Inkjet recording apparatus

An inkjet recording apparatus that enables a cap and a recording head stuck together to be easily separated is provided. The inkjet recording apparatus has a rotatably supported cap holder retaining a cap for covering ejection orifices in a recording head, and an actuator that moves the cap holder to bring the cap into contact with and away from the recording head. A first contact portion configured to seal an ejection orifice row and a second contact portion connected to the outer surface of the first contact portion and configured to be pressed against the ejection orifice surface are provided on a surface of the cap to be brought into contact with the ejection orifice surface. The actuator acts on the cap holder at a position to the second contact portion side of the rotational axis of the cap holder.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an inkjet recording apparatus that performs recording by ejecting ink from a recording head onto a recording medium. More specifically, the present invention relates to an inkjet recording apparatus that has a cap for covering ejection orifices in a recording head.

2. Description of the Related Art

An inkjet recording apparatus performs recording by selectively ejecting ink from a plurality of ejection orifices in accordance with image information. Such an inkjet recording apparatus uses a cap for covering ejection orifices to protect the recording head and to prevent ink from drying. A typical cap is made of an elastomer, such as rubber, to ensure sealing performance.

If a cap is kept in contact with an ejection orifice surface of a recording head for a certain period of time, the cap may stick to the recording head depending on the materials of the cap and the ejection orifice surface or storage condition after shipment. When the recording apparatus is turned on when the cap and the recording head stick together, they may not be easily separated, which may cause malfunction.

Japanese Patent Laid-Open Nos. 7-276658 and 2005-169713 each disclose an inkjet recording apparatus that enables a cap to be easily removed from an ejection orifice surface of a recording head, by separating the contact surfaces of the cap and the ejection orifice surface from one end, and subsequently separating the remaining portion of the contact surfaces. Japanese Patent Laid-Open No. 10-128987 discloses an inkjet recording apparatus in which an anti-stick liquid is applied to one of the contact surfaces of the recording head and the cap.

As the quality of images produced by inkjet recording apparatuses these days improves, the size of ejection orifices in recording heads further decreases and the density of the ejection orifices becomes higher. This requires improvement in sealing performance of caps for covering ejection orifice surfaces of recording heads. To improve sealing performance of caps, unnecessary deformation of the caps in a capped state needs to be eliminated. However, if caps are more tightly brought into contact with ejection orifice surfaces of recording heads, the caps more strongly stick thereto. This results in a problem in that a large force is required to remove the caps from the ejection orifice surfaces of the recording heads.

SUMMARY OF THE INVENTION

The present invention provides an inkjet recording apparatus that enables a cap and a recording head stuck together to be easily separated with a small force.

According to an aspect of the present invention, an inkjet recording apparatus that performs recording by ejecting ink from a recording head onto a recording medium includes a cap having a first contact portion configured to seal ejection orifices by being pressed against an ejection orifice surface of the recording head; a second contact portion connected to an outer surface of the first contact portion, the second contact portion being configured to be pressed against the ejection orifice surface; a cap holder retaining the cap, the cap holder being rotatably supported by a base; and a moving mechanism configured to move the cap holder to bring the first contact portion into contact with and away from the ejection orifice surface. The moving mechanism acts on the cap holder at a position to the second contact portion side of a rotational axis of the cap holder.

DESCRIPTION OF THE EMBODIMENTS

First Exemplary Embodiment

Embodiments of the present invention will now be described with reference to the accompanying drawings. Like reference numerals refer to like parts or corresponding parts throughout the various views.FIG. 1is a perspective view of an inkjet recording apparatus suitable for embodying the present invention. InFIG. 1, a carriage101carries a recording head107and is supported in a manner capable of reciprocating along a guide shaft102and a guide rail104. The carriage101is driven by a driving force from a carriage motor108transmitted through a belt109. A recording medium110is conveyed through the nip of a conveying roller105and a pinch roller (not shown) to a platen106, where the recording medium110faces the recording head107. The guide shaft102and the conveying roller105are supported by a chassis103. An eject roller113is provided downstream of the platen106with respect to the conveying direction of the recording medium110. An auxiliary roller112is pressed against the eject roller113. The recording head107performs recording onto the recording medium110being conveyed on the platen106by the conveying roller105and the eject roller113.

During recording, the carriage101moves at a constant speed after it begins to move and accelerate. At this time, the recording head107ejects ink from the ejection orifices onto the recording medium110facing the recording head107to form an image. When recording of one line is completed, the carriage101decelerates to stop. When the carriage101begins to decelerate, the conveying roller105and the eject roller113rotate to convey the recording medium110by a predetermined amount for recording of the next line. The carriage101then starts to move in the reverse direction. While the carriage101moves at a constant speed after acceleration, the recording medium110is not conveyed. The recording of the next line is performed by driving the recording head107while the carriage101is moving. Recording on the entire recording medium110is performed by alternately performing driving of the recording head107during movement of the carriage101and conveyance of the recording medium110at a predetermined pitch. The recording medium110after going through recording is ejected from the main body of the apparatus by the eject roller113.

FIG. 2shows an arrangement of ejection orifices in an ejection orifice surface of a recording head. An ejection orifice surface151of the recording head107has a plurality of ejection orifices provided in a predetermined arrangement. The ejection orifice surface151according to the present embodiment has a black-ink ejection orifice row153athrough which black ink is ejected and color-ink ejection orifice rows153bthrough which color ink is ejected. The color-ink ejection orifice rows153binclude, for example, cyan-ink, magenta-ink, and yellow-ink ejection orifice rows.

Referring back toFIG. 1, a recovery unit115for preventing the recording head107from being clogged and for maintaining and restoring ink ejecting performance is provided at a predetermined position where recording is not performed. The recovery unit115has a cap for covering the ejection orifices in the recording head107, a wiper for cleaning the ejection orifice surface, and a pump connected to the cap for vacuuming ink. The cap protects the ejection orifice surface and prevents ink from drying. The wiper wipes ink and dust deposited around the ejection orifices. The pump, usually a tube pump that creates negative pressure by pressing a tube, vacuums unwanted ink in the ejection orifices and the cap.

FIG. 3is a perspective view of a cap unit120of the inkjet recording apparatus according to the first embodiment.FIG. 4is a plan view of the cap unit120.FIG. 5is a side view of the cap unit120. The recovery unit115has the cap unit120for covering the ejection orifices by bringing a cap121into contact with the ejection orifice surface151. The cap121has a black contact portion160configured to seal the black-ink ejection orifice row153aby being pressed against the ejection orifice surface151of the recording head107, a first contact portion161configured to seal the color-ink ejection orifice rows153b, and a second contact portion162connected to the outer surface of the first contact portion161, configured to be pressed against the ejection orifice surface151. The second contact portion extends perpendicular to the rotational axis of a cap holder122.

The second contact portion162connects to the outer surface of the first contact portion161at one end, which is denoted by a connecting portion164, and ends at the other end, which is denoted by an end portion163. The first contact portion161and the second contact portion162form obtuse angles α and β on the other side of the area sealing the color-ink ejection orifice rows153b.

The cap121has a plurality of engaging portions124that project from the side surfaces thereof. The cap holder122has cap retainer portions125at positions corresponding to the engaging portions124. By engaging the engaging portions124of the cap121with the cap retainer portions125of the cap holder, the cap121is positioned on and fitted to the cap holder122. The second contact portion162is provided in the vicinity of one of the cap retainer portions125of the cap holder122, i.e., in the vicinity of one of the engaging portions124of the cap121. The cap holder122has a shaft123that is rotatably supported by a base116of the recovery unit115. A spring117urges the cap holder122to bring the cap121into contact with the ejection orifice surface151. The cap121contains an ink absorber131facing the black-ink ejection orifice row153aand an ink absorber132facing the color-ink ejection orifice rows153b. A black-ink tube133for vacuuming black ink and a color-ink tube134for vacuuming color ink are each connected to the cap holder122at one end and to a tube pump at the other end.

An actuator180(shown inFIG. 5) moves the cap holder122to bring the cap121into contact with and away from the ejection orifice surface151of the recording head107. A point of application126is located between the shaft123, which serves as the rotational axis of the cap holder122, and the end portion163of the second contact portion162. An end of a lever181of the actuator180is in contact with the point of application126. When an actuating shaft182of the actuator180is driven to rotate the lever181counterclockwise inFIG. 5, the cap holder122is brought away from the ejection orifice surface151(downward inFIG. 5), through the point of application126. At this time, a clockwise moment about the shaft123, i.e., a moment that brings the second contact portion162away from the ejection orifice surface151from the end portion163, acts on the cap holder122. Thus, the actuator180applies a force to the portion between the shaft123of the cap holder122and the end portion163of the second contact portion162to bring the cap121away from the ejection orifice surface151, overcoming the resistance of the spring117. The point of application126may be provided at a position relatively close to the shaft123as shown inFIG. 5, so that a force of the actuator180acts on a position close to the shaft123.

FIGS. 6A to 6Care side views of the second contact portion162in contact with the ejection orifice surface151. It is desirable that the second contact portion162have a shape that enables the cap121and the ejection orifice surface151to be easily separated. As shown inFIG. 6A, the second contact portion162may be rounded at the end portion163. Alternatively, as shown inFIG. 6B, the second contact portion162may decline from the connecting portion164toward the end portion163. Further alternatively, as shown inFIG. 6C, the second contact portion162may have a larger surface roughness than the first contact portion161to reduce the area in contact with the ejection orifice surface151.

FIGS. 7A to 7Dare plan views of the first contact portion161and the second contact portion(s)162. As shown inFIG. 7A, a plurality of the second contact portions162that extend perpendicular to the rotational axis of the cap holder122may be provided on the outer surface of the first contact portion161. As shown inFIG. 7B, the second contact portions162may have different lengths. Alternatively, as shown inFIG. 7C, the first contact portion161may have a plurality of chevron-shaped portions. Alternatively, as shown inFIG. 7D, the first contact portion161may have an arch-shaped portion.

Second Exemplary Embodiment

FIGS. 8A to 8Care side views of a cap unit according to a second embodiment, whereinFIG. 8Ashows a state in which a cap221is in contact with the ejection orifice surface151,FIG. 8Bshows a state in which the cap221begins to be separated from the ejection orifice surface151, andFIG. 8Cshows a state in which the cap221has been removed from the ejection orifice surface151. As shown inFIGS. 8A to 8C, the cap221has a first engaging portion224aand a second engaging portion224bthat project from the side surfaces thereof. The first engaging portion224ais provided at a position corresponding to the second contact portion160. In the capped state, the top surface of the first engaging portion224ais closer to the ejection orifice surface151than the top surface of the second engaging portion224b. A cap holder222has a first retainer portion225aand a second retainer portion225bengageable with the engaging portions224aand224b, respectively. When the above-described actuator moves the cap holder222away from the ejection orifice surface151, the first retainer portion225acomes into contact with the first engaging portion224abefore the second retainer portion225bcomes into contact with the second engaging portion224b. This structure allows the cap221to be removed from the ejection orifice surface151from the second contact portion162side.

Third Exemplary Embodiment

FIG. 9is a plan view of a cap unit according to a third embodiment. The present embodiment is characterized by a second contact portion arranged parallel to the moving direction of the carriage. InFIG. 9, a cap321is provided to cover the ejection orifices by being brought into contact with the ejection orifice surface151of the recording head107. A cap holder322retains the cap321. The cap321has a black contact portion360configured to seal the black-ink ejection orifice row153aby being pressed against an ejection orifice surface151, a first contact portion361configured to seal the color-ink ejection orifice rows153b, and a second contact portion362connected to the outer surface of the first contact portion361, configured to be pressed against the ejection orifice surface151. The second contact portion362is arranged parallel to the moving direction of the carriage101that reciprocates while carrying the recording head107, as described above.

The second contact portion362connects to the outer surface of the first contact portion361at one end, and ends at the other end. The first contact portion361and the second contact portion362form obtuse angles α and β on the other side of the area sealing the color-ink ejection orifice rows153b. It is desirable that the second contact portion362have a shape that allows the cap121to be easily removed from the ejection orifice surface151. As shown inFIG. 6A, the second contact portion362may be rounded at the end portion363. Alternatively, as shown inFIG. 6B, the second contact portion362may decline from the connecting portion toward the end portion. Further alternatively, as shown inFIG. 6C, the second contact portion362may have a larger surface roughness than the first contact portion361to reduce the area in contact with the ejection orifice surface151.

FIGS. 10A to 10Dare plan views of the first contact portion and the second contact portion(s). As shown inFIG. 10A, a plurality of second contact portion362that extend parallel to the moving direction of the carriage101may be provided on the outer surface of the first contact portion361. As shown inFIG. 10B, the second contact portions362may have different lengths. Alternatively, as shown inFIG. 10C, the first contact portion361may have a plurality of chevron-shaped portions. Alternatively, as shown inFIG. 10D, the first contact portion361may have an arch-shaped portion.

FIGS. 11A and 11Bare front views showing removal of a cap with movement of a carriage, according to the third embodiment, whereinFIG. 11Ashows a capped state in which the cap321is in contact with the ejection orifice surface151of the recording head107, andFIG. 11Bshows a state in which the cap321has been removed from the ejection orifice surface151with movement of the carriage101. A cap removing lever370is connected to a cap holder322. When the carriage101carrying the recording head107is moved leftward from the position shown inFIG. 11A, the carriage101comes into contact with the cap removing lever370and pushes it downward. This moves the cap holder322downward, whereby the cap321begins to be separated from the ejection orifice surface151from the second contact portion362side.

According to the third embodiment, movement of the carriage101carrying the recording head107from the capped position causes the cap321to be removed from the ejection orifice surface151. Accordingly, the cap321and the ejection orifice surface151stuck together can be separated with a small force. The disadvantages associated with sticking between the recording head107and the cap321can thus be overcome at a low cost and with a small space, providing a reliable inkjet recording apparatus.

The present invention is applicable not only to single-function recording apparatuses such as printers, facsimile machines, and copying machines, but also to recording apparatuses used in multifunction recording apparatuses and systems.

According to the embodiments of the present invention, an inkjet recording apparatus that enables a cap and a recording head stuck together to be easily separated with a small force is provided.

This application claims the benefit of Japanese Application No. 2007-181724 filed Jul. 11, 2007, which is hereby incorporated by reference herein in its entirety.