JP3767394B2 - Recording head unit and ink jet recording apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a recording head unit for ejecting ink and an ink jet recording apparatus including the recording head unit.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a recording apparatus such as a printer that performs recording on a recording medium such as paper or an OHP sheet is provided with a recording head for performing a recording operation on the recording medium. Examples of such a recording head include an ink jet head, a dot impact type head, and a thermal transfer type head. Among these, the ink jet head has a relatively simple configuration, and can easily perform high-speed printing and high quality printing. Known as a recording head.
[0003]
A recording head unit having an inkjet head has a nozzle opening surface on which a plurality of nozzles for ejecting ink are formed. If foreign matter such as ink or dust adheres to the nozzle opening surface near the nozzle, the flying direction of ink droplets ejected from the nozzle changes, ink does not eject from the nozzle, or ink ejection is not suitable for recording. In such a case, an ink ejection recovery process for removing the cause of the ink ejection failure is performed.
[0004]
As means for performing such ink jetting recovery processing, there is a wiper means for rubbing the nozzle opening surface of the recording head unit to remove foreign matters such as ink and dust adhering to the nozzle opening surface.
[0005]
[Problems to be solved by the invention]
A cover plate that is rolled with a metal material and formed into a plate shape is disposed on the nozzle opening surface that is rubbed against the wiper means. When the surface of the cover plate is formed into a plate shape by rolling, minute irregularities are formed, and the minute irregularities have a length in the direction along the rolling direction. When the cover plate is arranged so that the rolling direction when the plate is formed is orthogonal to the rubbing direction of the nozzle opening surface by the wiper means, the length direction of the minute unevenness is slid by the wiper means. Since it is perpendicular to the rubbing rubbing direction, when the nozzle opening surface of the recording head unit is rubbed by the wiper means during the ink jetting recovery process, ink, dust, etc. There is a problem that foreign matter tends to remain, and foreign matter on the nozzle opening surface cannot be removed well.
[0006]
The present invention has been made to solve the above-described problems, and a recording head unit and ink jet recording capable of satisfactorily removing foreign matters on a nozzle opening surface on which a cover plate obtained by rolling a metal material is disposed. An object is to provide an apparatus.
[0007]
[Means for Solving the Problems]
In order to achieve this object, according to the first aspect of the present invention, there is provided a recording head unit having a recording head for recording on a recording medium by ejecting ink from nozzles, wherein the nozzle opening surface is rubbed by a wiper means. A cover plate that is rolled with a metal material and formed into a plate shape, disposed on the opening surface of the nozzle and rubbed by the wiper means, and the surface of the cover plate is formed by rolling The cover plate has minute irregularities having a length along the rolling direction so that the rolling direction when the cover plate is plate-shaped is substantially parallel to the rubbing direction of the nozzle opening surface by the wiper means. It is attached to.
[0008]
If comprised in this way, the rolling direction when the cover plate rolled by metal material and formed in plate shape will be plate shape will be substantially parallel to the rubbing direction of the said nozzle opening surface by the said wiper means. Therefore, the length direction of minute irregularities formed by rolling on the surface of the cover plate is substantially parallel to the rubbing direction rubbed by the wiper means, and the wiper means During the rubbing of the nozzle opening surface, foreign matter is unlikely to remain on the unevenness.
[0009]
According to a second aspect of the present invention, in the first aspect of the present invention, the nozzle opening surface includes a nozzle forming member in which the nozzle is formed, and a contact angle of the nozzle forming member with respect to ink is determined by the cover plate. It is characterized by being larger than the contact angle with respect to the ink.
[0010]
With this configuration, when the nozzle opening surface is rubbed with the wiper means, the contact angle of the nozzle forming member with respect to the ink is larger than the contact angle of the cover plate with respect to the ink. The rubbed ink is difficult to remain.
[0011]
According to a third aspect of the present invention, in the second aspect of the present invention, the contact angle of the nozzle forming member with respect to ink is 40 degrees or greater than the contact angle of the cover plate with respect to ink.
[0012]
According to such a configuration, when the nozzle opening surface is rubbed by the wiper means, the contact angle of the nozzle forming member with respect to the ink is 40 degrees or more larger than the contact angle of the cover plate with respect to the ink. Almost no ink rubbing on the member remains.
[0013]
According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the nozzle opening surface is formed in a protruding portion protruding from the main body frame, and the cover plate is a nozzle of the protruding portion. It is formed in a shape that covers from the opening surface to the side surface that is rubbed against the wiper means.
[0014]
According to such a configuration, when the nozzle opening surface is rubbed by the wiper means, the wiper means comes into contact with the side surface of the protruding portion, and a corner formed by the nozzle opening surface and the side surface is formed. Although the wiper means rubs, the corners thereof are covered with the cover plate, and therefore, foreign matter hardly remains on the corners when the wiper means rubs the nozzle opening surface.
[0015]
Further, in the invention of claim 5, in the ink jet recording apparatus, characterized by comprising a recording head unit according to any one of claims 1 to 4, and said wiper unit.
[0016]
According to such a configuration, when the wiper means rubs the nozzle opening surface of the recording head, foreign matter is unlikely to remain on the irregularities on the surface of the cover plate.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of a color ink jet printer as an ink jet recording apparatus of the present invention. In FIG. 1, this color inkjet printer 21 is for printing on an ink cartridge 22 as an ink supply member filled with four color inks of cyan, magenta, yellow and black, and on a paper 23 as a recording medium. A head unit 25 as a recording head unit including an ink jet head 24 as a recording head, a carriage 26 as a support member on which the ink cartridge 22 and the head unit 25 are mounted, and the carriage 26 reciprocates in a linear direction. A drive unit 27, a platen roller 28 that extends in the reciprocating direction of the carriage 26 and is disposed to face the ink jet head 24, a wiper means 45, and a purge device 29 are provided.
[0018]
The drive unit 27 is disposed at the lower end portion of the carriage 26 and extends parallel to the platen roller 28, the guide plate 31 is disposed at the upper end portion of the carriage 26 and extends parallel to the carriage shaft 30, and the carriage shaft 30. Two pulleys 32 and 33 disposed between both ends of the carriage shaft 30 between the guide plate 31 and an endless belt 34 spanned between the pulleys 32 and 33 are provided.
[0019]
A carriage shaft support portion 35 through which the carriage shaft 30 can be inserted is provided at the lower end portion of the carriage 26, and a guide plate contact portion 36 that can contact the guide plate 31 is provided at the upper end portion of the carriage 26. ing. An endless belt 34 is joined to the rear side surface of the carriage 26.
[0020]
When one pulley 32 is rotated in the forward and reverse directions by driving the carriage motor 32A, the carriage 26 joined to the endless belt 34 is moved along with the forward and reverse rotation of the pulley 32 to the carriage shaft 30 and the guide plate. 31 is reciprocated linearly along the width direction of the paper 23.
[0021]
The sheet 23 is fed from a sheet feeding cassette (not shown) provided on the side of the ink jet printer 21, and the nozzle opening surface 24 a of the head unit 25 facing downward with respect to the vertical direction and the platen roller 28. Predetermined recording is performed with ink that is introduced in between and ejected from a plurality of nozzles of the inkjet head 24, and then discharged. In FIG. 1, the paper feed mechanism and paper discharge mechanism for the paper 23 are not shown.
[0022]
A wiper means 45 is provided on the side of the platen roller 28 to remove the ink, dust and the like adhering to the nozzle opening surface 24a by sliding on the nozzle opening surface 24a of the head unit 25. A purge device 29 is provided on the side of the wiper means 45, and is arranged so as to face the nozzle opening surface 24a when the head unit 25 is at the reset position. The purge device 29 is used to prevent ejection failure caused by ink retention or bubble growth when the ink is initially introduced into the inkjet head 24.
[0023]
That is, the purge device 29 includes a suction cap 41 that can cover the nozzles of the inkjet head 24, a suction pump 38 and a cam 39, and a waste ink reservoir 42, and when the head unit 25 is in the reset position, The cam 39 is driven by a suction motor (not shown) to bring the suction cap 41 into contact with the nozzle opening surface 24 a to cover the nozzle with the suction cap 41, and to remove defective ink containing bubbles and the like accumulated in the ink jet head 24. The inkjet head 24 is recovered by being suctioned by the suction pump 38 by driving. Accordingly, it is possible to perform an ink jetting recovery process that prevents ejection failure due to ink retention or bubble growth at the initial ink introduction. The sucked defective ink is stored in the waste ink storage unit 42.
[0024]
The purging device 29 is provided with a protective cap 37 for each color so as to cover the nozzles for each color, and is applied to the nozzle opening surface 24a when the head unit 25 is at the stop position. It is configured to cover all the nozzles of each color.
[0025]
The wiper means 45 includes a wiper member 46 (FIG. 5) that slides on the nozzle opening surface 24a, a wiper holder 47 (FIG. 5) that supports the wiper member 46, and the wiper holder 47 that is in contact with the nozzle opening surface 24a. Moving means (not shown) that can move in the separating direction. The wiper member 46 is formed by molding using a rubber material, for example, EPDM. The moving means is provided with a wiper motor (not shown), and by controlling the wiper motor, the wiper member 46 is moved to a proximity position and a separation position with respect to the nozzle opening surface 24a.
[0026]
Next, the configuration of the head unit 25 will be described with reference to FIGS. 2, 3, and 4. A main body frame 1 of a head unit 25 mounted on a known carriage 26 that travels along a sheet 23 is an injection-molded product of a synthetic resin material such as polypropylene or polypropylene, and is formed in a substantially box shape with an open top surface. The mounting portion 3 can be detachably mounted with four ink cartridges 22 from above, and one side portion 3a of the mounting portion 3 can be connected to an ink discharge portion (not shown) of each ink cartridge 22. Ink supply passages 4 a, 4 b, 4 c, 4 d communicate with the lower surface of the bottom plate 5 of the main body frame 1. A rubber packing (not shown) is provided on the upper surface of the one side portion 3a of the mounting portion 3 so as to be in close contact with the ink discharge portion.
[0027]
The bottom plate 5 is formed in a horizontal shape so as to protrude downward from the mounting portion 3, and on the lower surface side of the bottom plate 5, two front head units 6 described in detail later are arranged in parallel. Are formed in a stepped shape. A plurality of cavities 9a and 9b for fixing with a UV adhesive are formed in each support portion 8 so as to penetrate vertically.
[0028]
The front head unit 6 includes a cavity plate (not shown) having a nozzle plate 43 in which a plurality of nozzles 54 are formed, and a plate type that is bonded and laminated to the cavity plate via an adhesive or an adhesive sheet. In order to electrically connect the piezoelectric actuator (not shown) and an external device to the upper surface, a flexible flat cable 40 is laminated and bonded with an adhesive, and the lower surface of the lowermost cavity plate It is assumed that ink is ejected downward from the nozzle 54 opened to the side. The nozzle plate 43 is subjected to ink repellent treatment with fluorine, and the contact angle of the nozzle plate 43 with respect to the ink is 80 to 90 degrees. One front head unit 6 is provided with a nozzle 54, a piezoelectric actuator, and the like for ejecting ink of two colors.
[0029]
The plurality of cavities 9a and 9b are formed at locations where the vicinity of the four corners of the front head unit 6 is fixed. In the embodiment, of the two support portions 8 and 8, In a place where one side (long side in the embodiment) is adjacent, the spaces 9a, 9a are formed wide so as to straddle the back surfaces of the two front head units 6, 6 arranged side by side.
[0030]
Further, a cover plate 44 made of an elastic thin metal plate (for example, stainless steel) is fixed along the front surface (lower surface) of the front head unit 6. Since the cover plate 44 is rolled with a metal material and formed into a plate shape, minute irregularities are formed on the front surface 44e and the back surface 44h as shown in FIG. The minute unevenness has a length in the direction along the rolling direction. And as shown in FIG. 6, the rolling direction (arrow C direction shown in FIG. 6) when it is plate-shaped is the rubbing direction (arrow B direction shown in FIG. 6) of the nozzle opening surface 24a by the wiper member 46. A cover plate 44 is attached so as to be substantially parallel. That is, the length direction of minute irregularities formed by rolling on the surface 44e of the cover plate 44 is substantially parallel to the rubbing direction (the direction of arrow B shown in FIG. 6) rubbed by the wiper member 46. Further, the contact angle between the surface 44e of the cover plate 44 and the ink is approximately 30 degrees.
[0031]
The cover plate 44 has a hole 44a corresponding to the nozzle plate 43 at the central portion, and bent portions 44b and 44c are formed along the side surface of the main body frame 1 from the lower surface side of the bottom plate 5 at both ends. The portion 44b covers the lower surface side of the middle portion of the flexible flat cable 40.
[0032]
The outer periphery of the cover plate 44 is sealed and fixed to the main body frame 1 with a sealing agent such as a silicone adhesive. That is, between the left and right side edges of the cover plate 44 and the ribs 5a rising on the left and right sides of the bottom plate 5, and between the tip of the other bent portion 44c of the cover plate 44 and the side surface of the main body frame 1, The sealing agent is filled in a substantially U shape, and the sealing agent is filled between the inside of one bent portion 44b and the flexible flat cable 40 and between the cable 40 and the side surface of the main body frame 1 respectively. .
[0033]
A gap between the inner periphery of the hole 44 a of the cover plate 44 and the front surface of the front head unit 6 is sealed with an adhesive that bonds the cover plate 44 and the front head unit 6. Thereby, the space between the two front head units 6 is closed by the cover plate 44, and the space between the main body frame 1 and the outer periphery of the front head unit 6 is sealed via the cover plate 44 and the sealant. Te, ink or between gap between the main body frame 1 and the front head unit 6, paper dust, it is possible to prevent the dust from entering the electrical short circuit of the electrical connection portion between the piezoelectric actuator and the flexible flat cable 40 Can be prevented. Further, the one bent portion 44b can guide the pulling direction of the flexible flat cable 40 and can protect the cable 40. Thus, the nozzle plate 43 and the cover plate 44 are arranged on the nozzle opening surface 24a of the head unit 25.
[0034]
A CPU (not shown) controls the entire color inkjet printer 21 based on a program stored in a ROM (not shown), and controls the carriage motor 32A, the suction motor, the wiper motor, and the like, for example.
[0035]
An ink ejection recovery process using the wiper means 45 configured as described above will be described. The ink ejection recovery process is performed by the program in the ROM and the CPU controlling the carriage motor 32A, the suction motor, and the wiper motor.
[0036]
Then, the ink ejection recovery process is performed when the power of the color inkjet printer 21 is turned on or immediately before the start of recording. In the ink ejection recovery process, a wiping operation is performed so that the wiper means 45 slides on the nozzle opening surface 24a to remove foreign matters such as ink and dust on the nozzle opening surface 24a. During the wiping operation, as shown in FIG. 5, the head unit 25 is disposed at a predetermined position that does not face the wiper member 46. Then, the wiper motor is driven, the wiper holder 47 moves in the direction approaching the nozzle opening surface 24a side, and is stopped at a position where the wiper member 46 can contact the nozzle opening surface 24a.
[0037]
From this state, when the carriage motor 32A is driven to move the head unit 25 in the direction toward the wiper member 46 (direction of arrow A shown in FIG. 6), the wiper member 46 is relatively opposed to the nozzle opening surface 24a. Then, rubbing in the direction of arrow B to remove foreign matters such as ink and dust adhering to the nozzle opening surface 24a. Thereafter, the wiper member 46 is moved to a separated position where it cannot contact the nozzle opening surface 24a.
[0038]
As described above, when the cover plate 44 formed into a plate shape by rolling with a metal material is formed into a plate shape, the rolling direction (the direction of arrow C shown in FIG. 6) is the nozzle opening by the wiper member 46. Since it is attached so as to be substantially parallel to the rubbing direction of the surface 24a (the direction of arrow B shown in FIG. 6), the length direction of minute irregularities formed by rolling on the surface 44e of the cover plate 44 is the wiper member 46. When the wiper member 46 rubs the nozzle opening surface 24a with the wiper member 46, the foreign matter such as ink and dust hardly remains on the unevenness. Can be removed.
[0039]
Further, it was confirmed that when the contact angle of the nozzle plate 43 with respect to the ink is larger than the contact angle of the cover plate 44 with respect to the ink, the ink rubbed against the nozzle plate 43 by the wiper member 46 hardly remains on the nozzle plate 43. Therefore, this makes it easier to remove foreign matters from the nozzle plate 43.
[0040]
Furthermore, when the contact angle of the nozzle plate 43 with respect to the ink is larger than the contact angle of the cover plate 44 with respect to the ink by 40 degrees or more, the ink that has rubbed the nozzle plate 43 with the wiper member 46 hardly remains on the nozzle plate 43. confirmed. Therefore, in this way, foreign matters can be reliably removed from the nozzle plate 43.
[0041]
If the cover plate is formed so as to cover the protruding rib 5a of the bottom plate 5 protruding relative to the main body frame 1, that is, the side surface (protruding) where the cover plate is rubbed against the wiper member 46 from the nozzle opening surface 24a. If the shape covering the ribs 5a) is formed, the angle formed by the wiper member 46 by the nozzle opening surface 24a and the side surface (projecting rib 5a) when the wiper member 46 rubs the nozzle opening surface 24a. Although the corner portion is covered with the cover plate, when the wiper member 46 rubs the nozzle opening surface 24a, foreign matters such as ink and dust are less likely to remain in the corner portion.
[0042]
Further, in the color inkjet printer 21 including the head unit 25 including the cover plate 44 as described above, foreign matters such as ink and dust are exposed to the surface 44e of the cover plate 44 when the wiper member 46 rubs the nozzle opening surface 24a. Therefore, the ink is ejected from the nozzles 54 of the inkjet head 24 and recording on the paper 23 can be performed satisfactorily.
[0043]
In this embodiment, the cover plate 44 corresponds to the head unit 25 that ejects a plurality of colors of ink. However, the cover plate 44 may correspond to a head unit that ejects a single color of ink.
[0044]
Further, the nozzle opening surface 24a of the head unit 25 is directed downward, but may be directed obliquely downward, or may be directed laterally (horizontal direction).
[0045]
In this embodiment, the ink ejection recovery process is performed only by the wiper unit 45. However, the ink ejection recovery process by the purge device 29 and the wiper unit 45 may be performed. In the ink ejection recovery process in this case, the suction pump 38 is operated to suck the defective ink from the nozzle 54 via the suction cap 41, and then wiped by the wiper member 46.
[0046]
【The invention's effect】
As is apparent from the above description, according to the first aspect of the present invention, the cover plate that is rolled with a metal material and formed into a plate shape has a rolling direction when the wiper has the plate shape. Is attached so as to be substantially parallel to the rubbing direction of the nozzle opening surface by means, so that the length direction of minute irregularities formed by rolling on the surface of the cover plate is rubbed by the wiper means. When the wiper means rubs the nozzle opening surface almost in parallel with the rubbing direction, it is difficult for the foreign matter to remain on the irregularities, so the foreign matter can be reliably removed from the nozzle opening surface.
[0047]
According to a second aspect of the present invention, the contact angle of the nozzle forming member with respect to the ink is larger than the contact angle of the cover plate with respect to the ink. The removed ink can be removed from the nozzle forming member.
[0048]
According to a third aspect of the present invention, the contact angle of the nozzle forming member with respect to the ink is 40 degrees or more larger than the contact angle of the cover plate with respect to the ink, so that the ink rubbed on the nozzle forming member remains almost. In addition, the rubbed ink can be reliably removed from the nozzle forming member.
[0049]
According to a fourth aspect of the present invention, when the wiper means slides on the nozzle opening surface, the wiper means abuts on the side surface of the protruding portion, and is formed by the nozzle opening surface and the side surface. The wiper means is rubbed against the corner of the nozzle, and since the corner is covered with the cover plate, when the wiper means rubs the nozzle opening surface, foreign matter is unlikely to remain on the corner, Foreign matter can be reliably removed from the nozzle opening surface including the corner portion.
[0050]
According to a fifth aspect of the present invention, foreign matters are less likely to remain on the irregularities on the surface of the cover plate when the wiper means rubs the nozzle opening surface of the recording head unit. Ink is ejected onto the recording medium, and good recording can be performed on the recording medium.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a color ink jet printer as an ink jet recording apparatus of the present invention.
FIG. 2 is a perspective view with the nozzle side of the head unit facing up.
FIG. 3 is an exploded perspective view of components of the head unit.
FIG. 4 is an exploded perspective view of the components of the head unit as viewed from above the main body frame.
FIG. 5 is an explanatory diagram showing a state in which a wiper member approaches a nozzle opening surface during wiping.
FIG. 6 is an explanatory diagram showing a rolling direction of a cover plate and a rubbing direction by a wiper member.
FIG. 7 is a cross-sectional view of a cover plate showing irregularities formed on the surface of the cover plate.
[Explanation of symbols]
21 Color Inkjet Printer 24 Inkjet Head 24a Nozzle Opening Surface 25 Head Unit 43 Nozzle Plate 44 Cover Plate 45 Wiper Means 46 Wiper Member

Claims (5)

In a recording head unit having a recording head for recording on a recording medium by ejecting ink from nozzles, the nozzle opening surface being rubbed by a wiper means,
Rolled with a metal material, formed into a plate shape, disposed on the opening surface of the nozzle, and provided with a cover plate rubbed by the wiper means,
The surface of the cover plate has fine irregularities formed by rolling and having a length along the rolling direction,
The recording head unit, wherein the cover plate is attached so that a rolling direction when it is plate-shaped is substantially parallel to a rubbing direction of the nozzle opening surface by the wiper means. The nozzle opening surface includes a nozzle forming member that forms the nozzle,
The recording head unit according to claim 1, wherein a contact angle of the nozzle forming member with respect to ink is larger than a contact angle of the cover plate with respect to ink.   The recording head unit according to claim 2, wherein a contact angle of the nozzle forming member with respect to ink is 40 degrees or more larger than a contact angle of the cover plate with respect to ink.   The nozzle opening surface is formed in a protruding portion that protrudes with respect to the main body frame, and the cover plate is formed in a shape that covers from the nozzle opening surface of the protruding portion to a side surface that is slid by the wiper means. The recording head unit according to claim 1, wherein the recording head unit is a recording head unit. An ink jet recording apparatus comprising: the recording head unit according to claim 1; and the wiper means.

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