JP4755119B2 - Liquid supply member for liquid discharge head, liquid discharge apparatus, and image forming apparatus - Google Patents

Description

  The present invention relates to a liquid supply member for a liquid discharge head, a liquid discharge apparatus, and an image forming apparatus.

  As an image forming apparatus such as a printer, a facsimile machine, a copying apparatus, and a multifunction machine of these, for example, a liquid ejection apparatus including a recording head composed of a liquid ejection head (droplet ejection head) that ejects liquid droplets of a recording liquid (liquid) Is used to convey a liquid (hereinafter also referred to as “paper”, but the material is not limited, and a recording medium, a recording medium, a transfer material, recording paper, etc. are also used synonymously). (Hereinafter also referred to as ink) is applied to a sheet to form an image (recording, printing, printing, and printing are also used synonymously).

  The image forming apparatus means an apparatus for forming an image by discharging a liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. The term “not only” means not only giving an image having a meaning such as a character or a figure to a medium but also giving an image having no meaning such as a pattern to the medium. Further, the liquid is not limited to the recording liquid and ink, and is not particularly limited as long as it is a liquid capable of forming an image. Further, the liquid ejection apparatus means an apparatus that ejects liquid from a liquid ejection head, and is not limited to an apparatus that forms an image.

  As the liquid ejection head, a piezoelectric plate is provided with a diaphragm on a part of the wall of the liquid chamber filled with ink, and the diaphragm is displaced by a piezoelectric actuator or the like to change the volume in the liquid chamber to increase the pressure and eject droplets. There is known a thermal-type head in which a head or a heating element that generates heat when energized is provided in the liquid chamber, and the pressure in the liquid chamber is increased by bubbles generated by the heat generation of the heating element to discharge droplets.

  In such a liquid ejection type image forming apparatus, the number of nozzles and the number of heads are increased in order to increase the speed. Recently, a line-type image forming apparatus that forms a long head by joining a plurality of short heads and forms an image without scanning the head has been adopted.

  However, when the head becomes longer and the number of nozzles increases, the probability of occurrence of ejection failure increases, and one of the causes of ejection failure is the entry of bubbles in the liquid chamber of the head. That is, if bubbles enter the liquid chamber, ink is not supplied and ejection is not performed, or droplet ejection pressure is absorbed and abnormal ejection occurs. Even if a small bubble is attached to the vicinity of the nozzle, for example, the droplet bends and flies, resulting in an abnormal image.

  There are various forms in which bubbles enter the liquid chamber in the head. In some cases, the ink may flow from a flow path for supplying ink to the head, or may be sucked from a nozzle. Further, in a head that discharges droplets by boiling the ink using a heating element, minute bubbles may remain in the liquid chamber during the discharge process.

In this way, when bubbles enter the liquid chamber, discharge (not often referred to as idle discharge or preliminary discharge) unrelated to image formation is performed, or the negative pressure is formed by capping the nozzle surface. Thus, there is known a method of discharging air bubbles together with ink by suction or pressurizing an ink supply path with a pump or the like. When air bubbles are discharged by these methods, although there is a method of recycling the discharged ink, basically, a large amount of ink is used regardless of image formation and is wasted. In addition, there exists patent document 1 as a recycled thing.
JP 2005-212350 A

  There is no method other than discharging the air bubbles in the liquid chamber by the above-described method, but there is a method for removing the air bubbles in the ink supply path by circulating ink in the ink supply path. According to this method, it is possible to avoid bubbles in the ink supply path from entering the liquid chamber without discharging ink even when the head is elongated as described above. However, in the method of discharging bubbles in the ink supply path by circulating ink, there is a problem that the meniscus formed in the nozzle of the head is destroyed by the circulating pressure of ink, and ink oozes out or sucks bubbles from the nozzle. is there.

In view of this, there is an ink jet recording apparatus that seals the nozzle surface during ink circulation as described in Japanese Patent Application Laid-Open No. H10-228707. This is because the ink supply passage for guiding ink from the ink tank to the common liquid chamber of the recording head, the ink discharge passage for guiding ink from the common liquid chamber to the ink tank, and the discharge port sealing for sealing the discharge port communicating with the common liquid chamber And an ink pump for pressure-feeding ink from the ink tank to the common liquid chamber, and the ink pump is operated with the discharge port sealed by the discharge port sealing means so that the ink supply passage, the common liquid chamber, and the ink are supplied from the ink tank. By circulating the ink through the discharge passage, the air in the ink flow path is discharged into the ink tank together with the ink.
Japanese Patent No. 2821920

Further, as described in Patent Document 3, the ink supply path is divided by a partition having a plurality of communication paths into a side closer to and far from the individual liquid chamber of the head, and an ink inflow pipe and an ink outflow pipe are arranged on the far side. There is a head in which the ink circulation pressure does not affect the meniscus. This is a common liquid that has a circulation path between the thermal head and the ink tank, includes an ink pressure feeding means in the circulation path, and communicates with a plurality of liquid paths that respectively communicate with a plurality of ejection ports that eject ink. A first common liquid chamber that communicates directly with the plurality of liquid passages; and a first common liquid chamber that is adjacent to the first common liquid chamber and opposite to the plurality of liquid passage sides; And a plurality of communication passages therebetween, and a part of the circulation path, which is divided into a second common liquid chamber having an inflow port from the ink tank and an outflow port to the ink tank.
Japanese Patent Application Laid-Open No. 08-238772

  As described above, in the method of discharging the bubbles in the liquid supply path by circulating the liquid, the meniscus formed in the nozzle of the head is destroyed by the circulating pressure of the liquid, and the liquid oozes out or sucks the bubbles from the nozzle. Therefore, the measures described in Patent Documents 2 and 3 are taken.

  However, in the configuration in which the nozzle surface is sealed during the circulation of the liquid as described in Patent Document 2, it is difficult to completely seal the head when the head is elongated, and the liquid is discharged during the circulation of the liquid. Thus, there is a problem that an image cannot be formed.

  Further, as described in Patent Document 3, the liquid supply path is divided into a partition having a plurality of communication paths, the side near and far from the individual liquid chamber of the head, and a liquid inflow pipe and a liquid outflow pipe are provided on the far side. In the configuration in which the liquid circulation pressure does not affect the meniscus, it is effective to prevent the bubbles in the ink supply path from entering the individual liquid chamber, but the bubbles and nozzles generated in the individual liquid chamber Even when bubbles sucked from the air flow upstream due to buoyancy or the like, there is a problem that the partition stays near the individual liquid chamber by the partition wall and cannot be discharged to the outside by a circulating flow.

  The present invention has been made in view of the above-mentioned problems. The bubbles in the liquid supply path including bubbles flowing backward from the head are discharged without circulating the liquid to the outside by the circulation flow, and the meniscus is further circulated by the circulation pressure. An object of the present invention is to provide a liquid supply member for a liquid discharge head that does not have an adverse effect such as destroying the liquid, a liquid discharge apparatus including the liquid supply member, and an image forming apparatus.

  In order to solve the above problems, a liquid supply member for a liquid discharge head according to the present invention is a liquid discharge head having a common liquid chamber that supplies liquid to a plurality of liquid chambers that communicate with a plurality of nozzles that discharge droplets. A liquid supply member connected to supply liquid to a common liquid chamber of the liquid discharge head, the liquid supply member having a liquid circulation path through which the liquid circulates along the direction in which the nozzles of the liquid discharge head are arranged; And a supply port for supplying liquid to the liquid circulation path and a discharge port for discharging liquid from the liquid circulation path are provided at the end in the longitudinal direction of the liquid circulation path. In addition, a communication port communicating with the common liquid chamber is provided, the communication port is narrower than the liquid circulation path, and at least one of the supply port side and the discharge port side is deeper than the other parts. .

  A liquid supply member for a liquid discharge head according to the present invention is connected to a liquid discharge head having a common liquid chamber that supplies liquid to a plurality of liquid chambers that communicate with a plurality of nozzles that discharge droplets. A liquid supply member that supplies liquid to the common liquid chamber, and has a liquid circulation path in which the liquid circulates along the arrangement direction of the nozzles of the liquid discharge head, and is provided at the end of the liquid circulation path in the longitudinal direction. A supply port for supplying a liquid to the liquid circulation path and a discharge port for discharging the liquid from the liquid circulation path, and a communication port communicating with the common liquid chamber is provided on the common liquid chamber side of the liquid circulation path. It was set as the structure by which the rib is arrange | positioned around the communicating port.

  A liquid supply member for a liquid discharge head according to the present invention is connected to a liquid discharge head having a common liquid chamber that supplies liquid to a plurality of liquid chambers that communicate with a plurality of nozzles that discharge droplets. A liquid supply member for supplying a liquid to the common liquid chamber, the liquid supply member having a liquid circulation path inside which the liquid circulates along the direction in which the nozzles of the liquid discharge head are arranged, and the length of the liquid circulation path At the end in the direction, a supply port for supplying liquid to the liquid circulation path and a discharge port for discharging liquid from the liquid circulation path are provided, and ribs are formed on the inner wall surface of the liquid circulation path on the common liquid chamber side. It was set as the composition.

  Here, it is preferable that the ribs have a configuration in which the portions on the supply port side and the discharge port side of the liquid circulation path are relatively higher in height than the other portions.

  A liquid supply member for a liquid discharge head according to the present invention is connected to a liquid discharge head having a common liquid chamber that supplies liquid to a plurality of liquid chambers that communicate with a plurality of nozzles that discharge droplets. A liquid supply member that supplies liquid to the common liquid chamber, and has a liquid circulation path in which the liquid circulates along the arrangement direction of the nozzles of the liquid discharge head, and is provided at the end of the liquid circulation path in the longitudinal direction. A liquid supply path for supplying the liquid to the liquid circulation path and a discharge port for discharging the liquid from the liquid circulation path, and the flow path of the liquid circulation path orthogonal to the flow when the liquid flows from the supply port toward the discharge port The cross-section is narrow at the center and has a large area on both sides. One large area communicates with the opening of the common liquid chamber, and the other large area is connected to the supply port and the discharge port. Is provided .

  Here, due to the rib formed on the wall surface in the short direction of the liquid circulation path, the flow channel cross section of the liquid circulation path perpendicular to the flow when the liquid flows from the supply port to the discharge port is narrowed at the center. Thus, it is preferable that both sides have a large area.

  In the liquid supply member for a liquid discharge head according to the present invention, the cross section of the flow path in the direction perpendicular to the flow when the liquid flows from the supply port to the discharge port has a convex shape upward. Can do. Moreover, it can be set as the structure without the part which inhibits the flow of a liquid between the upper opening of a common liquid chamber, and the top | upper surface of a liquid circulation path.

  A liquid supply member for a liquid discharge head according to the present invention is connected to a liquid discharge head having a common liquid chamber that supplies liquid to a plurality of liquid chambers that communicate with a plurality of nozzles that discharge droplets. A liquid supply member for supplying a liquid to the common liquid chamber, the liquid supply member having a liquid circulation path through which the liquid circulates along the direction in which the nozzles of the liquid discharge head are arranged. A supply port for supplying liquid and a discharge port for discharging liquid from the liquid circulation path are provided, and either the supply port or the discharge port is provided at a portion other than the longitudinal end of the liquid circulation path. Corresponding to the ports provided in other parts, a rectifying member for adjusting the flow with the common liquid chamber is provided.

  In the liquid supply member for a liquid discharge head according to the present invention, the portion that forms the communication port may be formed of a high thermal conductivity material. Moreover, in the liquid supply member for a liquid ejection head according to the present invention including a rib, the rib may be formed of a high thermal conductivity material.

  A liquid supply member for a liquid discharge head according to the present invention is connected to a liquid discharge head having a common liquid chamber that supplies liquid to a plurality of liquid chambers that communicate with a plurality of nozzles that discharge droplets. A liquid supply member for supplying a liquid to the common liquid chamber, the liquid supply member having a liquid circulation path inside which the liquid circulates along the direction in which the nozzles of the liquid discharge head are arranged, and the length of the liquid circulation path At the end in the direction, a supply port for supplying liquid to the liquid circulation path and a discharge port for discharging liquid from the liquid circulation path are provided, and the common liquid chamber side of the liquid circulation path is connected to the common liquid chamber. A port is provided, and the communication port has a narrower width than the liquid circulation path.

  The liquid discharge apparatus according to the present invention is configured to include the liquid supply member according to the present invention that supplies liquid to the liquid discharge head.

  The image forming apparatus according to the present invention includes the liquid supply member according to the present invention that supplies liquid to the liquid discharge head.

  According to the liquid supply member for a liquid discharge head according to the present invention, the liquid circulation path through which the liquid circulates along the direction in which the nozzles of the liquid discharge head are arranged is provided at the end of the liquid circulation path in the longitudinal direction. A supply port for supplying liquid to the liquid circulation path and a discharge port for discharging liquid from the liquid circulation path are provided, and a communication port communicating with the common liquid chamber is provided on the common liquid chamber side of the liquid circulation path. Since the opening is narrower than the liquid circulation path and at least one of the supply port side and the discharge port side is deeper than the other part, bubbles generated in the liquid discharge head or upstream of the liquid supply path The air bubbles that have flowed into the liquid discharge head can be discharged by a circulating flow without destroying the meniscus of the liquid discharge head.

  According to the liquid supply member for a liquid discharge head according to the present invention, the liquid circulation path through which the liquid circulates along the direction in which the nozzles of the liquid discharge head are arranged is provided at the end of the liquid circulation path in the longitudinal direction. A supply port for supplying a liquid to the liquid circulation path and a discharge port for discharging the liquid from the liquid circulation path, and a communication port communicating with the common liquid chamber is provided on the common liquid chamber side of the liquid circulation path. Since ribs are arranged around the communication port, bubbles generated in the liquid discharge head and bubbles flowing from the upstream of the liquid supply path into the liquid discharge head can be circulated without destroying the meniscus of the liquid discharge head. Can be discharged.

  According to the liquid supply member for a liquid discharge head according to the present invention, the liquid circulation path through which the liquid circulates along the direction in which the nozzles of the liquid discharge head are arranged is provided at the end of the liquid circulation path in the longitudinal direction. Since the supply port for supplying the liquid to the liquid circulation path and the discharge port for discharging the liquid from the liquid circulation path are provided, and a rib is formed on the inner wall surface on the common liquid chamber side of the liquid circulation path, Bubbles generated in the liquid discharge head and bubbles flowing into the liquid discharge head from the upstream side of the liquid supply path can be discharged by a circulating flow without destroying the meniscus of the liquid discharge head.

  According to the liquid supply member for a liquid discharge head according to the present invention, the liquid circulation path through which the liquid circulates along the direction in which the nozzles of the liquid discharge head are arranged is provided at the end of the liquid circulation path in the longitudinal direction. A liquid supply path for supplying the liquid to the liquid circulation path and a discharge port for discharging the liquid from the liquid circulation path, and the flow path of the liquid circulation path orthogonal to the flow when the liquid flows from the supply port toward the discharge port The cross-section is narrow at the center and has a large area on both sides. One large area communicates with the opening of the common liquid chamber, and the other large area is connected to the supply port and the discharge port. Therefore, bubbles generated in the liquid discharge head and bubbles flowing into the liquid discharge head from the upstream of the liquid supply path can be discharged by a circulating flow without destroying the meniscus of the liquid discharge head. That.

  According to the liquid supply member for a liquid discharge head according to the present invention, the supply port for supplying the liquid to the liquid circulation path has a liquid circulation path in which the liquid circulates along the arrangement direction of the nozzles of the liquid discharge head. And a discharge port for discharging the liquid from the liquid circulation path, and either the supply port or the discharge port is provided in a part other than the longitudinal end of the liquid circulation path, and is provided in a part other than the longitudinal end. Since the flow straightening member is arranged to adjust the flow between the common liquid chamber and the corresponding ports, the bubbles generated in the liquid discharge head and the bubbles flowing into the liquid discharge head from the upstream of the liquid supply path are removed. The liquid discharge head can be discharged by a circulating flow without destroying the meniscus.

  According to the liquid supply member for a liquid discharge head according to the present invention, the liquid circulation path through which the liquid circulates along the direction in which the nozzles of the liquid discharge head are arranged is provided at the end of the liquid circulation path in the longitudinal direction. A supply port for supplying liquid to the liquid circulation path and a discharge port for discharging liquid from the liquid circulation path are provided, and a communication port communicating with the common liquid chamber is provided on the common liquid chamber side of the liquid circulation path. Since the opening is configured to be narrower than the liquid circulation path, bubbles generated in the liquid discharge head and bubbles flowing into the liquid discharge head from upstream of the liquid supply path can be circulated without destroying the meniscus of the liquid discharge head. Can be discharged.

  Since the liquid ejection apparatus according to the present invention includes the liquid supply member according to the present invention that supplies the liquid to the liquid ejection head, stable droplet ejection can be performed.

  Since the image forming apparatus according to the present invention includes the liquid supply member according to the present invention that supplies liquid to the liquid discharge head, stable droplet discharge can be performed.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. A first embodiment of a liquid supply member for a liquid discharge head according to the present invention will be described with reference to FIGS. 1 is a perspective explanatory view showing a head unit configured by connecting a liquid supply member according to the present invention to a liquid discharge head, FIG. 2 is a longitudinal sectional view of the head unit, and FIG. FIG. 3 is a cross-sectional view in the short-side direction of the head unit along the line AA in FIG. 2.

  The liquid discharge head 1 is a thermal head, and includes a heating element substrate 2 and a flow path substrate 3. The flow path substrate 3 is provided with a plurality of nozzles 5 for discharging droplets and a plurality of individual liquid chambers 6 with which the nozzles 5 communicate with each other, and the heating element substrate 3 corresponds to each individual liquid chamber 6 with a heating element. An element is provided. The heating element substrate 2 is connected to energizing means such as FPC (not shown), and the heating element 4 is driven by inputting a pulse voltage or the like to the heating element 4 via the energizing means. Film boiling occurs in the liquid in the chamber 6, and liquid droplets (droplets) are ejected from the nozzle 5. In the present embodiment, as shown in FIG. 1, two nozzle rows in which a plurality of nozzles 5 are arranged in the longitudinal direction of the head are formed, and the individual liquid chambers 6 corresponding to the nozzles 5 are shown in FIG. As shown, the liquid is supplied from a common liquid chamber 7 provided at the center of the heating element substrate 2.

  Then, the liquid according to the present invention for supplying the liquid to the common liquid chamber 7 as shown in FIGS. 2 and 3 corresponding to the opening forming the common liquid chamber 7 of the heating element substrate 2 of the liquid discharge head 1. A liquid circulation path 11 of the supply member 10 is connected.

  The liquid supply member 10 has a liquid circulation path 11 through which a circulating liquid flows. The liquid circulation path 11 is a narrow communication channel 11b having a relatively small opening cross-sectional area on the side connected to the liquid discharge head 1 (narrow cross section) to the common liquid chamber 7 of the liquid discharge head 1 from the liquid supply member 10. The main flow path 11a has a wide opening cross-sectional area on the side far from the head 1, which also serves as a communication port for the liquid to communicate. Then, at both ends of the liquid supply member 10 in the longitudinal direction (the direction along the arrangement direction of the nozzles of the liquid discharge head 1), a supply port 12 that supplies the liquid in communication with the main channel 11a and a discharge port that discharges the liquid 13 is formed. Note that the opening cross-sectional area is a direction (liquid supply member) orthogonal to the longitudinal direction of the liquid supply member 10 (the arrangement direction of the nozzles of the liquid discharge head 1, the circulation flow generation direction), as in the cross-sectional explanatory diagram shown in FIG. 10 in the cross-sectional area in the short direction).

  As will be described later, the liquid supply member 10 is disposed in a liquid supply path (not shown), and the liquid flows from the supply port 12 toward the discharge port 13 through the liquid circulation path 11 to circulate the liquid. In FIG. 2 and the like, arrows directed toward the supply port 12 and arrows directed outward from the discharge port 13 indicate the inflow direction and the discharge direction of the liquid, respectively (the same applies below).

The operation of the liquid supply member 10 configured as described above will be described in comparison with Comparative Example 1 shown in FIGS. 6 and 7 and Comparative Example 2 shown in FIGS. 8 and 9 in addition to FIGS. 4 and 5.
Although the liquid discharge head 1 discharges the liquid supplied from the supply port 12 of the liquid supply member 10, bubbles 50 are mixed from a liquid supply path (not shown) connected to the supply port 12 over time, and FIG. 4 and FIG. As shown, the liquid circulation path 11 may stay and accumulate on the top (top surface 11d). If the amount of bubbles 50 is small, no particular problem occurs. However, if the amount of bubbles 50 increases, problems such as mixing with the liquid into the individual liquid chamber 6 of the liquid discharge head 1 and causing defective discharge occur.

  Therefore, in this liquid supply member 10, the liquid flows from the supply port 12 to the discharge port 13 and circulates in the liquid supply path (not shown), so that the bubbles 50 ride on this liquid circulation flow and the liquid circulation path 11. It is discharged from the inside through the discharge port 13. At this time, the liquid circulation path 11 of the liquid supply member 10 connects the supply port 12 and the discharge port 13 to the main flow path 11a having a relatively wide cross-sectional area perpendicular to the circulation flow to thereby generate the circulation flow. Further, a narrow communication channel 11b having a relatively narrow opening cross-sectional area in a direction orthogonal to the circulation flow generation direction is provided between the liquid discharge head 1 and the liquid discharge head 1, so that the circulation flow is generated by the liquid discharge head. 1 will not cause problems.

  For example, in the configuration of Comparative Example 1 shown in FIGS. 6 and 7, the liquid circulation path 11 of the liquid supply member 10 is provided in the vicinity of the liquid discharge head 1 with a uniform cross section, and between the supply port 12 and the discharge port 13. When the circulation flow is generated, the bubbles 50 are efficiently discharged from the discharge port 13 along the flow having a large flow velocity indicated by the arrow 60. However, on the other hand, since a circulating flow having a high flow velocity is generated in the immediate vicinity of the common liquid chamber 7 of the liquid discharge head 1, the meniscus of the nozzle 5 of the liquid discharge head 1 is destroyed and the liquid overflows from the nozzle 5. On the contrary, there is a problem that bubbles are sucked from the nozzle 5.

  Further, in the configuration of the comparative example 2 shown in FIGS. 8 and 9, the circulating flow is generated at a position away from the liquid discharge head 1. That is, in this comparative example 2, since the supply port 12 and the discharge port 13 are formed above the liquid circulation path 11, a relatively large flow rate indicated by the arrow 61 can be formed in the upper part of the liquid circulation path 11, The lower part in the liquid circulation path 11 is a flow having a relatively small flow velocity as indicated by an arrow 62. Therefore, if the height h from the liquid discharge head 1 in FIG. 8 to the line connecting the supply port 12 and the discharge port 13 is increased and the position of the circulation flow is separated from the liquid discharge head 1, the configuration of Comparative Example 1 described above is obtained. The meniscus destruction problem can be avoided.

  However, in the configuration shown in the comparative example 2, since the cross-sectional area of the liquid circulation path 11 is increased, the flow rate of the circulation flow is reduced, and as a result, the problem of impairing the discharge of bubbles occurs. Further, if the flow rate of the circulation flow is increased in order to improve the bubble discharge performance, the liquid discharge head 1 is affected on the meniscus, and it is difficult to obtain good conditions.

  In contrast, as shown in FIGS. 4 and 5, in the liquid supply member 10 according to the present embodiment, the liquid circulation path 11 is a narrow communication channel 11 b having a narrow cross section on the side connected to the head 1. The main channel 11a has a wide cross section on the far side. As a result, in the narrow communication channel 11b, the walls forming the channel are close to each other, so that the liquid flows only at a low (small) flow rate (the magnitude and speed of the flow are indicated by arrows SB) and circulate. The flow is substantially formed in the main channel 11a ((the magnitude and speed of the flow are indicated by arrows MB). Therefore, the meniscus of the nozzle 5 of the liquid discharge head 1 is broken by the circulating flow. Therefore, it is possible to generate a circulation flow having a high flow velocity (large) and efficiently discharge the bubbles 50 in the liquid circulation path 11.

  Further, as shown in FIGS. 2 and 3, the liquid supply member 10 of the present embodiment has a narrow communication channel 11 b that serves as a communication port for the liquid supply member 10 over the entire opening region of the common channel 7 of the liquid ejection head 1. Is generated in the individual liquid chamber 6 of the liquid discharge head 1 because no member such as a partition wall is obstructed between the common flow path 7 and the top surface 11d of the liquid circulation path 11. When the bubble or the bubble sucked from the nozzle 5 moves to the common liquid chamber 7, it can float on the top surface 11d of the liquid circulation path 11 by buoyancy and can be discharged in a circulating flow.

  Here, the shape of the cross section in the direction orthogonal to the liquid flow direction of the liquid circulation path 11 of the liquid supply member 10 is not limited to that formed in a parallel plane as shown in FIG. For example, as shown to Fig.10 (a), the non-parallel surface shape by which the narrow communication flow path 11b is biased and arranged in the transversal direction with respect to the main flow path 11a may be sufficient. Moreover, as shown in FIG.10 (b), the shape where the main channel 11a and the narrow communication channel 11b are continuously connected by the inclined surface 11g may be sufficient. Further, as shown in FIG. 10C, even if the upper portion of the joint with the liquid discharge head 1 does not directly face the top surface of the main flow channel 11a, it travels along the inclined surface 11b1 of the narrow communication flow channel 11b. Any shape can be used as long as the bubbles can rise. Although not shown, each side or corner can be curved. Moreover, in this embodiment, although the internal diameter of the supply port 12 and the discharge port 13 is made the same, it does not necessarily need to be the same and it can also be set as the shape from which an internal diameter differs.

  As described above, the liquid circulation path in which the liquid circulates along the arrangement direction of the nozzles of the liquid discharge head, and the supply port for supplying the liquid to the liquid circulation path is provided at the longitudinal end of the liquid circulation path. And a discharge port for discharging liquid from the liquid circulation path, a communication port communicating with the common liquid chamber is provided on the common liquid chamber side of the liquid circulation path, and the communication port is narrower than the liquid circulation path Since the configuration is adopted, bubbles generated in the liquid discharge head and bubbles flowing into the liquid discharge head from the upstream side of the liquid supply path can be discharged by a circulating flow without destroying the meniscus of the liquid discharge head.

Next, a second embodiment of the liquid supply member according to the present invention will be described with reference to FIGS. 11 is a longitudinal sectional view of the head unit according to the embodiment, FIG. 12 is a short sectional view of the head unit along the line EE in FIG. 11, and FIG. 13 is a line FF in FIG. FIG.
The liquid supply member 10 in this head unit is obtained by changing the depth of the narrow communication channel 11b at both ends and the center of the supply port 12 and the discharge port 13.

  That is, a region (supply side region) that is a distance (length) Ls from the supply port 12 and a region (discharge side region) that is a distance Ls from the discharge port 13 are both ends, and a region excluding these supply side region and discharge side region. , And the depth Hb of the narrow communication channel 11b is deep at both ends (for example, depth Hb = Hb2 at the cross-sectional position in FIG. 13) and shallow at the center (depth Hb = Hb1 in FIG. 12). A difference in depth Yb is provided between the shallowest central portion and the deepest end portions. Further, the depth Hb of the narrow communication channel 11b is formed so as to gradually become deeper by forming the inclined surface 11h from the central portion toward the supply port 12 and the discharge port 13 side.

  By configuring in this way, it is possible to reliably avoid meniscus destruction at both ends of the liquid discharge head 1. That is, since the supply port 12 and the discharge port 13 are openings having an opening cross-sectional area smaller than that of the liquid circulation path 11, the liquid flow velocity is larger than that of the liquid circulation path 11. Therefore, the influence on the meniscus due to the circulation of the liquid is larger at both ends near the ports 12 and 13 than at the center far from the ports 12 and 13. Therefore, the meniscus breakage at both ends of the liquid discharge head 1 can be more reliably prevented by making the depth of the communication channel 11b at both ends where the supply port 12 and the discharge port 13 are provided deeper than the center.

  In addition, the cross-sectional change in the vicinity of the connection portion between the supply port 12, the discharge port 13 and the main flow path 11a is configured to be smooth. 12. By constituting so that it may become deep gradually toward the discharge port 13 side, the flow of the liquid in the main channel 11a is also stabilized.

  As described above, the liquid circulation path in which the liquid circulates along the arrangement direction of the nozzles of the liquid discharge head, and the supply port for supplying the liquid to the liquid circulation path is provided at the longitudinal end of the liquid circulation path. And a discharge port for discharging liquid from the liquid circulation path, a communication port communicating with the common liquid chamber is provided on the common liquid chamber side of the liquid circulation path, and the communication port is narrower than the liquid circulation path In addition, since at least one of the supply port side and the discharge port side is deeper than the other parts, bubbles generated in the liquid discharge head and bubbles flowing into the liquid discharge head from the upstream of the liquid supply path, It is more reliably avoided that the meniscus of the liquid discharge head is broken, and the liquid discharge head can be discharged by a circulating flow.

Next, a third embodiment of the liquid supply member according to the present invention will be described with reference to FIGS. 14 is a longitudinal sectional view of the head unit according to the embodiment, FIG. 15 is a plan sectional view of the head unit along the line GG in FIG. 14, and FIG. 16 is along the line HH in FIG. FIG. 3 is a cross-sectional view in the short-side direction of the same head unit.
The liquid supply member 10 in this head unit is provided with a communication port 17 communicating with the common liquid chamber 7 of the liquid discharge head 1 on the common liquid chamber side of the liquid circulation path 11. The plurality of ribs 16 are provided around the communication port 17 so as to rise toward the main channel 11a.

  Since the rib 16 is provided in this manner, the contact area between the liquid circulating on the common flow path 7 side of the liquid circulation path 11 and the wall surface increases, so when the liquid inside the liquid supply member 10 is circulated, The circulation flow becomes gentle on the common flow path side in the liquid circulation path 11, and adverse effects on the meniscus due to the circulation flow can be reduced.

  As described above, the liquid circulation path in which the liquid circulates along the arrangement direction of the nozzles of the liquid discharge head, and the supply port for supplying the liquid to the liquid circulation path is provided at the longitudinal end of the liquid circulation path. And a discharge port for discharging the liquid from the liquid circulation path, a communication port communicating with the common liquid chamber is provided on the common liquid chamber side of the liquid circulation path, and a rib is disposed around the communication port. With this configuration, bubbles generated in the liquid discharge head and bubbles flowing into the liquid discharge head from the upstream side of the liquid supply path can be discharged by a circulating flow without destroying the meniscus of the liquid discharge head.

Next, a fourth embodiment of the liquid supply member according to the present invention will be described with reference to FIGS. 17 is a longitudinal sectional view of the head unit according to the embodiment, FIG. 18 is a plan sectional view of the head unit along the line II in FIG. 17, and FIG. 19 is along the line JJ in FIG. FIG. 3 is a cross-sectional view in the short-side direction of the same head unit.
In the liquid supply member 10 of this head unit, a plurality of ribs 16 are formed on the inner wall surface of the liquid circulation path 11 on the common liquid chamber 7 side of the liquid discharge head 1, and both end portions where the supply port 12 and the discharge port 13 are provided. The height of each rib 16 is changed between the side and the center.

  That is, as in the second embodiment, an area having a length Ls from the supply port 12 (supply side area) and an area having a length Ls from the discharge port 13 (discharge side area) are both ends, and these supply side areas are used. And the area excluding the discharge side area is the center, and the height Hb of the rib 16 is deep at both ends and shallow at the center, and the difference in depth between the shallowest center and the deepest ends is Yb It is said. In addition, the ribs 16a and 16b are provided with inclined surfaces 16h on the supply port 12 and discharge port 13 sides so that the height of the ribs 16a and 16b gradually increases from the center toward the supply port 12 and discharge port 13 side. Is formed.

  By configuring in this way, it is possible to reliably avoid meniscus destruction at both ends of the liquid discharge head 1. That is, since the supply port 12 and the discharge port 13 are openings having an opening cross-sectional area smaller than that of the liquid circulation path 11, the liquid flow velocity is larger than that of the liquid circulation path 11. Therefore, the influence on the meniscus due to the circulation of the liquid is larger at both ends near the ports 12 and 13 than at the center far from the ports 12 and 13. Therefore, as in the third embodiment, while suppressing the flow on the common liquid chamber 7 side, the height of the ribs 16 at both ends where the supply port 12 and the discharge port 13 are provided is made higher than the central portion, thereby discharging the liquid. Meniscus destruction at both ends of the head 1 can be avoided more reliably. Further, by gradually changing the height of the ribs 16 in the both end regions, the cross-sectional change in the vicinity of the connection portion between the region supply port 12, the discharge port 13 and the liquid circulation path 11 becomes smooth, so that the flow is also stabilized.

  As described above, the liquid circulation path in which the liquid circulates along the arrangement direction of the nozzles of the liquid discharge head, and the supply port for supplying the liquid to the liquid circulation path is provided at the longitudinal end of the liquid circulation path. And a discharge port for discharging liquid from the liquid circulation path, and ribs are formed on the inner wall surface on the common liquid chamber side of the liquid circulation path, so that bubbles generated in the liquid discharge head and liquid supply Bubbles flowing into the liquid discharge head from the upstream of the path can be discharged by a circulating flow without destroying the meniscus of the liquid discharge head

Next, a fifth embodiment of the liquid supply member according to the present invention will be described with reference to FIGS. 20 is a plan sectional view of the head unit according to the embodiment, FIG. 21 is a sectional view of the head unit along the line KK in FIG. 20, and FIG. 22 is another example different from FIG. FIG. 21 is a cross-sectional view in the short-side direction of the same head unit taken along line KK in FIG.
In the liquid chamber supply member 10 of the head unit, in the third and fourth embodiments, the ribs 16 are formed mainly in parallel with the longitudinal direction (circulation flow generation direction) of the liquid circulation path 11, whereas the liquid circulation It is formed in a direction orthogonal to the longitudinal direction of the path 11 (circulation flow generation direction).

  In this configuration, in addition to an increase in the contact area between the liquid circulating on the common flow path 7 side of the liquid circulation path 11 and the wall surface, the liquid circulation path is formed in the direction in which the circulation flow is formed in the region where the ribs 16 are formed. 11 has an effect of increasing the loss of the flow due to the change in the opening cross-sectional area of the liquid 11, so that when the liquid in the liquid supply member 10 is circulated, the circulation flow is gently on the common flow path 7 side in the liquid circulation path 11. Thus, the adverse effect on the meniscus due to the circulating flow can be reduced.

  In this case, as in another example shown in FIG. 22, the height of the ribs 16 near (both ends) near the supply port 12 and the discharge port 13 is made higher than the height of the ribs 16 at the center. For the same reason as in the fourth embodiment, meniscus destruction at both ends of the liquid discharge head 1 can be avoided more reliably, and a cross section in the vicinity of the connection portion between the region supply port 12, the discharge port 13 and the liquid circulation path 11. The flow becomes stable because the change becomes smooth.

Next, a sixth embodiment of the liquid supply member according to the present invention will be described with reference to FIG. FIG. 23 is a cross-sectional view in the short-side direction of the head unit according to the embodiment.
The liquid supply member 10 of this head unit is formed in a triangular shape having a vertex in the vertically upward direction, with the cross section orthogonal to the circulating flow generation direction of the liquid circulation path 11. By narrowing the top surface 11d side so as to have a convex shape in this way, the bubbles in the liquid circulation path can be collected in one place, so that it is easy to discharge by the circulation flow, and the fine bubbles are combined at the top surface portion. It becomes a big bubble and becomes easy to discharge.

Next, a seventh embodiment of the liquid supply member according to the present invention will be described with reference to FIGS. 24 is a longitudinal sectional view of the head unit according to the embodiment, and FIG. 25 is a lateral sectional view of the head unit along the line LL in FIG.
The liquid supply member 10 of this head unit is the same as the liquid supply member 10 of the second embodiment except that the supply port 12 and the discharge port 13 are provided on the upper surface 11a (top surface) side of the liquid circulation path 11 at both ends in the longitudinal direction. Yes.

  That is, in the second embodiment, the supply port 12 and the discharge port 13 are provided at a position lowered from the top surface 11a of the liquid circulation path 11 in the height direction by the height Yh, whereas here, the supply port 12, The discharge port 13 is provided at a position lowered from the top surface 11d of the liquid circulation path 11 by a height Yh1 (Yh1 <Yh) in the height direction.

  As a result, the bubbles 50 stay in a floating state on the upper surface of the liquid circulation path 11 due to buoyancy, so that the circulation flow is generated at a position close to the top surface of the liquid circulation path 11 so as to increase the flow velocity, thereby generating the bubbles 50. It is easy to discharge. Therefore, the supply port 12 and the discharge port 13 are formed at positions close to the top surface portion of the liquid circulation path 11 so that the flow velocity near the top surface portion becomes large (fast).

  Further, like the liquid supply member 10 described in the first to seventh embodiments, the direction of the supply port 12 and the discharge port 13 is also in the longitudinal direction of the liquid circulation path 11, that is, the direction of the circulation flow generation direction. By providing them, the flow of the circulation flow tends to be only in one direction of circulation, so that the bubble discharge efficiency can be improved.

  That is, as in Comparative Example 3 shown in FIGS. 26 and 27, the supply port 12 and the discharge port 13 are arranged on the surface (top surface 11d) opposite to the surface connected to the liquid discharge head 1 of the liquid supply member 10. Even if it is provided (opened to the liquid circulation path 11), a circulation flow is generated, but the circulation flow becomes a flow as indicated by arrows 65 to 67, and the flow velocity component in the direction of the liquid discharge head 1 is increased, which is not preferable. .

Next, an eighth embodiment of the liquid supply member according to the present invention will be described with reference to FIG. FIG. 28 is a longitudinal sectional view of the head unit according to the embodiment.
The liquid supply member 10 of the head unit has a central portion in the longitudinal direction of a surface opposite to the surface connecting the supply port 12 to the liquid ejection head 1 of the liquid supply member 10 (the portion on the top surface 11d side: the top surface portion). The discharge ports 13 and 13 are provided at both ends in the longitudinal direction (or, conversely, the supply port 12 may be provided at both ends and the discharge port 13 may be provided at the center top side). . Other configurations are the same as those of the second embodiment.

  In the liquid circulation path 11, rectification is performed between the supply port 12 and the common liquid chamber 7 of the liquid discharge head 1 so as to arrange the flow of the liquid supplied from the supply port 12 in the direction toward the discharge ports 13 and 13. The member 18 is arranged. A surface of the rectifying member 18 facing the common liquid chamber 7 is an inclined surface 19, so that bubbles floating from the common liquid chamber 7 are not easily trapped by the rectifying member 18.

  With this configuration, when the supply port 12 (or the discharge port 13) is provided on the top surface of the central portion in the longitudinal direction of the liquid supply member 10, the circulating flow does not adversely affect the meniscus of the liquid discharge head 1. can do.

  That is, as in Comparative Example 4 shown in FIG. 29, in the configuration in which the rectifying member 18 is not provided, the distance between the supply port 12 and the discharge port 13 is short, so there are some surfaces where bubbles are easily discharged. Since the flow velocity component in the direction of the liquid ejection head 1 is large, there is a problem that the meniscus is liable to be adversely affected, and a flow in two directions opposite to the longitudinal direction is formed in one pipe line. As a result, eddy currents are generated, and the bubble discharge performance is relatively poor compared to the one-way flow.

  Therefore, when the supply port 12 or the discharge port 13 is provided in a direction that does not follow the flow of the circulation flow, a rectifying member 18 is formed between the liquid outflow inlet of the port and the common liquid chamber 7 of the liquid discharge head 1. By adjusting the flow, the circulating flow can be prevented from adversely affecting the meniscus of the liquid discharge head 1.

  As described above, the liquid circulation path in which the liquid circulates in the arrangement direction of the nozzles of the liquid discharge head is provided, and the supply port for supplying the liquid to the liquid circulation path and the discharge port for discharging the liquid from the liquid circulation path One of the supply port and the discharge port is provided in a portion other than the longitudinal end portion of the liquid circulation path, and the common liquid chamber is connected to the port provided in the portion other than the longitudinal end portion. By adopting a configuration in which a flow straightening member is provided in between, bubbles generated in the liquid discharge head and bubbles flowing into the liquid discharge head from upstream of the liquid supply path can be destroyed without destroying the meniscus of the liquid discharge head. It can be discharged by a circulating flow. Even when a supply port or a discharge port is provided in addition to the longitudinal end of the liquid supply member, the flow direction adversely affecting the head generated by the liquid circulation can be changed by the rectifying member. The supply member can be provided with a large number of ports to improve the efficiency of discharging bubbles.

  It is not preferable to provide the filter 14 inside the liquid circulation path 11 of the liquid supply member 10 as in the comparative example 5 shown in FIG. In other words, the configuration in which the filter 14 is provided is effective because the flow of the circulating flow hardly affects the liquid discharge head side, and the bubbles 50 in the main channel 11a are difficult to enter the liquid discharge head 1. However, conversely, bubbles 51 mixed from the nozzle 5 or generated inside the individual liquid chamber 6 move toward the common liquid chamber 7 and are trapped in the lower part of the filter 14 when heading toward the liquid circulation path 11. End up. The bubbles 51 cannot be discharged by the circulation flow, but must be discharged together with the liquid from the nozzle 5. Therefore, it is preferable not to provide a filter inside the liquid discharge head 1 or the liquid circulation path 11.

Next, a ninth embodiment of the liquid supply member according to the present invention will be described with reference to FIGS. 31 is a longitudinal sectional view of the head unit according to the embodiment, and FIG. 32 is a lateral sectional view of the head unit along the line NN in FIG.
In each of the embodiments described above, the narrow communication channel 11b of the liquid circulation path 11 is directly connected to the common liquid chamber 7 of the liquid ejection head 1 as in the second embodiment, or as in the third embodiment. The liquid supply member 10 having a structure in which the rib 16 is formed on the common liquid chamber 7 side of the liquid circulation path 11 has been described.

  In contrast, the liquid supply member 10 of the head unit according to the ninth embodiment includes a liquid buffer flow path 11 c between the narrow communication flow path 11 b of the liquid circulation path 11 and the liquid discharge head 1. That is, the cross section of the liquid circulation path 11 orthogonal to the flow of the liquid flowing from the supply port 12 toward the discharge port 13 is narrowed at the center (narrow communication flow path 11b). The main buffer channel 11a and the liquid buffer channel 11c have a large area, and the liquid buffer channel 11c, which is one large area, communicates with the common liquid chamber 7 through the communication port 17. The supply port 12 and the discharge port 13 are provided on the main channel 11a side which is the other large area portion.

  Even with such a configuration, the bubbles in the head 1 and the liquid circulation path 11 can be discharged using the circulation flow without destroying the meniscus. Furthermore, by providing the liquid buffer channel 11c, it becomes easier for the liquid buffer channel 11c to absorb the pressure wave when the droplet is ejected, so that the droplet ejection stability is improved.

  Further, here, the top surface 11d of the main channel 11a constituting the liquid circulation path 11 has a curved surface shape that protrudes upward in a cross-sectional shape in a direction orthogonal to the longitudinal direction. Further, the connecting portion between the main flow path 11a and the supply port 12 and the discharge port 13 is connected smoothly by the inclined surfaces 11e and 11f. By doing in this way, generation | occurrence | production of the vortex | eddy_current in the main flow path 11a, the peeling of a flow, etc. disappear, and a bubble can be discharged | emitted efficiently.

  As described above, the liquid circulation path in which the liquid circulates along the arrangement direction of the nozzles of the liquid discharge head, and the supply port for supplying the liquid to the liquid circulation path is provided at the longitudinal end of the liquid circulation path. And a discharge port for discharging the liquid from the liquid circulation path, and the cross-section of the liquid circulation path perpendicular to the flow when the liquid flows from the supply port toward the discharge port is narrowed at the center. By having a configuration in which both sides have a large area, one large area portion communicates with the opening of the common liquid chamber, and a supply port and a discharge port are provided on the other large area portion side, Bubbles generated in the liquid discharge head and bubbles flowing into the liquid discharge head from the upstream side of the liquid supply path can be discharged by a circulating flow without destroying the meniscus of the liquid discharge head.

  In addition, since the supply port and the discharge port are provided and the region where the circulation flow is generated can be narrowed within a range in which the normal liquid supply flow rate can be ensured, the flow rate of the circulation flow can be increased, so that the bubble discharge performance is further improved. By making the region close to the head a wide space and making it a buffer space that eliminates problems due to the propagation of the discharge pressure of the liquid discharge head, the discharge stability is further improved.

Next, a tenth embodiment of a liquid supply member according to the present invention will be described with reference to FIGS. 33 is a longitudinal sectional view of the head unit according to the embodiment, and FIG. 34 is a lateral sectional view of the head unit along the line OO in FIG.
Here, the third embodiment and the ninth embodiment are applied, and a rib 16 is provided at an intermediate portion of the liquid circulation path 11, and the liquid buffer flow path 11 c is provided above the common liquid chamber 7.

  Even in such a configuration, the bubbles in the head and the liquid circulation path 11 can be discharged using the circulation flow without breaking the meniscus. Furthermore, by providing the liquid buffer channel 11c, it becomes easier for the liquid buffer channel 11c to absorb the pressure wave when the droplet is ejected, so that the droplet ejection stability is improved.

Next, an eleventh embodiment of the liquid supply member according to the present invention will be described with reference to FIG. FIG. 35 is a cross-sectional view in the short-side direction of the head unit according to the embodiment.
The liquid supply member 10 of this head unit is a member (part) in which the main channel forming part 10a that forms the main channel 11a and the narrow communication channel forming part 10b that forms the narrow communication channel 11b are made of different materials. The narrow communication channel forming part 10b is formed of a material having a higher thermal conductivity than the main trunk channel forming part 10a. Here, as the material having a high thermal conductivity, a resin filled with a thermal conductive filler such as silica, alumina, boron nitride, magnesia, aluminum nitride, silicon nitride, or the like is also suitable.

  That is, the liquid discharge head 1 rises in temperature due to its own heat generation when its discharge frequency increases. In particular, the temperature rise is significant in the thermal type liquid discharge head 1 of a system in which a heating element is driven and droplets are discharged by film boiling. The rise in the temperature of the liquid ejection head 1 causes the temperature of the internal liquid to rise, and when the temperature of the ejected liquid changes, the ejection volume and ejection speed of the droplets change.

  Therefore, as in this embodiment, the narrow communication flow path forming portion 10b of the liquid supply member 10 which is the narrowest portion through which the liquid supplied to the liquid discharge head 1 passes is formed of a material having a high thermal conductivity such as metal. Then, the heat generated by the liquid discharge head 1 can be effectively taken away to prevent a temperature rise, the temperature of the liquid supplied to the liquid discharge head 1 can be easily stabilized, and stable droplet discharge characteristics can be easily realized. Become.

Next, a twelfth embodiment of the liquid supply member according to the present invention will be described with reference to FIGS. 36 is a cross-sectional view in the short-side direction of the head unit according to the embodiment, and FIG. 37 is a cross-sectional explanatory view taken along the line P-P in FIG.
Similarly to the eleventh embodiment, the liquid supply member 10 of the head unit includes a main channel forming portion 10a that forms the main channel 11a and a narrow communication channel forming portion 10b that forms the narrow communication channel 11b. In order to further enhance the heat dissipation effect of the narrow communication flow path forming portion 10b, internal fins 15a and external fins 15b are provided on the inner side and the outer side of the liquid circulation path 11, respectively. .

  By comprising in this way, the contact area with the liquid and external air in a liquid circulation path is expanded, and stabilization of temperature becomes still easier.

  Further, the internal fins 15a also have an action of reducing the influence of the circulating flow on the head 1 like the ribs 16 described in the fifth embodiment. Therefore, as for the direction of the internal fin 15a, at least for the narrow communication channel 11b, as shown in FIG. 36, the longitudinal direction of the internal fin 15a is the direction from the main channel 11a toward the liquid ejection head 1, that is, the circulation flow. It is preferable that the fins be orthogonal to each other. With this orientation, the circulation flow in the narrow communication channel 11b can be further suppressed without hindering the rising of bubbles from the common liquid chamber 7.

  Next, application to an image forming apparatus including a liquid ejection apparatus according to the present invention will be described. Here, an example will be described in which ink is ejected as a liquid and applied to an ink jet printer that can be applied to a facsimile machine, a copying machine, a multi-function machine thereof, or the like. However, the liquid ejection apparatus according to the present invention is not an ink. The present invention can also be applied to a liquid discharge head and a liquid discharge apparatus for discharging a liquid such as a DNA sample, a resist, and a pattern material, or an image forming apparatus including these.

First, a first embodiment of an image forming apparatus according to the present invention will be described with reference to FIGS. FIG. 38 is a configuration diagram of the image forming apparatus, FIG. 39 is an explanatory view showing a state during maintenance and recovery of the apparatus, and FIG. 40 is a schematic explanatory view for explaining a liquid supply path.
This image forming apparatus has four different colors (black, cyan, magenta) in which recording heads 1 (1K, 1C, 1M, 1Y) comprising a long liquid discharge head having a length corresponding to the maximum paper width to be conveyed are different. , Each line of yellow) is provided with four line printers. The four recording heads 1 are fixed to a head frame 36, and the four heads 1 can be simultaneously moved up and down by a head lifting mechanism (not shown).

  A recording sheet on which an image is recorded by ink is conveyed immediately below the recording head 1. The recording sheets are stacked and held on the sheet feeding tray 38, and are fed one by one by a separation sheet feeding mechanism (not shown), conveyed by the sheet conveying belt 30, and discharged onto the sheet discharge tray 39 after recording is completed.

  The paper conveying belt 30 is stretched by a belt conveying roller 31 and a tension roller 32. The surface layer is a high resistance layer made of a resin material, and the back layer is a medium resistance layer obtained by controlling the resistance of the resin material with carbon. It has a two-layer structure. The paper conveying belt 30 is in contact with a charging roller 33 in which an intermediate resistance layer is formed on the outer layer of the metal roller and a thin high resistance layer is formed on the outermost layer.

  Therefore, by applying a high voltage to the charging roller 33, a discharge occurs in the air gap near the nip portion between the paper conveyance belt 30 and the charging roller 33, and charges are attached on the paper conveyance belt 30. When the voltage applied to the charging roller 33 is a positive and negative AC voltage, positive and negative charges are alternately attached in a stripe pattern on the paper transport belt 30. When the recording paper is supplied to the paper transport belt 30 thus charged, the recording paper is attracted to the paper transport belt 30 by electrostatic force. Since printing can be performed with the recording paper firmly held on the paper conveyance belt 30, stable printing quality can be obtained even when printing is performed while conveying the paper at high speed.

  The recording head 1 is of a thermal type that obtains a discharge pressure by film boiling of ink by driving the heat generating element 4 as shown in the second embodiment, and a discharge energy acting part (heat generating element part) in the liquid chamber 6. The side shooter type configuration in which the ink flow direction to the nozzle 5 and the central axis of the opening of the nozzle 5 are perpendicular to each other is employed.

  With this configuration, the energy from the heating element 4 can be more efficiently converted into the formation of ink droplets and the kinetic energy of the flight, and the meniscus can be quickly restored by supplying ink. Have. Further, the side shooter can avoid a so-called cavitation phenomenon in which the heat generating element 4 is gradually destroyed by an impact when bubbles that are problematic in the edge shooter method disappear. That is, when bubbles grow in the side shooter and the bubbles reach the nozzle 5, the bubbles are brought into the atmosphere, and the bubbles do not contract due to a temperature drop. Therefore, there is an advantage that the life of the recording head is long.

The recording head 1 can be manufactured as follows, for example. First, the heating element substrate 2 is formed by laminating HfB ₂ as a heating resistor layer by RF magnetron sputtering on a silicon wafer having a SiO 2 film formed by thermal oxidation, and further laminating Al as an electrode layer by EB vapor deposition. Next, the Al layer was etched with a phosphoric acid-nitric acid etching solution by photolithography. Next, the heating resistor layer is etched using RIE. In order to expose the heating element 4, a resist film is formed on a portion excluding the portion corresponding to the exposed portion, and the Al is removed from the portion where the resist is not formed by treatment with an etching solution, so A heating element 4 is provided between them. Finally, a SiO ₂ layer as a protective layer is provided on the electrothermal converter, and a polyimide layer is provided in a portion other than the heating element array portion to form the heating element substrate 2.

  Next, a polymethylisopropenyl ketone (ODUR-1010 manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied onto PET as a soluble resin layer and dried to form a dry film on the heating element substrate 2 by laminating. Transcript. After pre-baking, pattern exposure corresponding to the individual liquid chamber 6 is performed, and development is performed using methyl isobutyl ketone / xylene = 2/1. Next, a resin composition comprising an epoxy resin, a cationic photopolymerization initiator, and a silane coupling agent is dissolved in a methyl isobutyl ketone / xylene mixed solvent at a concentration of 50 wt%, and a photosensitive coating resin layer is formed by spin coating. . Thereafter, pattern exposure and after baking corresponding to the nozzle 5 are performed, and then development is performed with methyl isobutyl ketone to form the nozzle 5.

  Further, it was immersed in methyl isobutyl ketone while applying ultrasonic waves, and the remaining soluble resin was eluted, and heated at 150 ° C. for 1 hour to completely cure the photosensitive coating material layer. Finally, the common liquid chamber 7 is formed by anisotropic etching of silicon with TMAH (tetramethylammonium hydroxide aqueous solution). At this time, the surface of the silicon substrate on which the nozzle 5 is formed is protected with a protective layer made of cyclized rubber so that the produced liquid chamber member 2 is not damaged.

  As described above, 600 dpi / row, 2400 CH / row (meaning that 2400 nozzles 5 are arranged in one row), the distance between nozzle rows is 240 μm, the maximum opening width of the common liquid chamber 7 is about 1.8 mm, and the length is about A 110 mm line type head can be produced.

  The liquid supply member 10 is the liquid supply member 10 according to the second embodiment, and a part having a cross-sectional flow path (liquid circulation path 11) shown in FIGS. 11 to 13 is cut / bonded with a transparent polycarbonate resin. It is manufactured and fixed to the liquid discharge head 1 by adhesion. The internal dimensions of the liquid supply member 10 are, for example, Wa: 5 mm, Wb: 2.4 mm, Ha: 6 mm, Hb: 4 mm, Yb: 1.5 mm, Ls: 5 mm in FIGS. 11 to 13. Then, a supply port 12 and a discharge port 13 are provided at both ends of the liquid supply member 10 at the central portion (Yh: 3 mm position) of the cross section of the main flow path 11a, and the liquid supply path (ink) as shown in FIG. Supply system).

  In this liquid supply path (system), the head tank 70 has a function of supplying ink to the recording head 1 and receiving bubbles and discharging them to the outside, and the inside is open to the first ink chamber 71 and the upper part to the atmosphere. The ink is divided into a second ink chamber 72 provided with a port 73, and ink can be transferred from the second ink chamber 72 to the first ink chamber 71 by a pump P2. An ink cartridge 76 is connected to the second ink chamber 72 so that the ink filtered by the filter 75 can be replenished to the second ink chamber 72 of the head tank 70 by the pump P1.

  An ink port is provided on the bottom surface of the second ink chamber 72 of the head tank 70 and is connected to the discharge port 13 of the liquid supply member 10 of the head 1 via a normally open valve V2. The ink amount in the second ink chamber 72 is managed by the liquid level detection sensor 74 so that the water head difference Sh between the ink liquid level and the head 1 becomes a constant value (10 to 150 mm).

  Here, during normal image formation, the pumps P1 and P2 are stopped and only the valve V2 is opened. Ink is supplied from the second ink chamber 72 to the recording head 1 via the discharge port 13. When the liquid level in the second ink chamber 72 becomes lower than a predetermined position due to ink consumption, the liquid level detection sensor 74 detects. Accordingly, the valve V1 is opened, the pump P1 is operated, and the ink is replenished from the ink cartridge 76 to the second ink chamber 72. The replenishment stop is controlled by a detection signal from the liquid level detection sensor 74.

  Further, when the head 1 is clogged, the head 1 is restored. The head 1 moves upward from the state of FIG. 38, and the maintenance unit 35 moves in the horizontal direction (from the state of FIG. 38 to the right in the figure: moved in the direction of the arrow) and is disposed directly below the head 1. Then, the head 1 is slightly lowered so that the nozzle surface 5a on which the nozzle 5 of the head 1 is formed is in close contact with the cap 40 held by the holder 43 of the maintenance unit 35 as shown in FIG. In this state, the valves V1 and V2 in FIG. 40 are closed and only the pump P2 is driven for a certain time.

  As a result, the ink in the first ink chamber 71 is pressurized and flows into the head 1. Since the valve V2 is closed, the ink is discharged from the nozzle 5 of the head 1. Together with the discharged ink, bubbles and foreign matters that have caused the clogging of the head 1 are removed. Then, after the pump P2 is stopped, the head 1 is raised to a level at which the head 1 is not in contact with the cap 40, and the maintenance unit 35 is moved in the horizontal direction (moved from the state in FIG. 39 to the right in the figure). The nozzle surface 5 a of the head 1 is wiped by the wiper blade 41 as in 42. After a meniscus is formed on the nozzle 5 by wiping, the valve V2 is opened to hold the head 1 in a negative pressure state corresponding to the hydraulic head difference Sh.

  Since the ink discharged from the head 1 is stored in the cap 40, the ink is sucked by the pump 45 and discharged to the waste liquid tank 44. If the ink in the cap 40 is filtered using a filter, it is possible to reuse the sucked ink by returning it to the second ink chamber 72 of the head tank 70 instead of the waste liquid tank 44.

  Thereafter, the recording operation is performed in the state of FIG. 38 by raising and lowering the head 1 and the horizontal movement of the maintenance unit 35, or waits until a recording instruction is issued in the state of FIG. By this recovery operation, clogging is eliminated and the head 1 can be maintained in a good state.

  Here, in the liquid supply system shown in FIG. 40, since the flow paths 80 and 81 connecting the liquid supply member 10 and the head tank 70 are usually resin tubes, air bubbles are gradually formed inside over time due to the air permeability of the tube material itself. Mixed. When a large amount of bubbles are accumulated inside the liquid supply member 10, the ink flows along the ink flow during the recording operation and enters the head 1, causing ink droplet ejection failure. In order to discharge air bubbles from the liquid supply member 10, in FIG. 40, only the pump P <b> 2 is driven with the valve V <b> 2 opened, and ink flows from the second ink chamber 72 to the first ink chamber 71. The ink enters the supply port 12 of the liquid supply member 10 from the first ink chamber 71, is discharged from the discharge port 13 together with the bubbles inside the liquid supply member, and returns to the second ink chamber 72. Bubbles in the ink rise in the second ink chamber 72 and are discharged from the atmosphere opening port 73.

  In order to evaluate the bubble discharge property when the liquid supply member 10 according to the present invention is used in this image forming apparatus, a three-way valve is attached upstream of the liquid supply member 10 to inject bubbles into the tube, and the liquid supply member While observing the inside of the pump 10, the pump P <b> 2 was operated to mix bubbles in the liquid supply member 10. After waiting until the flow inside the liquid supply member 10 stopped, the pump V2 was operated again to circulate ink at a flow rate of 60 ml / min. As a result, although small bubbles remained in the upper corner portion in the liquid supply member 10, it was confirmed that the bubbles could be discharged almost satisfactorily. Further, when the nozzle surface of the head 1 was observed, there was no problem such as ink bleeding from the nozzle 5, and good image formation could be performed without ejection failure.

  Next, after bubbles were mixed in the liquid supply member 10 in the same manner, the ink was circulated at 90 ml / min. As a result, no bubbles remained in the corners where the bubbles remained under the previous conditions, and the bubbles were discharged well. I did it. However, when the nozzle 5 was observed, it was confirmed that ink oozed out from the nozzle 5.

  Next, as described in the seventh embodiment (FIGS. 24 and 25), using the liquid supply member 10 in which the positions of the supply port 12 and the discharge port 13 are changed vertically upward (changed to Yh1: 1 mm), Similarly, a bubble discharge experiment was conducted. As a result, it was confirmed that even when the ink was circulated at 90 ml / min, there was no problem that the ink oozed out from the nozzle 5 and the bubbles could be discharged well.

  Furthermore, as another form, as shown in 6th Embodiment (FIG. 23), the upper corner | angular part of the main channel 11a is chamfered, and the top surface center part becomes convex upward (Wa: 5 mm, Wb: 2.4 mm, Ha: 6 mm, Hb: 4 mm, Yh: 3 mm, Yc: 1.5 mm, Wc: 1 mm). As a result, even when the ink was circulated at 60 ml / min, there was no problem that the ink oozed out from the nozzle 5, and the bubbles could be discharged well.

  Here, as a comparative example, as shown in Comparative Example 1 (FIGS. 6 and 7), a liquid supply member (Wc: 5 mm, Hc: 6 mm, Yh) in a form in which the narrow communication channel 11 b is removed from the liquid circulation channel 11. : 3 mm) was produced, and the same bubble discharge experiment was performed using this. As a result, it was possible to discharge the bubbles by circulating the ink at a flow rate of 60 ml / min, but the bleeding of the ink from the nozzle 5 was observed. Although the circulation flow rate was reduced and the positions of the supply port 12 and the discharge port 13 were offset upward, the conditions for ensuring the bubble discharge property without ink oozing out from the nozzle 5 were not obtained.

  Therefore, as in Comparative Example 2 (FIGS. 8 and 9), the bubble discharge evaluation was performed in the same manner as the configuration in which the height of the liquid circulation path 11 was increased (Wd: 5 mm, Hd: 12 mm, Yh: 3 mm). As a result, a flow rate of 120 ml / min or more was necessary to obtain good bubble discharge performance. However, when the ink water level in the second ink chamber 72 of the head tank 70 is low when the bubble discharge operation is performed. Although the frequency was low, a meniscus of the nozzle 5 was broken and a channel (nozzle 5) that did not discharge was generated.

  Thus, when it is necessary to make it the structure which increases the height of the liquid circulation path 11, the method made into the structure like 9th Embodiment (FIG.31 and FIG.32) is also effective. In the liquid supply member 10 of the ninth embodiment, a portion of the liquid circulation path 11 that is closest to the head 1 is a large space liquid buffer flow path 11c, and a narrow communication flow path 11b and a main flow path 11a are provided on the upper portion thereof. Yes. Bubbles generated in the head 1 and flowing into the common flow path 7 rise to the top surface 11d of the main flow path 11a by buoyancy. At this time, since the upper part of the liquid buffer channel 11c is inclined, bubbles do not stay in the liquid buffer channel 11c. In addition, since the top surface 11d of the main channel 11a has an upwardly convex curved shape, bubbles are easily collected at the top and easily discharged.

  In such a configuration, the influence of the circulating flow on the head 1 can be reduced by separating the position of the circulating flow from the head 1. In addition, the main channel 11a can be minimized to a cross-sectional area sufficient to ensure a flow rate in the recording operation, and the circulation flow can be speeded up to improve the bubble discharge performance. Further, since a buffer portion (buffer channel 11c) having a large volume is provided in a portion close to the head 1, the discharge pressure of the head 1 can be absorbed, which is effective for suppressing so-called mutual interference. This is particularly effective for a piezoelectric discharge head that discharges a plurality of types of droplets from a single nozzle.

  31 and 32, the dimensions of each part were set to Wia: 5 mm, Wic: 2.4 mm, Hia: 4 mm, Hib: 4 mm, Hic: 6 mm, Yh: 2 mm, and the evaluation of bubble discharge was performed in the same manner as described above. When carried out, bubbles could be completely discharged at a flow rate of 60 ml / min, and no meniscus destruction of the nozzle occurred. In addition, image formation could be performed while performing the ink circulation operation for discharging bubbles.

  In the above embodiment, since no filter is provided in the liquid supply member 10, even when bubbles are generated from the head side while repeating the recording operation, the liquid supply member 10 floats to the main channel 11a via the narrow communication channel 11b. Therefore, it was possible to discharge by ink circulation. On the other hand, when the recording operation is repeated using the liquid supply member 10 in which the filter 14 is provided between the narrow communication channel 11b and the main channel 11a as shown in FIG. , And accumulated in the narrow communication channel 11b, and could not be discharged outside unless the recovery operation described above.

  As described above, in the present invention, the communication portion of the liquid supply member with the head is narrowed so that the influence of the circulating flow does not reach the meniscus of the nozzle. Accordingly, a circulating flow can be formed during the recording operation. By performing the recording while circulating the ink, bubbles are not accumulated, and the recording operation is not interrupted to discharge the bubbles, thereby improving the recording throughput.

Next, a second embodiment of the image forming apparatus according to the present invention will be described.
Here, the liquid supply member 10 according to the fourth embodiment (FIGS. 17 to 19) is used as the liquid supply member 10. For the liquid supply member 10, a member having a cross-sectional flow path shown in FIGS. 18 and 19 was prepared by cutting / bonding a transparent polycarbonate resin, and was adhered and fixed to the liquid ejection head 1. In FIG. 19, the internal dimensions of the liquid flow path member 10 were Wa: 7 mm, Ha: 6 mm, Hb: 4 mm, Yb: 1.5 mm, and Ls: 5 mm. As the ribs 16, first, three ribs 16a having a thickness of 0.4 mm are provided at both ends in the longitudinal direction of the opening to the common liquid chamber 7 at a pitch of 0.9 mm, and the thickness in the width direction of the opening is 0.5 mm. Two ribs 16b were provided on both sides at intervals of 0.9 mm.

  Then, a supply port 12 and a discharge port 13 are provided at both ends in the longitudinal direction of the liquid supply member 10, and in the ink supply system (in the liquid supply path) as shown in FIG. 40, as in the first embodiment of the image forming apparatus. Connected and evaluated bubble discharge | emission property. As a result, the bubbles could be discharged well by circulating the ink at a flow rate of 70 ml / min through the bubbles intentionally mixed in the liquid supply member 10. Further, there was no problem such as ink bleeding from the nozzle 5, and good image formation could be performed without ejection failure.

Next, a third embodiment of the image forming apparatus according to the present invention will be described with reference to FIG.
Here, the liquid supply member 10 described in the second embodiment of the image forming apparatus is connected in the liquid supply path (ink supply system) shown in FIG. This ink supply system is different from the ink supply system of FIG. 40 described above in that a flow rate adjusting valve V3 is provided on the downstream side of the discharge port 13 of the liquid supply member.

  Thus, by providing the flow rate adjusting valve V3 downstream of the discharge port 13, the flow rate (Qc) of the ink discharged from the discharge port 13 can be adjusted. Therefore, the liquid circulation is achieved by reducing the flow rate Qc. Ink can be pumped from the path 11 to the head 1. Thereby, the bubble discharge in the liquid circulation path 11 and the bubble discharge in the head 1 can be performed simultaneously.

Next, specific examples of the eleventh embodiment of the liquid supply member shown in FIG. 35 and the twelfth embodiment shown in FIGS. 36 and 37 will be described.
In this specific example, the internal dimensions of the liquid supply member 10 are the same as those described in the first embodiment of the image forming apparatus, but the liquid supply member 10 is made of two different materials. Specifically, the main channel forming portion 10a that forms the main channel 11a is polycarbonate resin, and the narrow communication channel forming portion 10b that forms the narrow communication channel 11b is SUS. The head 1 is of the thermal type described in the first embodiment of the image forming apparatus.

  Since the temperature of the head 1 is particularly high in the thermal method, the head driving frequency is usually lowered, recording is temporarily suspended, or the number of nozzles to be driven is reduced. Since the narrow communication flow path forming portion 10b is formed of a material having a high thermal conductivity, the temperature rise can be reduced by directly taking the heat of the head 1 by adopting a form in which the narrow communication flow path forming portion 10b is directly bonded to the head 1. In addition, since the narrow part of the flow path is made of a material having high thermal conductivity, the heat of the ink can be efficiently taken away, and stable image formation can be performed even when continuous recording is performed. It was.

  Further, as shown in the twelfth embodiment (FIGS. 36 and 37), a plurality of fins 15a and 15b are provided on both the inside and outside of the narrow communication flow path forming portion 10b of the liquid supply member 10. As a result, the heat radiation efficiency has increased, and it has become possible to print an image with a larger print duty at a high speed. Further, in this liquid supply member 10, since the fins 15a in the flow path have the longitudinal direction set to the longitudinal direction, the heat radiation capability can be improved without hindering the floating of bubbles from the head 1. Further, since the fins 15a in the flow path are formed in a direction perpendicular to the direction in which the circulation flow flows, and the fins 15a are also provided at the bottom of the main flow path 11a, the circulation flow in the narrow communication flow path 11b portion. This effectively suppresses the flow caused by circulatory flow and improves the resistance to meniscus destruction by circulating flow.

Next, a specific example of the eighth embodiment of the liquid supply member shown in FIG. 28 will be described.
As described above, the liquid supply member 10 has the supply port 12 at the center of the liquid supply member 10 and the discharge ports 13 at both ends in the longitudinal direction of the liquid supply member. Further, a rectifying member 18 is provided at a position in the liquid circulation path 11 that is directly below the supply port 12. The rectifying member 18 is formed with a curved surface on the upper surface of the supply port 12 so that the supplied ink can be smoothly divided in the direction of the two discharge ports 13, and the lower surface (bottom surface) retains bubbles floating from the head 1. An inclined surface was used so as not to let it go.

  When this liquid supply member 10 is connected to the ink supply system shown in FIG. 40 or FIG. 43 and the bubble discharge evaluation is performed at the same circulation flow rate, the time is shorter than the case described in the first embodiment of the image forming apparatus. Air bubbles could be discharged. As a comparative experiment, when the same evaluation was performed in a configuration in which the rectifying member was not provided as shown in FIG. 29, there was a problem that bubbles were likely to remain in the region Q of FIG. In addition, there was a problem that the meniscus of the nozzle at the center of the head was easily broken.

  The present invention can be applied to various liquid ejection type heads, but the thermal type heads described in the above-described embodiments are particularly suitable because they easily increase the temperature including ink. Among the thermal type heads, the above-described side shooter type head is more preferable because bubbles are easily generated inside the head and the generated bubbles easily flow into the common liquid chamber.

FIG. 3 is a perspective explanatory view showing a head unit configured by connecting a liquid supply member provided for explanation of the first embodiment of the liquid supply member according to the present invention to a liquid discharge head and integrated therewith. It is longitudinal direction sectional drawing of the head unit. FIG. 3 is a cross-sectional view in the short-side direction of the head unit along the line AA in FIG. 2. FIG. 6 is a longitudinal sectional view of a head unit for explaining the operation of the embodiment. FIG. 5 is a cross-sectional view in the short-side direction of the head unit taken along line BB in FIG. 4. FIG. 6 is a longitudinal sectional view of the head unit of Comparative Example 1; FIG. 7 is a cross-sectional explanatory view taken along line CC in FIG. 6. Similarly, it is a longitudinal sectional view of a head unit of Comparative Example 2. FIG. It is sectional explanatory drawing which follows the DD line | wire of FIG. FIG. 6 is a schematic explanatory view for explaining another different cross-sectional shape of the liquid circulation path in the same embodiment. It is a longitudinal direction sectional view of a head unit for explanation of a 2nd embodiment of a liquid supply member concerning the present invention. FIG. 12 is a cross-sectional view in the short-side direction of the same head unit taken along line EE in FIG. 11. FIG. 12 is a cross-sectional view in the short-side direction of the same head unit taken along line FF in FIG. 11. FIG. 6 is a longitudinal sectional view of a head unit for explaining a third embodiment of a liquid supply member according to the present invention. FIG. 15 is a plan sectional view of the head unit taken along line GG in FIG. 14. It is sectional drawing of the transversal direction of the head unit which follows the HH line of FIG. It is a longitudinal section of a head unit for explanation of a 4th embodiment of a liquid supply member concerning the present invention. FIG. 18 is a cross-sectional plan view of the head unit taken along line II in FIG. 17. FIG. 18 is a cross-sectional view in the short-side direction of the same head unit taken along line JJ in FIG. 17. It is a plane sectional view of a head unit used for explanation of a 5th embodiment of a liquid supply member concerning the present invention. FIG. 21 is a cross-sectional view in the short-side direction of the same head unit taken along line KK in FIG. 20. FIG. 22 is a cross-sectional view in the short-side direction of the same head unit taken along line KK of FIG. 20 in another example different from FIG. 21. It is sectional drawing of the transversal direction of the head unit with which it uses for description of 6th Embodiment of the liquid supply member which concerns on this invention. It is a longitudinal direction sectional view of a head unit used for explanation of a 7th embodiment of a liquid supply member concerning the present invention. FIG. 25 is a cross-sectional view in the short-side direction of the same head unit taken along line LL in FIG. 24. 10 is a longitudinal sectional view of a head unit of Comparative Example 3. FIG. FIG. 27 is a cross-sectional view in the short-side direction of the same head unit taken along line MM in FIG. 26. It is a longitudinal cross-sectional view of the head unit with which it uses for description of 8th Embodiment of the liquid supply member which concerns on this invention. It is a longitudinal direction sectional view of a head unit of comparative example 4 used for explanation of operation of the embodiment. 10 is a cross-sectional view in the short-side direction of a head unit of Comparative Example 5. FIG. It is longitudinal direction sectional drawing of the head unit with which it uses for description of 9th Embodiment of the liquid supply member which concerns on this invention. FIG. 32 is a cross-sectional view in the short-side direction of the same head unit taken along line NN in FIG. 31. It is longitudinal direction sectional drawing of the head unit with which it uses for description of 10th Embodiment of the liquid supply member which concerns on this invention. FIG. 34 is a cross-sectional view in the short-side direction of the same head unit taken along the line OO in FIG. 33. It is sectional drawing of the transversal direction of the head unit with which it uses for description of 11th Embodiment of the liquid supply member which concerns on this invention. It is sectional drawing of the transversal direction of the head unit with which it uses for description of 12th Embodiment of the liquid supply member which concerns on this invention. FIG. 37 is an explanatory cross-sectional view taken along the line P-P in FIG. 36. 1 is a configuration diagram for explaining a first embodiment of an image forming apparatus according to the present invention; It is explanatory drawing which shows the state at the time of the maintenance recovery of the apparatus. FIG. 3 is a schematic explanatory diagram for explaining a liquid supply path of the apparatus. FIG. 6 is an explanatory diagram for explaining a maintenance / recovery operation of the image forming apparatus. It is explanatory drawing similarly used for description of a maintenance recovery operation | movement. FIG. 6 is a schematic explanatory diagram for explaining a liquid supply path of the image forming apparatus according to the third embodiment of the present invention.

Explanation of symbols

1. Liquid discharge head (recording head)
DESCRIPTION OF SYMBOLS 2 ... Heat generating body substrate 3 ... Flow path formation member 5 ... Nozzle 6 ... Liquid chamber 7 ... Common liquid chamber 10 ... Liquid supply member 11 ... Liquid circulation path 11a ... Main trunk flow path 11b ... Narrow communication flow path 11c ... Liquid buffer flow path 16 ... ribs

Claims (14)

A liquid supply member that is connected to a liquid discharge head having a common liquid chamber that supplies liquid to a plurality of liquid chambers that communicate with a plurality of nozzles that discharge droplets, and that supplies the liquid to the common liquid chamber of the liquid discharge head; There,
The liquid supply member has a liquid circulation path through which the liquid circulates along the direction in which the nozzles of the liquid ejection head are arranged.
At the end of the liquid circulation path in the longitudinal direction, a supply port for supplying liquid to the liquid circulation path and a discharge port for discharging liquid from the liquid circulation path are provided,
A communication port communicating with the common liquid chamber is provided on the common liquid chamber side of the liquid circulation path,
A liquid supply member for a liquid discharge head, wherein the communication port is narrower than the liquid circulation path, and at least one of the supply port side and the discharge port side is deeper than the other part. A liquid supply member that is connected to a liquid discharge head having a common liquid chamber that supplies liquid to a plurality of liquid chambers that communicate with a plurality of nozzles that discharge droplets, and that supplies the liquid to the common liquid chamber of the liquid discharge head; There,
The liquid supply member has a liquid circulation path through which the liquid circulates along the direction in which the nozzles of the liquid ejection head are arranged.
At the end of the liquid circulation path in the longitudinal direction, a supply port for supplying liquid to the liquid circulation path and a discharge port for discharging liquid from the liquid circulation path are provided,
A communication port communicating with the common liquid chamber is provided on the common liquid chamber side of the liquid circulation path,
A liquid supply member for a liquid discharge head, wherein a rib is disposed around the communication port. A liquid supply member that is connected to a liquid discharge head having a common liquid chamber that supplies liquid to a plurality of liquid chambers that communicate with a plurality of nozzles that discharge droplets, and that supplies the liquid to the common liquid chamber of the liquid discharge head; There,
The liquid supply member has a liquid circulation path through which the liquid circulates along the direction in which the nozzles of the liquid ejection head are arranged.
At the end of the liquid circulation path in the longitudinal direction, a supply port for supplying liquid to the liquid circulation path and a discharge port for discharging liquid from the liquid circulation path are provided,
A liquid supply member for a liquid discharge head, wherein a rib is formed on an inner wall surface of the liquid circulation path on the common liquid chamber side.   4. The liquid supply member of the liquid discharge head according to claim 2, wherein the rib has a relatively higher height at the supply port side and at the discharge port side of the liquid circulation path than at other portions. Liquid supply member for liquid discharge head A liquid supply member that is connected to a liquid discharge head having a common liquid chamber that supplies liquid to a plurality of liquid chambers that communicate with a plurality of nozzles that discharge droplets, and that supplies the liquid to the common liquid chamber of the liquid discharge head; There,
The liquid supply member has a liquid circulation path through which the liquid circulates along the direction in which the nozzles of the liquid ejection head are arranged.
At the end of the liquid circulation path in the longitudinal direction, a supply port for supplying liquid to the liquid circulation path and a discharge port for discharging liquid from the liquid circulation path are provided,
The flow path cross section of the liquid circulation path orthogonal to the flow when the liquid flows from the supply port toward the discharge port has a shape in which a substantially central part is narrowed and both sides have a large area, A liquid supply member for a liquid discharge head, wherein a large area portion communicates with an opening of the common liquid chamber, and the supply port and the discharge port are provided on the other large area portion side.   6. The liquid supply member for a liquid discharge head according to claim 5, wherein a rib formed on a wall surface in a short direction of the liquid circulation path is orthogonal to a flow when the liquid flows from the supply port to the discharge port. A liquid supply member for a liquid discharge head, wherein a cross section of the liquid circulation path has a shape in which a substantially central portion is narrowed and both sides have a large area.   The liquid supply member for a liquid discharge head according to any one of claims 1 to 6, wherein a cross section of the flow path in a direction perpendicular to the flow when the liquid flows from the supply port to the discharge port is convex upward A liquid supply member for a liquid discharge head, wherein   8. The liquid supply member for a liquid discharge head according to claim 1, wherein there is no portion that impedes liquid flow between the upper opening of the common liquid chamber and the top surface of the liquid circulation path. A liquid supply member for a liquid discharge head. A liquid supply member that is connected to a liquid discharge head having a common liquid chamber that supplies liquid to a plurality of liquid chambers that communicate with a plurality of nozzles that discharge droplets, and that supplies the liquid to the common liquid chamber of the liquid discharge head; There,
The liquid supply member has a liquid circulation path through which the liquid circulates along the direction in which the nozzles of the liquid ejection head are arranged.
A supply port for supplying liquid to the liquid circulation path and a discharge port for discharging liquid from the liquid circulation path are provided,
Either the supply port or the discharge port is provided in a portion other than the longitudinal end portion of the liquid circulation path, and the common liquid chamber corresponds to the port provided in the portion other than the longitudinal end portion. A liquid supply member for a liquid discharge head, characterized in that a flow straightening member for adjusting the flow is provided therebetween.   10. The liquid supply member for a liquid discharge head according to claim 1, wherein a portion forming the communication port is formed of a high thermal conductivity material.   7. The liquid supply member for a liquid discharge head according to claim 2, wherein the rib is formed of a high thermal conductivity material. A liquid supply member that is connected to a liquid discharge head having a common liquid chamber that supplies liquid to a plurality of liquid chambers that communicate with a plurality of nozzles that discharge droplets, and that supplies the liquid to the common liquid chamber of the liquid discharge head; There,
The liquid supply member has a liquid circulation path through which the liquid circulates along the direction in which the nozzles of the liquid ejection head are arranged.
At the end of the liquid circulation path in the longitudinal direction, a supply port for supplying liquid to the liquid circulation path and a discharge port for discharging liquid from the liquid circulation path are provided,
A communication port communicating with the common liquid chamber is provided on the common liquid chamber side of the liquid circulation path,
The liquid supply member for a liquid discharge head, wherein the communication port is narrower than the liquid circulation path.   13. A liquid ejection apparatus for ejecting liquid droplets from a liquid ejection head, comprising the liquid supply member according to claim 1 for supplying a liquid to the liquid ejection head. apparatus.   13. An image forming apparatus that forms an image by ejecting liquid droplets from a liquid ejection head, comprising the liquid supply member according to any one of claims 1 to 12 for supplying a liquid to the liquid ejection head. An image forming apparatus.

Images