JP2002160376A - Ink jet recording head and image recording apparatus equipped with it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a recording head at a low cost and to prevent a wiping member from being damaged. SOLUTION: A cover head 23 is constituted of a window frame part 41 having a substantially square shape open window part 40 exposing nozzle openings 12 and side wall parts 42 formed by bending the wall from the external peripheral edges of the window frame part 41 to the side faces of a head case 20. The pressed part 43 of an inner side face is formed around inner peripheral edges of the opening of the open window part 40 by gradually reducing the thickness by pressing toward the open window part 40 side and inclining the surface. The pressed part 44 of an outer side face 44 is formed by gradually reducing the thickness by pressing toward the outside and inclining the surface at a side between the mutual base ends of the side wall parts 42, 42, which are adjacent to each other at an outside corner position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called ink jet recording head for discharging ink droplets from nozzle openings.
Also, the present invention relates to an image recording apparatus provided with the recording head, and more particularly to an improvement of a cover head for protecting a head end portion.

[0002]

2. Description of the Related Art As an image recording apparatus such as a printer, a plotter or a facsimile, an apparatus having an ink jet recording head is widely used. The ink jet recording head includes, for example, a flow path unit that forms an ink flow path from a nozzle opening to a common ink chamber through a pressure chamber,
A head case having the flow path unit attached to the front end surface thereof, and ink droplets are ejected from nozzle openings by pressure fluctuations in the pressure chamber.

[0003] In this type of ink jet recording head, a cover head is attached to the tip of the recording head in order to protect the tip of the recording head. The cover head includes, for example, a window frame having a substantially rectangular opening window for exposing the nozzle opening, and a side wall bent from the outer peripheral edge of the window frame to the side surface of the head case,
The head is fixed so as to cover the tip of the head from outside.
The cover head is manufactured by drawing a thin metal plate.

[0004]

An image recording apparatus equipped with this type of recording head is suitably used for personal use, and there is a strong demand for cost reduction. For this reason, there is also a strong demand for cost reduction of the recording head. In view of the above, with respect to the above cover head, production by drawing, which tends to be expensive in terms of molds and materials, has been stopped, and production by relatively inexpensive bending has been attempted.

[0005] However, if the cover head is simply formed by bending, the edges of the outer corners of the window frame are sharpened, which causes a problem due to the sharp edges. . For example, if a wiping member for wiping ink adhered to the nozzle opening surface comes into contact with a sharp edge, the sharp edge may damage the wiping member by being scraped off. If the wiping member is damaged, uneven wiping of the ink occurs on the nozzle opening surface, and the wiping member needs to be replaced.

The present invention has been made in view of such circumstances, and an object thereof is to manufacture a recording head at low cost and prevent the wiping member from being damaged.

[0007]

Means for Solving the Problems The present invention has been proposed to achieve the above object, and the invention according to claim 1 has the nozzle opening face directed toward the tip of the head case and the nozzle opening face directed toward the tip. In the ink jet recording head including a cover head made of a metal plate that covers at least two sides of the flow passage unit, the cover head has a substantially square opening window that exposes a nozzle opening. A window frame portion, and a side wall portion formed by bending the outer peripheral edge of the window frame portion to the side surface side of the head case, and crushing the thickness toward the opening window side by crushing the opening inner peripheral edge of the opening window portion. The inner side pushing portion is formed by gradually decreasing the surface and inclining the surface, and the outer corner of the window frame portion and the side between the base ends of the adjacent side wall portions are crushed to be thick. Gradually decrease toward the outside An ink jet recording head is characterized by comprising forming an outer surface pressing portion that is inclined surface.

According to a second aspect of the present invention, the side wall is provided with a side opening window penetrating in the thickness direction, and the inner peripheral edge of the opening of the side opening window is crushed to reduce the thickness of the opening window. 2. The ink jet recording head according to claim 1, wherein a side wall surface pressing portion whose surface is inclined so as to gradually decrease toward the side is formed.

According to a third aspect of the present invention, a connecting bar is disposed at an outer corner of the window frame portion and between the base ends of the adjacent side wall portions, and the outer surface pressing portion is provided. The ink jet recording head according to claim 1 or 2, wherein the ink jet recording head is formed over the connecting bar.

According to a fourth aspect of the present invention, there is provided an ink jet recording head according to any one of the first to third aspects, and an ink droplet attached to a nozzle opening surface of the recording head can be wiped by a wiping member. An image recording apparatus comprising a wiping mechanism.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. Here, FIG. 1 is a perspective view of an ink jet printer 1 (hereinafter simply referred to as a printer 1) which is a typical image recording apparatus.

The printer 1 has a carriage 2 movably mounted on a guide shaft 3. The carriage 2 is moved in the recording width direction by a carriage scanning mechanism.
That is, it is moved in the main scanning direction. The carriage scanning mechanism functions as a head scanning mechanism, and includes a carriage motor 5 provided on one of the left and right ends of the frame 4, a driving pulley 6 connected to a rotation shaft of the carriage motor 5, and a left and right other ends of the frame 4. , A timing belt 8 which is stretched between the drive pulley 6 and the idle pulley 7 and connected to the carriage 2,
It is composed of a control device (not shown) for controlling the rotation drive of the carriage motor 5 and the like. In the present embodiment, the carriage motor 5 is configured by a pulse motor that rotates by an amount corresponding to the number of supplied pulse signals.

The above-mentioned carriage 2 is provided with a cartridge holding portion for holding the ink cartridge 10 in a detachable manner. An ink jet recording head 11 (hereinafter, referred to as a recording head 11) is attached to a lower surface of the carriage 2, that is, a surface facing the recording paper.
The recording head 11 ejects the ink supplied from the ink cartridge 10 as ink droplets from the nozzle openings 12 (see FIG. 2). During recording, the printer 1 ejects ink droplets from the nozzle openings 12 in synchronization with the movement of the carriage 2 in the main scanning direction, and rotates the paper feed roller 13 in conjunction with the reciprocation of the carriage 2, The recording paper 14 is moved in the paper feed direction. As a result, images, characters, and the like based on the print data are recorded on the recording paper 14.

A home position is set in an end area within the moving range of the carriage 2 and outside the printing area. The home position includes a wiping mechanism 17 for cleaning the surface of the nozzle plate 16 (see FIG. 3) of the recording head 11, that is, the nozzle opening surface 16 a, and closing the nozzle opening surface 16 a to close the nozzle opening 12. A cap member 18 of a capping mechanism for preventing the evaporation of the ink solvent is disposed adjacent to the left and right sides.

As shown in FIGS. 2 to 4, the recording head 11 is generally constituted by a head case 20, a flow path unit 21, a vibrator unit 22, a cover head 23 and the like.

As shown in FIG. 4 (a), the head case 20 is provided with a housing space 24 having a front end and a rear end both open, and is a block-shaped member having a substantially rectangular front end surface. It is molded by. This head case 20
The flow path unit 21 is joined to the front end face of the nozzle with the nozzle opening face 16a facing the front end side. Further, the transducer unit 22 is accommodated and fixed in the accommodation space 24 with the comb-shaped tip of the transducer group facing the opening on the tip side.

As shown in FIG. 4B, the flow path unit 21 includes a flow path forming plate 25, a nozzle plate 16,
6 and the nozzle plate 16 is connected to the flow path forming plate 2.
5, the vibration plate 26 is disposed on the back side of the flow path forming plate 25, and is integrated by bonding or the like.

The nozzle plate 16 is a thin plate-like member having a large number (for example, 96) of nozzle openings 12 formed in rows at a pitch corresponding to the dot formation density.
It is composed of stainless steel plate. A common ink chamber 27 into which the supplied ink flows and a nozzle opening 12 are provided in the flow path forming plate 25 laminated on the nozzle plate 16.
A pressure chamber 28 for generating an ink pressure necessary for discharging ink from the ink chamber, an ink supply port 29 for communicating the common ink chamber 27 and the pressure chamber 28, and the like are formed. The diaphragm 26 is made of a polymer film having elasticity.
0 is a double structure laminated on a support plate 31 made of a stainless steel plate. Then, the support plate 31 at the portion corresponding to the common ink chamber 27 and the support plate 31 at the portion corresponding to the pressure chamber 28 are removed by etching or the like, and a compliance portion is formed at the portion corresponding to the common ink chamber 27, A diaphragm is formed at a portion corresponding to the pressure chamber 28.

The vibrator unit 22 includes the vibrator group 3
4 and a fixing plate 35. The vibrator group 34 is arranged in a comb-like shape, and is disposed between dummy vibrators (not shown) located at both ends in the arrangement direction of the piezoelectric vibrators and between these dummy vibrators. And a large number of driving vibrators 36. Here, the driving vibrators 36 are piezoelectric vibrators involved in the ejection of ink droplets, and are cut into, for example, needles having a very small width of about 50 μm to 100 μm. This driving oscillator 3
.. Extend and contract in the longitudinal direction of the vibrator, and are arranged in a direction perpendicular to the direction of extension and contraction. The distal end face of each drive vibrator 36 is joined to the island 37 of the diaphragm. The dummy vibrator is a piezoelectric vibrator that does not participate in the ejection of ink droplets, and is formed for positioning the vibrator unit 22 in the head case 20 and the like.

The cover head 23 has a window frame portion 41 having a substantially rectangular opening window portion 40, and is bent at a substantially right angle from each side of the outer peripheral edge of the window frame portion 41 toward the side surface of the head case 20. And four molded side walls 42... And a thin metal plate, for example, having a thickness of 0.1 mm to
It is produced by processing a stainless steel plate of about 0.3 mm. The size of the window frame portion 41 is equal to the outer dimensions of the head case 20, and is substantially the same as the front end surface of the head case 20. The width of the side wall portion 42 is slightly shorter than the length of the corresponding peripheral edge (side) of the head case 20, and the length thereof is
It is formed in a substantially square shape slightly shorter than the height of zero.
Therefore, when the side wall portion 42 is bent and formed, the window frame portion 41 is formed.
The side wall 42 defines a space having a size that the head case 20 can just fit.

The opening window 4 provided in the window frame 41 described above.
0 denotes each nozzle opening 1 formed in the nozzle plate 16
2 are manufactured to a size that can be exposed. The opening window 40 of the present embodiment is formed as a rectangular opening having a size slightly smaller than the nozzle plate 16. Therefore, when the cover head 23 is attached, the outer sides of the flow path unit 21 are covered with the cover head 23, and the nozzle openings 12 face the outside of the recording head 11 through the opening windows 40. On the inner peripheral edge of the opening of the opening window portion 40, an inner surface pushing portion 43 is formed, whose thickness is gradually reduced toward the opening window portion 40 and whose surface is inclined. In addition, the side wall 4 adjacent to the outer corner of the window frame 41
Also on the side between the two base ends, there is formed an outer surface pressing portion 44 whose surface is inclined by gradually reducing the thickness toward the outside. The inner side pushing part 43 and the outer side pushing part 44 are provided to prevent breakage of the wiper blade 45 when the wiper blade 45 of the wiping mechanism 17 abuts, as described later. In the present embodiment, the sheet material (base material) is manufactured by crushing the sheet material in the thickness direction. As shown in FIG. 0 of wall thickness t.
It is processed so that it is 8 times or less and the inclination angle B of the surface becomes 60 degrees or less.

In this embodiment, since it is manufactured by the progressive feeding type, a connection residue 46 also called a tie bar portion, that is, a portion of the cover head 23 and the scrap are formed on the side between the base ends of the adjacent side walls 42, 42. Outer frame part 47
(See FIG. 6). The portion of the remaining connection 46 is similarly pressed.
That is, the above-mentioned outer surface pushing portion 44 is formed over the remaining connecting portion 46.

The cover head 23 having such a structure is manufactured by a press device. Referring to FIG. 6, first, a punching process is performed on the supplied strip 50 at a punching stage to produce a portion to be the cover head 23 (first step). In this step, a substantially rectangular opening 51, a substantially inverted U-shaped opening 52, a substantially inverted U-shaped opening 53, and an opening window 40 are formed by a punch and a die. Punch out the part. And
The substantially H-shaped opening 51, the substantially U-shaped opening 52, and the substantially inverted U-shaped opening 53 are provided at a small interval in the feeding direction of the band plate 50, and these openings are mutually connected. Is the connection residue 46 (tie bar portion) described above. The remaining connection portion 46 is made up of an outer frame portion 47 serving as a scrap and the side wall portions 42 and 42 adjacent to each other at an outer corner portion of the window frame portion 41.
To the sides between the base ends. In this punching process, the openings 40, 51, 52, and 53 may be punched simultaneously on the same stage, or may be punched in a plurality of stages.

After the punching process, the strip 50 is fed by a predetermined pitch and positioned on the face-pressing stage, and the necessary portions are face-pressed to produce face-pressing parts 43 and 44 (second step). In this step, the inner peripheral edge of the opening of the opening window portion 40, the side between the base ends of the side wall portions 42 shown by hatching in FIG.
Further, by pressing the portion of the remaining connection 46 between the upper die and the lower die, the inner surface pressing portion 43 and the outer surface pressing portion 4 are pressed.
4 is crushed and processed. The surface pressing is simultaneously performed on the inner peripheral edge of the opening of the opening window portion 40, the side between the base ends of the side wall portions 42 and 42, and each portion of the connection residue 46, thereby preventing an increase in man-hours. Like that.

After the surface pressing portions 43 and 44 have been manufactured, the band plate 50 is fed by a predetermined pitch and positioned on the bending stage, and cut off with the connection remaining 46 to separate the cover head 23 from the outer frame portion 47. At the same time, the side wall 42 is bent (third step). After this step, the cover head 23 is obtained.

As described above, when the cover head 23 is formed by bending or punching using a press device, a die can be manufactured at a lower cost than when manufactured by drawing. In addition, since various metal materials can be used for the plate material serving as the cover head 23, it can be manufactured at a low cost.

In order to attach the cover head 23 manufactured by the above procedure to the head case 20, a head in which the flow path unit 21 is installed in a space defined by the window frame 41 and the side walls 42. When the case 20 is inserted from the front end side and the nozzle plate 16 and the window frame portion 41 are in contact with each other, each side wall portion 42 and each side surface of the head case 20 are joined using an epoxy-based adhesive or the like.

Next, the wiping mechanism 17 will be described. As shown in FIG. 7, the wiping mechanism 17 includes a wiper blade 45 and a wiper blade 4.
Wiper holder 55 holding wiper 5 and wiper holder 5
And a wiper elevating mechanism (not shown) for moving the upper and lower members 5 in a vertical direction.

The wiper blade 45 is a wiping member of the present invention, and is a plate-like member made of a water-repellent elastic member such as rubber or elastomer. The width of the wiper blade 45 is, as shown in FIG.
The length is set slightly longer than the length of the corresponding side of the recording head 11 to prevent the ink from being wiped off. The wiper holder 55 is, for example, a box-shaped member having an open top surface that holds the lower half of the wiper blade 45, and is formed of, for example, a synthetic resin. The wiper elevating mechanism is configured to electrically control the elevating and lowering of the wiper holder 55, and in this embodiment, the elevating state is controlled by an electromagnet. That is, in the demagnetized state of the electromagnet, the wiper holder 55
And the wiper blade 45 is located at the lower end of the movable range by its own weight. At this lower end position, the upper end edge of the wiper blade 45 is
It is located a little lower than the height of 6. In addition, when the electromagnet is excited, the wiper holder 55 moves upward by the magnetic force from the electromagnet. In this upwardly moved state, the upper edge of the wiper blade 45 is
As shown in FIG. 8B and FIG.
Located a little higher than. The wiping mechanism 17 controls the lifting and lowering of the wiper holder 55, and wipes the ink droplets attached to the nozzle opening surface 16a of the recording head 11 with the wiper blade 45 in cooperation with the carriage scanning mechanism.

Next, the operation of the printer 1 having the above configuration will be described focusing on the wiping operation on the nozzle surface of the recording head 11.

When the power of the printer 1 is turned on, an initialization operation for initializing each unit is performed. In this initialization operation, a flushing operation for forcibly ejecting ink droplets and a wiping operation for wiping ink adhered to the nozzle surface are performed as necessary. In addition, the ink cartridge 10
Immediately after the replacement, the flushing operation and the wiping operation are performed.

In the flushing operation, as shown in FIG. 7A, the cap member 18 of the capping mechanism moves upward to close the nozzle opening surface 16a of the recording head 11, and
In this closed state, ink droplets are ejected from the recording head 11. Further, a suction pump (not shown) communicating with the internal space of the cap member 18 is operated as necessary to make the inside of the cap member 18 negative pressure, and ink is forcibly discharged from the recording head 11.

In the wiping operation, as shown in FIG. 7B, the wiper holder 55 and the wiper blade 45 are moved upward, and then the carriage 2 is moved toward the wiper blade 45. Due to the movement of the carriage 2, the upper end portion of the wiper blade 45 comes into contact with the side surface of the recording head 11. At this time, as shown in FIGS. 8 (a) and 8 (b), Since the outer-side pushing portion 44 is formed on the side between the ends and the portion of the remaining connection 46, the wiper blade 45 moves smoothly along the inclined surface of the outer-side pushing portion 44. For this reason, the problem that the wiper blade 45 is scraped and damaged can be prevented, and the wiper blade 45 can be used for a long period of time. Then, with the wiper blade 45 in contact with the nozzle surface, the recording head 11
Are moved alternately in the left-right direction in accordance with the size of the nozzle opening surface 16a, the wiper blade 45 relatively moves, and the ink attached to the nozzle opening surface 16a is wiped off. Also in this case, since the wiper blade 45 moves smoothly along the inclined surface of the inner-side pushing portion 43, it is possible to prevent the wiper blade 45 from being chipped and damaged. When the wiping operation is completed, the electromagnet is returned to the demagnetized state, the wiper holder 55 is moved downward, and the contact state between the wiper blade 45 and the nozzle plate 16 is released.

Incidentally, the present invention is not limited to the above-described embodiment, and various modifications can be made based on the description in the claims.

For example, in the above-described embodiment, the tie bar 46 (tie bar portion) is connected to the side between the base ends of the side walls 42, 42. However, the tie bar 46 is limited to this position. Not something. For example, you may arrange | position at the front-end | tip corner of the side wall part 42. In this case, as shown in FIG. 9, the outer surface pressing portion 44 is formed on an arc-shaped side between the base ends of the side wall portions 42. Also in this configuration, the same effect as in the above-described embodiment can be obtained. Further, as shown in FIG. 9B, the outer surface pushing portion 44 may be formed so as to be enlarged to the side edge near the base end of the side wall portion 42.

As shown in FIG. 10, in the cover head 23 in which the side wall 42 is formed with a side opening window 56 penetrating in the thickness direction, the side wall surface is pushed by the inner peripheral edge of the opening of the side opening window 56. By providing the portion 57, damage to the wiper blade 45 can be prevented, as in the above-described embodiment. And this side wall surface pushing part 57
It may be formed selectively with respect to the contact area with the wiper blade 45, or may be formed over the entire inner peripheral edge of the opening.

Although the cover head 23 is configured to cover each side of the flow path unit 21, the present invention is not limited to this configuration.
Any configuration that covers the sides may be used.

Further, the wiping member of the present invention is not limited to the wiper blade 45 described above, but may be any structure that can wipe the ink on the nozzle opening surface 16a. For this reason, the wiping member may be manufactured in a block shape, or may be made of a liquid-absorbing member such as felt or sponge.

[0039]

As described above, according to the present invention, the following effects can be obtained. That is, on the inner peripheral edge of the opening of the opening window portion in the cover head, an inner surface pushing portion whose surface is inclined by gradually reducing the thickness toward the opening window side by crushing is formed, and the outside of the window frame portion is formed. Since the outer surface pressing portion in which the thickness is gradually reduced outward by crushing and the surface is inclined is formed on the side between the base ends of the adjacent side walls at the corners, The wiping member moves smoothly along the inclined surface of the outer surface pushing portion or the inner surface pushing portion. For this reason, even if a bending process that can be made relatively inexpensively in terms of a mold and a material is used, a sharp edge hardly occurs, and a problem that the wiping member is cut and damaged can be prevented. As a result, the wiping member can be used for a long time.

[Brief description of the drawings]

FIG. 1 is a perspective view of an ink jet printer.

FIG. 2 is an external perspective view of a recording head.

FIG. 3 is a perspective view of the recording head with a cover head removed.

FIG. 4 is a diagram illustrating an internal structure of a recording head.
3A is a cross-sectional view of a main part of a recording head, and FIG. 3B is a cross-sectional view of a main part of a flow channel unit.

FIG. 5 is a diagram illustrating a cross-sectional shape of a surface pressing unit.

FIG. 6 is a diagram illustrating a method of manufacturing a cover head.

FIG. 7A illustrates a flushing operation.
(B) and (c) are figures explaining a wiping operation.

FIGS. 8A and 8B are diagrams illustrating a wiping operation.

FIGS. 9A and 9B are diagrams illustrating a modified example, in which FIGS.
FIG. 4 is an explanatory diagram of a wiping operation.

FIGS. 10A and 10B are diagrams illustrating another modified example, and FIGS. 10A and 10B are diagrams illustrating a wiping operation. FIGS.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink-jet printer 2 Carriage 3 Guide shaft 4 Frame 5 Carriage motor 6 Driving pulley 7 Idling pulley 8 Timing belt 10 Ink cartridge 11 Inkjet recording head 12 Nozzle opening 13 Paper feed roller 14 Recording paper 16 Nozzle plate 16a Nozzle opening surface 17 Wiping mechanism 18 Cap member 20 Head case 21 Flow path unit 22 Vibrator unit 23 Cover head 24 Storage space 25 Flow path forming substrate 26 Vibration plate 27 Common ink chamber 28 Pressure chamber 29 Ink supply port 30 Elastic film 31 Support plate 34 Vibrator group 35 Fixed plate 36 Driving vibrator 37 Island part 40 Opening window part 41 Window frame part 42 Side wall part 43 Inner side pushing part 44 Outer side pushing part 45 Wiper blade 46 Connecting bar 47 Outer frame part of band plate 5 0 Belt plate 51 H-shaped opening 52 U-shaped opening 53 F-shaped opening 55 Wiper holder 56 Side opening window

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takayuki Iijima 3-3-5 Yamato, Suwa City, Nagano Prefecture Inside Seiko Epson Corporation (72) Inventor Katsuhiro Okubo 3-3-5 Yamato Suwa City, Nagano Prefecture Seiko Epson Co., Ltd. F-term (reference) 2C056 EA16 HA01 JB04

Claims (4)

[Claims] 1. An ink jet recording head comprising a metal plate cover head which is joined to a front end of a head case with a nozzle opening surface facing the front end side and covers at least two sides of the flow passage unit. In the above, the cover head comprises: a window frame having a substantially rectangular opening window exposing a nozzle opening; and a side wall bent from an outer peripheral edge of the window frame to a side surface of the head case. The inner peripheral edge of the window frame is formed on the inner peripheral edge of the window frame by pressing the inner surface of the window frame to gradually reduce the wall thickness toward the side of the opening and to incline the surface. An ink jet type characterized by forming an outer surface pressing portion having a surface inclined by gradually reducing the thickness outward by crushing, on the side between the base ends of the side wall portions that match with each other. Recording head. 2. A side opening window portion penetrating in the thickness direction in the side wall portion, and the thickness of the side opening window is gradually reduced toward the opening window side by crushing the inner peripheral edge of the opening. 2. The ink jet recording head according to claim 1, wherein a side wall surface pressing portion whose surface is inclined by being formed is formed. 3. A connecting bar is disposed at an outer corner portion of the window frame portion and between the base ends of the adjacent side wall portions, and the outer surface pressing portion is formed over the connecting bar. The ink jet recording head according to claim 1 or 2, wherein 4. An ink jet recording head according to claim 1, further comprising a wiping mechanism capable of wiping ink droplets adhered to a nozzle opening surface of the recording head by a wiping member. An image recording apparatus characterized by the above-mentioned.