JP2006231876A - Liquid droplet injection recording head, liquid droplet injection recording apparatus, and method of manufacturing liquid injection recording head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid injection recording head and a liquid injection apparatus, which prevent degradation of a droplet landing accuracy by detecting ink adhesion conditions on an orifice surface. <P>SOLUTION: The liquid injection recording head of the present invention has: a water repellent part 3 formed around a nozzle 2; a hydrophilic part 4 formed in the other part than the water repellent part 3 in the orifice surface; an electrode 5a as a sensor which is formed in the hydrophilic part 4 around the water repellent part 3 and detects adhesion of liquid; and an electrode 5b which is formed with a space around the electrode 5a. A liquid injection apparatus main body has an electric signal detecting unit 16 for measuring a resistance value between the electrodes 5a and 5b. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid jet recording head and a liquid jet recording apparatus used in a printer as an output device such as a copying machine, a facsimile machine, a word processor, and a host computer, and more particularly to recording by ejecting ink or the like as flying droplets from a discharge port. The present invention relates to a liquid jet recording head used in a liquid jet recording apparatus that performs recording by being attached to a medium, and a method of manufacturing the liquid jet recording head.

  The present invention also relates to a liquid jet recording apparatus having a mechanism for detecting and removing liquid adhering to the vicinity of a discharge port of a liquid jet recording head that performs recording by discharging ink or the like.

In the ink jet system, a liquid jet recording head provided with a plurality of ink discharge ports having an extremely fine diameter is used. When recording is performed, ink is ejected from these ink ejection ports in accordance with the input of a predetermined recording signal, and is deposited on the recording medium. With the recent increase in image quality and miniaturization, very fine ink droplets have been ejected, and mist tends to increase. In a recording apparatus using such a liquid jet recording head, when ink adheres to the orifice surface of the head, it is dragged by that, the ink ejection direction is shifted, and the dot landing accuracy on the recording medium may deteriorate. there were. In order to solve this problem, as shown in FIG. 6, a recording head that detects the state of ink 207 adhesion near the nozzle 202 on the orifice surface 201 of the head has been proposed (see Patent Document 1). This recording head has an electrode 205a formed on the orifice surface 201 so as to surround the periphery of the nozzle 202, and an electrode 205b formed adjacent to the electrode 205a with a minute gap. The electrodes 205a and 205b are connected to the electrical signal detection circuit 216, and the electrical change when the ink 207 is deposited on the gap is read by the electrical signal detection circuit 216. The presence or absence is detected. If the ink 207 adheres to the orifice surface 201, the ejection is stopped and the orifice surface 201 is recovered.
JP 2000-15838 A

However, the conventional recording apparatus described above has the following problems.
1. Since the electrode 205a is formed so as to surround the periphery of the nozzle 202, when the ink 207 adheres to the nozzle 202 side from the gap, that is, in the vicinity of the nozzle 202, the adhesion state of the ink 207 cannot be detected. Incorrect landing on the recording medium cannot be prevented.
2. The orifice surface 201 provided with a plurality of nozzles 202 with extremely fine diameters has the property of repelling the ink 207 to some extent, so that only ink droplets remain sparsely on the orifice surface 201 and the state of ink 207 adhesion. Cannot be detected correctly.

  Therefore, in order to solve the above-described problems, the present invention detects a state of ink adhesion on the orifice surface, and can prevent a drop in landing accuracy, a liquid jet recording head, a liquid droplet jet recording apparatus, and It is an object of the present invention to provide a method for manufacturing a liquid jet recording head.

  In order to achieve the above object, a liquid jet recording head according to the present invention is a liquid jet recording head having an orifice surface on which nozzles for discharging liquid are formed. A lyophilic portion formed on the orifice surface other than the lyophobic portion, and a sensor formed on the lyophilic portion around the lyophobic portion to detect liquid adhering to the lyophilic portion. And

  According to the present invention, it is possible to prevent the landing accuracy from being lowered by detecting the ink adhesion state on the orifice surface.

[1. Configuration of liquid jet recording apparatus]
First, the liquid jet recording apparatus used for detecting the ink adhesion state on the orifice surface of the liquid jet recording head in this embodiment will be described.

  The liquid jet recording apparatus used in this embodiment shown in FIG. 1 includes a carriage 109 on which a recording head 13 for ejecting ink is mounted on a recording medium 6 and an adsorption stage 103 on which the recording medium 6 is mounted. Have.

  Further, the liquid jet recording apparatus of this embodiment includes a carriage (CR) linear motor 101 as a moving unit of the carriage 109, and includes a suction stage 103 and an LF linear motor 102 as moving units of the recording medium 6. The line feed (LF) linear motor 102 is fixed to a surface plate 108 so that the surface of the suction stage on which the recording medium 6 is placed is always parallel to the surface of the surface plate even when the suction stage 103 moves. On the other hand, the CR linear motor 101 is fixed on the surface plate 108 with high rigidity through the bases 104 and 105, and adjusted so that the carriage 109 moves in parallel with the surface surface of the surface plate, that is, the surface of the suction stage. Yes. Each of the CR linear motor 101 and the LF linear motor 102 includes linear encoders 111 and 112 and origin sensors 106 and 107, which are used as servo control inputs when the linear motors are moved, and are used for the linear operation on the CR side. The encoder 111 is also used for generating ink ejection timing.

In addition, the liquid jet recording apparatus according to this embodiment includes a head recovery unit 120 for removing ink attached to the orifice surface of the recording head 13. Furthermore, a personal computer (not shown) is connected to the liquid jet recording apparatus via a Centronics interface or a USB interface, and a recording medium is printed with ink ejected from the head based on graphic information data transmitted from the personal computer. 6 is recorded on the surface.
[2. Recording operation of liquid jet recording apparatus]
Next, the recording operation of the droplet jet recording apparatus in the present embodiment will be described with reference to FIG.

  FIG. 2 is an overall block diagram of the droplet jet recording apparatus in the present embodiment. The main control unit 14 is a central part that controls the entire liquid jet recording apparatus including the recording head 13, the suction stage 103, the CR linear motor 101, the LF linear motor 102, and the like, and stores a CPU, an operation program, and the like. And a working RAM for writing and reading various data.

  The recording head 13 is mounted in the carriage 109 shown in FIG. 1, and the recording head 13 is moved by moving the carriage 109. Therefore, the CR motor driver 31 is operated by a CR linear motor in response to a command from the motor controller 30. 101 is controlled. Further, the LF motor driver 32 controls the LF linear motor 102 according to a command from the motor controller 30 in order to move the recording medium 6 placed on the suction stage 103. The vacuum pump 33 sucks the air in the suction stage 103 and uses the pressure difference between the atmospheric pressure and the suction stage 103 to suck the recording medium 6 for recording on the suction stage 103.

  The main control unit 14 outputs control signals to the linear motors 101 and 102 via the motor controller 30 and the motor drivers 31 and 32 to move the recording head 13 and the recording medium 6, while the head control unit The recording head 13 is driven by exchanging signals closely with each other.

  Specifically, the main control unit 14 passes graphic information data transmitted from the personal computer to the head control unit 12. The head control unit 12 performs a recording operation by driving the electrothermal conversion element corresponding to each nozzle of the recording head 13 according to the graphic information data passed from the main control unit 14.

  Further, the main control unit 14 outputs a control signal to the CR linear motor 102 via the motor controller 30 and the CR motor driver 31 in order to move the recording head 13 to a recording start position (not shown). Further, the main control unit 14 outputs a control signal to the LF linear motor via the motor controller 30 and the LF motor driver 32 in order to move the recording medium 6 to the recording start position.

  That is, the main control unit 14 performs recording while moving the recording head 13 in the main scanning direction, and when one scan is completed, moves the recording medium 6 in the sub-scanning direction (that is, the next recording position). After that, recording is repeatedly performed while moving the recording head 13 in the main scanning direction again.

When recording is repeated as described above, ink gradually adheres to the orifice surface of the recording head 13. The electric signal detector 16 is for detecting the ink adhesion state, and detects the presence or absence of ink adhesion by measuring a resistance value between electrodes provided in the recording head 13 described later. Here, when ink adhesion is detected, the main control unit 14 controls the head recovery unit 120 for removing the adhered ink via the recovery unit driving unit 121.
[3. Configuration of droplet jet recording head]
〔Example〕
Next, a method for detecting ink adhering to the orifice surface 1 of the recording head 13 of this embodiment will be described. FIGS. 3A to 3C are schematic diagrams for explaining a method of detecting ink attached to the orifice surface 1 of the recording head 13.

  First, the configuration of the droplet jet recording head according to the present invention will be described.

  As shown in FIG. 3A to FIG. 3C, a plurality of nozzles 2 (discharge ports) are arranged on the orifice surface 1 at a pitch of 600 dpi, the nozzle 2 has a diameter of 22 μm, and the periphery of the nozzle 2 A water repellent (liquid repellent) portion 3 is formed. The water repellent part 3 is preferably formed from 5 to 50 μm from the outer periphery of the nozzle 2. In this embodiment, the water repellent part is formed from the nozzle 2 to 10 μm. The water repellent portion 3 is for preventing a part of the ink 7 ejected from the nozzle 2 from remaining in the vicinity of the nozzle 2 as much as possible. 3A to 3C, a hydrophilic (lyophilic) portion 4 is formed on a portion other than the water repellent portion 3 on the orifice surface 1. Electrodes 5 a and 5 b are provided around the water repellent portion 3 in the hydrophilic portion 4. The electrode 5a is provided on the outer periphery of the water-repellent part 3 so as to leave a slight gap and substantially surround it. In this embodiment, the electrode 5a is formed with a gap of about 10 μm from the water repellent part 3, and the electrode 5b is provided so as to surround the outer periphery of the electrode 5a with a slight gap (about 2 μm) from the electrode 5a. Yes. Each electrode 5 a, 5 b is electrically connected to the electric signal detection circuit 16.

  In the recording head of this embodiment, when a part of the ink 7 ejected from the nozzle 2 adheres to the orifice surface 1, it gathers in this hydrophilic portion 4. That is, when the ink 7 adheres to the water repellent part 3, the ink 7 does not remain in the water repellent part 3, flows to the hydrophilic part 4 formed so as to surround the water repellent part 3, and collects in the hydrophilic part 4.

  FIG. 3A shows an example in which the electrodes 5a and 5b are formed so as to surround the rectangular water-repellent portion 3 formed so as to surround the nozzles 2 arranged linearly in a U-shape.

  FIG. 3B shows an example in which the distance between the electrode 5a and the electrode 5b is slightly wider (about 5 μm) than that in FIG. Thus, by providing a little wider gap between the electrodes 5a and 5b, the presence of attached ink is not detected unless a certain amount of ink is collected. In the case of this configuration, since it becomes possible to detect immediately before the ink adheres to the vicinity of the nozzle 2, it is possible to improve the accuracy of ink landing prediction, and to reduce unnecessary recovery operation. Reducing the number of recovery operations not only can reduce ink consumption, but can also reduce deterioration of the orifice surface 1.

FIG. 3C shows an example in which electrodes are provided independently along the discharge port array on both sides in the longitudinal direction of the rectangular water-repellent portion 3. That is, the electrode 5a and the electrode 5b are provided on one side in the longitudinal direction of the water repellent part 3, and the electrode 5c and the electrode 5d independent of the electrodes 5a and 5b are provided on the other side. The resistance between the electrodes can be separately measured on the left and right of the part 3. Thereby, it can be grasped which side of the longitudinal direction of the water repellent part 3 the ink droplet is attached.
[4. Ink adhesion on orifice surface]
Next, the ink adhesion on the orifice surface of the droplet jet recording head will be specifically described.

  [2. As described in [Recording Operation of Liquid Jet Recording Apparatus], the recording operation of the droplet jet recording apparatus in FIG. 1 is performed while moving the recording head 13 in the main scanning direction. Is moved in the sub-scanning direction (that is, the next recording position), and then repeatedly performed while moving the recording head 13 in the main scanning direction again.

  When recording is repeated, ink 7 adheres on the orifice surface 1. FIG. 4A to FIG. 4D schematically show how the ink 7 gradually adheres to the orifice surface 1.

As shown in FIG. 4A, no ink is initially deposited on the orifice surface 1. Thereafter, by repeating the recording operation, the mist of the ink 7 ejected from the nozzle 2 floats without landing on the recording medium, or due to the influence of the satellite of the ink 7 ejected from the nozzle 2, FIG. ) And (c), the ink 7 gradually adheres on the orifice surface 1. Then, as shown in FIG. 4D, the ink 7 may adhere to the vicinity of the nozzle 2 in some cases. A water repellent part 3 is provided in the vicinity of the nozzle 2. The purpose of the water repellent part 3 is to make it easy to return the ink 7 to the nozzle 2 without leaving the overflow of the ink 7 when the meniscus is formed in the vicinity of the nozzle 2. Further, even when the mist of the ink 7 adheres to the water repellent portion 3, extremely small ink droplets are attached separately. On the other hand, since the mist of the ink 7 tends to gather in the hydrophilic portion 4, the amount of the ink 7 that adheres also increases.
[5. Ink adhesion status detection method]
Next, a method for detecting ink adhering to the orifice surface 1 will be described.

  [4. As described in “Adhesion of Ink onto Orifice Surface”], the ink 7 adheres to the orifice surface 1 by repeatedly performing the recording operation. If the adhered ink 7 adheres to the vicinity of the nozzle 2, the ink ejection direction may shift, and the dot landing accuracy on the recording medium may deteriorate. In order to prevent inaccurate landing of the ink on the recording medium, it is important to detect the adhering ink before the ink 7 adheres to the vicinity of the nozzle 2.

  That is, the feature of the present embodiment is that the adhering ink is detected before the water-repellent portion 3 near the ejection port is so exposed that the adhering ink is detected on the orifice surface at the hydrophilic portion 4 where the ink easily adheres. Can be detected, and ink landing accuracy can be improved.

  In the detection method, the electrical signal detection unit 16 measures the resistance value between the electrodes, which changes when the ink 7 adheres between the electrodes 5a and 5b formed on the hydrophilic portion 4 with a minute gap therebetween. . This change in resistance value indicates that the ink 7 has started to adhere between the electrodes 5a and 5b, that is, the hydrophilic portion 4 of the orifice surface 1, and the orifice surface 1 before the ink 7 has adhered to the vicinity of the nozzle 2. It becomes possible to accurately detect the upper ink adhesion state.

  The measurement of the resistance value between the electrodes as described above is performed while the recording operation on the recording medium is repeatedly performed, and it is detected that the ink 7 starts to adhere to the hydrophilic portion 4 of the orifice surface 1. Then, the main control unit 14 temporarily suspends recording when recording for one scan on the recording medium is completed, or when recording for one page on the recording medium is completed.

  Thereafter, recording may be resumed after a recovery operation described later is performed. As a result, the ejection of the ink 7 onto the recording medium can be controlled, and the ink can be prevented from landing inaccurately.

The ink 7 is not particularly limited as long as it has conductivity, but in this example, an organic palladium-containing solution (palladium acetate-ethanolamine complex aqueous solution (2.0 wt%) was used. Although the present embodiment has been described using a serial type liquid jet recording head, the present invention is also applied to a line head type liquid jet recording head provided with a number of nozzles corresponding to the width direction of the recording paper. Applicable.
[6. Adhesive ink recovery operation]
Next, the recovery operation of the ink adhering to the orifice surface 1 will be described with reference to FIGS.

  [5. As described in the method of detecting the ink adhesion state], when it is detected that the ink 7 starts to adhere to the hydrophilic portion 4 of the orifice surface 1, the main control unit 14 first temporarily performs the recording operation on the recording medium. Interrupt. Thereafter, in order to remove the adhering ink 7 on the orifice surface 1 of the recording head 13, the main control unit 14 outputs a control signal to the CR linear motor via the motor controller 30 and the CR motor driver 31. Is moved to the position of the head recovery unit 120. When the movement is completed, the main control unit 14 controls the head recovery unit 120 via the recovery unit driving unit 121 to remove the adhered ink 7 on the orifice surface 1 of the recording head 13. When this recovery operation (removal of attached ink 7) is completed, the main control unit 14 may resume the recording operation on the recording medium. In addition, when removing the adhesion ink 7, it is desirable that the place to be removed can be specified. For example, as shown in FIG. 3C, if the structure can detect the presence or absence of the ink 7 separately attached to both sides in the vicinity of the nozzle 2, the attached ink 7 may be removed only from the corresponding portion.

The head recovery unit 120 used in the present invention is of a type that wipes the orifice surface 1 of the recording head 13 by wiping the orifice surface 1 with a blade or the like. A recovery system unit for maintaining and recovering the ink ejection performance of the head may be used.
[7. Method for creating liquid jet recording head]
Next, a method for manufacturing the liquid jet recording head in the present embodiment will be described with reference to FIGS.

  First, a heat storage layer 202 is formed on a silicon substrate 201, 25 μm square heaters (heating resistors) 203 are arranged at 600 dpi, and a protective layer 204 is formed thereon (FIG. 5A).

  Next, 15 μm of a mold resist 208 is applied, and the shape of the nozzle channel is patterned by exposure and development (FIG. 5B).

  Next, a photosensitive epoxy material 212 for forming a nozzle flow path and a discharge port is applied, and a photosensitive liquid repellent material layer 20 is formed on the photosensitive epoxy material 212 with a photosensitive liquid repellent material (see FIG. 5 (c)).

  Next, as shown in FIG. 5 (d), pattern exposure is performed through a mask 210 having a mask pattern of a limit resolution or less, and development processing is performed, so that only the photosensitive liquid repellent material layer 20 is partially removed. The non-liquid repellent region 20a and the discharge port 207 were formed (FIG. 5E). The limiting resolution here refers to a pattern in which the photosensitive epoxy material 212 is not developed up to the silicon substrate 201. Thereafter, an ink supply port 205 is formed from the back surface of the substrate by dry etching, and the water repellent portion 3 formed by the photosensitive liquid repellent material layer 20 and the other non-liquid repellent region portion 20a are formed in the vicinity of the discharge port 207. The hydrophilic portion 4 and the resist that has become the mold material are removed using a stripping solution to complete the head chip with the nozzle 2 (FIG. 5F). Further, an electrode 5 is formed on the hydrophilic portion 4 by using Al or the like by a vapor phase method such as sputtering or vapor deposition, or a liquid phase method such as plating (FIG. 5G).

1 is a schematic view of a droplet jet recording apparatus in an embodiment of the present invention. FIG. 3 is a control block diagram of the liquid jet recording apparatus in the embodiment of the present invention. FIG. 3 is a schematic view of an orifice surface of a droplet jet recording head according to an embodiment of the present invention. It is a schematic diagram of how ink adheres to an orifice surface. It is a manufacturing process flow diagram of the liquid jet recording head of the present invention. It is a schematic diagram of an example of an orifice surface of a recording head of a conventional example.

Explanation of symbols

2 Nozzle 3 Water repellent part 4 Hydrophilic part 5a, 5b Electrode

Claims (5)

In a liquid jet recording head having an orifice surface on which nozzles for discharging liquid are formed,
A liquid repellent part formed around the nozzle of the orifice surface;
A lyophilic part formed on the orifice surface other than the liquid repellent part,
A liquid jet recording head, comprising: a sensor that is formed in the lyophilic portion around the lyophobic portion and detects liquid adhering to the lyophilic portion.   The sensor includes a first electrode formed in the lyophilic portion around the liquid-repellent portion, and a second electrode formed with a space around the first electrode. 2. A liquid jet recording head according to 1. In a liquid jet recording apparatus that performs recording on a recording medium by jetting liquid,
A liquid jet recording head according to claim 1 or 2,
A liquid jet recording apparatus comprising: a measuring unit that measures a resistance value between the first electrode and the second electrode.   The liquid jet recording apparatus according to claim 3, further comprising recovery means for recovering the ejection characteristics of the liquid jet recording head. Forming a nozzle for discharging liquid into an orifice having a lyophilic portion;
Forming a liquid repellent portion around the nozzle;
Forming a sensor for detecting the liquid adhering to the lyophilic portion in the lyophilic portion around the lyophobic portion.

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