This application claims priority to Japanese Patent Application No. 2010-036970, filed Feb. 23, 2010, the entire subject matter and disclosure of which is incorporated herein by reference.
1. Filed of the Disclosure
The features described herein relate to recording apparatuses for forming images on recording media, and wiping devices for wiping contaminants on ejection surfaces.
2. Description of the Related Art
A known ink jet printer includes an ink jet head, a frame moving mechanism for vertically moving the ink jet head, a maintenance unit for the ink jet head, and a horizontal movement mechanism for horizontally moving the maintenance unit. In this ink jet printer, the maintenance unit is horizontally moved to a position opposing the ink jet head after the ink jet head has been raised from a printing position to a head maintenance position. Then, after purge, the ink jet head is lowered so as to bring a wiper and an ejection surface of the ink jet head into contact with each other and wipe the ejection surface while the maintenance unit is horizontally moved toward a retracting position. Thus, the ink jet head may be recovered from an ejection failure.
However, in the ink jet printer described above, when the maintenance unit is horizontally moved to a position opposing the ink jet head, the ink jet head needs to be raised to the head maintenance position to avoid contact between the wiper and the ejection surface. Therefore, the ink jet printer has a space allowing vertical movement of the head, which increases the size of the printer in the height direction. Furthermore, not only a mechanism for horizontally moving the wiper, but also a mechanism for vertically moving the head, which uses another driving source, is required. Consequently, the number of components constituting these mechanisms is increased, further increasing the size of the printer and increasing the manufacturing costs due to increased component count.
According to one embodiment described herein, a recording apparatus may comprise a recording head which has an ejection surface provided with ejection ports through which liquid is ejected, and a wiping device configured to move in a wiping direction along the ejection surface and wipe contaminants from the ejection surface. The wiping device may comprise a wiper. The wiping device may comprise a wiper holder configured to hold the wiper. The wiping device may comprise a cam mechanism configured to support the wiper holder and change the height of the wiper holder, such that the wiper is positioned at a contacting height at which the wiper is in contact with the ejection surface when the cam mechanism is moving in the wiping direction, and such that the wiper is positioned at a separation height at which the wiper is not in contact with the ejection surface when the cam mechanism is moving in the retracting direction opposite to the wiping direction. The wiping device may comprise a guide mechanism configured to support the cam mechanism so as to be slidable in the wiping direction. The wiping device may comprise a moving device configured to move the wiper and the wiper holder together with the cam mechanism by moving the cam mechanism selectively in either the wiping direction or a retracting direction.
According to another embodiment herein, a wiping device may be configured to wipe contaminants from an ejection surface provided with ejection ports through which liquid is ejected, by being moved in a wiping direction along the ejection surface. The wiping device may comprise a wiper. The wiping device may comprise a wiper holder configured to hold the wiper. The wiping device may comprise a cam mechanism configured to support the wiper holder and change the height of the wiper holder, such that the wiper is positioned at a contacting height at which the wiper is in contact with the ejection surface when the cam mechanism is moving in the wiping direction, and such that the wiper is positioned at a separation height at which the wiper is not in contact with the ejection surface when the cam mechanism is moving in the retracting direction opposite to the wiping direction. The wiping device may comprise a guide mechanism configured to support the cam mechanism so as to be slidable in the wiping direction. The wiping device may comprise a moving device configured to move the wiper and the wiper holder together with the cam mechanism by moving the cam mechanism selectively in either the wiping direction or a retracting direction.
Other objects, features, and advantages of embodiments of the present invention will be apparent to persons of ordinary skill in the art from the following description of embodiments with reference to the accompanying drawings.
Various embodiments, and their features and advantages, may be understood by referring to
Referring to
The printer 1 is a line-type color ink jet printer. The printer 1 includes a rectangular-parallelepiped-shaped casing 1a. A sheet-output portion 31 is provided on the top plate of the casing 1a. The inner space of the casing 1a may be divided into spaces A, B, and C from above. In the spaces A and B, a sheet-conveying path continuous with the sheet-output portion 31 is formed. In the space A, the conveyance of a sheet P and image formation on the sheet P are performed. In the space B, a sheet-feed operation is performed. The space C accommodates ink cartridges 39, which function as ink supply sources.
The space A accommodates a plurality of, e.g., four, ink jet heads 10 (hereinafter, “heads 10”), wiping devices 40 for wiping ejection surfaces 10a of the heads 10 (described below, see
The plurality of, e.g., four, heads 10 are substantially rectangular-parallelepiped-shaped, which are elongated in the main scanning direction. The heads 10 are arranged at predetermined intervals in the sub-scanning direction and are supported by the casing 1a via a head frame 3. The heads 10 each include a stacked body consisting of a flow path unit having ink flow paths, including pressure chambers, and an actuator for applying pressure to ink in the pressure chambers (both of them are not shown). The bottom surfaces of the heads 10 function as the ejection surfaces 10a. The ejection surfaces 10a have a plurality of ejection ports (not shown) through which ink is ejected. During image formation, magenta, cyan, yellow, and black ink is ejected from the heads 10 onto the sheet P being conveyed.
The conveying unit 21 includes a nip roller 4, a separation plate 5, a plurality of, e.g., two, belt rollers 6 and 7, and an endless conveying belt 8 that is wound around and runs between the belt rollers 6 and 7. The belt roller 7, functioning as a driving roller, is rotated clockwise in
In the loop of the conveying belt 8, a plate-like platen 19 is disposed so as to oppose the ejection surfaces 10a of the plurality of, e.g., four, heads 10. The upper loop of the conveying belt 8 is supported by the platen 19 from inside, and a gap suitable for image formation is provided between an outer peripheral surface 8a and the ejection surfaces 10a.
A silicon layer having low-viscosity is formed on the outer peripheral surface 8a of the conveying belt 8. The sheet P fed to the conveying unit 21 by the guide member is pressed against the outer peripheral surface 8a by the nip roller 4 and is conveyed in the sub-scanning direction, as indicated by bold arrows.
The sheet P is then separated from the outer peripheral surface 8a by the separation plate 5 on the right side in
The guide member includes an upstream guide portion and a downstream guide portion. The upstream guide portion connects a sheet-feed unit 1b and the conveying unit 21 and includes guides 27a and 27b and a feed roller pair 26. The downstream guide portion connects the conveying unit 21 and the sheet-output portion 31 and includes guides 29a and 29b and a plurality of, e.g., two, feed roller pairs 28. Each of the feed roller pairs 26 and 28 are rotated by feed motors (not shown), under the control of the controller 1p.
The sheet-feed unit 1b is disposed in the space B such that it can be attached to or removed from the casing 1a in the main scanning direction. As shown in
The sheet P fed by the sheet-feed roller 25 is sent to the conveying unit 21 by the feed roller pair 26, along the guides 27a and 27b. The sheet P is conveyed along the conveying belt 8 by the rotation of the belt roller 6. An image is formed on the sheet P during conveyance. Then, the sheet P having undergone image formation is conveyed upward by the feed roller pairs 28 along the guides 29a and 29b. Finally, the sheet P is discharged onto the sheet-output portion 31 through the opening 30 provided at the top of the casing 1a. In this manner, the sheet conveying path extending from the sheet-feed unit 1b to the sheet-output portion 31 is formed in the printer 1.
Herein, the “sub-scanning direction” is the direction parallel to the direction in which the sheet P is conveyed by the conveying unit 21, and the “main scanning direction” is the direction parallel to the horizontal plane and perpendicular to the sub-scanning direction. The main scanning direction and the sub-scanning direction are both parallel to the horizontal plane (the ejection surfaces 10a of the heads 10) and perpendicular to the vertical plane.
An ink unit 1c is disposed in the space C such that it can be attached to or removed from the casing 1a in the main scanning direction. The ink unit 1c includes a cartridge tray 35 and a plurality of, e.g., four, cartridges 39. The plurality of, e.g., four, cartridges 39 contain each of magenta ink, cyan ink, yellow ink, and black ink. These cartridges 39 are stored side-by-side in the sub-scanning direction in the tray 35.
The controller 1p disposed in the space A includes a central processing unit (CPU) functioning as an arithmetic processing unit, a read only memory (ROM) that stores programs executed by the CPU and data used in executing the programs, a random access memory (RAM) that temporarily stores data necessary to execute the programs, an input/output interface that sends the data to or receives the data from an outer device connected to the printer 1. The controller 1p receives image data of an image to be recorded on the sheet P from a personal computer (PC), functioning as the outer device, through the interface, and stores the image data in the RAM. The controller 1p controls the conveyance of the sheet P and the recording on the sheet P, on the basis of the image data stored in the RAM.
The controller 1p, upon receipt of a recording instruction, activates the entire conveying path. More specifically, the controller 1p first drives the conveying motor to rotate the belt roller 6 and stands by until the moving speed of the conveying belt 8 stabilizes at a predetermined speed. During the stand-by, the controller 1p converts the image data contained in the recording instruction into recording data compatible with the arrangement of the ejection ports and stores the data in a predetermined region of the RAM. Once the moving speed of the conveying belt 8 has stabilized at a predetermined speed, the controller 1p drives the sheet-feed motor and the feed motors to rotate the sheet-feed roller 25 and the feed roller pairs 26 and 28, sequentially feeding the sheets P to the conveying unit 21. A sheet sensor 32 is positioned downstream of the nip roller 4 in the sheet conveying direction. The controller 1p determines the timing at which ink is ejected from the heads 10, on the basis of a detection signal received from the sensor 32. When the sheet P passes immediately below the ejection surfaces 10a, ink droplets are ejected from the ejection ports, on the basis of the recording data. Thus, a desired color image is formed on the sheet P. Thereafter, the sheet P is sent to the sheet-output portion 31 by the feed roller pairs 28.
Herein, contaminants, such as ink, paper dust, and particles, are deposited on the ejection surfaces 10a with time, and ink in the less frequently used ejection ports becomes viscous. Because these situations degrade the ink ejection performance, the controller 1p performs processing for recovering the ejection performance (maintenance) periodically or every time a predetermined number of sheets have undergone recording. The maintenance includes purge, in which ink is forcibly discharged from the ejection ports by driving a pump, and wiping, in which contaminants such as ink on the ejection surfaces 10a are removed using a wiper 41 after the purge.
Next, referring to
Referring to
Referring to
The wiper 41 is an elastic member made of, for example, rubber. The wiper 41 has a substantially right-angled triangular pole shape extending in the sub-scanning direction and is disposed such that the right-angled portion is positioned on the lower side. The wiper 41 has substantially the same length as the ejection surface 10a in the sub-scanning direction and has a constant lateral cross-section across the entirety in the sub-scanning direction (see
The wiper holder 42 is a horizontal plate-like member to which the wiper 41 is fixed. The wiper 41 is secured to the top surface of the wiper holder 42, at the center thereof. Referring to
Referring to
Furthermore, the plate-like member 63 has a plurality of, e.g., two, upwardly projecting guide poles 65 on the top surface, at positions corresponding to the holes 42a. The guide poles 65 have an outside diameter that is slightly smaller than the inside diameter of the holes 42a and a length such that the upper ends thereof stay in the holes 42a even when the wiper 41 is positioned at a position at which it can be in contact with the ejection surface 10a (contacting position). Thus, the wiper holder 42 may be prevented from being shifted relative to the plate-like member 63 in the horizontal direction, when it is moved vertically.
A plate spring 80 is disposed between the plate-like member 63 and the wiper holder 42. This plate spring 80 is secured to the top surface of the plate-like member 63 at one end and to the bottom surface of the wiper holder 42 at the other end. Referring to
Referring to
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Referring to
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Next, the operation of the respective parts of the wiping device 40 that wipes the ejection surface 10a of the head 10 after purge will be described.
Before wiping, the respective parts of the wiping device 40 are in stand-by mode. Referring to
For example, when the purge of the head 10 is completed under the control of the controller 1p, and the instruction for wiping by the wiper 41 is issued, the wiping device 40 is transferred to wiping mode. At this time, in the whole conveying path, the driving of the respective parts is stopped. Furthermore, the head frame 3 is moved in the main scanning direction by the head moving mechanism (not shown) under the control of the controller 1p, as indicated by bold arrows in
Then, under the control of the controller 1p, the pulley 72 is rotated forward, causing the belt 73 to run. At this time, as the belt 73 runs, the cam plates 51 move from a retracted position in the wiping direction (to the left side in
When the wiper 41 arrives at a position opposing the ejection surface 10a, the edge of the ejection surface 10a comes into contact with the inclined surface 41b of the wiper 41. As a result, the wiper 41 and the wiper holder 42 move downward, while resisting the urging force of the plate spring 80. More specifically, referring to
Once the wiper 41 has passed the position opposing the ejection surface 10a, the wiper 41 and the wiper holder 42 move upward to a position at which the projections 42b come into contact with the upper portions of the horizontal rear end portions 53c. Then, by moving the wiper 41, the wiper holder 42, the cam plates 51, the guide mechanism 60, and the like to a wiping completing position (a position closest to the conveying unit 21 in the moving range in the main scanning direction) in this state, wiping of the ejection surface 10a by the wiper 41 is completed.
After this, under the control of the controller 1p, the pulley 72 is rotated backward, returning the wiper 41, the wiper holder 42, the cam plates 51, the guide mechanism 60, and the like to the retracted position. At this time too, because the static friction between the shafts 61 and the hollow pipes 64a is greater than the sum of the static friction between the projections 42b and the inner surfaces of the guide holes 53 and the static friction between the projections 63a and the inner surfaces of the guide holes 54, only the cam plates 51 are moved in the wiping direction. Consequently, the projections 42b in contact with the upper corners of the horizontal rear end portions 53c move obliquely downward while making contact with the upper portions of the inclined portion 53a and then come into contact with the upper corners of the horizontal front end portions 53b. In other words, the wiper 41 moves from the contacting height to the separation height. Then, in this state, as the cam plates 51 move in the retracting direction, the wiper 41, the wiper holder 42, the guide mechanism 60, and the like pass the position opposing the ejection surface 10a and return to the retracted position. The respective parts of the wiping device 40 thus complete the wiping operation and return to the stand-by mode.
Thereafter, the head 10 moves from the maintenance position to the recording position as the head moving mechanism moves the head frame 3. The controller 1p, upon receipt of a next recording instruction at this stage, activates the entire conveying path and restarts the recording operation. If the controller 1p does not receive a next recording instruction at this stage, it causes the ejection surface 10a to be covered with a cap (not shown) and waits for a next recording instruction.
As has been described above, according to the ink jet printer 1 of this embodiment, when the moving mechanism 70 moves the cam plates 51 in the wiping direction, the cam plates 51 change the height of the wiper holder 42 such that the wiper 41 is positioned at the contacting height at which the wiper 41 can be in contact with the ejection surface 10a. Thus, the ejection surface 10a can be wiped with the wiper 41. When the moving mechanism 70 moves the cam plates 51 in the retracting direction, the cam plates 51 change the height of the wiper holder 42 such that the wiper 41 is positioned at the separation height at which the wiper 41 cannot be in contact with the ejection surface 10a. This enables the wiper 41 to be retracted while the wiper 41 and the ejection surface 10a are separated. As has been described, moving the cam plates 51 in the wiping direction and the retracting direction by the moving mechanism 70 makes it possible to wipe the ejection surface 10a with the wiper 41 and to retract the wiper 41 while the wiper 41 and the ejection surface 10a are separated. In other words, moving the cam mechanism 50 by the moving mechanism 70 makes it possible to change the height of the wipers 41, without using a driving source in addition to the driving source for supplying a driving force to the moving mechanism 70. Accordingly, it is possible to reduce the number of components used in the printer body, to reduce the size of the printer body, and to reduce the manufacturing costs of the printer 1. In addition, it is possible to reduce the size of the printer body incorporating such wiping devices 40, and the manufacturing costs of the wiping devices 40 can be reduced with a reduction in the number of components.
Furthermore, because the cam mechanism 50 has a plurality of, e.g., two, cam plates 51 having the guide holes 53, the configuration is simplified.
The embodiments have been described above. However, the present invention is not limited to the above-described embodiments, and it may be variously modified within the scope described in the claims. For example, as long as the cam mechanism can change the height of the wiper depending on the moving directions, i.e., the wiping direction or the retracting direction, a structure other than the above-described cam mechanism 50 may be used. Furthermore, the plate spring 80 functioning as the urging member may be made of another elastic member, or it does not necessarily have to be provided. In addition, although the cam plates 51 have the guide holes 54 fitted with the projections 63a of the plate-like member 63 in the above-described embodiments, the guide holes 54 and the projections 63a do not necessarily have to be provided. In such a case, it is possible that the belt 73 is configured to prevent the cam plates 51 from being shaken in the vertical direction.
The recording apparatus of the present invention may be applied to both line-type recording apparatuses and serial-type recording apparatuses. Furthermore, the recording apparatus of the present invention may be applied not only to printers, but also to facsimiles and copiers. In addition, the recording head of present invention may be used to eject droplets other than ink droplets.
Number | Date | Country | Kind |
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2010-036970 | Feb 2010 | JP | national |