JP6312547B2 - Inkjet head and printer - Google Patents

Description

  The present invention relates to an inkjet head and a printer used in an inkjet printer.

  There is a patent document in which an ink jet head having a heater (different from a heater for generating bubbles in a thermal ink jet head) is disclosed (for example, Patent Document 1). In Patent Document 1, in a piezo ink jet head, a resistor serving as a heater is formed on a piezoelectric actuator substrate for the purpose of increasing the temperature of the ink and lowering the viscosity of the ink.

JP 2008-55899 A

  In the technique of Patent Document 1, various inconveniences occur. For example, since the piezoelectric actuator substrate is provided with a heater, the piezoelectric actuator substrate becomes complicated, and the cost of the piezoelectric actuator substrate may increase. The piezoelectric actuator substrate is stacked on a thin plate-like flow path member in which nozzles and pressure chambers are formed, and the heater of the piezoelectric actuator substrate heats a relatively small amount of ink contained in the flow path member. As a result, the amount of ink discharged has a great influence on the temperature of the ink, which may make it difficult to stabilize the viscosity of the ink.

  Therefore, it is desirable to provide an inkjet head that can heat ink more suitably.

  An ink jet head according to an aspect of the present invention includes: a head body having a plurality of nozzles that open in a predetermined opening direction; a drive unit that generates a driving force for discharging ink from the plurality of nozzles; and the opening direction. A plurality of ink supply paths that extend from the opposite direction toward the head body, are arranged in a direction perpendicular to the opening direction, and communicate with the head body; and are positioned in the opposite direction with respect to the head body; A first heater having a size extending over an array of the plurality of ink supply paths.

  An inkjet head according to another aspect of the present invention includes a head body having a plurality of nozzles and a drive unit that generates a driving force for ejecting ink from the plurality of nozzles, and a wall portion that communicates with the head body. A plurality of ink buffer portions each having at least a portion made of a flexible film, the volume of which can be changed, and a heater; and the plurality of ink buffer portions have a wall between adjacent ink buffer portions. The first and second buffer groups are configured by sharing the parts, and the heater is located between the first and second buffer groups.

  Preferably, the drive unit is a piezoelectric actuator substrate, and the piezoelectric actuator substrate, the first buffer group, the heater, and the second buffer group are arranged in a direction opposite to a direction in which the plurality of nozzles are opened. These are arranged in this order.

  Preferably, the apparatus further includes a driver IC for driving and controlling the driving unit, and the driver IC, the first buffer group, the heater, and the second buffer group are arranged in a predetermined direction in this order. The first buffer group includes an ink buffer unit for black ink.

  Preferably, the first buffer group includes first and second ink buffer portions sharing a wall portion facing the driver IC, and the driver IC of the first and second ink buffer portions. The ink buffer portion located on the side is for black ink.

  Preferably, five or more of the plurality of ink buffer portions are provided, and each of the first and second buffer groups includes two ink buffer portions sharing a wall portion facing the heater, At least one of the first and second buffer groups includes two ink buffer portions arranged along the wall portion facing the heater.

  Suitably, the said heater is a film heater and comprises the said flexible film of the said ink buffer part.

  A printer according to an aspect of the present invention includes the inkjet head, a scanning unit that relatively moves the medium and the inkjet head, and a control unit that controls the inkjet head.

  According to said structure, an ink can be heated more suitably. For example, the piezoelectric actuator substrate can be simplified and / or the ink temperature can be stably controlled.

FIG. 2 is a perspective view schematically illustrating a main part of the printer according to the embodiment of the invention. The perspective view which shows typically the principal part of the inkjet head of the printer of FIG. The perspective view seen from the direction different from FIG. 2 which shows typically the principal part of the inkjet head of the printer of FIG. FIG. 4 is a schematic cross-sectional view taken along line IV-IV in FIG. 2. FIG. 5A and FIG. 5B are schematic cross-sectional views showing a specific example of the first heater and another specific example. 6A and 6B are schematic cross-sectional views showing specific examples and modifications of the second heater. The typical sectional view showing the modification of a buffer part.

  Hereinafter, an inkjet head according to the present embodiment will be described with reference to the drawings. For the same or similar configurations, different numbers (“first”, “second”) and capital letters (““ first ink supply path 45A ”,“ second ink supply path 45B ”) A ”and“ B ”). In this case, the same or similar configuration such as “ink supply path 45” may not be distinguished by omitting numbers and capital letters.

  FIG. 1 is a perspective view schematically showing a main part of a printer 1 according to an embodiment of the present invention.

  The printer 1 is an ink jet printer. More specifically, for example, the printer 1 is a piezo head type, serial head type, and off-carriage type color printer. The printer 1 may realize a color image with an appropriate number of colors of ink, but in this embodiment, it is assumed that a color image is realized with four colors of black, yellow, magenta, and cyan.

  The printer 1 includes, for example, a transport unit 3 that transports a medium (for example, paper) 101 in a transport direction indicated by an arrow y 1, a head 5 that ejects ink droplets toward the transported medium 101, and the head 5 as a medium 101. Controls the operation of the printer 1 including the scanning unit 7 that reciprocates in the sub-scanning direction (arrow y2) perpendicular to the conveyance direction, the ink cartridge 9 that supplies ink to the head 5, and the ink ejection operation from the head 5. And a control unit 11 that performs.

  As the ink droplets are ejected from the head 5 to the medium 101 repeatedly in a range extending in the main scanning direction, which is a direction orthogonal to the sub-scanning direction, the head 5 is reciprocated by the scanning unit 7. A strip-shaped two-dimensional image is formed on the medium 101. Further, the medium 101 is intermittently conveyed by the conveyance unit 3, so that a continuous two-dimensional image is formed on the medium 101 by connecting the band-shaped two-dimensional images.

  For example, the transport unit 3 transports a plurality of media 101 stacked on a supply stack (not shown) one by one to a discharge stack (not shown). The transport unit 3 may have a known appropriate configuration. In FIG. 1, the conveyance path 3 is illustrated as a straight path, and includes a conveyance unit 3 having a roller 13 that contacts the medium 101, a motor 15 that rotates the roller 13, and a driver 17 that applies drive power to the motor 15. Yes.

  The scanning unit 7 may have a known appropriate configuration. For example, the scanning unit 7 includes a guide rail (not shown) that supports a carriage (not shown) on which the head 5 is mounted so that it can be guided in the sub-scanning direction, a belt (not shown) fixed to the carriage, and the belt spans. And a motor 19 that rotates the pulley, and a driver 21 that applies driving power to the motor 19. The head 5 may be defined including a carriage, but in the following description, the head 5 is described as not including a carriage.

  The ink cartridge 9 is installed at a location different from the head 5 (so as not to move with the head 5). The ink cartridge 9 is connected to the head 5 via a flexible tube. A plurality (four in this embodiment) of ink cartridges 9 are provided corresponding to the number of ink colors ejected by the head 5.

  The control unit 11 includes, for example, a CPU, a ROM, a RAM, and an external storage device. The control unit 11 outputs control signals to the driver 17 of the transport unit 3, the driver 21 of the scanning unit 7, and the driver (described later) of the head 5, and controls the operations of the transport unit 3, the scanning unit 7, and the head 5.

  FIG. 2 is a perspective view showing the main part of the head 5 as seen from the positive side in the z direction. FIG. 3 is a perspective view showing the main part of the head 5 as seen from the negative side in the z direction. 4 is a cross-sectional view taken along line IV-IV in FIG.

  2 and 3, for convenience of illustration, some of the members shown in FIG. 4 are omitted or shown by dotted lines. In FIG. 4, a part of the cross section other than the line IV-IV is shown. In FIG. 4, an arrow that does not indicate a leader line or a coordinate system indicates the flow of ink.

  The head 5, for example, a head main body 23 that ejects ink droplets, an ink supply member 25 that supplies ink to the head main body 23, a driver IC 27 (FIG. 4) that controls the operation of the head main body 23, and heats the ink. The first heater 29 and the second heater 31 are provided.

  The head main body 23 has, for example, a generally thin rectangular parallelepiped shape, and has a first surface 23a facing the medium 101 and a second surface 23b on the back side thereof. The head body 23 includes a flow path member 33 that forms an ink flow path, and a piezoelectric actuator substrate 35 that generates a driving force for ejecting ink from the flow path member 33.

  The flow path member 33 is formed, for example, roughly in a thin rectangular parallelepiped shape, and constitutes the first surface 23a. The flow path member 33 has a flow path for each color, and a plurality of flow paths corresponding to a plurality of colors are sequentially arranged in the sub-scanning direction (x direction), for example. As shown in FIG. 4, the flow paths corresponding to the respective colors include a plurality of nozzles 33 a that open to the first surface 23 a, a plurality of pressure chambers 33 b that are not illustrated that communicate with the plurality of nozzles 33 a, and a plurality that is not illustrated. A common channel 33c communicating with the pressure chamber, and a supply port 33d located at an end of the common channel 33c.

  In the flow path corresponding to each color, the plurality of nozzles 33a and the plurality of pressure chambers 33b are arranged, for example, in the main scanning direction (y direction), and two or four of these arrangements are arranged in parallel in the sub-scanning direction. Is arranged. For example, the common flow path 33c extends along the array between the arrays of the plurality of nozzles 33a.

  Although not particularly illustrated, the flow path member 33 is configured, for example, by laminating a plurality of plate-like members formed with through holes or grooves serving as flow paths in the z direction. The plurality of plate-like members are made of metal, for example. In addition, the plate-shaped member which comprises the 1st surface 23a may be comprised with resin, and another plate-like member may be comprised with a metal.

  The piezoelectric actuator substrate 35 is formed in, for example, a thin plate shape that covers most of the flow path member 33 (portion excluding the supply port 33d), and constitutes the second surface 23b. The piezoelectric actuator substrate 35 is formed of, for example, a unimorph type piezoelectric actuator substrate. Although not particularly illustrated, an elastic body, a common electrode, a piezoelectric body, and a plurality of individual electrodes are laminated in order from the flow path member 33 side. It is configured.

  The elastic body constitutes the upper surface of the plurality of pressure chambers 33b. A potential different from that of the common electrode is selectively applied to the plurality of individual electrodes. When a voltage is applied between the individual electrode and the common electrode, the elastic body bends due to the inverse piezoelectric effect of the piezoelectric body. Thereby, pressure is applied to the ink in the pressure chamber 33b, and ink droplets are ejected from the nozzle 33a.

  The ink supply member 25 includes, for example, a (non-flexible) base 37 in which a groove or a through hole through which ink flows is formed, and flexible first film 39A to fifth film 39E (on the base 37). 4).

  The base 37 is made of, for example, a resin. In the drawing, the base body 37 is shown as if it was integrally formed. However, actually, a plurality of members may be appropriately combined. The film 39 is affixed to the base 37 with an adhesive or the like so as to cover the concave groove or the like of the base 37, and constitutes an ink flow path between the base 37 and the film 39. The film 39 is made of resin, for example.

  The ink supply member 25 is, for example, a first ink introduction path 41A to a fourth ink introduction path 42D (41A to 41D in FIG. 4 to 41A), first buffer portion 43A to fourth buffer portion 43D (43B and 43D in FIG. 2, 43A and 43C in FIG. 3, 43A to 43D in FIG. 4), and first ink supply path 45A to fourth. An ink supply path 45D (45A to 45D in FIGS. 2 and 3 and 45A in FIG. 4) is provided.

  The ink introduction path 41, the buffer unit 43, and the ink supply path 45 are connected to each other with the same capital letters (A to D) attached to each other, and the ink introduction path 41 and the buffer unit connected to each other. Each of the combinations 43 and the ink supply path 45 corresponds to ink of each color.

  The plurality of ink introduction paths 41 are, for example, schematically summarized. The plurality of buffer units 43 are summarized and summarized, for example. The plurality of ink supply paths 45 are, for example, schematically summarized. For example, the plurality of ink introduction paths 41, the plurality of buffer units 43, and the plurality of ink supply paths 45 are roughly arranged in this order in an appropriate direction (for example, the y direction).

  The plurality of ink introduction paths 41 are configured, for example, by forming a plurality of concave grooves on one main surface of a substantially thin rectangular parallelepiped portion of the base body 37 and closing the plurality of concave grooves with the fifth film 39E. ing. The plurality of ink introduction paths 41 (grooves) are separated from each other by, for example, ribs of the base 37 and are adjacent to each other (the ribs are shared). A portion of the base 37 where the plurality of ink introduction paths 41 are formed is, for example, parallel to the head body 23, and by extension, the plurality of ink introduction paths 41 extend in a plane parallel to the head body 23.

  The base 37 is formed with a first introduction port 47A to a fourth introduction port 47D (47A to 47D in FIGS. 2 and 3 and 47A in FIG. 4) that open to the ends of the plurality of ink introduction paths 41. The plurality of introduction ports 47 are arranged in a line in an appropriate direction, for example. For example, a plurality of tubes connected to the plurality of cartridges 9 are connected to the plurality of introduction ports 47 through connector parts (not shown). Thereby, ink is supplied to the plurality of ink introduction paths 41.

  2 to 4 are schematic diagrams, the plurality of ink introduction paths 41 extend linearly in the same direction, but may actually be bent appropriately. For example, the plurality of introduction ports 47 are arranged in a line in the y direction, and the plurality of ink introduction paths 41 extend from the plurality of introduction ports 47 in the x direction with different lengths and then bend and extend in the y direction. Also good.

  The plurality of buffer units 43 are grouped in two. That is, the first buffer unit 43A and the second buffer unit 43B constitute a first buffer group 49A (FIG. 4), and the third buffer unit 43C and the fourth buffer unit 43D constitute a second buffer group 49B (FIG. 4). doing.

  In each buffer group 49, the two buffer portions 43 are configured by forming recesses on both main surfaces of the substantially thin rectangular parallelepiped portion of the base body 37 and closing the two recesses with the film 39. Thus, in each buffer group 49, the buffer parts 43 are put together by partitioning the plurality of buffer parts 43 by the wall part (concave bottom part) made of the base body 37 (sharing the wall part in common) ( Grouped.)

  In each buffer group 49, the two buffer portions 43 are configured to be partitioned by a wall portion facing the head body 23, and are provided in a stacked manner in the direction in which the head body 23 faces. Further, the two buffer groups 49 are disposed so as to be stacked and separated from each other in the direction in which the head body 23 faces.

  The shape of the buffer unit 43 is, for example, a thin rectangular parallelepiped shape. However, the buffer part 43 may be provided with a rib for rectification inside thereof, or may have a shape other than a rectangle in plan view. Further, the height of the bottom surface of the buffer portion 43 (the bottom surface of the concave portion of the base body 37) may be formed so as to change locally.

  For example, the ink introduction path 41 and the buffer unit 43 are formed by a first introduction side communication path 51A to a fourth introduction side communication path 51D mainly composed of the base body 37 (51A to 51D in FIGS. 2 and 3 and 51A in FIG. 4). ). As a result, the ink in the ink introduction path 41 is supplied to the buffer unit 43. The plurality of introduction-side communication paths 51 extend, for example, from the end portions of the plurality of ink introduction paths 41 to the negative side in the z direction with a length corresponding to the position in the z direction of the corresponding buffer part 43.

  2 to 4 are schematic diagrams, the plurality of introduction side communication paths 51 do not cross each other, and the arrangement direction and arrangement order on the plurality of ink introduction paths 41 side, and the plurality of buffers. The arrangement direction and arrangement order on the part 43 side are the same. However, in practice, the plurality of introduction side communication passages 51 may appropriately cross each other, and the end portions thereof may be at appropriate positions. For example, in the two introduction side communication passages 51 connected to the two buffer portions 43 of each buffer group 49, one introduction side communication passage 51 is a corner portion on the x direction positive side and the y direction positive side of the buffer portion 43. The other introduction side communication passage 51 may be opened at the corner of the buffer part 43 on the x direction negative side and the y direction positive side.

  For example, the ink supply path 45 is mainly configured by a through hole formed in the base 37. The plurality of ink supply paths 45 extend, for example, from the side opposite to the side where the plurality of nozzles 33 a are opened toward the head body 23, and are arranged in a line along one edge of the head body 23. . The arrangement direction is, for example, the sub-scanning direction (x direction), and is a direction orthogonal to the arrangement direction of the plurality of ink introduction paths 41, the plurality of buffer units 43, and the plurality of ink supply paths 45. The shape of the cross section (cross section orthogonal to the z direction) of the ink supply path 45 may be an appropriate shape such as a circle, an ellipse, or a rectangle, and the shape and area of the cross section are constant in the z direction. It may be different or different.

  Note that the through-hole constituting the ink supply path 45 is configured by, for example, forming a plurality of cylindrical portions 37 a on the base 37. 2 to 4 are schematic diagrams, the cross section of each cylindrical portion 37a is rectangular, and the plurality of cylindrical portions 37a have the same shape and size and are arranged on a straight line. As a result, the plurality of cylindrical portions 37a have shapes that cannot be individually identified from the outer surface. Actually, the plurality of cylindrical portions 37a may be formed in a shape that can be individually identified from the outer surface. For example, the inner and outer corners of each tubular portion 37a are chamfered, the shapes and sizes of the plurality of tubular portions 37a are different from each other, or the arrangement of the plurality of tubular portions 37a is slightly deviated from a straight line. May be.

  The buffer unit 43 and the ink supply path 45 are, for example, a first derivation side communication path 53A to a fourth derivation side communication path 53D (53A to 53D in FIG. 2, 53A and 53C in FIG. In FIG. 4, they are communicated by 53A). As a result, the ink in the buffer unit 43 is supplied to the ink supply path 45. For example, the plurality of lead-out side communication passages 53 extend from the end portions of the plurality of buffer portions 43 to the top of the ink supply path 45 with a length corresponding to the position of the corresponding buffer portion 43 in the z direction.

  2 to 4 are schematic diagrams, the plurality of outlet communication paths 53 do not cross each other, and the arrangement direction and arrangement order on the plurality of buffer units 43 side, and the plurality of ink supplies. The arrangement direction and arrangement order on the path 45 side are the same. However, in practice, the plurality of outlet side communication passages 53 may appropriately cross each other, and the end portions thereof may be at appropriate positions. For example, in the two outlet side communication paths 53 connected to the two buffer parts 43 of each buffer group 49, one outlet side communication path 53 is an end of the buffer part 43 on the positive side in the x direction and the negative side in the y direction. The other lead-out side communication passage 53 may be located at the negative end of the buffer 43 in the x direction negative side and the y direction negative side.

  2 to 4 are schematic diagrams, the introduction side communication path 51 and the outlet side communication path 53 connected to each other via the buffer unit 43 have the same connection position with respect to the buffer unit 43 in the x direction. However, in actuality, the positions of the connection to the buffer unit 43 may be different from each other in the x direction, such as being located on the diagonal line of the buffer unit 43.

  The tip of the ink supply path 45 is connected to, for example, a supply port 33d that opens on the main surface of the flow path member 33 opposite to the first surface 23a. As a result, ink is supplied from the ink supply path 45 to the flow path member 33. The ink supply member 25 and the flow path member 33 are fixed by, for example, fixing them to a carriage (not shown).

  In the ink supply member 25, which color of ink is assigned to which flow path may be appropriately set. However, it is preferable that black ink is allocated to the first buffer unit 43A located closest to the head body 23 (driver IC 27 side) among the plurality of buffer units 43. In the ink supply member 25, the plurality of flow paths corresponding to the plurality of colors of ink may have substantially the same cross-sectional area and length as each other, or the cross-sectional area and / or length of the flow path of a specific color ink. The length may be greatly different from the cross-sectional area and / or length of the flow path of the other color ink.

  The driver IC 27 is electrically connected to the piezoelectric actuator substrate 35 via the FPC 55, for example. Specifically, for example, the FPC 55 includes a facing portion 55 a that faces the piezoelectric actuator substrate 35 and an extending portion 55 b that extends from the piezoelectric actuator substrate 35. Although not particularly illustrated, a plurality of extraction electrodes extracted from the plurality of individual electrodes are exposed on the surface of the piezoelectric actuator substrate 35 opposite to the flow path member 33, and the plurality of extraction electrodes are opposed to the opposing portion. The plurality of pads 55a are joined by a plurality of bumps. As a result, the FPC 55 is fixed and electrically connected to the piezoelectric actuator substrate 35. The driver IC 27 is mounted on the extending portion 55b. Note that the FPC 55 is connected to the control unit 11 via, for example, another FPC (not shown) and / or a cable.

  For example, the driver IC 27 is disposed on the opposite side of the head body 23 from the side on which the nozzle 33a is opened. For example, in the example of FIG. 4, the driver IC 27 is disposed in a stacked manner with respect to the piezoelectric actuator substrate 35 by bending the FPC 55 and overlapping the extending portion 55 b with the facing portion 55 a. The extending portion 55b is fixed to the head main body 23 by, for example, an adhesive or an appropriate member. A member interposed between the facing portion 55a and the extending portion 55b and appropriately positioning the extending portion 55b and / or the driver IC 27 may be provided.

  The shape and size of the driver IC 27 and the position with respect to the head main body 23 in plan view may be set as appropriate. For example, the driver IC is formed in a long shape, and is arranged at the end or the center of the head main body 23 with the longitudinal direction facing the x direction or the y direction.

  For example, data on the amount of ink to be ejected for all the nozzles 33a is input from the control unit 11 to the driver IC 27 for each predetermined driving cycle. The driver IC 27 applies a reference potential to the common electrode and selectively outputs a drive signal having a predetermined waveform to the plurality of individual electrodes based on the input data. In addition, the driver IC 27 sets, for example, the number of times of outputting one of a plurality of drive vibrations prepared in advance or outputting the drive signal within the drive cycle based on the input data.

  The first heater 29 is disposed in a space surrounded by the head main body 23, the plurality of ink supply paths 45, and the first buffer portion 43A (the one closest to the head main body 23 among the plurality of buffer portions 43). Preferably, the first heater 29 is located entirely or partially on the ink supply path 45 side with respect to the center of the head main body 23 in a plan view of the head main body 23. From another viewpoint, preferably, the first heater 29 is adjacent to the cylindrical portion 37 a constituting the ink supply path 45. Further, the first heater 29 has a size that extends across the plurality of ink supply paths 45 in the x direction (the ink supply paths 45 at both ends may not extend completely). Therefore, the first heater 29 can heat the ink in the ink supply member 25, particularly the ink in the ink supply path 45.

  The second heater 31 is disposed in a space surrounded by the two buffer groups 49 and the plurality of ink supply paths 45. Further, the second heater 31 faces the flexible wall portion (film 39) of the buffer portion 43, and is preferably ½ or more of the area of the film 39, more preferably equivalent to the film 39. Has an area of Further, preferably, the second heater 31 has a size extending over the plurality of ink supply paths 45 in the x direction. Therefore, the second heater 31 can heat the ink in the ink supply member 25, particularly the ink in the plurality of buffer units 43.

  The first heater 29 and the second heater 31 are configured to include, for example, a conductor having a relatively high resistance value, and generate heat when power is supplied. These heaters may be, for example, chip type or film type. For example, the film heater may have a structure in which heating wires extending in a predetermined pattern such as a meander shape are sandwiched between insulating films. The heating wire is made of, for example, nichrome or iron / chromium / aluminum alloy. Further, the film heater may have a structure in which an insulating film and a conductive film are overlapped, and electrodes for applying a voltage are arranged on both edges of the conductive film. The conductive film is made of, for example, carbon, tin oxide, or graphite.

  The driver IC 27 or another driver (not shown) supplies power to the first heater 29 and the second heater 31 based on a control signal from the control unit 11 and controls the operation of these heaters. Although not particularly illustrated, a temperature sensor for detecting the temperature of each heater and / or ink may be provided at an appropriate position in the head 5. Then, feedback control of each heater may be performed by the control unit 11 or the driver of each heater based on the temperature detected by the temperature sensor.

  As described above, in the present embodiment, the first heater 29 and the second heater 31 are not provided on the piezoelectric actuator substrate 35 to heat the ink in the head main body 23, but basically the ink supply member 25. The ink in the ink supply member 25 is heated by being arranged. Therefore, for example, the piezoelectric actuator substrate 35 can have the same configuration as the conventional one, and the complexity of the piezoelectric actuator substrate 35 is reduced. Further, for example, since a relatively large amount of ink in the ink supply member 25 is heated, the influence of the ink ejection amount on the change in the ink temperature is reduced, and the ink can be stably maintained at a constant temperature. it can.

  The ink is also heated by heat from the driver IC 27, the piezoelectric actuator substrate 35, and the like. Therefore, the first heater 29 and the second heater 31 can contribute to quickly raising the temperature of the ink when the printer 1 is started, that is, when the ink is not yet heated by the driver IC 27 or the like. That is, the heater can contribute to quickly bringing the printer 1 into a steady state. When the heater is used in this way, the target temperature of the ink is the temperature of the ink when the heater 1 is not heated and the printer 1 is in a steady state.

  In addition, the first heater 29 and the second heater 31 are configured so that, for example, the temperature of the ink is maintained at a temperature equal to or higher than the temperature that the ink heated by the driver IC 27 or the like can reach in the steady state of the printer 1. Regardless of the driving state (image type) of the IC 27 or the like, it is possible to contribute to managing the temperature of the ink constant.

  More specifically, the head 5 of the present embodiment includes a plurality of nozzles 33a that open in a predetermined opening direction (z-direction negative side) and a piezoelectric actuator substrate 35 that generates a driving force for ejecting ink from the plurality of nozzles 33a. A plurality of ink supply paths 45 extending from the direction opposite to the opening direction (z-direction positive side) toward the head main body 23 and arranged in a direction orthogonal to the opening direction (x-direction) and leading into the head main body 23. The first main body 23 is positioned in a direction opposite to the opening direction (z-direction positive side) with respect to the head main body 23 (including an aspect in which a part of the head main body 23 is positioned), and has a size extending over an array of the plurality of ink supply paths 45. Heater 29 (or second heater 31).

  Accordingly, it is possible to heat a relatively large amount of ink immediately before flowing to the head main body 23 in the plurality of ink supply paths 45. As a result, the ink temperature can be controlled efficiently and stably.

  The head 5 communicates with the head body 23 having a plurality of nozzles 33a and a piezoelectric actuator substrate 35 that generates a driving force for discharging ink from the plurality of nozzles 33a, and at least a part of the wall portion is allowed. It has a plurality of buffer parts 43 which are constituted by a flexible film 39 and whose volume can be changed, and a second heater 31. The plurality of buffer units 43 are grouped by sharing a wall portion between the adjacent buffer units 43, and thereby a first buffer group 49A and a second buffer group 49B are configured. The second heater 31 is positioned between the first buffer group 49A and the second buffer group 49B (including a mode in which a part is positioned).

  Therefore, the change in the volume of the buffer unit 43 absorbs the ink pressure fluctuation due to the sudden increase / decrease in the ink ejection amount, and the influence of the pressure fluctuation on the image quality can be reduced. And since the 2nd heater 31 is arrange | positioned between the several buffer part 43 put together into two, it can heat the ink corresponding to a several color efficiently. In addition, the buffer part 43 is often formed to be relatively shallow and wide with the direction facing the flexible wall part (film 39) as the thickness direction so that the pressure fluctuation can be effectively absorbed. That is, in the buffer unit 43, the surface area of the ink is often increased. Also by this, the second heater 31 can efficiently heat the ink. In particular, the second heater 31 can effectively heat the ink by facing the buffer portion 43 in a relatively wide area in the thickness direction of the buffer portion 43. Can be heated.

  In the present embodiment, the head body 23 has a piezoelectric actuator substrate 35. The piezoelectric actuator substrate 35, the first buffer group 49A, the second heater 31, and the second buffer group 49B are arranged in this order in the direction opposite to the opening direction of the plurality of nozzles 33a.

  Therefore, for example, the heat of the second heater 31 is transmitted to the ink in the buffer unit 43 of the first buffer group 49 </ b> A, and this ink flows through the buffer unit 43. Accordingly, the heat of the second heater 31 is not easily transmitted directly to the piezoelectric actuator substrate 35. As a result, the piezoelectric actuator substrate 35 is affected by the heat of the second heater 31 for controlling the ink temperature, and the possibility that the characteristics of the piezoelectric actuator substrate 35 fluctuate is reduced.

  In the present embodiment, the head 5 further includes a driver IC 27 that drives and controls the piezoelectric actuator substrate 35. Further, the driver IC 27, the first buffer group 49A, the second heater 31, and the second buffer group 49B are arranged in this order in a predetermined direction (a direction opposite to the opening direction of the plurality of nozzles 33a). The first buffer group 49A includes a first buffer unit 43A for black ink.

  Therefore, it is easy to raise the temperature of the inks of a plurality of colors evenly. Specifically, first, black ink is generally used in a larger amount than other color inks. Therefore, in order to maintain the temperature of the black ink at a temperature equivalent to that of the other color ink, it is necessary to apply a larger amount of heat to the black ink than to the other color ink. On the other hand, since the driver IC 27 generates heat, the black ink contained in the first buffer group 49A arranged on the driver IC 27 side can be intensively heated by the driver IC 27. In addition, the driver IC 27 increases the amount of power applied to the piezoelectric actuator substrate 35 as a larger amount of ink is ejected from the head body 23, and the amount of heat generation increases. Therefore, as the amount of black ink used is larger, the amount of heat applied to the black ink can be increased, and the temperatures of the black ink and other colors can be made equal.

  The above-described effect of heating the black ink mainly includes the first buffer group 49 </ b> A including two buffer portions 43 sharing a wall portion facing the driver IC 27, and the driver of the two buffer portions 43 is a driver. This is conspicuous when the first buffer unit 43A located on the IC 27 side is for black ink.

  Hereinafter, specific examples or modifications of the first heater 29 and the second heater 31 will be described with reference to FIGS. 5 and 6.

  FIG. 5A is a cross-sectional view showing a specific example of the first heater 29. The cross-sectional view corresponds to a part of FIG.

  In this specific example, the first heater 29 is a film heater. The first heater 29 is affixed to the outer surfaces of the plurality of cylindrical portions 37a constituting the plurality of ink supply paths 45 with an adhesive or the like. According to such a configuration, for example, the heat of the first heater 29 can be efficiently transmitted to the ink in the ink supply path 45. Further, for example, the downsizing of the head 5 is facilitated.

  FIG. 5B is a cross-sectional view showing another specific example of the first heater 29. The cross-sectional view corresponds to a part of FIG.

  Also in this specific example, the first heater 29 is constituted by a film heater. In this specific example, a heat sink 57 made of a metal plate is fixed to the driver IC 27 with an adhesive or the like, and the first heater 29 is attached to the heat sink 57 with an adhesive or the like. According to such a configuration, for example, the first heater 29 generates heat when the amount of heat generated by the driver IC 27 is small, and the same state as when the amount of heat generated by the driver IC 27 is large can be reproduced.

  In addition, the driver IC 27 alone may be used as the first heater 29. In this case, for example, the driver IC 27 is disposed along the outer surface of the plurality of cylindrical portions 37a constituting the plurality of ink supply paths 45 at the position of the first heater 29 in FIG. Specifically, the driver IC 27 may be attached to one surface of the heat sink 57 made of a metal plate with an adhesive or the like, and the other surface may be attached to the cylindrical portion 37a with an adhesive or the like. Further, a plurality of cylindrical portions constituting the plurality of ink supply paths 45 are formed on a surface different from the surface in contact with the driver IC by making the cross-sectional shape of the heat sink 57 shown in FIG. You may affix on the outer surface of 37a with an adhesive agent. In any case, the heat generated by the driver IC 27 can be efficiently transmitted to the ink in the ink supply path 45.

  FIG. 6A is a cross-sectional view showing a specific example of the second heater 31. The cross-sectional view corresponds to a part of FIG.

  In this specific example, the second heater 31 is a film heater. The second heater 31 is affixed to the heater installation portion 61 provided between the two buffer groups 49 with an adhesive or the like. The heater installation part 61 is made of, for example, a metal plate having an area equivalent to that of the buffer part 43, and is fixed to the base 37 as a part of the ink supply member 25 so as to face the buffer part 43. The second heater 31 is overlaid on one surface of the heater installation portion 61.

  In FIG. 6, the heater installation unit 61 is arranged at an equal distance with respect to the two buffer groups 49, but may be arranged at a position close to either one. Further, a total of two sets of heater installation portions 61 and second heaters 31 facing each buffer group 49 may be provided. The second heater 31 may be folded and pasted on both main surfaces of the relatively thick heater installation portion 61.

  FIG. 6B is a cross-sectional view showing a modification of the second heater 31. The cross-sectional view corresponds to a part of FIG.

  In this modification, the flexible first film 239A to the fourth film 239D constituting the walls of the plurality of buffer parts 43 are constituted by film heaters. The second film 239B and the third film 239C function as the second heater 31. Of the four films, only the second film 239B and / or the third film 239C may be configured by a film heater.

  According to this modification, for example, since the second heater 31 is also used as the flexible film 239 constituting the buffer unit 43, the size of the head 5 and the manufacturing process of the head 5 can be simplified. . Further, for example, the second heater 31 can directly heat the ink in the buffer unit 43 and is efficient.

  FIG. 7 is a schematic cross-sectional view showing a modification of the buffer unit. This cross-sectional view corresponds to the cross-sectional view seen from the right side of FIG. 4 as understood from the orthogonal coordinate system xyz.

  This modification shows an example of the configuration of the buffer unit in the case where ink of five or more colors (seven colors in the example of FIG. 7) is used. Also in this case, as in the embodiment, the plurality of buffer units 43 and 243 are grouped into the first buffer group 249A and the second buffer group 249B, and the second heater 31 is disposed therebetween. In addition, each buffer group 249 includes, for example, two buffer parts 243 (or 43) sharing a wall (not shown) facing the second heater 31 as in the embodiment.

  Further, each buffer group 249 includes a plurality (two) of buffer parts 243 arranged along the wall part facing the second heater 31. More specifically, for example, the buffer unit 43 corresponding to the black ink has the same configuration as that of the embodiment, and the buffer unit 243 corresponding to the ink of other colors is different from the buffer unit 43 of the embodiment. The plane is divided and configured. By increasing the area of the buffer portion 43 corresponding to the black ink, it is possible to apply a large amount of heat to the black ink that is generally used in a larger amount than other color inks. Note that the buffer portions 243 adjacent to each other in the xy plane are partitioned by ribs formed in concave portions similar to the buffer portion 43 of the embodiment in a member corresponding to the base body 37 of the embodiment, although not particularly illustrated. (Shares ribs).

  According to such a configuration, for example, the ink in the two buffer groups 249 can be efficiently heated as in the embodiment. Also, for example, when the ink color becomes 5 or more, the buffer portion is not increased in the stacking direction (z direction) of the two buffer groups 249 and the second heater 31 (this aspect is also included in the present invention). The buffer portion is increased in a direction (x direction) intersecting (more specifically, orthogonal) to the stacking direction, so that the plurality of inks are averaged by the second heater 31 between the two buffer groups 249. Can be heated.

  The present invention is not limited to the above embodiments (including specific examples) or modifications, and may be implemented in various aspects.

  For example, the printer (inkjet head) is not limited to a piezo head type, a serial head type, and an off-carriage type. For example, the printer may be a thermal head type, a line head type, and / or an on-carriage type. The configuration of a portion other than the inkjet head in the printer (for example, a media transport unit) may be an appropriate configuration other than the illustrated configuration. The medium is not limited to paper, and may be made of metal or resin.

  The configuration of the ink supply member that configures the flow path leading to the inside of the head body is not limited to the illustrated one. For example, the plurality of introduction paths (41) may be configured to cross three-dimensionally or may be configured only by the base body 37. Further, for example, the plurality of buffer units may not be grouped into two buffer groups. For example, the two buffer groups may be opposed to each other in a direction orthogonal to the opening direction of the plurality of nozzles. Further, for example, the buffer unit may not be provided, or the buffer unit may be directly connected to the head body without providing the ink supply path.

  The driver IC is not limited to one, and a plurality of driver ICs may be provided. For example, the FPC joined to the head main body may have two extending portions extending from the head main body, and a driver IC may be mounted on each of the two extending portions. These two driver ICs may be disposed between the head main body and the buffer unit.

DESCRIPTION OF SYMBOLS 5 ... Head, 23 ... Head main body, 33a ... Nozzle, 35 ... Piezoelectric actuator board | substrate (drive part), 45 ... Ink supply path, 29 ... 1st heater, 31 ... 2nd heater, 39 ... Film, 43 ... Buffer part ( Ink buffer portion), 49A, first buffer group, 49B, second buffer group.

Claims (8)

A head body having a plurality of nozzles that open in a predetermined opening direction, and a driving unit that generates a driving force for discharging ink from the plurality of nozzles;
A plurality of ink supply paths extending from a direction opposite to the opening direction toward the head body, arranged in a direction orthogonal to the opening direction, and communicating with the head body;
A plurality of ink buffer portions individually communicating with the plurality of ink supply paths, wherein at least a part of the wall portion is configured by a flexible film, and the volume of the ink buffer portions can be changed;
A first heater located in the opposite direction with respect to the head body and having a size over the array of the plurality of ink supply paths;
I have a,
The plurality of ink buffer portions are grouped by sharing a wall portion between adjacent ink buffer portions, thereby forming a first and a second buffer group,
In the direction opposite to the opening direction, the head body, the first buffer group, and the second buffer group are arranged in this order,
The first heater is an ink-jet head positioned between the head body and a first buffer group . A head body having a plurality of nozzles and a driving unit that generates a driving force for discharging ink from the plurality of nozzles;
A plurality of ink buffer portions that communicate with the inside of the head body, and at least a part of the wall portion is made of a flexible film, and the volume of which can be changed;
A heater,
Have
The plurality of ink buffer portions are grouped by sharing a wall portion between adjacent ink buffer portions, thereby forming a first and a second buffer group,
The heater is an inkjet head positioned between the first and second buffer groups. The drive unit is a piezoelectric actuator substrate;
The inkjet according to claim 2, wherein the piezoelectric actuator substrate, the first buffer group, the heater, and the second buffer group are arranged in this order in a direction opposite to a direction in which the plurality of nozzles are opened. head. A driver IC for driving and controlling the driving unit;
These are arranged in the order of the driver IC, the first buffer group, the heater, and the second buffer group in a predetermined direction,
The inkjet head according to claim 2, wherein the first buffer group includes an ink buffer unit for black ink. The first buffer group includes first and second ink buffer portions sharing a wall portion facing the driver IC,
The inkjet head according to claim 4, wherein an ink buffer portion located on the driver IC side among the first and second ink buffer portions is for black ink. The plurality of ink buffer units are provided in 5 or more,
Each of the first and second buffer groups includes two ink buffer portions sharing a wall portion facing the heater,
6. The inkjet head according to claim 2, wherein at least one of the first and second buffer groups includes two ink buffer portions arranged along the wall portion facing the heater. . The inkjet head according to claim 2, wherein the heater is a film heater, and constitutes the flexible film of the ink buffer unit.   A printer comprising: the inkjet head according to claim 1; a scanning unit that relatively moves a medium and the inkjet head; and a control unit that controls the inkjet head. .

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