Patent Application
20140218440
1. Field of the Invention
The present invention relates to a printing apparatus and a cleaning method and, more particularly, to an inkjet printing apparatus and a cleaning method of wiping the orifice surface of an inkjet printhead mounted in the apparatus.
2. Description of the Related Art
Ink may stick to a surface (to be referred to as an orifice surface hereinafter) where orifices are formed in a printhead mounted in an inkjet printing apparatus (to be referred to as a printing apparatus hereinafter) and impede normal discharge. To prevent such a failure, the printing apparatus generally includes a wiping unit configured to wipe ink sticking to the orifice surface. To wipe the orifice surface, the wiping unit includes, for example, a wiping member made of an elastic material and a contact member used to make the wiping member contact the orifice surface. A wiping operation is performed by making the wiping member contact the orifice surface and slide at a predetermined timing.
In a so-called serial printing apparatus which performs printing by discharging ink to a printing medium while reciprocally moving a carriage with a printhead mounted on it, a method of wiping the orifice surface by moving the contact member during suspension of the reciprocating motion is known. There is also known a method of wiping the orifice surface by moving the printhead in a state in which the contact member is in contact. The latter wiping method is effective especially when the wiping frequency is high. That is, since the wiping operation can be performed during the reciprocating motion of the carriage, a single wiping operation can be done in a short time as compared to the method of performing the wiping operation during suspension of the reciprocating motion of the carriage.
Japanese Patent Laid-Open No. 2005-21809 discloses an example in which a sheet-like wiping member is made to slide in the vertical direction against the orifice array of the printhead, thereby performing wiping. The sheet-like wiping member is known to exert a greater wiping effect than a wiping method of causing a so-called wiper blade to slide.
As the inkjet printing apparatuses and printing methods thereof have diversified in recent years, printing using a plurality of color inks or inks reactive with each other may be done by a single or a plurality of printheads. In this case, if the wiping operation is performed by a single wiping member, an ink may mix in the orifices of another ink, and color mixing or an ink discharge failure due to solidification by reaction may occur.
In the method disclosed in Japanese Patent Laid-Open No. 2005-21809, the sheet-like wiping member is wound, thereby preventing an ink discharge failure due to color mixing and ink solidification by reaction from occurring. However, the effect is not sufficient.
Accordingly, the present invention is conceived as a response to the above-described disadvantages of the conventional art.
For example, a printing apparatus and a cleaning method thereof according to this invention are capable of preventing ink color mixing or a discharge failure from occurring in a wiping operation during the reciprocating motion of a carriage.
According to one aspect of the present invention, there is provided a printing apparatus. The apparatus comprises: a printhead formed by arranging a plurality of orifice arrays in a first direction perpendicular to a second direction, each of the orifice arrays including a plurality of orifices configured to discharge ink and arranged in the second direction; a carriage, on which the printhead is mounted, configured to move in the first direction; a wiper for wiping an orifice surface of the printhead using a windable sheet-like wiping member; a moving unit configured to move part of the sheet-like wiping member so that an area of the part of the sheet-like wiping member contacts to the orifice surface or retracts from the orifice surface; a winder for winding the sheet-like wiping member; and a control unit configured to control so that the moving unit moves the part of the sheet-like wiping member to make the area contact the orifice surface of the printhead, the moving unit moves the sheet-like wiping member toward the orifice surface according to movement of the carriage, and each orifice of at least one of the plurality of orifice arrays is wiped while the winder winds the sheet-like wiping member.
According to another aspect of the present invention, there is provided a cleaning method in a printing apparatus including a printhead formed by arranging a plurality of orifice arrays in a first direction perpendicular to a second direction, each of the orifice arrays including a plurality of orifices configured to discharge ink and arranged in the second direction, and a carriage, on which the printhead is mounted, configured to move in the first direction.
The method comprises: moving an area of part of a windable sheet-like wiping member so that the area contacts to the orifice surface of the printhead; wiping orifices of at least one of the plurality of orifice arrays while moving the sheet-like wiping member toward the orifice surface as the carriage moves; and moving the part of the sheet-like wiping member so that the area of the part of the sheet-like wiping member used for the wiping is retracted from the orifice surface.
The invention is particularly advantageous since it is possible to prevent a problem such as color mixing or a discharge failure in the wiping operation during the reciprocating motion of the carriage. Additionally, in the wiping operation during the reciprocating motion of the carriage, one or a plurality of orifice arrays can selectively be wiped while suppressing the operation time of the wiping operation. This makes it possible to reduce ink solidification on the ink discharge surface of the printhead as well as color mixing and a discharge failure.
Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings).
Exemplary embodiments of the present invention will now be described in detail in accordance with the accompanying drawings. The relative arrangement of constituent elements set forth in the embodiments do not limit the scope of the present invention unless it is specifically stated otherwise.
In this specification, the terms “print” and “printing” not only include the formation of significant information such as characters and graphics, but also broadly includes the formation of images, figures, patterns, and the like on a print medium, or the processing of the medium, regardless of whether they are significant or insignificant and whether they are so visualized as to be visually perceivable by humans.
Also, the term “print medium” not only includes a paper sheet used in common printing apparatuses, but also broadly includes materials, such as cloth, a plastic film, a metal plate, glass, ceramics, wood, and leather, capable of accepting ink.
Furthermore, the term “ink” (to be also referred to as a “liquid” hereinafter) should be extensively interpreted similar to the definition of “print” described above. That is, “ink” includes a liquid which, when applied onto a print medium, can form images, figures, patterns, and the like, can process the print medium, and can process ink. The process of ink includes, for example, solidifying or insolubilizing a coloring agent contained in ink applied to the print medium.
Further, a “printing element” generically means an ink orifice or a liquid channel communicating with it, and an element for generating energy used to discharge ink, unless otherwise specified.
The printing apparatus 1 is a serial printing apparatus and performs printing while causing a conveyance unit (not shown) to intermittently convey a printing medium in the Y direction and moving the carriage 2 with the printhead 3 mounted on it in the X direction perpendicular to the Y direction that is the printing medium conveyance direction. The printing apparatus 1 has a large size in the X direction to enable printing on a relatively large printing medium (for example, A1 size).
The printhead 3 is detachably mounted on the carriage 2. The carriage 2 reciprocally moves along the X direction together with the printhead 3. More specifically, the carriage 2 is supported to be movable along a guide shaft 4 arranged along the X direction, and fixed to an endless belt 5 that moves approximately parallel to the guide shaft 4. The endless belt 5 reciprocally moves due to the driving force of a carriage motor (CR motor) so as to reciprocally move the carriage 2 in the X direction.
In addition, a scale 6 provided with slits at a predetermined interval is arranged along the moving direction (X direction) of the carriage 2. An encoder sensor (not shown) mounted on the carriage 2 reads the scale as the carriage 2 moves, thereby detecting the moving-direction position of the carriage 2.
The printhead 3 includes the plurality of orifices 3a formed in an orifice surface 3b shown in
An energy generation element that generates discharge energy used to cause the orifice 3a to discharge ink is arranged in each fluid channel of the printhead 3. In this embodiment, an electrothermal transducer that locally heatsink to cause film boiling and causes the orifice to discharge the ink by the pressure is used. However, the present invention is not limited to this, and an electromechanical transducer such as a piezoelectric element may be used. Note that in the following description, each orifice 3a and a corresponding fluid channel will inclusively be referred to as a nozzle.
In the printhead 3, inks containing different color materials, for example, cyan, light cyan, magenta, light magenta, yellow, and black inks are supplied from ink tanks (not shown) storing the inks in correspondence with the above-described six orifice arrays. Each ink tank provided in the printing apparatus main body is connected, via a tube (not shown), to the ink supply port of a corresponding one of the orifice arrays 11 to 16 and supplies the ink. Note that these inks can arbitrarily be set, and the types and colors of the inks to be mounted are merely examples.
As shown in
Driving circuits 105, 106, 107, and 108 of a conveyance motor (LF motor) 113 of a conveyance mechanism, a carriage motor (CR motor) 114, the printhead 3, and a recovery unit 7 are connected to the input/output port 104. Sensors such as a head temperature sensor 112 that detects the temperature of the printhead 3, an encoder sensor 111 fixed to the carriage 2, and a temperature and humidity sensor 109 that senses the temperature and humidity as the use environment of the printing apparatus 1 are also connected to the input/output port 104. The main control unit 100 is connected to a host computer (to be referred to as a host hereinafter) 115 via an interface circuit 110.
When the recovery unit 7 forces the printhead 3 to discharge ink, a recovery processing counter 116 counts the amount of ink. A preliminary discharge counter 117 counts the amount of ink of preliminary discharge performed before, after, or during printing. A marginless ink counter 118 counts the amount of ink printed outside the printing medium area when performing marginless printing. A discharge dot counter 119 counts the amount of ink discharged during printing.
The outline of a printing operation executed by the printing apparatus having the above-described arrangement is as follows. That is, when print data is received from the host 115 via the interface circuit 110, the print data is rendered on the buffer of the RAM 103. When the printing operation is instructed, the conveyance mechanism (not shown) operates and conveys a printing medium to a position facing the printhead 3. At this time, the carriage 2 moves in the X direction along the guide shaft 4. As the carriage 2 moves, the printhead 3 discharges ink droplets, and an image corresponding to one carriage scan is printed on the printing medium. After that, the conveyance unit conveys the printing medium in the Y direction perpendicular to the carriage 2 by one scan printing. The above-described operation is repeated, thereby forming a predetermined image on the printing medium.
Note that the position of the carriage 2 is detected by causing the main control unit 100 to count pulse signals output from the encoder sensor 111 in accordance with the movement of the carriage 2. That is, the encoder sensor 111 detects the slits formed at a predetermined interval in the scale 6 (see
Several embodiments will be described next concerning a cleaning operation of the printhead and, more particularly, a wiping operation of the orifice surface of the printhead executed by the printing apparatus having the above-described arrangement.
The recovery unit 7 includes suction recovery mechanisms 7A and 7B, an elevating mechanism (not shown) that moves the suction recovery mechanisms up and down, and a wiping unit 8. The suction recovery mechanisms 7A and 7B perform suction recovery processing that is one form of recovery processing.
The suction recovery processing is processing of forcibly sucking ink from a plurality of nozzles formed in the printhead so as to replace the ink in the nozzles with ink suitable for discharge. More specifically, each of the suction recovery mechanisms 7A and 7B covers an orifice surface 3b with a cap, generates a negative pressure in the cap by a pump (not shown) communicating with the cap, and forcibly sucks ink from the orifices 3a by the negative pressure. Note that the suction recovery mechanisms 7A and 7B perform the suction recovery processing for three orifice arrays 11 to 13 and three orifice arrays 14 to 16, respectively.
The wiping unit 8 is provided at a position where it can face the reciprocating motion turning position of the printhead 3 (for example, the home position of the printhead) in the vertical direction (Z direction). The wiping unit 8 includes a wiping member 9 made of sheet-like material, a contact member 10 used to make the wiping member 9 contact the orifice surface 3b, and a contact member holding unit (not shown) that is movable between the contact position of the contact member 10 and the retracted position where the contact member 10 is not in contact. The moving direction is the Z direction, that is, the direction perpendicular to the orifice surface.
Note that referring to
Referring to these drawings, the time elapses, and the printhead 3 moves in the order of FIG. 6A→FIG. 6B→FIG. 6C→FIG. 6D→
First, as shown in
Next, as shown in
Then, as shown in
When the above-described operation is performed, the contact surface of the wiping member 9 can be changed between when wiping the orifice array 16, when wiping the orifice array 15, and when wiping the orifice array 14. This enables selective wiping.
Note that although selective wiping of the three orifice arrays on the downstream side in the moving direction of the printhead 3 has been described above, the combination of the selective wiping target orifice arrays is not limited to this.
In the above-described example, the orifice arrays are selectively wiped in the direction in which the printhead 3 moves toward the X contact position. However, the wiping operation may be done when the printhead moves away from the X contact position. For example, the wiping operation may be performed for the orifice arrays 13, 12, and 11 in this order concerning the scanning direction of the printhead shown in
An example in which a certain orifice array and an orifice array group including a plurality of orifice arrays are selectively wiped will be described.
Referring to these drawings, the time elapses, and a printhead 3 moves in the order of FIG. 7A→FIG. 7B→FIG. 7C→FIG. 7D→
First, as shown in
Next, as shown in
Then, as shown in
When the above-described operation is performed, the contact surface of the wiping member 9 can be changed between when wiping the orifice array 16 and when wiping the orifice arrays 15 and 14. This enables selective wiping.
In this embodiment, the same contact surface on the wiping member is used for the orifice arrays 15 and 14, unlike the first embodiment. This is effective in a case where, for example, the orifice array 16 discharges cyan ink, the orifice array 15 discharges magenta ink, and the orifice array 14 discharges black ink. That is, if the orifice arrays 16 and 15 are wiped by the same contact surface, color mixing may be conspicuous. However, if the orifice arrays 15 and 14 are wiped in this order, and the orifice array 14 discharges black ink, color mixing is inconspicuous, and selective wiping is unnecessary. At this time, in a case where wiping is performed in the order of orifice array 15→orifice array 14, wiping can be executed by a single wiping operation without winding the wiping member. It is therefore possible to save the use amount of the wiping member.
Note that although selective wiping of the orifice array 16 and the orifice array group including the orifice arrays 15 and 14 has been described above, the combination of the selective wiping target orifice arrays is not limited to this. In this example, the orifice arrays are selectively wiped in the direction in which the printhead 3 moves toward the X contact position. However, the wiping operation may be done when the printhead 3 moves away from the X contact position, as described in the first embodiment.
In this embodiment, a description will be made assuming that two printheads 3 are mounted on a carriage 2 in
Hence, inks containing various color materials can be used in correspondence with 12 orifice arrays included in the two printheads 3. For example, cyan, light cyan, magenta, light magenta, yellow, black, red, green, blue, orange, gray, and light gray inks are supplied from ink tanks (not shown) storing the inks.
Note that in this embodiment, a case where the two printheads 3 are mounted has been described. However, the present invention is not limited to this, and a plurality of printheads such as three or four printheads may be mounted.
In correspondence with the two printheads 3 mounted on the carriage 2, the recovery unit 7 according to this embodiment includes two additional suction recovery mechanisms 7C and 7D in addition to suction recovery mechanisms 7A and 7B. Hence, the elevating mechanism (not shown) that moves the suction recovery mechanisms up and down also copes with the up/down movement of the four suction recovery mechanisms.
Note that the suction recovery mechanisms 7A and 7B perform the suction recovery processing for three orifice arrays 11 to 13 and three orifice arrays 14 to 16 of one of the two printheads, respectively. The suction recovery mechanisms 7C and 7D perform the suction recovery for the three orifice arrays 11 to 13 and the three orifice arrays 14 to 16 of the other printhead, respectively.
Note that although
As is apparent from
An X contact position indicated by a broken line in
First, at the timing shown in
At the timing shown in
After completion of the wiping operation of the second orifice array group, the winding unit 9A winds the wiping member 9 by an amount corresponding to the area used to wipe the orifice arrays 11 to 16, that is, the area 15A. Note that the winding operation is performed with the contact member 10 remaining pushed up but may be performed after the contact member 10 is lowered.
When the above-described operation is performed, the contact surface of the wiping member used the wiping operation can be changed between the inks discharged from the orifice arrays 21 to 26 and those discharged from the orifice arrays 11 to 16. For this reason, for example, if one of the inks discharged from the orifice arrays 21 to 26 and one of the inks discharged from the orifice arrays 11 to 16 are reactive with each other, the wiping operation can prevent the inks from mixing and reacting on the orifice surfaces of the printheads.
In a case where the orifice array interval 30 does not exist between the two printheads, the contact member needs to be lowered to the position where the orifice surface of the printhead does not contact the wiping member to feed the new contact surface of the wiping member. It is necessary to then perform the operation of feeding the new contact surface, and after that, push up the contact member again. Hence, a long time is required to complete the series of wiping operations. In this embodiment, however, the orifice array interval 30 exists between the orifice arrays to be selectively wiped. It is therefore possible to feed the new contact surface in a state in which the wiping member 9 exists at the contact position and suppress the wiping operation time.
An example will be described here in which a wiping unit including two contact members (first contact member and second contact member) 10A and 10B that are independently movable between the Z retracted position and the Z contact position is used, unlike the first to third embodiments.
First, at the timing shown in
In
At the timing shown in
After completion of the wiping operation of the second orifice array group, a winding unit 9A winds the wiping member 9 by an amount corresponding to the area used to wipe the orifice arrays 11 to 16 and the orifice arrays 21 to 26, that is, the areas 16A and 15A.
As described above, in this embodiment, after the first wiping target orifice array group is wiped, the contact member that contacts the wiping member is switched without winding the wiping member, as compared to the third embodiment. This makes it possible to feed the new contact surface of the wiping member.
Note that although a case where the orifice array interval 30 is formed between the printheads 31 and 32 has been described in the third and fourth embodiments, the present invention is not limited to this. For example, concave portions may be provided between the orifice arrays of one printhead to provide orifice array intervals in the printhead.
In the third and fourth embodiments as well, an example has been described in which the orifice arrays are selectively wiped in the direction in which the printhead 3 moves toward the X contact position. However, the wiping operation may be done when the printhead moves away from the X contact position.
The present invention is applicable to any apparatus using a printing medium made of paper, cloth, leather, nonwoven fabric, OHP sheet, or metal. Specific examples of the applicable apparatus are office machines such as a printer, copying machine, and facsimile apparatus using an inkjet printing method and industrial production machines.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2013-018957, filed Feb. 1, 2013, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-018957 | Feb 2013 | JP | national |
