corresponding to the discharge opening having the smaller opening area. It is characterized by being.

  Preferably, the volume of the flow path corresponding to the discharge port having the larger opening area is equal to the plurality of discharge ports of the discharge unit by suction of all the ink in the flow path corresponding to the discharge port having the smaller opening area. When the ink is discharged through the nozzle, the volume of the opening is determined to be a volume at which all the ink is discharged from the flow path corresponding to the larger discharge port.

  A recording head comprising: an ejection unit provided with a plurality of ejection ports having different opening areas; and a plurality of flow paths for supplying ink corresponding to the plurality of different ejection ports of the ejection unit. In an inkjet recording apparatus that performs recording by ejecting ink from the recording head to a recording medium, a plurality of ejection ports having different opening areas of the ejection unit that perform suction by bringing a cap into contact with the ejection unit The plurality of flow paths of the recording head correspond to discharge openings having a smaller flow area corresponding to the discharge openings having a larger opening area. It includes a relationship larger than the volume of the flow path.

  Preferably, the volume of the flow path corresponding to the discharge port having the larger opening area is such that all ink in the flow path corresponding to the discharge port having the smaller opening area is absorbed by the recovery means by the suction of the recovery means. When discharged through a plurality of discharge ports, the opening area is set to a volume at which at least all of the ink is discharged from a flow path corresponding to a larger discharge port.

  According to the above configuration, the volume of the flow path with respect to the discharge port that discharges more ink due to the large opening area is made larger than the volume of the flow path with respect to the discharge port with a small opening area. It is possible to eliminate ink. Further, when the suction force or the suction amount is set so that at least all of the ink in the discharge port channel having a small opening area can be discharged, the suction force or the like causes the ink to be discharged more than the above. By determining the volume of the flow path so that at least all of the ink is discharged, it is possible to perform good suction recovery, and it is possible to eliminate wasted ink consumed by the recovery process.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a schematic diagram mainly showing an ink supply path from an ink tank to a recording head and a suction recovery configuration in the ink jet recording apparatus according to the first embodiment of the present invention.

  In FIG. 1, reference numeral 101 denotes a head cartridge. The head cartridge 101 includes head chips 104A and 104B and flow paths 103Y, 103LM, 103C, 103M, 103 PigBk, 103LC, and 103Bk for supplying individual inks to these chips. The head cartridge 101 is filled with yellow (Y), light magenta (LM), cyan (C), magenta (M), pigment black (PigBk), light cyan (LC), and dye black (Bk). A mounting portion for detachably mounting the stored ink tanks 102Y, 102LM, 102C, 102M, 102PigBk, 102LC, and 102Bk is provided.

  The head chip 104A communicates with each of a plurality of discharge ports (hereinafter also referred to as discharge port groups or nozzle groups) that discharge yellow, light magenta, cyan, magenta, light cyan, and dye black ink, and the respective discharge ports. An ink path and a common liquid chamber are provided. Ink is ejected from each ejection port by bubbles generated by the thermal energy of the heater provided in the corresponding ink path. The head chip 104B is a head chip corresponding to the pigment black ink, and basically has the same structure as the head chip 104A. Here, as described later, the diameter of the ejection port, that is, the opening area of the head chip 104A differs depending on the color of the ink. The detailed structure of these head chips 104A and 104B is described in Patent Document 2, for example. In applying the present invention, it is apparent from the following description that the structure of the head chip is not limited to that described in this document.

  The flow paths 103Y, 103LM, 103C, 103M, 103PigBK, 103LC, and 103Bk for supplying ink from each ink tank to the corresponding ejection port group of the head chip depend on the ink color, as will be described in detail later. The channel length is different.

  The cap 105A is in contact with the ejection port surface so as to cover the ejection port group of each ink of the head chip 104A. Similarly, the cap 105B contacts the ejection port surface of the head chip 104B. In the suction recovery process, each pump 106A, 106B is driven in a state where each cap is in contact with the head chip, so that the ink path in the head chip, the common liquid chamber, Sucks and discharges ink in each flow path. These discharged inks are guided and held by the ink absorber 107.

  FIG. 2 shows a view of the head cartridge 101 shown in FIG. 1 as viewed from the bottom surface on which the head chip is provided, along with the arrangement of the ink tanks. In this figure, the outline of each head chip is shown as a diagram. In addition, although each channel is not actually visible, the inside of the cartridge is shown and the length of each channel can be known. As will be described below, the flow paths 103Bk and 103Y of the dye black ink Bk and the yellow ink Y have longer flow path lengths than the other flow paths.

In the suction recovery by the cap 105A, as described above, six types of ink are sucked simultaneously. Here, the number of discharge ports constituting each ink discharge port group is the same. However, the opening area of the discharge ports is about 216 μm ^{2 for} all of the discharge ports of the ink Bk and the ink Y. In contrast, ink C, M, LC, LM is half 216Myuemu ² about the discharge port, the remaining half is about ² 66 .mu.m. Accordingly, the sum of the opening areas of the ejection port groups of the inks C, M, LC, and LM is smaller than that of the inks Bk and Y. Here, when the common cap 105A is brought into contact with and simultaneously sucked, the same suction force acts on each ink ejection port group. In contrast, the discharge port group having a small opening area has a higher discharge resistance. For this reason, the ink per unit time sucked through the discharge port groups of the inks C, M, LC, and LM having the smaller sum of the opening areas than the discharge port groups of the inks Bk and Y having the larger sum of the opening areas, respectively. The amount is small.

  In the present embodiment, on the other hand, the flow path length shown in FIGS. That is, the ink tanks 102Bk and 102Y of the inks Bk and Y having a large sum of the opening areas are respectively arranged on the outermost side with respect to the head chip 104A, and the flow path lengths of these flow paths 103Bk and 103Y are the flow of other inks. The length is longer than the flow path length of the paths 103C, 103M, 103LC, and 103LM. Further, in the present embodiment, the flow path 103Bk is made longer than the flow path 103Y. In this embodiment, since the diameter of each flow path is made the same, the volume of each flow path is the same as the above-described relationship between the flow path lengths.

  In the above configuration, the suction force or suction amount for suction recovery is set to a suction force or suction amount that can discharge at least all of the ink in each of the channels C, M, LC, and LM having a small opening area of the ejection port group. To do. At this time, more ink is discharged per unit time from the ejection port group of the inks Bk and Y having a large sum of the opening areas. Therefore, even if the lengths of the flow paths 103Bk and 103Y of the inks Bk and Y (and hence the volume in the present embodiment) are increased as described above, at least all of the ink in the flow paths Can be discharged. In other words, the flow path lengths of the flow paths 103Bk and 103Y are set to a length (volume) that allows at least all of the ink to be discharged by the set suction force or suction amount.

  In this way, by increasing the volume of the flow path for the discharge port group that discharges more ink due to the large sum of the opening areas, the volume of the flow path for the discharge port group having a small sum of the opening areas is increased. It is possible to eliminate the ink that is discharged.

  Furthermore, when the suction force or suction amount is set so that at least all of the ink in the flow path of the discharge port group having a small total opening area can be discharged, the suction force of the discharge port group can discharge more ink. By determining the volume of the flow path so that at least all of the ink in the flow path is discharged, it is possible to perform good suction recovery and to eliminate wasteful ink consumed by the recovery process. it can.

(Second Embodiment)
In the second embodiment of the present invention, the dye cartridge (Bk), cyan (C), magenta (M), yellow (Y), and light cyan as shown in FIG. 3 are added to the head cartridge 101 shown in FIG. The present invention relates to a flow path configuration in the case where a head chip 104 having a discharge port group for discharging each ink of (LC) and light magenta (LM) is provided.

The number of ejection ports in each ejection port group of the head chip 104 is the same. On the other hand, the opening area of the discharge ports is about 216 μm ^{2 for the} ink Bk and Y discharge port groups, and about half of the discharge ports of the inks C, M, LC, and LM are about 216 μm ² and the remaining half. Is about 66 μm ² . As described above, the sum of the opening areas of the discharge ports of the inks C, M, LC, and LM is smaller than that of the discharge ports of the inks Bk and Y.

  Therefore, in the present embodiment, as shown in FIG. 3, the ink tanks for the inks Bk and Y are arranged on the outermost side with respect to the head chip 104. And by this arrangement | positioning, the length of those flow paths 103Bk and 103Y is made longer than another flow path similarly to 1st Embodiment mentioned above.

(Third embodiment)
In the third embodiment of the present invention, as shown in FIG. 4, pigment black (PigBk), dye black (Bk), cyan (C), magenta (M), and yellow (Y) are ejected. The present invention relates to a flow path configuration.

  As shown in FIG. 4, each of the inks C and M uses one ink tank, but the flow path for the head chip is divided into two forks. That is, for these inks, two sets of ejection port groups are formed on the head chip 104A. As in the first embodiment, two caps are used, the first cap is the head chip 104B in which the ejection ports of the ink PigBk are formed, and the second cap is the ink Bk, C, M, Y. Each of the head chips 104A formed with the discharge port group is capped and a suction operation is performed.

In the head chip 104A, the number of ejection ports in the ejection port group for the inks Bk and Y is the same, but the number of ejection ports in the ejection port group for the inks C and Y is twice that of the inks Bk and Y. The opening area of the discharge port, ink Bk, Y is all 216Myuemu about ^2, ink C, M is half of the discharge ports 216Myuemu ² about the remaining half is about ² 66 .mu.m. As a result, the sum of the opening areas of the ejection port groups of the inks C and M is larger than that of the inks Bk and Y.

  Therefore, in this embodiment, the ink tank 102C for the ink C is arranged on the outermost side with respect to the head chip 104A so that the flow path of the ink C is the longest.

  As described above, according to each embodiment of the present invention, the volume of the flow path with respect to the discharge port group that discharges more ink due to the large sum of the opening areas is set to the discharge port group with the small sum of the opening areas. By making it larger than the volume of the flow path, it is possible to eliminate wastefully discharged ink.

  Furthermore, when the suction force or the suction amount is set so that at least all of the ink in the flow path of the discharge port group having a small total opening area can be discharged, the flow of the discharge port group from which more ink is discharged by the suction force or the like. By determining the volume of the flow path so that at least all of the ink in the path is discharged, it is possible to perform good suction recovery, and it is possible to eliminate wasted ink consumed by the recovery process. .

  Further, since the amount of ink necessary for the recovery process can be reduced, the volume of the absorber for holding the discharged ink can be reduced, and the apparatus size can be reduced.

  FIG. 5 is a perspective view showing a schematic structure of the ink jet printer according to each embodiment described above. As shown in FIG. 5, the carriage 11 is mounted with the head cartridge having the configuration shown in each of the above embodiments. Then, it is connected to a part of the driving belt 15 that transmits the driving force of the head driving motor 14 and can move to face the recording surface of a recording medium such as print paper (not shown) conveyed on the platen 12. . By this movement, it is possible to scan the recording medium with the head chip of the head cartridge. Further, the carriage 11 can move the head cartridge 13 to the home position, and perform capping by the cap of each of the above-described embodiments and suction recovery processing via the cap.

FIG. 2 is a schematic diagram illustrating a configuration of an ink supply path from an ink tank to a recording head and suction recovery mainly in an ink jet recording apparatus according to an embodiment of the present invention. It is a figure which shows the bottom view in which the head chip is provided with the arrangement | positioning of an ink tank of the head cartridge which concerns on 1st Embodiment of this invention. It is a figure which shows the bottom view in which the head chip is provided with the arrangement | positioning of an ink tank with respect to the head cartridge which concerns on 2nd Embodiment of this invention. It is a figure which shows the bottom view in which the head chip is provided with the arrangement | positioning of an ink tank with respect to the head cartridge which concerns on 2nd Embodiment of this invention. 1 is a perspective view illustrating a schematic configuration of an ink jet recording apparatus according to an embodiment of the invention.

Explanation of symbols

101 Head cartridge 102Y, 102LM, 102C, 102M, 102PigBk, 102LC, 102Bk Ink tank 103Y, 103LM, 103C, 103M, 103PigBk, 103LC, 103Bk Flow path 104A, 104B Head chip 105A, 105B Cap

Claims (10)

In a recording head comprising: an ejection unit provided with a plurality of ejection ports having different opening areas; and a plurality of flow paths for supplying ink corresponding to the plurality of different ejection ports of the ejection unit,
The plurality of flow paths include a relationship in which a volume of a flow path corresponding to a discharge port having a larger opening area is larger than a volume of a flow path corresponding to a discharge port having a smaller opening area. Recording head.   The recording head according to claim 1, wherein the volume varies depending on the length of the flow path.   The plurality of discharge ports having different opening areas each have a different opening area for each discharge port group configured by a plurality of discharge ports, whereby the sum of the opening areas for each discharge port group is different. The recording head according to 1 or 2.   The plurality of discharge ports having different opening areas have a different number of discharge ports for each discharge port group composed of a plurality of discharge ports, whereby the sum of the opening areas for each discharge port group is different. The recording head according to claim 1.   The volume of the flow path corresponding to the discharge opening having the larger opening area is such that all ink in the flow path corresponding to the discharge opening having the smaller opening area is sucked through the plurality of discharge openings of the discharge section. 5. The volume according to claim 1, wherein when the ink is discharged, the volume is determined so that at least all of the ink is discharged from the flow path corresponding to the discharge port having a larger opening area. Recording head. Using a recording head comprising: a discharge section provided with a plurality of discharge openings having different opening areas; and a plurality of flow paths for supplying ink corresponding to the plurality of different discharge openings of the discharge section, respectively. In an ink jet recording apparatus that performs recording by discharging ink from the recording head to a recording medium,
Comprising a recovery means for performing suction by bringing a cap into contact with the discharge portion, and discharging ink through a plurality of discharge ports having different opening areas of the discharge portion;
The plurality of flow paths of the recording head include a relationship in which the volume of the flow path corresponding to the ejection opening having the larger opening area is larger than the volume of the flow path corresponding to the ejection opening having the smaller opening area. An ink jet recording apparatus.   The inkjet recording apparatus according to claim 6, wherein the volume varies depending on the length of the flow path.   The plurality of discharge ports having different opening areas each have a different opening area for each discharge port group configured by a plurality of discharge ports, whereby the sum of the opening areas for each discharge port group is different. The ink jet recording apparatus according to 6 or 7.   The plurality of discharge ports having different opening areas have a different number of discharge ports for each discharge port group composed of a plurality of discharge ports, whereby the sum of the opening areas for each discharge port group is different. The ink jet recording apparatus according to claim 6. The volume of the flow path corresponding to the discharge port having the larger opening area is such that all the ink in the flow path corresponding to the discharge port having the smaller opening area is discharged by the plurality of discharge portions of the discharge portion by the suction of the recovery means. 10. The volume according to claim 6, wherein when the ink is discharged through an outlet, the volume of the opening is set to a volume at which at least all ink is discharged from a flow path corresponding to a larger discharge port. An ink jet recording apparatus according to any one of the above.

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