JP2006256029A - Inkjet head and manufacturing method and image forming device using the inkjet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet head which permits sufficient cleaning of the vicinities of the outlets of nozzle openings and the maintenance of high print quality. <P>SOLUTION: A nozzle plate 224 on which a row of nozzle openings made up of a plurality of nozzle openings 225 to discharge ink droplets and at least edges 242 adjacent to the row of nozzles of the nozzle plate 224 from among the edges of a nozzle plate protecting member 240 having a nozzle plate protection member 240 to cover and protect at least a part of the nozzle plate 224 are formed in such a manner as to gradually reduce the thickness of the members toward the row of nozzles. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet head used in an ink jet recording apparatus, and more particularly, to a configuration of a nozzle plate protection member of the ink jet head, a manufacturing method thereof, and an image forming apparatus using the ink jet head.

  An ink jet recording head generally includes a flow path forming member having a flow path communicating with a nozzle plate provided with a plurality of nozzle openings for discharging ink droplets, and an actuator for pressurizing ink in the flow path. And the actuator is driven to pressurize the ink in the flow path, eject ink droplets from the nozzle openings, and record on the recording medium. A nozzle protection member is provided at the peripheral edge of the nozzle surface.

  In the invention described in Japanese Patent Laid-Open No. 2001-293881 (Patent Document 1), notches are formed in each corner of the side surface of the nozzle protection member, which can be manufactured by bending and can be manufactured at low cost. The nozzle surface can be closely attached.

  In the invention described in Japanese Patent Application Laid-Open No. 2004-284255 (Patent Document 2), a nozzle cover that covers the outer edge of the nozzle plate is provided, and a plurality of nozzle row groups are formed in the opening that exposes the nozzle surface of the nozzle cover. By providing a bar that is bridged between the nozzle surfaces to cover the nozzle surface, the exposed area can be minimized and damage to the nozzle surface can be prevented.

In the invention described in Japanese Patent Laying-Open No. 2003-341079 (Patent Document 3), the nozzle cover has elasticity, the two opposing sides of the opening are formed to warp toward the nozzle plate side, and the nozzle is returned so as to return its warp. By pressing and attaching to the surface, the nozzle surface can be brought into close contact.
JP 2001-293881 A JP 2004-284255 A Japanese Patent Laid-Open No. 2003-341079

  In some conventional techniques, a nozzle plate protection member is formed by drawing or bending a metal material, or a box shape is formed by molding a resin material. Each of these forms a box-shaped three-dimensional shape, and is in close contact with the nozzle surface with high accuracy, so that the wiping operation and effect with the wiper blade are sufficient, that is, the ink is left unwiped. In order to maintain a clean nozzle surface for a long period of time, it was not always sufficient. As a result, sufficient cleanliness in the vicinity of the nozzle hole outlet cannot be obtained, and ink droplets are not ejected normally, leading to a decrease in print quality.

  An object of the present invention is to provide an ink jet head capable of solving the problems as described above, obtaining a sufficient cleanliness near the nozzle hole outlet, and maintaining high print quality.

Problems and objects of the invention of claim 1
By making the shape of the nozzle plate protection member sufficiently accurate, the adhesion accuracy between the nozzle surface and the nozzle plate protection member is improved, so that the wiping blade comes into contact with the nozzle surface with high accuracy, so that the nozzle hole Obtain sufficient cleanliness near the outlet. In addition, it is possible to reduce the amount of ink remaining on the boundary between the nozzle surface and the nozzle plate protection member to a sufficient level. Furthermore, since the step at the inner end of the nozzle plate protection member with which the tip of the wiper blade comes into contact can be reduced, scratches and wear on the tip of the wiper blade can be prevented, and stable wiping performance can be maintained for a long period of time. be able to.
By enabling these, it is possible to provide an ink jet head capable of maintaining high print quality.

Problems and objects of the inventions of claims 2 and 3:
In order to configure the nozzle plate protection member with a flat plate-like member, it is necessary to increase the thickness of the member to some extent in order to ensure the rigidity of the member. Even if the nozzle plate protection member is in close contact with the surface of the nozzle plate with high precision, it is impossible to prevent the wiper blade tip from being scratched or worn. Ink is left behind at the boundary between the nozzle plate protection member and the nozzle plate protection member.
These can be reduced by gradually reducing the thickness of the nozzle plate protection member toward the nozzle row.

Problems and objects of the invention of claim 4
The box-shaped nozzle plate protection member is generally fixed at the side surface of the head frame, but bending or drawing is required when manufacturing the part. Positioning and fixing can be performed by the holes provided in the nozzle plate and the pins provided in the head frame, so that the component cost is low and the assembly is simple, so that the cost can be reduced.

Problems and objects of the inventions of claims 5 and 6:
If the surface of the nozzle plate protection member is uneven, ink may be left unwiped during wiping, or the wiping blade may be damaged or worn, maintaining stable wiping performance for a long period of time. become unable. Since it can be fixed to the pin with the pin receiving member, or fixed to the concave portion of the frame member, it can be fixed without providing irregularities or holes on the surface of the nozzle plate protection member.

Problems and objects of the inventions of claims 7 and 8:
The surface of the nozzle plate protection member and the edge on the side adjacent to the nozzle row will be rubbed or abutted by the wiping blade, and if there is not enough rigidity, it may be turned up or broken. . However, if the thickness is increased excessively, the step becomes large and the wiping property is impaired, and the distance between the nozzle and the object to be printed is set as small as possible (to improve the image quality). There is also a risk of touching and getting dirty. It is desirable to fix as close as possible to the edge on the side adjacent to the nozzle row, and the component thickness can be reduced. In addition, in order to secure the adhesive strength, it is not desirable to bond the nozzle plate and the nozzle plate protection member from above the water repellent treatment, so that a part of the nozzle plate surface that is not partly water repellent treated is made. It is desirable to bond there. Furthermore, since the portion that has not been subjected to the water-repellent treatment is likely to adhere to the ink when exposed, wiping cannot be performed cleanly, so it is necessary to provide the portion that is hidden by the nozzle plate.

Problems and objects of the invention of claim 9:
The part that has not been subjected to the water repellent treatment can be masked at the time of carrying out the water repellent treatment, or can be made by an appropriate means such as chemical treatment after the treatment. Expensive equipment is required, is troublesome, and costs increase.
After carrying out the water repellent treatment, it is possible to remove the water repellent treatment locally and make adhesive bonding possible by making a scratch line-like scratch at the corresponding part.

Problems and objects of the invention of claim 10
In order to achieve a uniform flat plate shape with a thin metal material, it is advantageous in terms of accuracy and cost to use a sheet-like member. When the nozzle row is elongated, a long nozzle plate protection member is required, and it is preferable to use a metal from the viewpoint of rigidity.

Problems and objects of the invention of claim 11:
Although it may be formed by resin molding or the like, it is difficult to achieve a uniform flat plate shape with a small thickness, and it is advantageous to use a resin sheet.

Problems and objects of the invention of claim 12:
When joining and fixing the nozzle plate protection member to the frame member and nozzle plate, if a general adhesive (one-component curing type, two-component curing type, instant bonding type, etc.) is used, the curing time will be very long. The pot life is short and the handling is inconvenient. After joining using the UV curable adhesive, it becomes possible to irradiate UV light through the nozzle plate protection member, and the above-mentioned problems are solved.

Problems and objects of the invention of claim 13:
The invention described above assumes that the nozzle plate protection member is integrated and is in the form of one component. However, when the head becomes longer, the nozzle plate protection member becomes a part having a longer length than the width. Further, since the opening corresponding to the nozzle row is provided with an opening, it becomes a weak component and may be deformed or broken during handling in the parts manufacturing process or handling during the head assembly. There is. The part of the nozzle plate protection member that connects the upstream side and the downstream side in the wiper blade wiping operation direction is weak and has the highest risk of damage from that part. It can be almost eliminated.

Problems and objects of the invention of claim 14
There is a need for an inexpensive and high-quality image recording apparatus. Further, in the future, it will be required to increase the speed of the image recording apparatus, and it is considered that the length of the head will be increased, and the present invention can cope with this.

Problems and objects of the invention of claim 15:
Ink often adheres to the surface of the nozzle plate protection member. If ink remains on the surface of the nozzle plate protection member, it may adhere to the surface of the object to be printed, or may fall on a nearby member and become dirty. It is difficult to form the entire nozzle plate protection member with a water-repellent material because it is difficult to form a thin flat plate, or the rigidity is insufficient if the thickness is reduced. Therefore, the surface is generally coated with a water repellent material. However, in the case of forming by bending or drawing as described above, if the water-repellent treatment is not performed after the processing, the water-repellent surface is often damaged at the time of processing, and a predetermined performance is often not obtained.
According to the fifteenth aspect of the present invention, since the nozzle plate protection member is composed of a planar member, there is no bending process and the water repellent treatment can be performed before the process. Furthermore, since water repellent treatment can be performed before processing, it is possible to process many batches at once, reducing the cost of parts and providing stable parts with low variations in water repellent treatment quality. It becomes possible to do.

  According to a first aspect of the present invention, there is provided an inkjet head comprising a nozzle plate in which a nozzle hole array comprising a plurality of nozzle holes for discharging ink droplets is formed, and a nozzle plate protection member that covers and protects at least part of the nozzle plate. The main part of the nozzle plate protection member is formed of a flat plate member.

  According to a second aspect of the present invention, in the first aspect of the invention, at least an edge of the nozzle plate protection member that is perpendicular to a wiping operation direction of a wiper blade that wipes residual ink is adjacent to a nozzle row of the nozzle plate. The edge is formed so that the thickness of the member gradually decreases toward the nozzle row.

  According to a third aspect of the present invention, in the second aspect of the present invention, when the edge shape of the nozzle plate protection member is based on the thickness of the nozzle plate protection member, the dimension perpendicular to the nozzle surface is 1 / The horizontal dimension is 2 t or less and the horizontal dimension is 1 t or more.

  The invention of claim 4 is the invention according to any one of claims 1 to 3, wherein the nozzle plate protection member is formed by a pin implanted in a frame member provided around the nozzle plate and the nozzle plate protection member. It is characterized in that it is positioned and fixed with the bored hole.

  According to a fifth aspect of the present invention, in the fourth aspect of the present invention, the nozzle plate protection member is configured such that a pin implanted in the frame member and a back surface of the nozzle plate protection member are bonded and fixed via a pin receiving member. It is characterized by that.

  The invention of claim 6 is the invention according to any one of claims 1 to 3, wherein the nozzle plate protection member has a concave portion provided in the frame member and a back surface of the nozzle plate protection member bonded and fixed by an adhesive. It is characterized by being.

  The invention of claim 7 is the invention of claim 5 or 6, wherein in the nozzle plate protection member, the non-water-repellent treatment region of the nozzle plate and the back surface of the nozzle plate protection member are bonded and fixed with an adhesive. It is characterized by that.

  According to an eighth aspect of the present invention, in the seventh aspect of the present invention, the non-water-repellent treatment region of the nozzle plate for adhesively bonding to the back surface of the nozzle plate protective member is covered with the nozzle plate protective member. It is characterized by.

  According to a ninth aspect of the present invention, in the eighth aspect of the invention, the non-water-repellent treatment region of the nozzle plate is a scratch-like non-water-repellent treatment intentionally applied from the water-repellent surface side after the water-repellent treatment is finished. It is characterized by being an area.

  The invention of claim 10 is characterized in that, in the invention of any one of claims 1 to 9, the main part of the nozzle plate protection member is formed of a metal sheet-like material.

  The invention of claim 11 is characterized in that, in the invention of any one of claims 1 to 9, a main part of the nozzle plate protection member is formed of a resin sheet material.

  The invention of claim 12 is characterized in that, in the invention of claim 11, the main part of the nozzle plate protection member is a material that transmits UV light.

  According to a thirteenth aspect of the present invention, in the invention according to any one of the first to twelfth aspects, the nozzle plate protection member is divided into at least two parts upstream and downstream in the wiping operation direction of the wiper blade. It is characterized by that.

  A fourteenth aspect of the present invention is the image forming apparatus according to any one of the first to thirteenth aspects, further comprising a liquid droplet ejection head that ejects liquid droplets from a nozzle and forming an image on a recording medium. The discharge head is an ink jet head according to any one of claims 1 to 13.

  According to a fifteenth aspect of the invention, in any one of the first to third aspects, at least the surface side of the nozzle plate protection member is subjected to a water repellent treatment before the outer shape of the nozzle plate protection member is formed. It is characterized by that.

  In the ink jet head according to claim 1, since the nozzle protection member is made of a flat plate member, the accuracy is high and the step at the inner end of the nozzle plate protection member with which the tip of the wiper blade abuts can be reduced. Scratches and wear on the tip can be prevented, and stable wiping performance can be maintained for a long time. That is, by making these possible, it is possible to provide an ink jet head capable of maintaining high print quality.

  In the ink jet heads according to claims 2 and 3, since the step due to the nozzle protection member can be reduced, it is impossible to prevent scratches and wear on the tip of the wiper blade, or ink at the boundary between the nozzle surface and the nozzle plate protection member. It is possible to prevent the remaining of wiping from occurring.

  In the ink jet head according to claim 4, since the positioning and fixing can be performed by the hole provided in the nozzle plate and the pin provided in the head frame, the parts cost is low and the assembly is easy, so that the ink jet head can be manufactured at low cost. it can.

  In the ink jet heads according to the fifth and sixth aspects, the pin receiving member can be fixed to the pin, or the frame member concave portion can be fixed without providing irregularities or holes on the surface of the nozzle plate protection member, so that the wiping effect is improved.

  In the ink jet heads according to claims 7 and 8, the surface of the nozzle plate protection member and the edge adjacent to the nozzle row are rubbed or abutted by the wiping blade and are not sufficiently rigid. Although there is a risk of turning up or breaking, it is possible to prevent these problems, and it is possible to provide a head with excellent strength and durability.

  In the ink jet head according to claim 9, after carrying out the water repellent treatment, it is possible to remove the water repellent treatment locally by making a marking line-like scratch at the corresponding part, thereby enabling adhesive bonding, and it is inexpensive and effective. Can be fixed.

  In the ink jet head according to the tenth aspect, when the nozzle row is elongated, a long nozzle plate protection member is required, and it is preferable to use a metal from the viewpoint of rigidity. By using a metal, it can be formed of a thin material, and effective wiping becomes possible.

  In the ink jet head according to the eleventh aspect, since it is possible to achieve a uniform flat plate shape with a small thickness, it is possible to form a nozzle plate protection member that is inexpensive and highly accurate using a resin sheet.

  The inkjet head according to claim 12 can use a UV curable adhesive that can solve the problem that the curing time is very long, the pot life is short, and the handling is inconvenient, and is inexpensive and highly accurate. Assembling of the nozzle plate protection member becomes possible.

  In the ink jet head according to claim 13, there is a risk that the ink jet head may be deformed or broken during handling in a part manufacturing process or the like and in handling during head assembly. Thus, it is possible to form a highly accurate nozzle plate protection member.

  In the image forming apparatus according to the fourteenth aspect, an image forming apparatus with high image quality, high reliability, and low cost can be obtained by mounting an inkjet head with high accuracy and low cost.

  In the ink jet head manufacturing method according to claim 15, since the nozzle plate protection member is formed of a planar member, it is possible to perform batch water repellent treatment in a large size before processing without any bending work, and the water repellent treatment. Man-hours are reduced and costs can be reduced.

  1 to 4 are views for explaining an example of an ink jet head manufactured by the method of manufacturing a droplet discharge head according to the present invention. FIG. 1 is a plan sectional view of the ink jet head, and FIG. FIG. 3 is a sectional view taken along line III-III in FIG. 2, and FIG. 4 is a sectional view taken along line IV-IV in FIG.

  The ink jet head shown in FIGS. 1 to 4 includes an actuator substrate (actuator unit) 1, a nozzle / liquid chamber unit 10 in which a flow path substrate 2 that is a liquid chamber constituent member and a nozzle substrate 3 that is a nozzle forming member are joined. And by joining these three substrates 1, 2 and 3, the liquid chamber 6 in which the nozzle 4 for discharging droplets communicates via the nozzle communication path 5 which is a communication port, the liquid A fluid resistance portion 7 and an ink supply hole 8 for supplying a liquid (ink) to the chamber 6 are formed. Each liquid chamber 6 is partitioned by a liquid chamber interval wall 9.

  Actuator elements 11 are formed on the actuator substrate 1 corresponding to the respective liquid chambers 6. The actuator element 11 includes a diaphragm 12 and electrodes (individual electrodes) 14 facing the diaphragm 12 via a gap (air gap) 13 formed by sacrificial layer etching. In addition, the ink supply hole 8 of the flow path substrate 2 faces the actuator substrate 1 to form an ink supply path 18 through which ink is supplied from the outside.

  On the other hand, the flow path substrate 2 constituting the nozzle / liquid chamber unit 10 is obtained by, for example, anisotropically etching a single crystal silicon (Si) substrate having a crystal plane orientation (110) with a strong alkaline etching solution such as a KOH aqueous solution. A recess that becomes the liquid chamber 6 is formed. In addition, as the flow path substrate 2 serving as the liquid chamber constituent member, ceramics, polyimide, PPS, or the like can be used.

  The nozzle substrate 3 is formed of a resin member such as a polyimide film. A water repellent film 30 is formed on the discharge direction surface of the nozzle substrate 3 by a known method such as a plating film or a water repellent coating in order to ensure water repellency with ink.

  Here, the flow path substrate 2 in which the concave portion to be the liquid chamber 6 is formed and the nozzle substrate 3 in which the water repellent film 30 is formed are bonded in advance to form the nozzle / liquid chamber unit 10, as will be described later. The nozzle communication path (communication port) 5 of the flow path substrate 2 and the nozzle 4 of the nozzle substrate 3 are processed and formed by the second laser.

  A specific configuration of the actuator substrate 1 will be described with reference to FIGS. 3 and 4. An insulating film such as a thermal oxide film 22 is formed on the silicon substrate 21, and the individual electrode 14 is required on the thermal oxide film 22. The insulating film 23, the sacrificial layer 24 such as polysilicon, and the insulating film 25 are sequentially laminated on the individual electrode 14, and the diaphragm electrode 26 is formed on the insulating film 25 in a required shape. After patterning and further forming the insulating film 27, an etching hole (sacrificial layer removal hole) 28 is formed in the insulating films 25 and 27, and a sacrificial layer between the individual electrode 14 and the diaphragm electrode 26 is formed. Is removed by etching to form the gap 13, the communication path 17, and the diaphragm 12, and then seal the sacrificial layer removal hole 28 and improve the liquid resistance of the actuator element 11. The sealing Se'ekimaku 29 made of a resin material are formed on the vibrating plate 12.

  A polysilicon film is used as the individual electrode 14 and the diaphragm electrode 26. As the material of the electrode, a material having high temperature resistance, excellent workability, and less unevenness on the film formation surface is preferable. Other than polysilicon, a high melting point metal material such as TiN is also preferable. The individual electrode 14 is connected to an external electrode pad 32 via a pad wiring 31.

  Further, the individual electrode side insulating film 23 and the diaphragm side insulating film 25 formed on the opposing surface side of the individual electrode 14 and the diaphragm electrode 26 prevent damage due to short circuit and discharge at the time of contact, and the sacrificial layer 24. Combined with the remaining portion, it also serves as a spacer for the gap 13. Furthermore, as the sealing wetted film 29 formed on the vibration plate 12 and sealing the etching hole 28, a PBO film (polybenzoxazole film) is preferable.

  In the head configured as described above, the diaphragm 12 is used as a common electrode, and a driving pulse voltage is applied between the individual electrode 14, whereby the diaphragm is generated by the electrostatic force generated between the diaphragm 12 and the individual electrode 14. 12 is deformed and displaced toward the individual electrode 14. Thereafter, by discharging the drive pulse voltage, the diaphragm 12 is restored and deformed, and ink droplets are ejected from the nozzles 4 due to the change in the internal volume of the liquid chamber 6 and the action of pressure.

  Here, an example in which an electrostatic actuator is used as an actuator unit as a droplet discharge head manufactured by applying the method for manufacturing a droplet discharge head according to the present invention has been described, but the present invention is not limited to this. Instead, piezoelectric actuators such as electromechanical transducers, thermal actuators using film boiling for electrothermal transducers, and the like can also be used. However, the electrostatic actuator has advantages over other methods in terms of downsizing, high speed, high density, and power saving.

  FIG. 5 shows the configuration of an excimer laser processing machine that processes the nozzle holes. The excimer laser beam 42 emitted from the laser oscillator 41 is reflected by mirrors 43, 45, and 48 and guided to the processing table 50. Yes. The beam expander 44, the mask 46, the field lens 47, and the imaging optical system 49 are placed at predetermined positions so that an optimum beam reaches the workpiece on the optical path from the laser beam 42 to the processing table 50. Is provided. The workpiece 41 (nozzle plate) is placed on the machining table 50 and receives a laser beam. The processing table 50 is composed of a well-known XYZ table or the like, and can move a workpiece as necessary to irradiate a laser beam at a desired position.

FIG. 6 is a diagram showing an example related to the nozzle / liquid chamber portion of the head to which the present invention is applied. The nozzle / liquid chamber unit 60 is composed of a resin member 61 and a liquid chamber constituting member 62 with a thermoplastic adhesive 63. The surface of the resin member 61 is formed by sequentially laminating the SiO ₂ thin film layer 64 and the fluorine-based water repellent layer 65. A nozzle hole 61 a having a required diameter is formed in the resin member 61, and the liquid chamber constituting member 62 is formed. Forms a nozzle communication port 62a communicating with the nozzle hole 61a. Here, the fluorine-based water repellent layer 65 is formed to be thicker than the thickness of the conventional example. The SiO ₂ thin film layer 64 is formed by a method capable of forming a film at a temperature within a range that is not relatively heated, that is, does not cause thermal influence on the resin member. Specifically, it can be said that sputtering, ion beam vapor deposition, ion plating, CVD (chemical vapor deposition), P-CVD (plasma vapor deposition) and the like are suitable. In the conventional example, after sputtering of Si, the sputtered film is subjected to O ₂ treatment to generate a SiO ₂ film.

From the viewpoint of process time and material cost, it is advantageous that the thickness of the SiO ₂ thin film layer 64 is set to the minimum necessary thickness within a range in which adhesion can be secured. Further, if this film thickness becomes too thick, there may be a problem in nozzle hole processing with an excimer laser. That is, even if the resin member 61 is neatly processed into a nozzle hole shape, a part of the SiO ₂ thin film layer 64 may not be sufficiently processed, and may remain as a processing residue. Therefore, specifically, it can be said that a thickness of 1 to 300 mm is suitable as a range in which the adhesion can be secured and the SiO ₂ thin film layer 64 does not remain at the time of excimer laser processing. More preferably, the range of 10 to 100 mm is suitable. Various materials are known for the fluorine-based water-repellent material used for the fluorine-based water-repellent layer 65, but here, modified perfluoropolyoxetane (trade name: OPTOOL DSX) manufactured by Daikin Industries, Ltd. Necessary water repellency is obtained by vapor deposition of 200 mm. Incidentally, in this embodiment, the fluorine-based water repellent layer has a thickness of 100 mm. Reference numeral 66 denotes an adhesive tape attached to the fluorine-based water repellent layer 65 with an adhesive 67, which is peeled off after the nozzle hole is processed.

FIG. 7 schematically shows a manufacturing process of the nozzle plate shown in FIG.
FIG. 7A shows a material that becomes a base material of the nozzle forming member. For example, Kapton that is a Dupont polyimide film or Upilex made by Ube Industries is a suitable material. Here, as the resin film 61, an upilex film having a thickness of 25 μm is used.

FIG. 7B shows a step of forming a thin SiO ₂ layer 64 on the surface of the resin film 61. The SiO ₂ thin layer 64 is formed using a sputtering method performed in a vacuum chamber. As a sputtering method, after sputtering Si, forming an SiO ₂ film by applying O ₂ ions to the Si surface improves the adhesion of the SiO ₂ film to the resin film, and also provides a homogeneous and dense A film was obtained, which was found to be more effective in improving the wiping durability of the water-repellent film.

FIG. 7C is a step of applying the fluorine-based water repellent 65, and as a coating method, methods such as spin coater, roll coater, screen printing, spray coater, etc. can be used. A method of forming a film by vacuum deposition is used, and it has been confirmed that the use of this method improves the adhesion of the water-repellent film and leads to an improvement in wiping durability. Further, it is possible to obtain the better effect that the vacuum deposition is performed in the vacuum chamber as it is after the SiO ₂ thin layer 64 in FIG. 7B is formed. That is, it is considered that once the work is taken out from the vacuum chamber after the SiO ₂ thin layer 64 is formed, the adhesion is impaired by impurities and the like adhering to the surface. Various materials are known as fluorine-based water repellent materials, but here, by using a modified perfluoropolyoxetane (Optool DSX manufactured by Daikin Industries) as a fluorine amorphous compound, the required water repellency for ink is obtained. Could get.

  FIG. 7D shows a joining process of the liquid chamber constituent members. Various materials can be used as the material of the liquid chamber constituent member, but silicon was used in this embodiment. An epoxy-based adhesive is applied as a thin film to the joint surface side of the liquid chamber constituting member 62 that has been subjected to necessary pattern etching in advance, and the water-repellent treated nozzle forming member shown in FIG. 62a is a communication port that has been etched in advance.

  FIG. 7E shows a process of applying the adhesive tape 66, which is applied to the surface coated with the fluorine-based water repellent layer 65 with the adhesive 67 of the adhesive tape 66. When the adhesive tape 66 is applied, it is necessary to apply the adhesive tape 66 so that no bubbles are involved. If there are bubbles, the nozzle holes opened at the positions where the bubbles are located may become poor quality due to deposits during processing.

  FIG. 7F shows a nozzle hole processing step in which an excimer laser is irradiated from the liquid chamber constituent member side through the communication port 62a to form the nozzle hole 61a. The excimer laser processing depth is good enough to be processed into the thickness of the adhesive tape. After processing the nozzle holes, the adhesive tape 66 is peeled off and the components are supplied to the head assembly in the next process.

  In the above description, only one nozzle hole is shown and described, but in practice, a plurality of nozzle holes are simultaneously processed within a possible range. Further, in the state where a plurality of nozzle / liquid chamber units are integrated, it is more efficient to perform the steps from FIG. 7A to FIG. 7F at the same time in FIG.

  Referring to FIG. 8, an example will be described in which each step is performed in a state where a plurality of the plurality of nozzle / liquid chamber units are integrated, and then the member is cut and divided into individual nozzle / liquid chamber unit chips. .

  First, as shown in FIG. 8, for example, a region to be the liquid chamber constituent member 72 is allocated to a 6-inch Si wafer 71, and each of the regions is formed by using a generally known semiconductor manufacturing photolitho process or the like. A predetermined liquid chamber pattern is formed in a portion that becomes the liquid chamber constituting member 72. FIG. 8 shows an arrangement example in which 42 liquid chamber constituting members 72 (chips) are allocated to a 6-inch wafer.

  Thereafter, a liquid resin material to be a nozzle forming member is applied to the surface of the liquid chamber constituting member 72 of the silicon wafer 71 by a known roller coating device or the like. Furthermore, the silicon wafer 71 to which the liquid resin material is applied is heated and cured to obtain the silicon wafer 71 in which a plurality of nozzle liquid chamber units are integrated. Next, each process is performed while handling the formation of the water-repellent film described in FIG. 7C and the laser processing described in FIG. At the stage where all the processes are completed, dicing is performed on each chip outer shape indicated by a chain line in FIG. 8 to form a chip for one head.

  Next, an example of the image forming apparatus according to the present invention provided with the droplet discharge head or the droplet discharge apparatus according to the present invention will be described with reference to FIGS. 9 is a side view for explaining the overall configuration of the image forming apparatus, FIG. 10 is a plan view of the principal part of the apparatus, and the recording head 107 shown in FIGS. 9 and 10 is the present invention described so far. Is reflected.

  The image forming apparatus shown in FIG. 9 and FIG. 10 holds the carriage 103 slidably in the main scanning direction by a guide rod 101 and a guide rail 102 that are horizontally mounted on left and right side plates (not shown). The carriage 103 is attached to the timing belt 105 between the pulley 106a attached to the motor 104 and the pulley 106b arranged on the other side, and the main scanning motor 104 passes the timing belt 105 through the timing belt 105 in the direction indicated by the arrow (main scanning direction). ) To move and scan.

  For example, the carriage 103 includes a plurality of recording heads 107 including four droplet ejection heads that eject ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). The ink discharge ports are arranged in a direction crossing the main scanning direction, and are mounted with the ink droplet discharge direction facing downward. In addition, as a droplet discharge head constituting the recording head 107, a droplet discharge head using a piezoelectric actuator such as a piezoelectric element is used.

  The carriage 103 is also equipped with a sub-tank 108 for each color for supplying each color ink to the recording head 107. Ink is supplied to the sub tank 108 from a main tank (ink cartridge) through an ink supply tube (not shown).

  On the other hand, as a paper feeding unit for feeding paper 112 stacked on a paper stacking unit (pressure plate) 111 such as a paper feeding cassette 110, a half-moon roller (separately feeding paper 112 one by one from the paper stacking unit 111) A separation pad 114 made of a material having a large friction coefficient is provided opposite the sheet feeding roller 113 and the sheet feeding roller 113, and the separation pad 114 is urged toward the sheet feeding roller 113 side.

  As a transport unit for transporting the paper 112 fed from the paper feed unit below the recording head 107, a transport belt 121 for electrostatically attracting and transporting the paper 112, and a paper feed unit A counter roller 122 for transporting the paper 112 fed through the guide 115 while sandwiching it between the transport belt 121 and the paper 112 fed substantially vertically upward is changed by about 90 ° and copied on the transport belt 121. A conveying guide 123 for adjusting the pressure and a tip pressure roller 125 urged toward the conveying belt 121 by a pressing member 124. Further, a charging roller 126 that is a charging unit for charging the surface of the transport belt 121 is provided.

  Here, the conveyance belt 121 is an endless belt, is stretched between the conveyance roller 127 and the tension roller 128, and the conveyance roller 127 is rotated from the sub-scanning motor 131 via the timing belt 132 and the timing roller 133. By doing so, it is configured to circulate in the belt conveyance direction (sub-scanning direction) of FIG. It has a back layer (medium resistance layer) and a ground layer which are made of the same material as the surface layer and have resistance controlled by carbon.

  The charging roller 126 is arranged so as to contact the surface layer of the conveyor belt 121 and rotate following the rotation of the conveyor belt 121, and applies 2.5N to both ends of the shaft as a pressing force. The transport roller 127 also serves as an earth roller, and is in contact with the middle resistance layer (back layer) of the transport belt 121 and is grounded.

  In addition, a guide member 136 is disposed on the back side of the conveyance belt 121 so as to correspond to a printing area by the recording head 107. The upper surface of the guide member 136 protrudes toward the recording head 107 from the tangent line of two rollers (the conveyance roller 127 and the tension roller 128) that support the conveyance belt 121. Thereby, the conveyor belt 121 is pushed up and guided by the upper surface of the guide member 136 in the printing region.

  Further, as a paper discharge unit for discharging the paper 112 recorded by the recording head 107, a separation unit for separating the paper 112 from the conveying belt 121, a paper discharge roller 142 and a paper discharge roller 143, and paper discharge A paper discharge tray 144 for stocking the paper 112 to be printed.

  A double-sided paper feeding unit 151 is detachably mounted on the back. The double-sided paper feeding unit 151 takes in the paper 112 returned by the reverse rotation of the transport belt 121, reverses it, and feeds it again between the counter roller 122 and the transport belt 121.

  In the image forming apparatus configured as described above, the sheets 112 are separated and fed one by one from the sheet feeding unit, and the sheet 112 fed substantially vertically upward is guided by the guide 115, and includes the conveyance belt 121 and the counter roller 122. The leading end is guided by the conveying guide 123 and pressed against the conveying belt 121 by the leading end pressure roller 125, and the conveying direction is changed by approximately 90 °.

  At this time, a positive voltage output and a negative output are alternately repeated from the high voltage power supply to the charging roller 126 by a control circuit (not shown), that is, an alternating voltage is applied, and a charging voltage pattern in which the conveying belt 121 alternates, that is, In the sub-scanning direction, which is the circumferential direction, plus and minus are alternately charged in a band shape with a predetermined width. When the paper 112 is fed onto the conveyance belt 121 charged alternately with plus and minus, the paper 112 is attracted to the conveyance belt 121 by electrostatic force, and the paper 112 is conveyed in the sub-scanning direction by the circular movement of the conveyance belt 121. Is done.

  Therefore, by driving the recording head 107 according to the image signal while moving the carriage 103, ink droplets are ejected onto the stopped paper 112 to record one line, and after the paper 112 is conveyed by a predetermined amount, Record the next line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 112 has reached the recording area, the recording operation is finished, and the paper 112 is discharged onto the paper discharge tray 144.

  FIG. 11 is an exploded perspective view of an inkjet head to which the present invention is applied. In the above description of the configuration of the inkjet head using FIGS. 1 to 4, an embodiment using an electrostatic actuator has been described. However, here, an inkjet head using a piezoelectric actuator according to another embodiment is used. explain.

  In FIG. 11, the inkjet head 200 is formed of a flow path unit 220, a head case 230, a nozzle plate protection member 240, and the like. The flow path unit 220 is bonded onto the head case 230, and the surface of the flow path unit 220 is It is covered with a nozzle plate protection member 240. The flow path unit 220 has a configuration in which a nozzle plate 224 is bonded to the surface of the flow path plate 221 and a vibration plate 226 is bonded to the opposite surface, and the flow path plate 221 has a plurality of ink supply paths 222 separated by partition walls (not shown). The pressure chambers 223 having communication holes at the ends are formed in two rows in the longitudinal direction at a predetermined pitch. The resin frame 231 constituting the head case 230 has a plurality of ink supply paths 222 formed in the flow path plate 221 and a common liquid chamber 232 for supplying ink to the pressure chamber 223, and has a ground electrode 233. Yes. In addition, a metal substrate 235 having an opening 234 at the center and having a PZT 236 connected to the FPC 237 bonded to the surface is accommodated. The PZT 236 bonded on the metal substrate 235 is grooved corresponding to the plurality of ink supply paths 222 and pressure chambers 223 formed in the flow path plate 221.

  The separated individual PZT 236 is bonded to the diaphragm 226 by an adhesive layer, and each electrode of the individual PZT 236 is mounted by the FPC 237 and individually driven and controlled by a control unit (not shown). Ink is supplied from the common liquid chamber 232 to the pressure chamber 223 via an ink supply port 227 formed in the vibration plate 226. In the nozzle plate 224, a row of nozzle holes 225 is formed corresponding to the row of the plurality of pressure chambers 223 formed in the flow path plate 221, and an opening 241 exposing the nozzle hole row is formed on the surface thereof. It is covered with a nozzle plate protection member 240.

  12 is a partially exploded perspective view showing a mounting portion of the nozzle plate protection member 240, and FIG. 13 is a cross-sectional view of the nozzle plate protection member 240 taken along line XIII-XIII in FIG. The nozzle plate protection member 240 is formed of a flat plate-like member, and an opening 241 is formed at a position corresponding to a row in which a plurality of nozzle holes 225 are arranged so that the nozzle holes 225 are exposed and can be wiped. . An end portion of the opening 241 is provided with an inclined portion 242 in the periphery so that the wiping operation can be performed smoothly. The thickness of the nozzle plate protection member 240 is set to be as small as possible. However, it is necessary to have such a thickness that it can be handled and rigid enough not to bend or bend when rubbed. It is. If there is a certain thickness, when the wiper blade moves while rubbing the nozzle surface during the wiping, the wiper blade collides with the end of the opening 241, and therefore the boundary between the nozzle surface and the end of the opening 241 The ink will not be wiped off and will remain. Also, the portion of the tip of the wiper blade that comes into contact with the end may be gradually scraped or deformed, resulting in the remaining ink being left unwiped.

  The inclined portion 242 of the nozzle plate protection member 240 is provided to prevent these inks from being left unwiped. The shape of the inclined portion 242 protects the nozzle plate so that the operation of the wiper blade is as smooth as possible. When the thickness of the member 240 is t, it is preferable that the vertical dimension y of the inclined portion tip is y = <(1/2) t, and the horizontal dimension x is x => t. As a method for forming the inclined portion, the outer shape of the nozzle plate protection member 240 and the opening 241 are removed by a punching process or the like, and then shaped by press pressurization, or the press pressurization punch is set at an appropriate temperature. And may be formed by being heated and deformed under pressure. Here, the surface of the nozzle plate is generally subjected to a water repellent treatment in order to optimize the ejection of ink droplets and to improve the wiping effect in wiping. In this embodiment, It is preferable to carry out before processing the outer shape of the nozzle plate protection member 240.

  FIG. 14 is a diagram for explaining an example in the case of performing a water repellent treatment. FIG. 14 shows a state before the outer shape of the nozzle plate protection member 240 is removed, and the nozzle plate protection member material 240 ′ is It is a thin metal sheet or resin film, and has an area enough to cut out a large number of nozzle plate protection members 240. 240 ″ indicates a size corresponding to one nozzle plate protection member 240 (that is, the nozzle plate protection member 240). For example, as shown in FIG. After the water treatment, the above-described punching process and slanted part forming process are performed, and by using such a treatment method, a batch water repellent treatment is possible, and the cost can be reduced.

  Next, the configuration of the head case 230 and the flow path unit 220 which are the receiving side of the nozzle plate protection member 240 will be described with reference to FIGS. FIG. 12 shows a state before the head case 230 and the flow path unit 220 are already assembled and the nozzle plate protection member 240 is assembled. FIG. 15 is a sectional view showing a positional relationship of a part of the state after assembling the nozzle plate protection member 240. That is, the flow path unit 220 is aligned with a predetermined recess 251 of the resin frame 231 and joined. The height is set so that the nozzle surface of the nozzle plate 224 is substantially flush with the nozzle plate protection member support surface 252 of the resin frame 231. A rib 253 is provided on the outer periphery of the upper surface of the resin frame 231, and the difference in height between the nozzle plate protection member support surface 252 and the rib 253 is the same as the thickness of the nozzle plate protection member 240. After the assembly, the surface of the rib 253 and the surface of the nozzle plate protection member 240 are almost the same height. The nozzle plate protection member support surface 252 is provided with an adhesive receiving recess 254 for fixing the nozzle plate protection member 240. FIG. 12 shows an example in which two locations are provided on both sides, but this may be done by selecting an appropriate number of locations in consideration of the size of the head and the like.

  In the embodiment shown in FIG. 12, after the head case 230 and the flow path unit 220 are assembled, the adhesive 260 is dropped into the adhesive receiving recess 254. Thereafter, the nozzle plate protection member 240 is inserted into the nozzle protection member support surface 252 and pressed to be brought into close contact with the adhesive to be cured. By doing so, as shown in the partial cross-sectional view shown in an enlarged view in FIG. 16, the peripheral end of the nozzle plate is covered with the nozzle plate protection member 240, and the nozzle plate protection member 240 is the nozzle protection member. It is fixed to the support surface 252. With this configuration, the operation of wiping the nozzle surface by the wiping blade can be smoothly wiped cleanly with almost no steps.

  FIG. 17 is a diagram for explaining an embodiment of another positioning and fixing method of the nozzle plate protection member 240. The embodiment shown in FIG. 17 is a pin 255 provided on the nozzle frame 231 and the nozzle plate protection member 240. The nozzle protection member support surface 252 of the resin frame 231 has a concave portion 254 whose wall surface is inclined, and a pin 255 is provided at the center of the concave portion 254. It has been planted. On the other hand, a hole 243 is provided in the nozzle plate protection member 240, and the hole has a shape surrounded by a concave recess. The hole 243 is inserted into a pin 255 and fixed. Since there is nothing protruding from the surface of the nozzle plate protection member 240 in this state, it may be used as it is. However, in order to prevent this from remaining due to ink remaining in the recessed portion, the nozzle It is more effective to fill the adhesive filler 260 also to ensure the fixing of the plate protection member 240.

  FIG. 18 shows another embodiment, in which the nozzle plate protection member support surface 252 of the resin frame 321 has a recess 254, and a pin 255 is implanted in the center thereof. For example, a ring-shaped pin receiving member 256 is inserted around the pin 255. Here, the pin 255, the pin receiving member 256, and the nozzle plate protection member 240 are separated from each other, and although not shown in FIG. 18, an adhesive is applied between the members during assembly. In this state, positioning and fixing can be performed by curing the adhesive while pressing the nozzle plate protection member 240. With this configuration, the nozzle plate protection member 240 can be reliably fixed and positioned and fixed without any unevenness on the surface of the nozzle plate protection member 240, so that the wiping operation can be effectively performed.

  As described above, in order to effectively perform the wiping operation, it is preferable to make the thickness of the nozzle plate protection member 240 as thin as possible. However, if the thickness is too thin, the rigidity is reduced, and the frictional force when wiping with the wiping blade is performed. Then it will be bent or deformed. Therefore, if the nozzle plate protection member 240 is fixed as close as possible to the edge of the nozzle plate protection member 240, such a fear can be eliminated.

  FIG. 19 is a partial cross-sectional view for explaining the embodiment. As described above, the surface of the nozzle plate 224 has been subjected to water repellent treatment, but a non-water repellent treatment region 228 is provided in a part thereof. Form. A small amount of adhesive 260 is dropped on the non-water-repellent treatment region 228 and the nozzle plate protection member 240 is assembled as described above, so that the nozzle plate protection member 240 is fixed to the nozzle plate 220 near the edge. Therefore, there is no risk of bending or deformation as described above.

  20 and 21 show the form of the non-water-repellent treatment region. In FIG. 20, the nozzle plate is masked in advance by a method such as masking the non-water-repellent treatment region at the time of the water-repellent treatment or chemical treatment after the water-repellent treatment. A non-water-repellent treatment region 229 is provided at 224. In FIG. 21, the water repellent treatment surface is scratched with a marking needle-shaped scratching tool after the water repellent treatment, so that the water repellent treatment is partially peeled off and the portion is described with a small amount of adhesive. The nozzle plate protection member 240 is joined in the same manner as described above. 229 'indicates the wound. Since the non-water-repellent treatment region 228 described here does not repel water, if it is exposed to the nozzle surface, the ink tends to adhere, and even if wiping is performed, the ink will not be wiped cleanly. Therefore, it is appropriate that the non-water-repellent treatment region 228 is a portion that is covered with the nozzle plate protection member 240 after assembly.

  In the embodiments so far, the material of the nozzle plate protection member 240 has not been specifically described. However, it is preferable that the nozzle plate protection member 240 be formed of a resin-like material having high rigidity. For example, PPS (polyphenylene sulfide), PI (polyimide) and the like are preferable. Further, as described with reference to FIGS. 15 and 16, when the nozzle plate protection member 240 is bonded with the adhesive 260, the nozzle plate protection member 240 may be formed of a material that transmits UV light. In this case, a UV curable adhesive can be used, and the curing time can be greatly shortened, thereby contributing to the cost reduction of the head.

  Further, in the case where the nozzle plate protection member 240 inevitably becomes large due to an increase in the number of nozzles in the head or the like, the nozzle plate protection member 240 may be formed of a metal material. The metal material has higher rigidity than the resin material, and can sufficiently cope with an increase in the size and length of the head. For example, a material for a leaf spring such as stainless steel is suitable.

FIG. 22 shows another embodiment in which the nozzle plate protection member 240 is divided into _two parts 240 ₁ and 240 ₂ . As described above, it is natural that an increase in the printing speed of an ink jet printer will be required in the future, and it is expected that the number of nozzles of the head will increase further. In such a case, with the nozzle plate protection member 240 as described so far, the rigidity is lowered and the opening 241 of the nozzle plate protection member 240 is gradually increased, and the portion where the material is discarded increases. As shown in FIG. 22, these are prevented by dividing the nozzle plate protection member without forming it integrally. In other words, the portion that needs to protect the nozzle plate against the wiping operation is left, and the portion that connects it is removed.

As shown in FIG. 22, two nozzle plate protection members 240 ₁ and 240 ₂ are provided on the upstream side and the downstream side of the wiping wiping operation (which may be upstream or downstream in FIG. 22). The two nozzle plate protection members are installed as a control and are the same part. In this case, the end portion of the nozzle plate 224 is not covered with the nozzle plate protection member 240 in the portion indicated by C in FIG. 22, but no force that peels off the nozzle plate is applied in the operation of the wiping blade. No problem at all. In this way, even if the nozzle plate protection member is long, there is little risk of deformation due to its simple shape, and there are few parts to throw away material, reducing the cost and reducing the cost of the effective nozzle plate. Protection is possible. The method for fixing the nozzle plate protection member can be the same as in the above embodiment.

An image forming apparatus is formed by mounting the head formed as described above, but the configuration is the same as that of FIGS. 9 and 10 described above except for the contents of the head portion, and the illustration is omitted.
Since the image forming apparatus according to the present invention is equipped with the droplet discharge head embodying the present invention, it is possible to provide an image forming apparatus (inkjet recording apparatus) that can cope with high image quality and high speed recording at low cost.

  Note that the image forming apparatus according to the present invention can also be applied to a printer, a facsimile machine, a copying machine, a multi-function machine thereof, and the like. Further, the present invention can also be applied to a droplet discharge head or a droplet discharge device that discharges a liquid other than ink, such as a DNA sample, a resist, or a pattern material, or an image forming apparatus that includes these.

It is a plane cross-section explanatory drawing of an inkjet head. It is a top view of the state which decomposed | disassembled the inkjet head shown in FIG. FIG. 3 is a cross-sectional explanatory view taken along line III-III in FIG. 2. It is sectional drawing which follows the IV-IV line of FIG. It is a figure which shows the structure of the excimer laser processing machine which processes a nozzle hole. It is a figure which shows the example regarding the nozzle and the liquid chamber part of the inkjet head to which this invention is applied. It is the figure which showed typically the manufacturing process of the nozzle plate shown in FIG. It is a figure which shows the example in the case of forming in the state integrated with the several nozzle and the liquid chamber unit on the single silicon wafer. 1 is a side view illustrating an overall configuration of an image forming apparatus to which an inkjet head according to the present invention is applied. It is a principal part top view of the image forming apparatus shown in FIG. It is a disassembled perspective view of the inkjet head to which this invention is applied. It is a partial exploded perspective view which shows the attachment part of a nozzle plate protection member. It is sectional drawing of a nozzle plate protection member. It is a figure for demonstrating the example in the case of performing a water repellent process. It is sectional drawing which shows the positional relationship of the part of the assembled state about the structure of a nozzle plate protection member and a flow-path unit. It is a figure which shows the state in which the nozzle plate protection member is closely_contact | adhered to the nozzle plate protection member support surface. It is a figure for demonstrating the example of the positioning fixing method of a nozzle plate protection member. It is a figure for demonstrating another positioning fixing method of a nozzle plate protection member. It is a fragmentary sectional view explaining the example which made the nozzle plate protection member adhere to a nozzle plate by the edge part. It is a figure for demonstrating the example which provides a non-water-repellent process area | region in a nozzle plate. It is a figure for demonstrating the example which damages a water-repellent treatment surface with a marking needle-shaped damage tool. It is a figure for demonstrating the example which divides | segments a nozzle plate protection member into two components.

Explanation of symbols

DESCRIPTION OF SYMBOLS 200 ... Inkjet head, 220 ... Channel unit, 221 ... Channel plate, 222 ... Ink supply path, 223 ... Pressure chamber, 224 ... Nozzle plate, 225 ... Nozzle hole, 226 ... Vibration plate, 227 ... Ink supply port, 228 ... water-repellent treatment region, 230 ... head case, 231 ... nozzle frame, 240 ... nozzle plate protection member, 240 ₁ , 240 ₂ ... divided nozzle plate protection member, 241 ... opening, 242 ... inclined part, 251... Recessed portion provided in the nozzle frame, 252... Nozzle plate protection member supporting surface, 253... Rib, 254.

Claims (15)

  In the inkjet head, comprising: a nozzle plate in which a nozzle hole array including a plurality of nozzle holes for discharging ink droplets is formed; and a nozzle plate protection member that covers and protects at least a part of the nozzle plate, the nozzle plate protection member An ink jet head characterized in that a main part of the head is formed of a flat plate member.   Of the edge of the nozzle plate protection member perpendicular to the wiping operation direction of the wiper blade for wiping off residual ink, at least the edge adjacent to the nozzle row of the nozzle plate is gradually moved toward the nozzle row. The inkjet head according to claim 1, wherein the inkjet head is formed so as to be thin.   When the edge shape of the nozzle plate protection member is based on the thickness of the nozzle plate protection member, the vertical dimension with respect to the nozzle surface is 1/2 t or less and the horizontal dimension is 1 t or more. The inkjet head according to claim 2.   2. The nozzle plate protection member is positioned and fixed by a pin implanted in a frame member provided around the nozzle plate and a hole formed in the nozzle plate protection member. 4. The inkjet head according to any one of items 1 to 3.   5. The inkjet head according to claim 4, wherein the nozzle plate protection member has a pin implanted in the frame member and a back surface of the nozzle plate protection member bonded and fixed via a pin receiving member.   4. The nozzle plate protection member according to claim 1, wherein a recess provided in the frame member and a back surface of the nozzle plate protection member are bonded and fixed with an adhesive. 5. Inkjet head.   The inkjet head according to claim 5 or 6, wherein the nozzle plate protection member has a non-water-repellent treatment region of the nozzle plate and a back surface of the nozzle plate protection member bonded and fixed with an adhesive.   The inkjet head according to claim 7, wherein a non-water-repellent treatment region of the nozzle plate for adhesive bonding to the back surface of the nozzle plate protection member is entirely covered by the nozzle plate protection member.   The non-water-repellent treatment region of the nozzle plate is a scratch-like non-water-repellent treatment region intentionally applied from the water-repellent surface side after the water-repellent treatment is finished. Inkjet head.   The ink jet head according to claim 1, wherein a main part of the nozzle plate protection member is formed of a metal sheet material.   The ink jet head according to claim 1, wherein a main part of the nozzle plate protection member is formed of a resin sheet material.   The inkjet head according to claim 11, wherein a main part of the nozzle plate protection member is made of a material that transmits UV light.   The inkjet head according to any one of claims 1 to 12, wherein the nozzle plate protection member is divided into at least two parts upstream and downstream in the wiping operation direction of the wiper blade.   14. An image forming apparatus that includes a droplet discharge head that discharges droplets from a nozzle and forms an image on a recording medium, wherein the droplet discharge head is the inkjet head according to claim 1. An image forming apparatus.   4. The inkjet head according to claim 1, wherein at least a surface side of the nozzle plate protection member is subjected to water repellent treatment before the outer shape of the nozzle plate protection member is formed. 5. An inkjet head manufacturing method for manufacturing.