JP2015066819A - Droplet jet apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to detect whether an ink droplet is injected from plural nozzles at a time with a simple constitution.SOLUTION: Three metal plates 7a to 7c are arranged along a transportation direction in which plural nozzles 10 are arranged. A detection surface of the metal plates 7a to 7c has a parallelogram shape, and both side edges 32c, 32d thereof in the transportation direction are inclined with respect to the transportation direction and a vertical direction. The detection surface 31 of the metal plates 7a to 7c are respectively lapped over plural passage spaces R through which ink droplets injected from the plural nozzles 10 pass viewed from a scan direction which is made to be the transportation direction and the vertical direction. At least one end of an upper end and a lower end of plural portions 33 lapped over the plural passage spaces R of the detection surface 31 is formed by the edge 32c, 32d. A current detector 41, for detecting a current value of a flowing current, is connected to each of the metal plates 7a to 7c.

Description

  The present invention relates to a droplet ejecting apparatus that ejects droplets from a nozzle.

  In Patent Document 1, with the electrode plate pair disposed so as to sandwich one nozzle of the recording head, the recording head is driven so as to eject ink droplets from this nozzle. When ink droplets are ejected from this nozzle, the ejected ink droplets pass between the electrode plate pairs, so that the capacitance between the electrode plate pairs varies. On the other hand, when ink droplets are not ejected from this nozzle, ink droplets do not pass between the electrode plate pairs, so the capacitance between the electrode plate pairs does not vary. From the above, it is possible to detect whether or not an ink droplet has been ejected from the nozzle depending on whether or not the capacitance between the electrode plate pair varies. In Patent Document 1, immediately before starting recording on a recording medium, whether or not ink droplets are ejected is detected individually for all nozzles in the same manner as described above.

JP 2000-158670 A

  Here, in Patent Document 1, as described above, in order to detect whether or not ink droplets have been ejected for all nozzles, the capacitance between the electrode plate pair is individually detected for each nozzle. There is a need. For this reason, as the number of nozzles of the recording head increases, the time required to detect whether or not ink droplets have been ejected from all the nozzles becomes longer.

  Here, if the electrode plate pairs as described above are individually provided for the plurality of nozzles, it is possible to detect whether or not ink droplets are ejected at once for the plurality of nozzles. However, in this case, it is necessary to arrange a large number of electrode plate pairs in high density according to the arrangement of the nozzles, and the structure of the apparatus becomes complicated.

  An object of the present invention is to provide a droplet ejecting apparatus capable of detecting whether or not droplets are ejected at once for a plurality of nozzles with a simple configuration.

  A droplet ejecting apparatus according to a first aspect of the present invention includes a droplet ejecting head having a plurality of nozzles arranged in a predetermined arrangement direction and ejecting droplets in an ejection direction intersecting the arrangement direction, and a detection surface. The detection surfaces extend along the arrangement direction and the ejection direction, and a plurality of liquids through which droplets ejected from the plurality of nozzles pass, respectively, are viewed from the direction orthogonal to the arrangement direction and the ejection direction. A metal member that can be disposed so as to overlap the droplet passage space, and a signal detection unit that detects an electrical signal corresponding to a change in the number of droplets facing the detection surface. The position of at least one of the upstream end and the downstream end in the ejection direction is different between the plurality of portions overlapping the plurality of droplet passage spaces.

  According to the present invention, the method of changing the number of droplets facing the detection surface differs between when the droplets are ejected from all the nozzles and when the droplets are not ejected from some of the nozzles. Furthermore, at this time, the position of at least one of the upstream end and the downstream end in the ejection direction of the detection surface is different between the plurality of portions overlapping the plurality of droplet passage spaces. The method of changing the number of droplets facing the detection surface differs depending on whether or not the droplets are ejected from the nozzle. From the above, according to the present invention, it is detected at a time whether or not droplets have been ejected from a plurality of nozzles by detecting an electrical signal corresponding to a change in the number of droplets facing the detection surface. Accordingly, it is possible to identify the non-ejection nozzles from which the droplets were not ejected. Furthermore, in the present invention, the metal member has a detection surface that can be arranged so as to overlap with the plurality of droplet passage spaces, and is common to the plurality of nozzles. From the above, according to the present invention, it is possible to detect at a time whether or not droplets have been ejected from a plurality of nozzles with a simple configuration.

  The droplet ejection device according to a second aspect is the droplet ejection device according to the first aspect, wherein the signal detection means detects the current or voltage of the metal member as the electrical signal.

  When the liquid droplet ejected from the nozzle approaches or separates from the detection surface, the voltage of the metal member fluctuates due to the electric charge of the liquid droplet, and a current flows through the metal member. Further, the increase and decrease in voltage and current are reversed between when the droplet approaches the detection surface and when the droplet moves away from the detection surface. Therefore, according to the present invention, it is possible to detect at a time whether or not droplets have been ejected from a plurality of nozzles by detecting the current or voltage of the metal member as an electrical signal.

  A droplet ejection device according to a third invention is the droplet ejection device according to the first invention, wherein the metal member includes a first metal member and a second metal member, and the first metal member and The second metal member can be arranged such that the detection surface of the first metal member and the detection surface of the second metal member sandwich the plurality of droplet passage spaces, and the signal detection means is The capacitance between the detection surface of the first metal member and the detection surface of the second metal member is detected as the electrical signal.

  The capacitance between the two detection surfaces varies depending on the number of droplets positioned between the detection surface of the first metal member and the detection surface of the second metal member. Therefore, according to the present invention, it is possible to detect at a time whether or not droplets have been ejected from a plurality of nozzles by detecting the capacitance between these two sensing surfaces as an electrical signal.

  A droplet ejection device according to a fourth invention is the droplet ejection device according to any one of the first to third inventions, wherein the length of the detection surface in the ejection direction is equal to the plurality of droplet passage spaces. The overlapping portions are different.

  According to the present invention, the length of the detection surface in the ejection direction is made different between the plurality of portions that overlap the plurality of droplet passage spaces, so that the upstream end and the downstream end of the detection surface in the ejection direction can be obtained. Among them, the position of at least one end can be made different between a plurality of portions overlapping with a plurality of droplet passage spaces.

  The droplet ejection device according to a fifth aspect is the droplet ejection device according to any one of the first to fourth aspects, wherein the detection surface is in the state where the plurality of passage spaces overlap each other. At least one of the upstream end and the downstream end in the direction forms a straight edge, and the edge is arranged in a state where the detection surface and the plurality of passage spaces overlap each other. When viewed from a direction orthogonal to the ejection direction, the space overlaps the plurality of droplet passage spaces.

  According to the present invention, since the detection surface has such a straight edge, the upstream end and the downstream in the ejection direction in the state where the detection surface overlaps the plurality of droplet passage spaces. The position of at least one of the side ends can be made different between the plurality of portions overlapping the plurality of droplet passage spaces.

  A liquid droplet ejecting apparatus according to a sixth aspect is the liquid droplet ejecting apparatus according to the fifth aspect, wherein the detection surface overlaps the plurality of passage spaces with respect to the arrangement direction and the ejection direction. The hypotenuse has a shape of a parallelogram having an inclined hypotenuse, and the hypotenuse is the plurality of the plurality of the seeing surfaces when viewed from a direction orthogonal to the arrangement direction and the injection direction in a state where the detection surface overlaps the plurality of passage spaces. It overlaps with the space that spans the droplet passage space.

  According to the present invention, the shape of the metal member can be simplified.

  A droplet ejection device according to a seventh invention is the droplet ejection device according to any one of the first to sixth inventions, wherein the detection surface and the plurality of passage spaces overlap with each other in the arrangement direction. A plurality of the metal members arranged, and the signal detection unit individually detects the electrical signal for each metal member, and each metal member has a plurality of passage spaces on the detection surface, respectively. In the overlapped state, the position of at least one end in the ejection direction differs between the plurality of portions overlapping the plurality of droplet passage spaces.

  Even when different metal members have portions where the positions of both ends in the injection direction are the same on the detection surface, the non-injection nozzle can be identified. Thereby, the freedom degree of design of each metal member becomes high. In addition, unlike the present invention, when detecting whether or not droplets are ejected from a plurality of nozzles using only one metal member, between the portions that overlap each droplet passage space on the detection surface, It is necessary to reduce the difference in the position of at least one of the upstream end and the downstream end in the injection direction and to detect the electrical signal at a short time interval. As a result, it may be detected whether or not liquid droplets are ejected from a plurality of nozzles based on the detection result of the electrical signal, and there is a possibility that the accuracy of specifying the non-ejecting nozzles may be reduced when the non-ejecting nozzles are specified. is there. In the present invention, each metal member only needs to be able to detect a change in the number of droplets ejected from some of the plurality of nozzles. The difference between at least one of the upstream end and the downstream end in the ejection direction between a plurality of portions overlapping the droplet passage space can be increased, and an electrical signal can be detected at a long time interval. it can. Thereby, a non-injection nozzle can be specified accurately.

  A droplet ejection device according to an eighth invention is the droplet ejection device according to the seventh invention, wherein the detection direction of the plurality of metal members overlaps the plurality of passage spaces, and the arrangement direction and When viewed from a direction orthogonal to the ejection direction, at least a part of the plurality of droplet passage spaces overlaps the detection surface of two or more metal members.

  According to the present invention, based on the electrical signals detected for two or more metal members, whether or not droplets have been ejected from the nozzles corresponding to the droplet passage spaces that overlap the detection surfaces of the two or more metal members, respectively. The nozzle is a non-injecting nozzle only if any of the electrical signals detected for two or more metal members indicate that the nozzle is a non-injecting nozzle. For example, the non-injection nozzle can be specified with higher accuracy.

  According to a ninth aspect of the present invention, there is provided the liquid droplet ejecting apparatus according to any one of the first to eighth aspects, wherein the liquid droplets are ejected based on the electrical signal detected by the signal detecting means. Non-injection nozzle specifying means for specifying non-injection nozzles that are not performed is further provided.

  According to the present invention, it is possible to identify a non-ejecting nozzle in which a droplet has not been ejected based on the electrical signal detected by the signal detecting means.

  According to the present invention, it is possible to detect at a time whether or not droplets have been ejected from a plurality of nozzles with a simple configuration.

1 is a schematic configuration diagram of a printer according to an embodiment of the present invention. It is the figure which looked at FIG. 1 from the direction of arrow II. FIG. 3 is a diagram when FIG. 2 is viewed from the direction of an arrow III when detecting ejection of an ink droplet from a nozzle. FIG. 2 is a block diagram illustrating a hardware configuration of a printer. It is a figure which shows the change of the number of ink droplets which oppose a metal plate, (a) shows the case where an ink droplet is ejected from all the nozzles, (b) shows the case where an ink droplet is not ejected from a certain nozzle. ing. (A1)-(c1) is a figure which shows the change of the electric current value in each metal plate in the case of Fig.5 (a), (a2)-(c2) is each metal in the case of FIG.5 (b) It is a figure which shows the change of the electric current value in a board. (A) is a figure equivalent to FIG. 2 of the modification 1, (b) is a figure equivalent to FIG. 2 of the modification 2. (A) is a figure equivalent to FIG. 2 of modification 3, (b) is a figure equivalent to FIG. 2 of modification 4, (A) It is a figure equivalent to FIG. 2 of the modification 5. (b) It is a figure equivalent to FIG. 2 of the modification 6. FIG. 10 is a diagram corresponding to FIG. (A) is a figure equivalent to FIG. 2 of the modification 8, (b) is a figure equivalent to FIG. 2 of the modification 9. FIG. 10 is a diagram corresponding to FIG.

  Hereinafter, preferred embodiments of the present invention will be described.

  As shown in FIGS. 1 to 3, the printer 1 according to the present embodiment (“droplet ejecting apparatus” of the present invention) includes a carriage 2, an ink jet head 3 (“droplet ejecting head” of the present invention), and conveyance. The roller 4, the purge unit 5, the flushing foam 6, and three metal plates 7 a to 7 c (“metal member” of the present invention) are provided.

  The carriage 2 is supported by two guide rails 11 extending in the scanning direction, and reciprocates in the scanning direction along the guide rails 11. The inkjet head 3 is mounted on the carriage 2 and ejects ink droplets vertically downward (the “ejection direction” in the present invention) from a plurality of nozzles 10 formed on the nozzle surface 3a which is the lower surface thereof. The plurality of nozzles 10 are arranged in a transport direction (the “arrangement direction” in the present invention) orthogonal to the scanning direction to form a nozzle row 9, and the inkjet head 3 includes two nozzles arranged in the scanning direction. A nozzle row 9 is formed. The conveyance rollers 4 are arranged on the upstream side and the downstream side of the carriage 2 in the conveyance direction, and convey the recording paper P in the conveyance direction.

  In the printer 1, printing is performed on the recording paper P by ejecting ink droplets from the nozzles 10 of the inkjet head 3 that moves in the scanning direction together with the carriage 2 while transporting the recording paper P in the transport direction by the transport roller 4. Do.

  The purge unit 5 includes a suction cap 21, a suction pump 22 and a waste liquid tank 23. The suction cap 21 is arranged on the right side of the region through which the recording paper P conveyed by the conveyance roller 4 passes, and is provided at a position facing the plurality of nozzles 10 when the carriage 2 moves to the right side as much as possible. ing. Further, when the carriage 2 approaches the suction cap 21, the suction cap 21 is lifted in conjunction with the movement of the carriage 2 by a lifting mechanism (not shown), and the plurality of nozzles 10 are connected to the suction cap 21. When the carriage 2 moves to a position opposite to the suction cap 21, the suction cap 21 is in close contact with the nozzle surface 3 a of the inkjet head 3 and covers the plurality of nozzles 10.

  The suction pump 22 is a tube pump or the like and is connected to the suction cap 21. The waste liquid tank 23 is connected to the suction pump 22. In the printer 1, the suction pump 22 is driven in a state where the suction cap 21 covers the plurality of nozzles 10, thereby discharging thickened ink, bubble foreign matters, and the like in the inkjet head 3 from the plurality of nozzles 10. The so-called suction purge can be performed. Further, the ink discharged by the suction purge is stored in the waste liquid tank 23.

  The flushing foam 6 is made of a material that can absorb ink, such as sponge, and is disposed on the left side of the region through which the recording paper P conveyed by the conveying roller 4 passes. The printer 1 can perform so-called flushing in which the inkjet head 3 is driven and ink is ejected from the nozzles 10 while the carriage 2 is moved to a position where the plurality of nozzles 10 and the flushing foam 6 face each other. It has become.

  The three metal plates 7a to 7c are plate-like bodies made of a metal material, and are arranged along the transport direction. The left side surface of the metal plates 7a to 7c serves as a detection surface 31 for detecting a change in the number of ink droplets facing each other as described later. The detection surface 31 has a parallelogram shape, the upper and lower edges 32a and 32b are parallel to the transport direction, and the edges 32c and 32d (the “slanted sides” of the present invention) on both sides in the transport direction are the transport direction and They are inclined with respect to the vertical direction and are parallel to each other. In FIG. 2, the edges 32 c and 32 d are inclined with respect to the transport direction and the vertical direction so that the lower part is positioned upstream of the transport direction, but the edges 32 c and 32 d are the lower part. You may incline with respect to a conveyance direction and a perpendicular direction so that it may be located in the conveyance direction downstream.

  Further, when viewed from the scanning direction, the plurality of passage spaces R through which the ink droplets ejected from the plurality of nozzles 10 overlap the detection surface 31 of any one of the metal plates 7a to 7c. Further, the edge 32d on the downstream side in the conveyance direction of the detection surface 31 of the metal plate 7a spans the first to fourth passage spaces R from the upstream in the conveyance direction in FIG. It overlaps with space.

  Further, the edge 32c on the upstream side in the transport direction of the detection surface 31 of the metal plate 7b is 2 to 2 from the upstream side in the transport direction in FIG. 2 in the passing space R overlapping the detection surface 31 of the metal plate 7b when viewed from the scanning direction. It overlaps the space that spans the fifth passage space R. Further, the edge 32d on the downstream side in the transport direction of the detection surface 31 of the metal plate 7b is 5 to 5 from the upstream side in the transport direction in FIG. 2 in the passage space R overlapping the detection surface 31 of the metal plate 7b when viewed from the scanning direction. It overlaps the space that spans the eighth passage space R.

  Further, the edge 32c on the upstream side in the conveyance direction of the detection surface 31 of the metal plate 7c is 6 to 6 from the upstream side in the conveyance direction in FIG. 2 in the passing space R overlapping the detection surface 31 of the metal plate 7b when viewed from the scanning direction. It overlaps with the space that spans the ninth passage space R. Further, the edge 32d on the downstream side in the transport direction of the detection surface 31 of the metal plate 7c is 9 from the upstream side in the transport direction in FIG. 2 of the passing space R overlapping the detection surface 31 of the metal plate 7c when viewed from the scanning direction. It overlaps with the space that spans the tenth passage space R.

  And by arrange | positioning the metal plates 7a-7c in this way, in the metal plates 7a-7c, between each of the some parts 33 which overlap with the some passage space R of the detection surface 31, respectively, an upper end (in an injection direction) Among the positions of the upstream end) and the lower end (downstream end in the injection direction), at least one end has a different vertical position. Further, in the metal plates 7a to 7c, the plurality of portions 33 have different vertical lengths L from each other. In FIG. 2, each portion 33 is hatched, and the length L is shown only for one portion 33.

  In the present embodiment, the detection surface 31 of the metal plate 7a and the detection surface 31 of the metal plate 7b, and the detection surface 31 of the metal plate 7b and the detection surface 31 of the metal plate 7c overlap each other when viewed from the vertical direction. ing. Thereby, the passage space R corresponding to the second to fourth nozzles 10 from the upstream side in the transport direction in FIG. 2 overlaps the detection surface 31 of the metal plate 7a and the detection surface 31 of the metal plate 7b when viewed from the scanning direction. Further, the passage space R corresponding to the sixth to eighth nozzles 10 from the upstream side in the transport direction overlaps the detection surface 31 of the metal plate 7b and the detection surface 31 of the metal plate 7c when viewed from the scanning direction.

  As described above, in the present embodiment, at least one of the upper ends and the lower ends of the plurality of portions 33 forms a linear edge inclined with respect to the transport direction and the vertical direction. And the detection surface 31 inclined at least one end among the upper end and the lower end of the plurality of portions 33 with respect to the transport direction and the vertical direction by the simple metal plates 7a to 7c having a parallelogram shape. It may be a straight edge.

  Each of the metal plates 7 a to 7 c is connected to a current detection device 41 (“signal detection means” of the present invention), and the current detection device 41 is grounded via a resistor 42. Thereby, the current value in each metal plate 7 can be detected by the current detection device 41.

  Next, the hardware configuration of the printer 1 will be described. The printer 1 includes a control device 50 in addition to the configuration described above. The control device 50 includes a CPU (Central Processing Memory), a ROM (Read Only Memory), a RAM (Random Access Memory), an ASIC (Application Specific Integrated Circuit), and the like. Control of the inkjet head 3, the conveyance roller 4, the suction pump 22, and the like is performed. Further, as described later, the control device 50 detects whether or not the ink droplets are ejected from the plurality of nozzles 10 according to the current value detected by the current detection device 41, so that the ink droplets are not ejected. Identify non-spray nozzles. That is, in the present embodiment, the control device 50 includes the non-injection nozzle specifying means according to the present invention.

  Note that the control device 50 may include only one CPU, and the processing required by the one CPU may be performed all at once, or a plurality of CPUs may be provided and the plurality of CPUs may share the necessary processing. May be. Further, the control device 50 may include only one ASIC, and may perform processing necessary for the one ASIC in a batch, or may include a plurality of ASICs and perform the processing necessary for the plurality of ASICs. May be.

  Next, a method for detecting whether or not ink droplets are ejected from the plurality of nozzles 10 in the inkjet head 3 will be described. In the inkjet head 3, ink droplets may not be ejected from some of the nozzles 10 due to thickening of the ink in the nozzles 10. In the present embodiment, as described below, by detecting whether or not ink droplets are ejected from the plurality of nozzles 10, non-ejection nozzles that have not ejected ink droplets are identified.

  In order to detect whether or not ink droplets are ejected from the plurality of nozzles 10, first, as shown in FIG. 3, a passage space R corresponding to the nozzles 10 constituting the right nozzle row 9 is formed in the transport direction. Then, the carriage 2 is moved to such a position as to be immediately downstream of the detection surface 31 of the metal plates 7a to 7c. Then, the inkjet head 3 is driven so that ink droplets are ejected from all the nozzles 10 constituting the right nozzle row 9, and current values in the metal plates 7a to 7c are detected by the current detection device 41 at regular time intervals. To do.

  Here, since the ink droplet ejected from the nozzle 10 has an electric charge, the ink droplet facing the detection surface 31 when the ink droplet approaches the detection surface 31 or moves away from the detection surface 31. When the number of fluctuates, current flows through the metal plates 7a to 7c by electrostatic induction. Further, the direction of the current flowing through the metal plates 7a to 7c is reversed when the number of ink droplets D facing the detection surface 31 increases and when the number of ink droplets D decreases.

  An example of the change in the current flowing through the metal plates 7a to 7c will be described. For example, as shown in FIGS. 5A and 5B, it is assumed that current values in the metal plates 7a to 7c are detected by the current detection device 41 at times T1 to T5, respectively. 5A and 5B show the positions of the ink droplets D at times T1 to T5. In a state before the ink droplets D are ejected from the nozzle 10, the number of ink droplets D facing the detection surfaces 31 of the metal plates 7a to 7c is zero.

  When ink droplets are ejected from all the nozzles 10, as shown in FIG. 5A, at time T1, four ink droplets D face the detection surface 31 of the metal plate 7a, and four ink droplets D are ejected. The ink droplet D faces the detection surface 31 of the metal plate 7b, and the two ink droplets D face the detection surface 31 of the metal plate 7c. That is, the number of ink droplets D facing the detection surface 31 of the metal plate 7a is increased by four, the number of ink droplets D facing the detection surface 31 of the metal plate 7b is increased, and the detection surface of the metal plate 7c is increased. The number of ink droplets D facing 31 increases by two. As a result, when the number of ink droplets D facing the detection surface 31 is increased by 1, the current flowing through the metal plates 7a to 7c is assumed to be I, and a current of about 4I flows through the metal plates 7a and 7b, and the metal plate 7c. A current of about 2I flows.

  At time T2, three ink droplets D face the detection surface 31 of the metal plate 7a, four ink droplets D face the detection surface 31 of the metal plate 7b, and three ink droplets D become the metal plate. It faces the detection surface 31 of 7c. That is, the number of ink droplets D facing the detection surface 31 of the metal plate 7a is decreased by one, the number of ink droplets facing the detection surface 31 of the metal plate 7b is not changed, and the detection surface 31 of the metal plate 7c is not changed. The number of ink droplets D facing each other increases by one. As a result, about -I current flows through the metal plate 7a, no current flows through the metal plate 7b, and about I current flows through the metal plate 7c. Here, the minus sign indicates that the direction of the current is opposite to the direction of the current when the number of ink droplets D facing the detection surface 31 of the metal plate 7a is increased.

  At time T3, two ink droplets D face the detection surface 31 of the metal plate 7a, four ink droplets D face the detection surface 31 of the metal plate 7b, and four ink droplets D become the metal plate. It faces the detection surface 31 of 7c. That is, the number of ink droplets D facing the detection surface 31 of the metal plate 7a is reduced by one, the number of ink droplets D facing the detection surface 31 of the metal plate 7b is not changed, and the detection surface 31 of the metal plate 7c is not changed. And the number of ink droplets D facing each other increases by one. As a result, about -I current flows through the metal plate 7a, no current flows through the metal plate 7b, and about I current flows through the metal plate 7c.

  At time T4, one ink droplet D faces the detection surface 31 of the metal plate 7a, four ink droplets D face the detection surface 31 of the metal plate 7b, and four ink droplets D become the metal plate. It faces the detection surface 31 of 7c. That is, the number of ink droplets D facing the detection surface 31 of the metal plate 7a is decreased by 1, and the number of ink droplets D facing the detection surface 31 of the metal plates 7b and 7c is not changed. As a result, a current of about -I flows through the metal plate 7a, and no current flows through the metal plates 7b and 7c.

  At time T5, the number of ink droplets facing the detection surfaces 31 of the metal plates 7a to 7c is all zero. That is, the number of ink droplets D facing the detection surface 31 of the metal plate 7a is decreased by one, the number of ink droplets D facing the detection surface 31 of the metal plate 7b is decreased, and the detection surface of the metal plate 7c is decreased. The number of ink droplets D facing 31 decreases by four. As a result, a current of about -I flows through the metal plate 7a, and a current of about -4I flows through the metal plates 7b and 7c.

  From the above, the current changes in the metal plates 7a to 7c when ink droplets are ejected from all the nozzles 10 are as shown in FIGS. 6 (a1) to (c1), respectively. In the present embodiment, current values in the metal plates 7a to 7c at times T1 to T5 when ink droplets are ejected from all the nozzles 10 are stored in advance in the RAM or the like of the control device 50.

  Next, as shown in FIG. 5B, a case where ink droplets are not ejected from the fourth nozzle 15 from the upstream side in the transport direction in the drawing will be described as an example. In this case, at time T1, three ink droplets D face the detection surface 31 of the metal plate 7a, and four ink droplets D face the detection surface 31 of the metal plate 7b. That is, the number of ink droplets D facing the detection surface 31 of the metal plate 7a is increased by three, and the number of ink droplets D facing the detection surface 31 of the metal plate 7b is increased by four. As a result, a current of about 4I flows through the metal plate 7a, and a current of about 4I flows through the metal plate 7b. In this case, at times T1 to T5, the number of ink droplets D facing the detection surface 31 of the metal plate 7c is not different from the case where the ink droplets D are ejected from all the nozzles 10. Omitted.

  At time T2, the three ink droplets D face the detection surface 31 of the metal plate 7a, and the three ink droplets D face the detection surface 31 of the metal plate 7b. That is, the number of ink droplets facing the detection surface 31 of the metal plate 7a does not change, and the number of ink droplets D facing the detection surface 31 of the metal plate 7b is reduced by one. As a result, no current flows through the metal plate 7a, and a current of about -I flows through the metal plate 7b.

  At time T3, the two ink droplets D face the detection surface 31 of the metal plate 7a, and the three ink droplets D face the detection surface 31 of the metal plate 7b. That is, the number of ink droplets D facing the detection surface 31 of the metal plate 7a is decreased by 1, and the number of ink droplets D facing the detection surface 31 of the metal plate 7b does not change. Thereby, a current of about -I flows through the metal plate 7a, and no current flows through the metal plate 7b.

  At time T4, one ink droplet D faces the detection surface 31 of the metal plate 7a, and three ink droplets D face the detection surface 31 of the metal plate 7b. That is, the number of ink droplets D facing the detection surface 31 of the metal plate 7a is decreased by 1, and the number of ink droplets D facing the detection surface 31 of the metal plate 7b does not change. Thereby, a current of about -I flows through the metal plate 7a, and no current flows through the metal plate 7b.

  At time T5, the number of ink droplets facing the detection surfaces 31 of the metal plates 7a and 7b is zero. That is, the number of ink droplets D facing the detection surface 31 of the metal plate 7a is decreased by one, and the number of ink droplets D facing the detection surface 31 of the metal plate 7b is decreased by three. As a result, a current of about -I flows through the metal plate 7a, and a current of about -3I flows through the metal plate 7b.

  From the above, when the ink droplet D is not ejected from the fourth nozzle nozzle 10 from the left in FIG. 5B, the current changes in the metal plates 7a to 7c are as shown in FIG. (C2)

  6 (a1) to (c1) and FIG. 6 (a2) to (c2) are compared, in the case shown in FIG. 5 (b), ink droplets D are ejected from all the nozzles 10. Compared to the case (FIG. 5A), the current value in the metal plate 7a decreases by about I at time T1, and increases by about I at time T2. Further, the current value in the metal plate 7b decreases by about I at time T2, and increases by about I at time T5.

  Even when the ink droplets D are not ejected from the other nozzles 10, any one of the current values at the times T1 to T5 of the metal plates 7a to 7c may be ejected from all the nozzles 10. Different. At this time, in the present embodiment, as described above, the positions of at least one of the upper end and the lower end are different between the plurality of portions 33 of the detection surfaces 31 of the metal plates 7a to 7c. 7a to 7c, the timing at which the ink droplet ejected from the nozzle 10 crosses the upper end of the portion 33 between the plurality of portions 33 (that is, the state in which the ink droplet D is not opposed to the metal plates 7a to 7c) And the timing at which the ink droplet ejected from the nozzle 10 crosses the lower end of the portion 33 (that is, the timing at which the ink droplet D switches from the state facing the metal plates 7a to 7c to the state not facing). Of these, at least one of the timings is different. Therefore, depending on which nozzle 10 is a non-ejection nozzle, the current value at which time of which metal plate is different from the current value when ink droplets are ejected from all nozzles 10 varies.

  In the above example, the current value in the metal plate 7a decreases by about I at time T1 and increases by about I at time T2, and the ink droplet D from the fourth nozzle 10 from the left in FIG. It indicates that it was not jetted. Further, the current value in the metal plate 7b is small by about I at time T2 and large by about I at time T5, and the ink droplet D was not ejected from the fourth nozzle 10 from the left in FIG. 5B. It is shown that.

  Therefore, in the present embodiment, the control device 50 receives ink droplets from all the nozzles 10 stored in advance in the current values detected at the current detection device 41 at times T1 to T5 and the RAM of the control device 50. The difference with the electric current value in time T1-T5 at the time of being injected is taken. For all nozzles, when this difference is smaller than a predetermined minute amount, it is determined that ink droplets have been ejected from all nozzles 10. On the other hand, if any of the difference between the actually measured current value and the previously stored current measured value is equal to or greater than the above minute amount, at which time of which metal plate the difference is A non-injection nozzle is specified based on whether it becomes more than the above minute amount. Thus, in this embodiment, it is possible to detect at a time whether or not ink droplets have been ejected from the plurality of nozzles 10. In the present embodiment, as described above, since the metal plates 7a to 7c correspond to the plurality of nozzles 10, respectively, a metal plate is individually provided for the plurality of nozzles 10. Compared with the case where it did, the structure of an apparatus can be simplified.

  In the present embodiment, the detection surfaces 31 of the three metal plates 7a to 7c arranged in the transport direction overlap with the passage space R corresponding to some of the nozzles 10 among the plurality of nozzles 10, respectively. Yes. Therefore, as in Modification Example 8 (see FIG. 11A) described later, only one metal plate is provided, and all the detection surfaces 31 of the one metal plate overlap the passage space R corresponding to the nozzle 10. The edges 32c and 32d of the detection surfaces 31 of the metal plates 7a to 7c are greatly inclined with respect to the transport direction, and the positions of the upper ends or the lower ends of the plurality of portions 33 in the vertical direction are greatly different from those in the case of the above. Can do. Thereby, since the time interval during which the number of ink droplets D facing the detection surface 31 changes is increased, the period of detecting the current value in the current detection device 41 can be increased.

  In this case, in each of the metal plates 7a to 7c, it is necessary that the positions of at least one of the upper end and the lower end in the vertical direction are different between the plurality of portions 33. Among the metal plates 7a to 7c, both the position 33 of the detection surface 31 of one metal plate and the portion 33 of the detection surface 31 of another metal plate coincide with each other in the upper end position and the lower end position. It may be. Accordingly, the degree of freedom in designing the metal plates 7a to 7c is increased.

  In the present embodiment, as described above, the passage space R corresponding to some of the nozzles 10 overlaps the detection surfaces 31 of the two metal plates when viewed from the scanning direction. Therefore, when ink droplets are not ejected from the nozzles 10 corresponding to the passing space R that overlaps the detection surfaces 31 of the two metal plates, the current values in these two metal plates are all the nozzles 10. This is different from the case where ink droplets are ejected from. For example, in the example of FIG. 5B, as described above, the current values in the two metal plates 7a and 7b are different from the case where the ink droplets D are all ejected from the nozzles 10, respectively.

  Therefore, in the present embodiment, for the nozzle 10 corresponding to the passage space R that overlaps the detection surfaces 31 of the two metal plates, any change in the current value in the two metal plates causes the ink droplet D from the same nozzle 10. Indicates that the nozzle 10 is not ejected. Thereby, the specific precision of a non-injection nozzle can be made high.

  In the same manner as described above, whether or not ink droplets are ejected from the plurality of nozzles 10 is also detected for the nozzles 10 constituting the left nozzle row 9.

  When one of the nozzles 10 constituting the two nozzle rows 9 is specified as a non-ejecting nozzle, first, flushing is performed on the non-ejecting nozzle, and whether or not ink droplets are ejected from the plurality of nozzles 10 again. Is detected. If the same nozzle is specified as a non-injection nozzle even after flushing, a suction purge is further performed.

  Next, modified examples in which various changes are made to the present embodiment will be described.

  In the above-described embodiment, a part of the passage space R overlaps the detection surfaces 31 of the two metal plates when viewed from the scanning direction, but the present invention is not limited to this. In one modified example (modified example 1), as shown in FIG. 7A, the metal plates 7a to 7c are arranged apart from each other in the transport direction to such an extent that the detection surfaces 31 do not overlap each other when viewed from the vertical direction. Yes. Each passing space R overlaps only the detection surface 31 of one metal plate among the three metal plates 7a to 7c when viewed from the scanning direction. Even in this case, it is possible to detect at a time whether or not ink droplets have been ejected from the plurality of nozzles 10 in the same manner as in the above-described embodiment.

  Further, in another modification (Modification 2), as shown in FIG. 7B, the edges 32c and 32d on both sides in the transport direction of the detection surface 31 of the metal plate 7a are as described above with respect to the vertical direction. The inclination is larger than that of the embodiment. And the 4th passage space R from the conveyance direction upstream has overlapped with the detection surface 31 of the three metal plates 7a-7c seeing from a scanning direction. In this case, for the fourth nozzle 10 from the upstream side in the transport direction, only when any change in the current value in the metal plates 7a to 7c indicates that the nozzle 10 is a non-injection nozzle. If the nozzle 10 is specified as a non-injecting nozzle, the non-injecting nozzle can be specified with higher accuracy.

  Moreover, in the above-mentioned embodiment, although the shape of the detection surface 31 of the metal plates 7a-7c was a parallelogram, it is not restricted to this. In another modification (Modification 3), as shown in FIG. 8A, the detection surfaces 62 of the metal plates 61a to 61c have a trapezoidal shape, and the upper edge 63a is in the transport direction and the vertical direction. The lower edge 63b is parallel to the transport direction, and the edges 63c and 63d on both sides of the transport direction are parallel to the vertical direction.

  In this case, in the metal plates 61a to 61c, the lengths in the vertical direction are different between the plurality of portions 64 of the detection surface 62 that overlap with the plurality of passage spaces R when viewed from the scanning direction, and the position of the upper end. Are different from each other. Therefore, even in this case, it is possible to detect at a time whether or not ink droplets have been ejected from the plurality of nozzles 10 in the same manner as in the above-described embodiment.

  In Modification 3, the upper edge 63a of the detection surface 62 is inclined with respect to the transport direction and the vertical direction, and the lower edge 63b is parallel to the transport direction. However, the present invention is not limited to this. . As shown in FIG. 8B, in Modification 3, the upper edge 63a of the metal plates 61a to 61c is parallel to the transport direction, and the lower edge 63b is inclined with respect to the transport direction and the vertical direction. (Modification 4). In this case, the position of the lower end differs among the plurality of portions 64. Therefore, even in this case, it is possible to detect at a time whether or not ink droplets have been ejected from the plurality of nozzles 10 in the same manner as in the above-described embodiment.

  In the above-described embodiment, one of the upper and lower ends of the plurality of portions 33 of the detection surfaces 31 of the metal plates 7a to 7c has linear edges 32c and 32d inclined with respect to the transport direction and the vertical direction. However, it is not limited to this.

  In another modification (Modification 5), as shown in FIG. 9A, the edges 68a and 68b on both sides in the transport direction of the detection surfaces 67 of the metal plates 66a to 66c are curved. Even in this case, on the detection surfaces 67 of the metal plates 66a to 66c, the positions of at least one of the upper end and the lower end in the vertical direction are different between the plurality of portions 69, respectively. Therefore, it is possible to detect at a time whether or not ink droplets have been ejected from the plurality of nozzles 10 in the same manner as in the above-described embodiment.

  In another modification (Modification 6), as shown in FIG. 9B, the edges 73a and 73b on both sides in the transport direction of the detection surfaces 72 of the metal plates 71a to 71c are in the vertical direction and the transport direction. It has a staircase shape that is folded alternately. In this case, the portions 73a1 and 73b1 extending in the transport direction among the edges 73a and 73b that are alternately bent in the vertical direction and the transport direction are respectively viewed from the scanning direction of the detection surfaces 72 of the metal plates 71a to 71c. It becomes the upper end and lower end of the part 74 which overlaps with the passage space R. Even in this case, on the detection surfaces 72 of the metal plates 71a to 71c, the positions of at least one of the upper end and the lower end in the vertical direction are different between the plurality of portions 74 overlapping the plurality of passage spaces R when viewed from the scanning direction. . Therefore, it is possible to detect at a time whether or not ink droplets have been ejected from the plurality of nozzles 10 in the same manner as in the above-described embodiment.

  Moreover, in the above-mentioned embodiment, in the detection surfaces 31 of the metal plates 7a to 7b, some of the plurality of portions 33 have different lengths in the vertical direction are not limited to this. In another modification (Modification 7), as shown in FIG. 10, the detection surface 77 of the metal plates 76 a to 76 c has an upper edge 78 a and a lower edge 78 b with respect to the transport direction and the vertical direction. Inclined parallel to each other, both edges 78c and 78d in the transport direction are parallel to the vertical direction. In this case, in the detection surfaces 77 of the metal plates 76a to 76c, the lengths in the vertical direction are all the same between the plurality of portions 79 overlapping the plurality of passage spaces R as viewed from the scanning direction. The positions of the upper end and the lower end are different among the plurality of portions 79. Therefore, it is possible to detect at a time whether or not ink droplets have been ejected from the plurality of nozzles 10 in the same manner as in the above-described embodiment.

  Moreover, in the above-mentioned embodiment, although the three metal plates 7a-7c of the same shape were located in a line in the conveyance direction, it is not restricted to this. For example, the shapes of the three metal plates 7a to 7c may be different from each other. Further, for example, two or four or more metal plates may be arranged in the transport direction. Furthermore, it is not limited to arranging a plurality of metal plates side by side in the transport direction.

  In another modification (Modification 8), as shown in FIG. 11A, only one metal plate 81 is provided. The detection surface 82 of the metal plate 81 has a parallelogram shape, and an upper edge 83a and a lower edge 83b are inclined in parallel with each other with respect to the transport direction and the vertical direction. 83c and 83d are parallel to the vertical direction. The metal plate 81 is arranged so that the edges 83a and 83b of the detection surface 82 extend over all the passage spaces R, so that the detection surface 92 overlaps with all the passage spaces R when viewed from the scanning direction. .

  In another modification (Modification 9), only one metal plate 86 is provided as shown in FIG. The detection surface 87 of the metal plate 86 has a trapezoidal shape, the upper edge 88a is inclined with respect to the transport direction and the vertical direction, and the lower edge 88b is parallel to the transport direction. Edges 88c and 88d on both sides are parallel to the vertical direction. The metal plate 86 is arranged so that the edges 88a and 88b extend over all the passage spaces R, so that the detection surface 87 overlaps with all the passage spaces R when viewed from the scanning direction. In the modified example 7, the upper edge 88a may be parallel to the transport direction, and the lower edge 88b may be inclined with respect to the transport direction and the vertical direction.

  In the case of the modified example 8, the positions of the upper end and the lower end in the vertical direction are different between the portions 84 of the detection surface 82 that overlap with the plurality of passage spaces R when viewed from the scanning direction. In the case of the modification 9, the position of the upper end in the vertical direction is different and the position of the lower end is the same between the portions 89 of the detection surface 87 that overlap with the plurality of passage spaces R when viewed from the scanning direction. Therefore, also in the modified examples 8 and 9, it is possible to detect whether or not ink droplets are ejected from the plurality of nozzles 10 at the same time as in the above-described embodiment.

  However, in the case of the modification 8, it is necessary to make the inclination of the edges 83a and 83b with respect to the transport direction smaller than the edges 32c and 32d of the above-described embodiment and the modification 1, the edges 78a and 78b of the modification 8, and the like. There is. As a result, in the modification 8, the difference between the positions of the upper end and the lower end in the vertical direction between the portions 84 is reduced. On the other hand, in the case of the modification 9, it is necessary to make the inclination of the edge 88a with respect to the conveyance direction smaller than the edge 63a of the modification 3 and the edge 68b of the modification 3. As a result, in the modified example 8, the difference in the position between the upper end and the vertical direction between the portions 89 is reduced. Therefore, in the modification examples 8 and 9, when detecting whether or not ink droplets are ejected from the plurality of nozzles 10 in the same manner as in the above-described embodiment, the current detecting device 41 causes the above-described embodiment. It is necessary to detect the current value at a time interval shorter than those of the modified examples 1, 3, 4, 6 and the like.

  In addition, the shape of the detection surface of the metal plate is not limited to that described in the above-described embodiment or modification. The detection surface of the metal plate may have a different shape such that the position of at least one of the upper end and the lower end is different between the plurality of portions overlapping the plurality of passage spaces R when viewed from the scanning direction. Good.

  In the above example, it is detected whether or not ink droplets are ejected from the plurality of nozzles 10 using a metal plate, but the present invention is not limited to this. For example, instead of a metal plate, a block-shaped metal member having the same detection surface as described above may be used.

  In the above-described embodiment, the current detection device 41 detects the current values in the metal plates 7a to 7c, and determines whether ink droplets are ejected from all the nozzles 10 based on the detected current values. Although the non-injection nozzle is specified, the present invention is not limited to this. When the charged ink droplets approach the detection surfaces 31 of the metal plates 7a to 7c and move away from the detection surfaces 31 of the metal plates 7a to 7c, the voltages of the metal plates 7a to 7c change due to electrostatic induction. Further, when the ink droplet approaches the detection surface 31 of the metal plates 7a to 7c, and when the ink droplet moves away from the detection surface 31 of the metal plates 7a to 7c, the voltage fluctuations of the metal plates 7a to 7c are reversed. Therefore, the voltages of the metal plates 7a to 7c may be detected, and whether or not ink droplets are ejected from the plurality of nozzles 10 may be detected based on the detected voltage value.

  In another modification (Modification 10), as shown in FIG. 12, in addition to the metal plates 7a to 7c, metal plates 91a to 91c facing the metal plates 7a to 7c are provided. The metal plates 91 a to 91 c are substantially the same plate-like bodies as the metal plates 7 a to 7 c, and the right surface in the scanning direction is the detection surface 92. Further, the metal plate 7a and the metal plate 91a, the metal plate 7b and the metal plate 91b, and the metal plate 7c and the metal plate 91c are respectively capacitance detection devices for detecting the capacitance between these metal plates. 93 ("signal detection means" of the present invention) is connected. The metal plates 7a to 7c and the metal plates 91a to 91c may have different shapes.

  The electrostatic capacitance detection device 93 is caused by a change in a current value detected by the current detection device 95 when an AC voltage is applied between the metal plates 7a to 7c and the metal plates 91a to 91c by the AC power source 94, respectively. Between the detection surface 31 of the metal plate 7a and the detection surface 92 of the metal plate 91a, between the detection surface 31 of the metal plate 7b and the detection surface 92 of the metal plate 91b, between the detection surface 31 of the metal plate 7c and the metal plate 91c. Capacitances with the detection surface 92 are detected. In this case, one of the metal plates 7a to 7c and the metal plates 91a to 91c corresponds to the first metal member according to the present invention, and the other metal member corresponds to the first metal member according to the present invention. It corresponds to 2 metal members.

  In Modification 10, when it is detected whether or not ink droplets are ejected from the plurality of nozzles 10, a plurality of passage spaces R corresponding to the plurality of nozzles 10 constituting one nozzle row 9 are in the scanning direction. The carriage 2 is moved so as to be between the detection surface 31 of the metal plate 7a and the detection surfaces 92 of the metal plates 91a to 91c. In this state, the inkjet head 3 is driven so as to eject ink droplets from all the nozzles 10, and the metal plate 7a and the metal plate 91a, the metal plate 7b and the metal plate 91b, and the metal at regular time intervals. The electrostatic capacitance between the detection surface 31 and the detection surface 92 is detected in the plate 7c and the metal plate 91c, respectively.

  The capacitance between the detection surface 31 and the detection surface 92 in the metal plate 7a and the metal plate 91a, the metal plate 7b and the metal plate 91b, and the metal plate 7c and the metal plate 91c is the number of ink droplets facing each other. It depends on. For this reason, when there are non-ejecting nozzles, the method of changing the capacitance is different compared to the case where ink droplets are ejected from all the nozzles 10. Therefore, as described above, in the metal plate 7a and the metal plate 91a, the metal plate 7b and the metal plate 91b, and the metal plate 7c and the metal plate 91c, the static electricity between the detection surface 31 and the detection surface 92, respectively. By detecting the electric capacity, it is possible to detect at a time whether or not ink droplets are ejected from the plurality of nozzles 10.

  The electrical signal for detecting whether or not ink droplets are ejected from the plurality of nozzles 10 is another electrical signal corresponding to a change in the number of ink droplets facing the detection surface of the metal plate. Also good.

  Further, in the above-described embodiment, the control device 50 determines whether or not ink droplets are all ejected from the nozzles 10 based on the current value measurement result by the current detection device 41, and the non-ejection nozzles. I have identified, but is not limited to this. The user may specify the non-injection nozzle based on the measurement result of the current value by the current detection device 41. In this case, for example, by operating an operation unit (not shown) of the printer 1, a signal indicating which nozzle 10 is a non-ejection nozzle is input to the printer 1, so that flushing or suction purge is performed on the printer 1. Let it be done.

  In the above-described embodiment, the ink droplet ejection direction from the nozzle 10 is parallel to the vertical direction, but the present invention is not limited to this. The ink droplet ejection direction from the nozzle 10 may be inclined with respect to the vertical direction. In this case, for example, in the above-described embodiment, the edges 32c and 32d may be inclined with respect to the transport direction and the ink droplet ejection direction.

  In the above description, an example in which the present invention is applied to an inkjet printer including a so-called serial inkjet head that reciprocates in the scanning direction together with the carriage has been described. However, the present invention is not limited thereto. For example, the present invention can be applied to an ink jet printer having a so-called line head extending over the entire length of the recording paper in the width direction. In this case, since the line head does not move, it is necessary to provide a mechanism for moving the metal plate. Furthermore, the present invention can also be applied to a droplet ejecting apparatus other than an ink jet printer that ejects droplets other than ink.

DESCRIPTION OF SYMBOLS 1 Printer 3 Inkjet head 7a-7c Metal plate 10 Nozzle 31 Detection surface 32c, 32d Edge 33 Part 41 Current detection apparatus 50 Control apparatus 61a-61c, 66a-66c, 71a-71c, 76a-76c, 81, 86, 91a- 91c Metal plate 62, 67, 72, 77, 82, 87, 92 Sensing surface 63a, 68a, 68b, 73a, 73b, 78a, 78b, 83a, 83b, 88a, 88c Edge 64, 69, 74, 79, 84, 89 part 93 capacitance detection device R passage space

Claims (9)

A liquid droplet ejecting head having a plurality of nozzles arranged in a predetermined arrangement direction and ejecting liquid droplets in an ejection direction intersecting the arrangement direction;
The detection surface has a detection surface, the detection surface extends along the arrangement direction and the ejection direction, and droplets ejected from the plurality of nozzles are viewed from the direction orthogonal to the arrangement direction and the ejection direction, respectively. A metal member that can be arranged so as to overlap a plurality of droplet passage spaces that pass therethrough;
A signal detection means for detecting an electrical signal corresponding to a change in the number of droplets facing the detection surface,
In the state where the detection surface overlaps with the plurality of passage spaces, a plurality of portions where positions of at least one of the upstream end and the downstream end in the ejection direction overlap with the plurality of droplet passage spaces Droplet ejector characterized by being different between the two.   The droplet ejecting apparatus according to claim 1, wherein the signal detection unit detects a current or a voltage of the metal member as the electrical signal. As the metal member, it has a first metal member and a second metal member,
The first metal member and the second metal member can be arranged such that the detection surface of the first metal member and the detection surface of the second metal member sandwich the plurality of droplet passage spaces. ,
The signal detection means detects an electrostatic capacitance between the detection surface of the first metal member and the detection surface of the second metal member as the electrical signal. The liquid droplet ejecting apparatus described.   4. The droplet ejecting apparatus according to claim 1, wherein lengths of the detection surfaces in the ejection direction are different between the plurality of portions overlapping the plurality of droplet passage spaces. 5. . The detection surface is in a state where the plurality of passage spaces overlap with each other, and at least one of the upstream end and the downstream end in the injection direction forms a linear edge,
The edge overlaps a space that spans the plurality of droplet passage spaces when viewed from a direction orthogonal to the arrangement direction and the ejection direction in a state where the detection surface and the plurality of passage spaces overlap. The liquid droplet ejecting apparatus according to claim 1, wherein: The detection surface has a parallelogram shape having a hypotenuse inclined with respect to the arrangement direction and the injection direction in a state of overlapping with the plurality of passage spaces,
The oblique side is overlapped with a space extending over the plurality of droplet passage spaces when viewed from a direction orthogonal to the arrangement direction and the ejection direction in a state where the detection surface overlaps the plurality of passage spaces. The droplet ejecting apparatus according to claim 5, wherein A plurality of the metal members arranged in the arrangement direction in a state where the detection surface and the plurality of passage spaces overlap,
The signal detection means individually detects the electrical signal for each metal member,
In each of the metal members, the position of at least one end in the ejection direction in the state of overlapping the plurality of passage spaces of the detection surface is between the plurality of portions overlapping the plurality of droplet passage spaces. The liquid droplet ejecting apparatus according to claim 1, wherein the liquid droplet ejecting apparatuses are different from each other.   In a state where the detection surfaces of the plurality of metal members overlap with the plurality of passage spaces, at least some of the plurality of droplet passage spaces when viewed from a direction orthogonal to the arrangement direction and the ejection direction. The droplet ejecting apparatus according to claim 7, wherein a passage space overlaps the detection surfaces of the two or more metal members.   9. The non-ejecting nozzle specifying means for specifying non-ejecting nozzles from which liquid droplets are not ejected based on the electrical signal detected by the signal detecting means is further provided. The droplet ejecting apparatus according to 1.

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