This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2006-011431, filed Jan. 19, 2006, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to an inkjet recording apparatus having a function of cleaning a nozzle plate provided in a recording head.
2. Description of the Related Art
Recent pervading inkjet printers simply/easily and inexpensively record images at a high speed. An inkjet printer generally carries a recording medium to face a recording head that ejects ink droplets. Then, when the recording medium is facing the recording head, the inkjet printer ejects ink droplets onto the recording medium from the recording head through nozzles. As a result, the inkjet printer records an image on the recording medium.
Nozzles of such an inkjet printer are formed on a nozzle plate. Dust, e.g., foreign particles or extraneous materials, a waste ink and others adhere to such a nozzle plate. When the inkjet printer records an image in a state where such dust or a waste ink has adhered to a part close to the nozzles of the nozzle plate, a discharging direction of ink droplets may change or ink droplets cannot be ejected in some cases. As a result, a quality of an image to be recorded may be possibly lowered. Thus, in the inkjet printer, the nozzle plate is generally conventionally cleaned. As a cleaning method, e.g., a mechanical wiping method and a cleansing method are known. According to the mechanical wiping method, for example, a wiper cleans off dust or a waste ink that has adhered to the nozzle plate, or an ink absorbing member, e.g., a sponge pressed against the nozzle plate sucks and removes dust or a waste ink that has adhered to the nozzle plate. Further, according to the cleansing method, a cap covers the nozzle plate, and discharges a cleaning liquid from the cap side to cleanse the nozzle plate.
However, in the mechanical wiping method, an ink-repellant coating layer (hereinafter, an ink-repellant coating) applied to the nozzle plate may be possibly abraded away to provoke an inconvenience in ink eject. Furthermore, when the nozzle plate is pressed by the wiper or the ink absorbing member, dust or a waste ink may possibly enter the nozzles to provoke clogging of the nozzles.
Moreover, in the cleansing method, a mechanism is complicated. Additionally, when a discharge pressure of the cleaning liquid is set large, the cleaning liquid may enter the recording head through the nozzles to be mixed with an ink.
In order to solve such problems, e.g., Jpn. Pat. Appln. KOKAI Publication No. 042678-1993 discloses a maintenance apparatus 100 for an inkjet printer.
Furthermore, Jpn. Pat. Appln. KOKAI Publication No. 2002-283581 discloses a head wiping apparatus for an inkjet printer. A wiper group having three wipers is provided in this head wiping apparatus. In regard to length dimensions of the wipers, the length increases toward the rear wiper from the front wiper. The front wiper is not in contact with a nozzle plate of a recording head, and the two rear wipers come into contact with the nozzle plate of the recording head to perform cleaning.
To achieve an object, according to the present invention, there is provided an inkjet recording apparatus comprising: a recording head having a nozzle plate on which a nozzle string constituted of a plurality of nozzles that eject an ink onto a recording medium is arranged; and a wiper that cleans a surface of the nozzle plate, wherein one of a first cleaning mode in which the wiper comes into contact with the nozzle plate, and a second cleaning mode in which the wiper is not in contact with the nozzle plate is selected at the time of cleaning, and the wiper relatively moves with respect to the nozzle string to perform the cleaning.
According to the present invention, when the wiper cleans the nozzle plate, one of a contact cleaning mode in which the wiper is brought into contact with the nozzle plate and a non-contact cleaning mode in which the wiper is not in contact with the nozzle plate is selected and executed. According to this structure, an ink-repellant coating applied to the nozzle plate surface can be prevented from being abraded away, and the inkjet recording apparatus that can stably eject an ink and record a high-quality image without provoking clogging for a long time can be provided.
Advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.
Embodiments according to the present invention will now be described in detail hereinafter with reference to the accompanying drawings.
In the following explanation, a carrying direction of a recording medium 2 is determined as an X axis direction or a sub-scanning direction, and a direction perpendicular to this carrying direction is determined as a Y axis direction, a main scanning direction, or a width direction of the recording medium 2 in the drawings. A direction perpendicular to the X axis and Y axis directions is determined as a Z axis direction or a vertical direction. Further, as shown in
A first embodiment will now be described with reference to
In the inkjet recording apparatus 1 are provided nozzles 3 that eject an ink onto a recording medium 2, a recording head 4 having the plurality of nozzles 3, a cleaning unit 5 that is provided on a side surface of the recording head 4 and cleans the nozzles 3, a sub-tank 7 that supplies the ink to the recording head 4 through a first ink path 6, and an ink bottle 9 that supplies the ink through a second ink path 8 in order to temporarily fill the sub-tank 7 with the ink. Furthermore, a non-illustrated carriage mechanism is provided to the inkjet recording apparatus 1. This carriage mechanism carries the recording medium 2 that records an image to an X axis direction.
As shown in
As shown in
The wiper support shaft 41 is a rectangular shaft-like member extending in the Z axis direction, and holds the wiper 40 on an upper surface thereof. Additionally, a spring engagement portion 41a extending from a side surface of this wiper support shaft 41 is formed at a substantially central part of the side surface. It is to be noted that an upper surface of this spring engagement portion 41a extends to a position close to an inner surface of the later-described housing 42. Therefore, the spring engagement portion 41a has a function of guiding movement of the wiper support shaft 41 in the Z axis direction. Further, an engagement piece 41b that restricts a movement range of the wiper support shaft 41 in the Z axis direction with respect to the housing 42 is formed below the spring engagement portion 41a in the Z axis direction and on the side surface of the wiper support shaft 41 on the Y axis side. The engagement piece 41b pierces an opening portion 42b formed in the later-described housing 42. Furthermore, the engagement piece 41b protrudes from the opening portion 42b so that it can come into contact with a later-explained latch portion 49b.
The housing 42 is a hollow shaft-like member. The housing 42 accommodates the wiper support shaft 41 in a hollow part thereof, and surrounds the wiper support shaft 41. The housing 42 holds the wiper support shaft 41 in such a manner that the wiper support shaft 41 can move in the Z axis direction. A spring engagement portion 42a extending toward the wiper support shaft 41 is formed on the upper inner surface of the housing 42 in the Z axis direction. This spring engagement portion 42a has a function serving as a locking portion of a later-explained spring 46, and a distal end thereof restricts movement of the wiper support shaft 41 in the X axis and the Y axis directions. That is, the spring engagement portions 41a and 42a move the wiper support shaft 41 along the Z axis direction alone, and also have a function of restricting movement of the wiper support shaft 41 so that this shaft does not oscillate in the X axis and the Y axis directions. Furthermore, an opening portion 42b is formed in the side surface of the housing 42 in the Y axis direction. This opening portion 42b has a size that allows the engagement piece 41b to be inserted therein. A lower edge of the opening portion 42b in the Z axis direction comes into contact with the engagement piece 41b. The size of the opening portion 42b is restricted in such a manner that a position of the wiper support shaft 41 in the Z axis direction with respect to the housing 42 is set to the lowest position at this moment. It is to be noted that an upper edge of the opening portion 42b is restricted to be set to a position sufficiently higher than a height position of the later-described latch portion 49b in the Z axis direction.
Moreover, a swiveling supporting point 42c that supports the swiveling piece 49 on an axis thereof is provided on a side surface of the housing 42 in the Y axis direction. The swiveling piece 49 is supported on the axis of this swiveling supporting point 42c to allow its swiveling motion. This swiveling piece 49 is a tabular member, and a latch portion 49b is formed at an upper end thereof in the Z axis direction. A cancel operating portion 49c with which a cancel pin 26 as a changing member comes into contact is formed at a lower end of the swiveling piece 49 in the Z axis direction. This swiveling piece 49 is urged in a counterclockwise direction by a spring not shown in
An opening portion 21a into which a later-explained set pin 25 can be inserted is formed at a part of the support base 21 corresponding to a part below the wiper support shaft 41.
A spring 46 is interposed between the wiper support shaft 41 and the housing 42. In more detail, the spring 46 is arranged between the spring engagement portion 41a and the spring engagement portion 42a. An urging force of the spring 46 urges the wiper support shaft 41 downwardly in the Z axis direction. It is to be noted that, when the wiper support shaft 41 is urged downwardly in the Z axis direction, the engagement piece 41b comes into contact with the lower edge of the opening portion 42b. As a result, a lower end position of the wiper support shaft 41 is specified in the housing 42.
The gap adjustment mechanism 11 also has a set pin 25 as a first adjustment member that adjusts a gap between the wiper 40 and the nozzle plate 34. The set pin 25 is provided at the wiper home position. The set pin 25 moves the wiper 40 toward the recording head 4 along the Z axis direction. In more detail, in a state where the cleaning unit 5 is placed at the wiper home position, the set pin 25 is provided below the opening portion 21a formed in the support base 21.
This set pin 25 can move in the Z axis direction by a non-illustrated drive mechanism, and pushes up the wiper support shaft 41 along the Z axis direction through the opening portion 21a.
This set pin 25 pushes up and moves up the wiper support shaft 41 along the Z axis direction. When the wiper support shaft 41 moves up, the engagement piece 41b moves (moves up) in the opening portion 42b. When the engagement piece 41b moves up, the engagement piece 41b comes into contact with the latch portion 49b. At this time, the swiveling piece 49 swivels in the clockwise direction in
Further, a cancel pin 26 (a changing member) that moves the wiper 40 to be retracted from the recording head along the Z axis direction is provided at the wiper cancel position. The cancel pin 26 is included in the gap adjustment mechanism 11. The cancel pin 26 is fixed at a position where it can comes into contact with a cancel operating portion 49c. When the cleaning unit 5 moves along the Y axis direction to approach the cancel pin 26, the cancel pin 26 comes into contact with the cancel operating portion 49c. As a result, the swiveling piece 49 swivels in the clockwise direction. When the swiveling piece 49 swivels in the clockwise direction, the latch portion 49b is retracted from a position below the engagement piece 41b. At the same time, the wiper support shaft 41 moves down by the urging force of the spring 46. The wiper support shaft 41 that keeps downward movement moves down until the engagement piece 41b comes into contact with the lower edge of the opening portion 42b.
Operations in non-contact cleaning (a second cleaning mode) and contact cleaning (a first cleaning mode) and an operation of the wiping portion 22 in each cleaning mode will now be described with reference to
Further,
An operation of the wiping portion 22 in the contact cleaning mode will be first explained.
The wiping portion 22 at the wiper home position is arranged in a state shown in
Then, the set pin 25 moves up by a non-illustrated drive mechanism. As a result, the wiper support shaft 41 is pushed to move upward by the set pin 25 against the urging force of the spring 46. The engagement piece 41b comes into contact with the latch portion 49b. Each of a distal end of the engagement piece 41b and a distal end of the latch portion 49b has an inclined surface. When the engagement piece 41b moves up, the latch portion 49b is swiveled in the Y axis direction (a right direction) in the drawing. That is, the swiveling piece 49 swivels around the swiveling supporting point 42c in the clockwise direction by the engagement piece 41b that is moving up (see
As a result, the latch portion 49b functions as a restricting member that restricts movement of the engagement piece 41b. That is, the latch portion 49b restricts a downward movement operation of the wiper support shaft 41, and firmly maintains the restricted state. At this time, the wiper 40 is placed at the highest position in the Z axis direction. Additionally, a height from the support base 21 to a distal end of the wiper 40 reaches a first position higher than a height from the support base 21 to the surface of the nozzle plate 34. At this time, a gap between the wiper 40 and the nozzle plate 34 is minimum, and the distal end of the wiper 40 comes into contact with the nozzle plate 34.
After the height position of the wiper 40 is set in this manner, the support base 21 relatively moves along the Y axis direction (in an arrangement direction of the nozzles 32). As a result, contact cleaning is executed.
At this time, as shown in
The wiping portion 22 moves along the Y axis direction, passes through a part of the recording head 4 facing the nozzle plate 34, and reaches the wiper cancel position. In the wiping portion 22 that has reached this position, the cancel pin 26 comes into contact with the cancel operating portion 49c. When the swiveling piece 49 is relatively pushed by the cancel pin 26, it swivels around the swiveling supporting point 42c in the clockwise direction. As a result, the latch portion 49b functioning as a stopper for the engagement piece 41b is retracted from a position below the engagement piece 41b (see
An operation of the wiping portion 22 in the non-contact cleaning mode will now be explained.
As shown in
In this state, the support base 21 relatively moves along the Y axis direction (the arrangement direction of the nozzles 32). As shown in
It is to be noted that, as to wettability of the wiper 40, the fact that the wiper 40 tends to more easily get wet than the surface of the nozzle plate 34 means that a surface free energy (a surface tension of a solid matter) of the wiper 40 is higher than that of the nozzle plate 34.
When the support base 21 reaches the wiper cancel position, the cancel pin 26 comes into contact with the cancel operating portion 49c. As a result, the swiveling piece 49 swivels in the clockwise direction. It is to be noted that the engagement piece 41b is already in contact with the lower edge of the opening portion 42b, and the wiper support shaft 41 is placed at the lower end position. Therefore, the height position of the wiper 40 does not vary. Further, the support base 21 moves in the opposite direction along the Y axis direction to return to the wiper home position.
How cleaning is executed in a series of image recording operations will now be explained with reference to
When a power supply of the inkjet recording apparatus 1 is turned on (a Step 1), the inkjet recording apparatus 1 carries out contact cleaning (a Step 2). Then, the number N of recording mediums on which images are to be recorded is input to the inkjet recording apparatus 1 (a Step 3). Subsequently, the inkjet recording apparatus 1 initializes the number of times m of non-contact cleaning to be set to zero as a counter (a Step 4). Then, the inkjet recording apparatus 1 initializes the number n of the recording mediums 2 that has been recorded to be set to zero (a Step 5). Furthermore, the inkjet recording apparatus 1 increments the number n of the recording mediums 2 that has been recorded by one every time an image on each recording medium 2 and, at the same time, decrements the number N of the recording mediums 2 on which images are to be recorded thereon by one (a Step 6). Then, the inkjet recording apparatus 1 judges whether the number N of mediums on which images are to be recorded is zero (a Step 7).
When the number N of the mediums on which images are to be recorded is not zero (the Step 7: NO), the inkjet recording apparatus 1 judges whether the number n of the recording mediums 2 that has been recorded is 500 (a Step 8). If the number n of the recording mediums 2 that has been recorded is not 500 (the Step 8: NO), the control returns to the Step 6.
If the number n of the recording mediums 2 that has been recorded is 500 (the Step 8: YES), the inkjet recording apparatus 1 judges whether the number of times m of non-contact cleaning is 10 (a Step 9).
If the number of times m of non-contact cleaning is not 10 (the Step 9: NO), the inkjet recording apparatus 1 carries out non-contact cleaning and increments the number of times m of non-contact cleaning by one (a Step 10), and the control returns to the Step 5.
If the number of times m of non-contact cleaning is 10 (the Step 9: YES), the inject recording apparatus 1 carries out contact cleaning (a Step 11), and the control returns to the Step 4.
If the number N of the recording mediums 2 on which images are to be recorded is zero (the Step 7: YES), the inkjet recording apparatus 1 performs contact cleaning (a Step 12). After contact cleaning, the inkjet recording apparatus 1 initializes a leaving time t to zero (a Step 13). Then, the inkjet recording apparatus 1 judges whether recording is continued (a Step 14).
If recording is not continued (the Step 14: NO), the operation is terminated.
If recording is continued (the Step 14: YES), the inkjet recording apparatus 1 judges whether the leaving time t is equal to or above 12 hours (a Step 15). If the leaving time t is equal to or above 12 hours (the Step 15: YES), the control returns to the Step 2. If the leaving time t is not equal to or above 12 hours (the Step 15: NO), the control returns to the Step 3.
Selection of contact cleaning and non-contact cleaning according to this embodiment will now be described.
When cleaning the nozzle plate 34, the ink accumulated on the nozzle plate 34 can be removed by constantly repeatedly rubbing the ink-repellant coating by the wiper 40. However, repeatedly rubbing the ink-repellant coating by the wiper 40 may lead to damaging the ink-repellant coating. When the ink-repellant coating is damaged, an eject failure may occur.
According to this embodiment, the non-contact cleaning mode is set, and the wiper 40 is arranged at a position slightly separated from the nozzle plate 34. At this time, according to this embodiment, the ink can be removed (in a non-contact manner) while utilizing a capillary action to prevent the wiper 40 from coming into contact with the nozzle plate 34. According to this embodiment, based on this method, cleaning can be performed without damaging the ink-repellant coating on the nozzle plate 34. Therefore, according to this embodiment, stable eject can be obtained.
Furthermore, in regard to a gap between the nozzle plate 34 and the wiper 40, it is good enough to select an appropriate gap calculated based on an amount of the ink, a viscosity degree of the ink, a surface tension of the ink and others in pressure purging or suction purging at the time of cleaning.
Incidentally, according to this embodiment, it is preferable that an ink amount in pressure purging s 1.2 ml, a viscosity degree of the ink is 10 mPa·s (25° C.), a surface tension is 28 mN/m (25° C.). As to a gap between the nozzle plate 34 and the wiper 40 in non-contact cleaning, approximately 0.1 mm to approximately 1 mm is preferable. Moreover, in regard to a relationship between the nozzle plate 34 and the wiper 40, it is preferable for the wiper 40 to more easily get wet than the nozzle plate 34. For example, when a fluorine-based coating is applied to the nozzle plate 34, it is possible to use NBR (Nitrile Butadiene Rubber), silicone, SBR (Styrene Butadiene Rubber), NR (Natural Rubber), PVC (PolyVinylChloride), chloroprene rubber, EPDM (Ethylene Propylene Diene Methylene linkage), urethane or the like to the wiper 40. Some of FKMs (fluorocarbon rubbers) having a low degree of rubber hardness can be also used for the wiper 40. Additionally, when the nozzle plate 34 is formed of polyimide, NBR (Nitrile Butadiene Rubber) can be used for the wiper. According to this embodiment, a fluorine-based coating is applied to the nozzle plate 34, and the wiper is formed of FKM and has characteristics of higher wettability than the nozzle plate 34.
Meanwhile, a recording head for a single color or a plurality of recording heads that eject inks in accordance with respective colors, e.g., black (K), cyan (C), magenta (M), and yellow (Y) are provided in the inkjet recording apparatus 1. In such an inkjet recording apparatus 1, when recording an image on the recording medium 2 of a small size, some of the recording heads 4 alone are used in some cases. When the recording heads 4 that are not used are left for a long time in, e.g., a recording standby mode or a power supply OFF state, a film of the ink is formed on the ink-repellant coating on the nozzle plate 34. This film is formed when a solvent in a small amount of ink that has remained in cleaning is evaporated and the ink is thickened or solidified.
In this case, when a height of the wiper 40 is set to bring the wiper 40 into contact with the nozzle plate 34 and cleaning using a mechanical force is performed, the film can be removed.
Further, even during recording, fine ink droplets remaining on the nozzle plate 34 are accumulated, dried, and solidified in some cases. According to this embodiment, the surface of the nozzle plate 34 can be maintained in an excellent state by performing contact cleaning, i.e., cleaning utilizing a mechanical force at fixed time intervals or for the fixed number of times between non-contact cleaning operations in order to avoid solidification. A contact length of the wiper 40 with respect to the nozzle plate 34 in contact cleaning is set to, e.g., 0.5 mm to 1.5 mm.
According to this embodiment, a frequency of non-contact cleaning is set to be higher than that of contact cleaning. For example, a single non-contact cleaning operation is carried out per 500 recording mediums during recording, and a single contact cleaning operation is performed when effecting 10 non-contact cleaning operations. Therefore, according to this embodiment, abrasions of the ink-repellant coating can be greatly reduced as compared with an example where contact cleaning alone is carried out. Additionally, according to this embodiment, in cleaning after being left for a fixed time, e.g., 12 hours or more in a non-recording mode or in a printer power supply OFF mode, contact cleaning is performed. In regard to an interval between respective cleaning operations, setting an appropriate value while considering a degree of dryness or eject properties of the ink can suffice.
According to this embodiment, contact cleaning and non-contact cleaning can be selected and performed at an appropriate timing by monitoring the number of times of contact cleaning, the number of times of non-contact cleaning, the number of recording mediums 2 that has been recorded, a leaving time, and others. Therefore, according to this embodiment, an excellent state of the nozzle plate 34 can be maintained, and a frequency of contact cleaning in recording can be set lower than that of non-contact cleaning. Further, according to this embodiment, contact cleaning is not performed each time between respective recording operations, but contact cleaning is carried out when the apparatus is left for a predetermined time to greatly suppress abrasions of the ink-repellant coating.
As described above, executing non-contact cleaning like this embodiment can reduce the number of times of contact cleaning. Therefore, the ink on the nozzle plate 34 can be removed, and abrasions of the ink-repellant coating applied to the surface of the nozzle plate 34 can be suppressed, and occurrence of a eject failure of the ink can be constrained, thereby recording a high-quality image.
Furthermore, the wiper support shaft 41 and the housing 42 have a rectangular solid shape in this embodiment, but they are not restricted to such a shape. For example, they may have a cylindrical shape as shown in
It is to be noted that, as the mechanism that adjusts the gap between the wiper 40 and the nozzle plate 34, a link mechanism or an elastic member may be used besides the mechanism utilizing the set pin 25. Moreover, according to this embodiment, the support base 21 may be moved up in the Z axis direction to adjust the gap between the wiper 40 and the nozzle plate 34.
A second embodiment will now be explained in detail with reference to
A wiping portion 22 according to this embodiment has a structure different from that of the wiping portion 22 in the first embodiment. Structures other than the wiping portion 22 according to this embodiment are the same as those in the first embodiment, thereby omitting a detailed explanation thereof. Additionally, like reference numerals denote parts equal to those in the first embodiment, thereby omitting a detailed explanation thereof.
As shown in
The wiper support shaft 41 is a rectangular shaft-like member extending in the Z axis direction, and holds the wiper 40 on an upper surface thereof in the Z axis direction. The wiper support shaft 41 is fixed on a bottom surface of the housing 42 in such a manner that it is arranged in the hollow housing 42. It is to be noted that heights of the wiper 40 and the wiper support shaft 41 are set in such a manner that a distal end of the wiper 40 held by the wiper support shaft 41 extends beyond the upper surface of the housing 42 in the Z axis direction.
The cover 52 is a hollow quadratic-prism-like member, and the wiper support shaft 41 is positioned in the hollow portion thereof. The cover 52 is provided in the housing 42 to be movable along the extending direction of the wiper support shaft 41. A pair of cover portions 52a are formed on the upper surface of the cover 52 in the Z axis direction. The cover portions 52a are positioned on both sides of the wiper 40 in the width direction thereof. A width of the cover portion 52a (a length in a Y axis direction) is formed to be narrower than a width of a main body portion of the cover 52. A step portion 52b formed of a difference in width between the cover portion 52a and the main body portion of the cover 52 comes into contact with a spring engagement portion 42a. As a result, upward movement of the cover 52 in the Z axis direction is restricted. Further, an engagement piece 52c that extends in the Y axis direction and restricts movement of the cover 52 in the Z axis direction is formed on the cover 52. This engagement piece 52c pierces an opening portion 42b formed in the later-described housing 42 and extends to an outer side surface of the housing 42. A spring 53 as an elastic member is disposed at a lower end of the cover 52. The spring 53 upwardly urges the cover 52 in the Z axis direction with respect to the housing 42.
The housing 42 is a hollow member. The wiper support shaft 41 is fixed in the housing 42. The housing 42 supports cover 52 through the spring 53 to be movable in the Z axis direction. A spring 51 is disposed on the bottom surface of the housing 42. The housing 42 is attached to an upper surface of the support base 21 through the spring 51.
Furthermore, an opening portion 42b is formed in the side surface of the housing 42 on a front side in a traveling direction along which a cleaning operation is performed in such a manner that the opening portion 42b extends along the Z axis direction. The engagement piece 42c is inserted into this opening portion 42b. The engagement piece 52c comes into contact with the upper edge and the lower edge of the opening portion 42b in the Z axis direction. As a result, movement of the cover 52 in the Z axis direction is restricted.
Moreover, a swiveling supporting point 42c of a swiveling piece 49 is provided on the side surface of the housing 42 on the front side in the traveling direction along which a cleaning operation is performed. The swiveling piece 49 is supported on an axis of this swiveling supporting point 42c to allow its swiveling motion. This swiveling piece 49 is a tabular member, and a latch portion 49b is formed at a lower end thereof in the Z axis direction. A cancel operating portion 49c with which a later-explained cancel pin 26 comes into contact is formed on the swiveling piece 49. This swiveling piece 49 is urged in a clockwise direction in
The support base 21 supports the housing 21 through the spring 51 in such a manner that the entire housing 42 can move along the Z axis direction.
The spring 51 is interposed between the support base 21 and the housing 42 and upwardly urges the housing 42 in the Z axis direction. It is to be noted that an elastic force of this spring 51 is set to be weaker than that of the spring 53 arranged between the cover 52 and the housing 42. Therefore, when the cover 52 is pushed from above, the spring 51 is first contracted, and then the spring 53 is contracted after the spring 51 is completely contracted.
A pair of set pins 25 (a second adjustment member) that bring the wiper 40 into contact with the nozzle plate 34 are provided at a wiper home position. The set pins 25 are included in a gap adjustment mechanism 11. In more detail, in a state where the cleaning unit 5 is placed at the wiper home position, the two set pins 25 are provided at upper positions in the Z axis direction where they face the cover portions 52a. This pair of set pins 25 can move in the Z axis direction by a non-illustrated drive mechanism, and downwardly push the cover portions 52a when they move down.
When the set pins 25 move down, the set pins 25 come into contact with the two cover portions 52a and further downwardly push the cover 52.
When the cover 52 is pushed from above, the spring 51 is first contracted because of a relationship in elastic force amount between the springs 51 and 53. Therefore, a position of the cover 52 in the housing 42 does not change, and the entire housing 42 including the cover 52 moves down.
The spring 51 is contracted to enter a state where it cannot be contracted any further (the housing 42 reaches a downward movement lower limit position), and the cover 52 is further pushed by the set pins 25. Then, the spring 53 is contracted. As a result, the cover 52 moves down in the housing 42. When the cover 52 moves down, the engagement piece 52c moves (moves down) in the opening portion 42b, and the engagement piece 52c comes into contact with the latch portion 49b. At the time of contact, the engagement piece 52c further moves down against the swiveling piece 49 urged by a non-illustrated spring while swiveling the swiveling piece 49 in the counterclockwise direction in
When the engagement piece 52c further moves down beyond the latch portion 49b, the swiveling piece 49 again further swivels in the clockwise direction in
It is to be noted that, when the set pins 25 move up, the entire housing 42 moves up with respect to the support base 21 by the urging force of the spring 51.
Furthermore, a cancel pin 26 as the gap adjustment mechanism 11 is provided at a wiper cancel position. The cancel pin 26 moves the wiper 40 to be retracted from the recording head 4 along the Z axis direction. The cancel pin 26 is provided at a position where it can come into contact with the cancel operating portion 49c. When the cleaning unit 5 moves to approach the cancel pin 26 and the cancel operating portion 49c comes into contact with the cancel pin 26, the cancel pin 26 swivels the swiveling piece 49 in the counterclockwise direction. As a result, the latch portion 49b is retracted from a position above the engagement piece 52c. Consequently, the cover 52 moves up in the housing 42 by the urging force of the spring 53. The cover 52 moves up until the engagement piece 52c comes into contact with the upper edge of the opening portion 42b in the housing 42.
Operations in non-contact cleaning and contact cleaning and operations of the wiping portion 22 in respective cleaning modes will now be explained with reference to
An operation of the wiping portion 22 in the contact cleaning mode will be first explained.
The wiping portion 22 at the wiper home position is arranged in a state depicted in
Then, the set pins 25 move down by the non-illustrated drive mechanism. The set pins 25 downwardly push the cover 52 from above. An elastic force of the spring 53 supporting the cover 52 is larger than an elastic force of the spring 51. Therefore, the spring 51 is contracted before the spring 53 is contracted. That is, when the set pins 25 downwardly push the cover 52, a position of the cover 52 in the housing 42 does not vary, but the entire housing 42 moves down.
When the spring 51 enters a state where it cannot be contracted any further (when the housing 42 reaches a downward movement lower limit position), then the spring 53 starts to contract as shown in
The cover 52 moves down, and the engagement piece 52c comes into contact with the latch portion 49b. Each of the engagement piece 52c and the latch portion 49b has an inclined surface at a distal end thereof. When the engagement piece 52c moves down, the latch portion 49b is pushed in the Y axis direction (a right direction) in the drawing. The swiveling piece 49 is swiveled in the counterclockwise direction by a moving force of the engagement piece 52c in the Z axis direction, and retracted from a movement path of the engagement piece 52c. Further, when the engagement piece 52c further downwardly moves down beyond the latch portion 49b, the swiveling piece 49 swivels in the clockwise direction by the urging force of the non-illustrated spring and returns to its original position (a position shown in
From this state shown in
When the set pins 25 further move up, the set pins 25 are separated from the cover portions 52a. In the wiping portion 22 from which the pushing force by the set pins 25 is removed, the wiper 40 extends in the Z axis direction apart from the cover portions 52a to be exposed. At this time, the upper end of the wiper 40 is placed above the surface of the nozzle plate 34 of the recording head 4. Moreover, the cover portions 52a is positioned above a mask plate 33 (see
Then, when the support base 21 is moved along the Y axis direction, the wiping portion 22 is moved along the Y axis to execute contact cleaning.
As shown in
When the wiping portion 22 moves in the Y axis direction and passes through the part opposed to the nozzle plate 34, the contact state achieved between the mask plate 33 and the cover 52 is released. Therefore, the entire housing 42 moves up to reach the height shown in
An operation of the wiping portion 22 in the non-contact cleaning mode will now be explained.
The wiping portion 22 is placed at the wiper home position.
From this state, the support base 21 moves along the traveling direction (along the Y axis direction) where the cleaning operation is performed. When the housing 42 moves from the wiper home position to the position opposed to the recording head 4, the housing 42 is moved down by the non-illustrated guide against the urging force of the spring 51. The upper surface of the cover 52 that has moved down moves close to the surface of the mask plate 33. At this time, the cover 52 is placed at the highest position in a movement range in the housing 42 by the urging force of the spring 53. Therefore, the upper surfaces of the cover portions 52a are placed at the higher position than that of the upper end of the wiper 40 in the housing 42.
When the support base 21 further moves in the traveling direction along which the cleaning operation is performed and the upper surfaces of the cover portions 52a reach a position opposed to the nozzle plate 34, the housing 42 is urged toward the recording head 4 by the urging force of the spring 51. In detail, the upper surfaces of the cover portions 52a are pushed by the urging forces of the springs 51 and 53 to come into contact with the upper side of the mask plate 33 (see
Moreover, the cover 52 is placed at an upper position along the Z axis direction to constantly cover the wiper 40 by the urging force of the spring 53. Therefore, the wiper 40 does not come into contact with the nozzle plate 34.
Accordingly, the wiper 40 does not come into contact with the nozzle plate 34 placed above the mask plate 33. Therefore, in non-contact cleaning, an ink-repellant coating formed on the nozzle plate 34 is not damaged. It is to be noted that, in non-contact cleaning, the height position of the wiper 40 is set to a height (a gap) that allows wiping away the ink on the nozzle plate 34 although the wiper 40 does not come into contact with the nozzle plate 34.
This state is maintained, and the wiper 40 passes through a region of the recording head 4 facing the nozzle plate 34 to move to the wiper cancel position.
The wiping portion 22 according to this embodiment is configured to hold the housing 42 with respect to the support base 21 through the spring 51 and further hold the cover 52 with respect to the housing 42 via the spring 53. According to this structure, even if the support base 21 is inclined or the height position is uneven in the Z axis direction, the cover 52 is pushed by the springs 51 and 53. Therefore, the cover 52 can assuredly come into contact with the mask plate 33. Additionally, since the elastic force of the spring 53 is set higher than that of the spring 51, the cover 52 demonstrates a positioning function. Therefore, according to this embodiment, a positional accuracy of the wiper 40 in the Z axis direction in non-contact wiping can be readily set.
Timings of basic recording and cleaning according to this embodiment are the same as those in the first embodiment, thereby omitting a description thereof. According to this embodiment, combining contact cleaning with non-contact cleaning allows cleaning the nozzle plate for a long time without provoking clogging and without abrading the ink-repellant coating. Therefore, according to this embodiment, the ink can be stably ejected, and a high-quality image can be recorded.
A third embodiment will now be explained in detail with reference to
A wiping portion 22 in this embodiment has a structure different from those of the wiping portions 22 in the first and the second embodiments. Other structures than the wiping portion 22 in this embodiment are the same as those in the first embodiment, thereby omitting a detailed explanation thereof. Further, like reference numerals denote parts equal to those in the first embodiment, thereby omitting a detailed explanation thereof.
As shown in
A height of the wiper 40 is adjusted at a wiper home position to which the cleaning unit 5 is retracted like the first embodiment (see
Timings of basic recording and cleaning are the same as those in the first embodiment.
According to this embodiment, the rotary portion 57 having the elliptic shape rotates without restraint by a non-illustrated power, and stops at an arbitrary position. A height position of the wiper holder 56 can be changed by rotation of the rotary portion 57. The height position of the wiper holder 56 can be changed based on the major-axis radius, the minor-axis radius, and the rotation angle of the rotary portion 57. Therefore, the height position of the wiper 40 supported by the wiper holder 56 can be adjusted. In this manner, a relative gap between the wiper 40 and the nozzle plate 34 can be changed on multiple stages.
As described above, according to this embodiment, changing the relative gap allows selectively effecting contact cleaning and non-contact cleaning. The relative gap can be set on three or more stages in accordance with, e.g., a magnitude of cleaning or a type of an ink.
According to this embodiment, contact cleaning and non-contact cleaning can be performed by changing the relative gap between the wiper 40 and the nozzle plate 34 on multiple stages. In this embodiment, combining contact cleaning with non-contact cleaning allows cleaning the nozzle plate for a long time without provoking clogging and without abrading an ink-repellant coating. Therefore, according to this embodiment, the ink can be stably ejected, and a high-quality image can be recorded.
Furthermore, since the gap adjustment mechanism 11 is arranged in the wiping portion 22 alone, the apparatus can be reduced in size.
A fourth embodiment will now be described in detail with reference to
A wiping portion 22 according to this embodiment has a structure different from those of the wiping portions 22 according to the first, the second, and the third embodiments. Other structures than the wiping portion 22 in this embodiment are the same as those in the first embodiment, thereby omitting a detailed explanation thereof. Furthermore, like reference numerals denote parts equal to those in the first embodiment, thereby omitting a detailed explanation thereof.
The wiping portion 22 is provided on a support base 21. The wiping portion 22 has a gap adjustment mechanism 11. In the wiping portion 22 are provided two wipers 60 and 61 that clean a nozzle plate 34, a rotary portion 57 that has the wipers 60 and 61 and an elliptic shape, and a pillar 58 provided on the support base 21 to support the rotary portion 57. The two wipers 60 and 61 have the same length, and are respectively provided on a major axis and a minor axis of the rotary portion 57. The rotary portion 57 can rotate by a non-illustrated power without restraint. The rotary portion 57 has a thickness corresponding to a width of each of the wipers 60 and 61. Further, as shown in
When the rotary portion 57 rotates and the major axis of the rotary portion 57 becomes horizontal (the major axis of the rotary portion 57 becomes parallel with the nozzle plate 34), the wiper 61 is separated from the nozzle plate 34 to perform non-contact cleaning. Furthermore, as shown in
As described above, the rotary portion 57 can rotate by a non-illustrated power without restraint. Therefore, a height of each of the wipers 60 and 61 according to this embodiment can be changed irrespective of positions, e.g., a wiper home position or a wiper cancel position. Accordingly, for example, when the cleaning unit 5 moves from the wiper home position to the wiper cancel position, contact cleaning can be carried out in this embodiment. When the cleaning unit 5 moves from the wiper cancel position to the wiper home position, non-contact cleaning can be performed in this embodiment. Moreover, according to this embodiment, when each of the wipers 60 and 61 of the rotary portion 57 stops at a position where it does not face the recording head, cleaning can be avoided.
Additionally, according to this embodiment, the wiper 60 can be directly fixed on the rotary portion 57, and one of contact cleaning and non-contact cleaning can be selected and switched based on rotation of the rotary portion 57. Therefore, spaces of the gap adjustment mechanism 11 and the wiping portion 22 can be reduced.
Timings of basic recording and cleaning according to this embodiment are the same as those according to the first embodiment.
According to this embodiment, the rotary portion 57 is rotated to select the wiper 60 or 61, thereby performing contact cleaning or non-contact cleaning. In this embodiment, combining contact cleaning with non-contact cleaning allows cleaning the nozzle plate for a long time without provoking clogging and without abrading an ink-repellant coating. Therefore, according to this embodiment, an ink can be stably ejected, and a high-quality image can be recorded.
In this embodiment, the two wipers 60 and 61 are arranged on the rotary portion 57. However, the present invention does not have to be restricted to this shape. For example, three wipers may be arranged on the rotary portion 57. As a result, gaps between the respective wipers and the nozzle plate are different from each other, and hence conditions when performing cleaning can be set in detail. In this manner, the number of wipers does not have to be restricted.
Further, when the rotary portion 57 has, e.g., a perfect circular shape, the wiper 60 has a length with which the wiper 60 comes into contact with the nozzle plate 34, and the wiper 61 has a length with which the wiper 61 does not come into contact with the nozzle plate 34, for example. When one of the wipers 60 and 61 has the length that allows contact with the nozzle plate 34 and the other has the length that does not allow contact with the nozzle plate in this manner, the same effect as that of this embodiment can be obtained.
A fifth embodiment will now be described in detail with reference to
A cleaning unit 5 according to this embodiment has a structure different from those of the cleaning units a according to the first to the fourth embodiments. Other structures than the cleaning unit 5 according to this embodiment are the same as those according to the first embodiment, thereby omitting a detailed explanation thereof. Furthermore, like reference numerals denote parts equal to those in the first embodiment, thereby omitting a detailed explanation thereof.
As shown in
On the other hand, as shown in
In the cleaning unit 5, when the shaft foot 68 with respect to the rotary cap 69 in each of the four height adjustment members 67 is moved down, the wiper 40 enters a non-contact state with respect to the nozzle plate 34 of the recording head 4 as shown in
A height of the wiper 40 is adjusted at the wiper home position where the cleaning unit 5 is retracted like the first embodiment (see
Timings of basic recording and cleaning according to this embodiment are the same as those according to the first embodiment.
In this embodiment, the height of the wiper 40 can be adjusted by the single frame 66 in which all the wipe blades 40 are arranged, and hence a mechanism is simple as compared with an example in which the height is changed in accordance with each wipe blade 40. Moreover, according to this embodiment, since the height can be adjusted on multiple stages, the height can be set on three or more stages in accordance with, e.g., a magnitude of cleaning or a type of an ink.
According to this embodiment, the height can be adjusted at a time by using the frame 66. Therefore, in this embodiment, contact cleaning and non-contact cleaning can be easily selected. According to this embodiment, combining contact cleaning with non-contact cleaning allows cleaning the nozzle plate for a long time without provoking clogging and without abrading an ink-repellant coating. Thus, according to this embodiment, an ink can be stably ejected, and a high-quality image can be recorded.
A sixth embodiment will now be described with reference to
In this embodiment, like reference numerals denote parts equal to those in the first embodiment, thereby omitting a detailed explanation thereof.
Drying and solidification of an ink depend on an evaporation amount of the ink. As shown in
Thus, an inkjet recording apparatus 1 according to this embodiment has each ambient temperature and an upper limit time in which the ink is not dried, thickened, and solidified at each ambient temperature as a table. The inkjet recording apparatus 1 makes reference to this table between respective recording operations to avoid contact cleaning beyond necessity. Drying, thickening, and solidification of the ink occur on the nozzle plate 34. Therefore, an ambient temperature is determined as a temperature in the vicinity of each nozzle 3 in each recording head 4. As a result, an interval between cleaning operations can be more efficiently controlled.
It is to be noted that a value of an ambient temperature and a value of a temperature in the table according to this embodiment vary depending on a type of the ink (e.g., an aqueous type, a solvent, or an oil-based type), and hence obtaining an optimum value for each ink can suffice.
A temperature gauge 75 as a measurement portion measures an ambient temperature outside each recording head 4. As shown in
Incidentally, in regard to a temperature to be measured, it is preferable to measure a temperature on the surface of the nozzle plate 34 or a temperature at a point placed in the vicinity of the surface of the nozzle plate 34. Therefore, according to this embodiment, a sensor portion of the temperature gauge may be provided on the surface of the nozzle plate 34, or the sensor portion of the temperature gauge may be provided on a mask plate 33.
Timings of recording and cleaning will now be explained with reference to
When a power supply of the inkjet recording apparatus 1 is turned on (a Step 21), the inkjet recording apparatus 1 starts measurement by using the temperature gauge 75 provided in the recording head 4 (a Step 22). Then, the inkjet recording apparatus 1 carries out contact cleaning (a Step 23). Further, the inkjet recording apparatus 1 initializes the leaving time t to zero in order to start timer measurement (a Step 24). Subsequently, an operator inputs the number N of recording mediums on which images are to be recorded (a Step 25). Then, the inkjet recording apparatus 1 initializes the number n of recording mediums that has already been recorded to zero as a counter (a Step 26). Furthermore, the inkjet recording apparatus 1 increments the number n of recording mediums that has been recorded by one every time recording is carried out, and also decrements the number N of recording mediums on which images are to be recorded by one (a Step 27).
Subsequently, the inkjet recording apparatus 1 judges whether the number N of recording mediums on which images are to be recorded is zero (a Step 28).
If the number N of recording mediums on which images are to be recorded is not zero (the Step 28: NO), the inkjet recording apparatus 1 reads the table at an average temperature T (a Step 29). This average temperature T is an average temperature from the leaving time t=0 to now. The inkjet recording apparatus 1 compares a time in the table corresponding to the average temperature T with a value of the timer (the leaving time (t)). Then, the inkjet recording apparatus 1 judges whether the value of the timer is equal to or below a time in table (a Step 30).
If the value of the timer is not equal to or below the time in table (the Step 30: NO), the inkjet recording apparatus 1 carries out contact cleaning (a Step 31). Moreover, the inkjet recording apparatus 1 initializes the leaving time t to zero in order to reset the timer (a Step 32). Subsequently, the control returns to the Step 26.
If the value of the timer is equal to or above the time in table (the Step 30: YES), the inkjet recording apparatus 1 judges whether the number n of the recording mediums that has been recorded is 500 (a Step 33).
If the number n of the recording mediums that has been recorded is 500 (the Step 33: YES), the inkjet recording apparatus 1 performs non-contact cleaning (a Step 34), and the control returns to the Step 26.
If the number n of the recording mediums that has been recorded is not 500 (the Step 33: NO), the control returns to the Step 27.
If the number N of the recording mediums on which images are to be recorded is zero (the Step 28: YES), the inkjet recording apparatus 1 performs contact cleaning (a Step 35). Then, the inkjet recording apparatus 1 initializes the leaving time t to zero in order to reset the timer (a Step 36), and judges whether recording is continued (a Step 37).
If recording is continued (the Step 37: YES), the inkjet recording apparatus 1 reads the table at the average temperature T (a Step 38). The inkjet recording apparatus 1 compares a time in the table corresponding to the average temperature T with a value of the timer (the leaving time (t)). Then, the inkjet recording apparatus 1 judges whether the value of the timer is equal to or below the time in the table (a Step 39).
If the value of the timer is not equal to or below the time in the table (the Step 39: NO), the control returns to the Step 23.
If the value of the timer is equal to or below the time in the table (the Step 39: YES), the control returns to the Step 25.
If recording is not continued (the Step 37: NO), the temperature monitor is stopped (a Step 40), and the power supply is turned off (a Step 41) to terminate the operation.
According to this embodiment, an ambient temperature in the vicinity of the nozzles 3 of each recording head 4 is measured by using the temperature gauge 75, and a type and a timing of cleaning are selected, thereby avoiding contact cleaning beyond necessity. Additionally, according to this embodiment, combining contact cleaning with non-contact cleaning allows cleaning the nozzle plate 34 for a long time without provoking clogging and without abrading the ink-repellant coating. Therefore, according to this embodiment, the ink can be stably ejected, and a high-quality image can be recorded.
A seventh embodiment will now be explained with reference to
A wiping portion 22 having a gap adjustment mechanism 11 according to this embodiment has a structure different from the wiping portions 22 according to the first to the sixth embodiments. Structures other than the wiping portion 22 in this embodiment are the same as those in the first embodiment, thereby omitting a detailed explanation thereof. Further, like reference numerals denote parts equal to those in the first embodiment, thereby omitting a detailed explanation thereof.
As shown in
As shown in
Timings of basic recording and cleaning are the same as those in the first embodiment.
According to this embodiment, the rotary portion 80 can rotate by a non-illustrated power without restraint to adjust the angle θ as compared with the fourth embodiment. Therefore, according to this embodiment, since the relative gap can be adjusted on multiple stages irrespective of a position of the wiper 81 on the circular rotary portion 80, contact cleaning or non-contact cleaning can be selected. Accordingly, for example, when the cleaning unit 5 moves from a wiper home position to a cleaning range, the wiper 81 comes into contact with the nozzle plate 34 (contact cleaning). When the cleaning unit 5 moves from a wiper cancel position to the cleaning range, the wiper 81 is separated from the nozzle plate 34 (non-contact cleaning). Alternatively, as shown in
Further, the relative gap between the wiper 81 and the nozzle plate 34 can be appropriately set based on a diameter of the rotary portion 80 and the angle θ.
According to this embodiment, combining contact cleaning with non-contact cleaning allows cleaning the nozzle plate for a long time without provoking clogging and without abrading an ink-repellant coating. Therefore, according to this embodiment, an ink can be stably ejected, and a high-quality image can be recorded.
Moreover, a plurality of wipers having different lengths may be provided on the rotary portion 80.
Additionally, the rotary portion 80 is used as a mechanism that inclines the wiper 81, but other structures, e.g., a link mechanism can be adopted.
It is to be noted that the recording head 4 is fixed and the cleaning unit 5 moves in the nozzle arrangement direction to clean the nozzle plate 34 in each of the foregoing embodiments. However, the cleaning unit 5 may be fixed, and the recording head 4 may move.
Further, in each of the foregoing embodiment, the recording head 4 is fixed, and the cleaning unit 5 moves closer to or away from the recording head 4 to change the gap between the cleaning unit 5 and the nozzle plate 34 of the recording head 4. However, the cleaning unit 5 may be fixed, and the recording head 4 may move closer to or away from the wiper.
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
Number | Date | Country | Kind |
---|---|---|---|
2006-011431 | Jan 2006 | JP | national |
Number | Name | Date | Kind |
---|---|---|---|
6286933 | Murakami et al. | Sep 2001 | B1 |
6761428 | Agarwal et al. | Jul 2004 | B2 |
6913338 | Rhoads et al. | Jul 2005 | B2 |
20010002837 | Takahashi et al. | Jun 2001 | A1 |
20020126178 | Toh et al. | Sep 2002 | A1 |
Number | Date | Country |
---|---|---|
5-42678 | Feb 1993 | JP |
2002-283581 | Oct 2002 | JP |
Number | Date | Country | |
---|---|---|---|
20070165063 A1 | Jul 2007 | US |