JP2008068520A - Inkjet image recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To permit a cleaning unit to rotate and move to a cleaning position below a head unit without interfering with the head unit with the head unit positioned in the head cleaning position and make a surplus action of temporarily evacuating the head unit from the cleaning position unnecessary. <P>SOLUTION: The cleaning unit 34 having a cleaning performing surface 38 with the same curvature as the ink discharge surface 32 of the head unit 27 has a rotary shaft 37 set at the center of curvature of the cleaning performing surface 38 when staying in the cleaning position. When the head unit 27 rises to the cleaning position from an image recording position separated from the surface of a drum 21 by a platen gap H driven by a head unit movement mechanism and positioned by a head unit positioning unit 28, the cleaning unit 34 rotates to the cleaning position from the evacuation position driven by the cleaning unit movement mechanism. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink jet image recording apparatus that performs recording by ejecting ink to a recording medium conveyed by a drum by a plurality of recording heads arranged in a direction along the circumference of the drum.

  Conventionally, ink jet recording apparatuses have been widely used. Inkjet recording apparatuses include those equipped with serial type recording heads mainly used for personal use and those equipped with line type recording heads used for industrial use and capable of high-speed recording.

  The line-type recording head is a recording head having a length corresponding to the dimension in the width direction of a recording medium conveyed by one long head or a plurality of short heads. An ink jet recording apparatus provided with this line type recording head has attracted attention in recent years because it can produce a high-quality recorded matter with a very high processing capacity.

  In an ink jet recording apparatus including a line type recording head, for example, one effective means for transporting a recording medium such as cut paper or roll paper is a transporting means using a drum.

  By the way, the recording head in the inkjet image recording apparatus includes a large number of nozzles. Then, recording is performed by ejecting ink from these nozzles. For this reason, depending on the image data to be recorded, there may be nozzles that are not used for a certain period.

Therefore, in order to prevent nozzles with a long period of non-use from being clogged with ink, it is necessary to perform head cleaning by the maintenance unit every time a fixed period elapses.
In this head cleaning, suction cleaning that sucks ink whose viscosity has increased by staying in the vicinity of the nozzle opening, and wiping that wipes residual ink adhering to the ink discharge surface (also referred to as nozzle formation surface) There is cleaning.

A configuration for performing head cleaning in an ink jet image recording apparatus that transports a recording medium by a drum in this manner is disclosed in Patent Document 1.
In Patent Document 1, the print head unit (head unit) is automatically adjusted to three positions by a lifting means: a printing position (downward limit), a non-printing position (upward limit), and a cleaning position during head cleaning when not printing. Is done. The washing board (cleaning unit) is formed so that it can be rotated around the rotation center of the drum by the rotation positioning means and can be selectively interposed and retracted between the print head unit and the drum outer peripheral surface in a separated state. Has been. With such a configuration, when performing head cleaning, first, the print head unit is raised to the non-printing position in the direction away from the drum by the lifting means. Next, the washing board is rotated to the cleaning position facing the print head unit by the rotation positioning means. When the washing board faces the print head unit, the print head unit is lowered to the head cleaning position by the lifting means to perform head cleaning.
Japanese Patent Application Laid-Open No. 11-042790

  However, in the conventional inkjet image recording apparatus, as described above, in order to prevent mutual interference between the print head unit and the wash board at the cleaning position, the print head unit is moved from the print position to the cleaning position, and the cleaning position. When moving from the printing position to the printing position, the print head unit must be retracted to a non-printing position further above the cleaning position. That is, an extra operation for temporarily saving is required.

  In this case, each time the head cleaning is executed, the print head unit reciprocates twice between the cleaning position and the non-printing position, and the time of the two reciprocations prolongs the processing time of the head cleaning execution, and increases the processing efficiency of the head cleaning execution. It will be greatly reduced.

  Accordingly, an object of the present invention is to provide an inkjet image recording apparatus that can efficiently perform cleaning without causing an excessive operation of temporarily retracting the head unit with a simple cleaning unit in order to solve the above-described problems. And

  In order to solve the above-described problems, an inkjet image recording apparatus of the present invention includes a cylindrical drum that conveys a recording medium, and a plurality of recording heads arranged along the circumferential direction of the drum. A head unit configured so that a virtual curve connecting the ink discharge surfaces has a curvature that is separated from the drum surface by a platen gap with respect to the central axis of the drum, and an image recording position and ink for recording the head unit. A head unit moving mechanism for moving between a head cleaning position for cleaning the discharge nozzle, a head unit positioning unit for positioning the head unit at a head cleaning position for cleaning, and a cleaning unit for cleaning the head unit. The cleaning execution surface of the cleaning unit. A cleaning unit in which the curvature of the virtual curve is configured to be substantially the same as the curvature of the virtual curve connecting the ink ejection surfaces of the recording head, and the cleaning unit includes a retracted position for performing image recording and a cleaning position for performing cleaning. And a cleaning unit moving mechanism for rotating between the head unit, moving the head unit from the image recording position to the head cleaning position, and rotating the cleaning unit from the retracted position to the cleaning position to perform cleaning. In the inkjet image recording apparatus, the cleaning execution surface moves in a direction away from the drum surface when the cleaning unit is rotated from the retracted position to the cleaning position, and the cleaning unit is positioned at the cleaning position. When you head unit As imaginary curve the virtual curve and Cleaning execution plane coincides, characterized in that the center of rotation of the cleaning unit is set.

  According to the present invention, it is possible to provide an ink jet image recording apparatus capable of performing cleaning efficiently without performing an excessive operation of temporarily retracting the head unit with a simple cleaning unit.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIGS. 1A and 1B are diagrams schematically illustrating the operation of the recording head and the cleaning unit at the time of image recording and cleaning of the inkjet image recording apparatus according to the first embodiment, taking up only the configuration of the main part. is there.

  First, the configuration of the main part around the recording head shown in FIG. The inkjet image recording apparatus 20 includes a cylindrical drum 21 that extends in the depth direction of the drawing and rotates counterclockwise in the drawing.

  The drum 21 wraps the recording medium 23 fed through the feeding guide roller 22 on the circumferential surface so that the circumferential surface of the drum 21 is substantially circulated between the feeding guide roller 22 and the discharge guide roller 24. Carry it as if

A plurality (four in this example) of recording heads 25 are arranged radially with respect to the rotation center axis 26 of the drum 21 along the circumferential rotation direction of the drum 21.
Although the four recording heads 25 are not visible in the figure, nozzle rows are arranged on the lower ink ejection surfaces. Each of the four recording heads 25 ejects ink of four colors of black, cyan, magenta, and yellow on the surface of the recording medium 23 from the nozzle row on the ink ejection surface according to the image information.

  The four recording heads 25 are collectively held by the head unit 27. The head unit 27 is held by a head unit positioning unit 28 so as to be slidable up and down.

  The head unit 27 is driven by a head unit moving mechanism (not shown) in particular, and does not change the positional relationship of the four recording heads 25 along the direction of the diameter D of the drum 21 shown in the drawing. Move up and down.

  This movement is performed between an image recording position when performing image recording close to the surface of the drum 21 and a head cleaning position when cleaning the ink discharge nozzles separated from the surface of the drum 21.

FIG. 1A shows a set position at the time of image recording of the head unit 27 which is positioned by moving downward by the head unit moving mechanism at the time of image recording.
That is, the head unit 27 is positioned at a set position at the time of image recording with respect to the surface of the drum 21 by abutting the lower portion of the abutting portion 29 against the lower stopper 31 of the head unit positioning unit 28.

  In this state, in the head unit 27, the center of curvature (arc) of the imaginary curve 32 connecting the ink ejection surfaces of the four recording heads 25 is separated from the drum surface by the platen gap H with respect to the central axis 26 of the drum 21. It is comprised so that it may become a position.

  FIG. 1B shows a set position at the time of cleaning of the head unit 27 which is moved and positioned upward as indicated by an arrow c by the head unit moving mechanism at the time of cleaning.

  That is, the head unit 27 is positioned at the set position for cleaning by abutting the upper portion of the abutting portion 29 against the upper stopper 33 of the head unit positioning unit 28.

  On the other hand, a cleaning unit 34 for cleaning the ink discharge surface of the recording head 25 of the head unit 27 is disposed in the vicinity of the head unit 27. In this example, the cleaning unit 34 is disposed downstream of the head unit 27 in the transport direction, but may be disposed upstream of the head unit 27 in the transport direction.

  The cleaning unit 34 includes four cleaning units 35 that clean the respective ink ejection surfaces of the four recording heads 25, a cleaning holding unit 36 that holds these cleaning units 35, and a rotation that rotates the cleaning holding unit 36. And a moving shaft 37.

  The curvature of the imaginary curve 38 connecting the cleaning execution surfaces of the four cleaning units 35 is configured to be substantially the same as the curvature of the imaginary curve 32 connecting the ink ejection surfaces of the recording head 25 described above.

  The above-described cleaning unit 34 is driven by a cleaning unit moving mechanism (not shown) in particular, and is in a retracted position when performing image recording shown in FIG. 1 (a) and cleaning when performing cleaning shown in FIG. 1 (b). Rotate to and from the position.

  In this example, the whole is configured such that when the cleaning unit 34 is in the retracted position, the cleaning unit 35 is stationary at a position where it does not contact the surface of the drum 21.

  This ink jet image recording apparatus 20 includes four cleaning heads 35 that are used for four recording heads 25 when the head unit 27 shown in FIG. 1B is in the head cleaning position and the cleaning unit 34 is in the cleaning position. Perform cleaning to clean the ink ejection surface.

  In this configuration, when the cleaning unit 34 pivots from the retracted position shown in FIG. 1A to the cleaning position shown in FIG. The cleaning execution surface to be formed moves in a direction away from the surface of the drum 21.

  When the cleaning unit 34 is positioned at the cleaning position indicated by the solid line in FIG. 1B, the above-described virtual curve 32 of the head unit 27 and the above-described virtual curve 38 of the cleaning execution surface of the cleaning unit 35 coincide with each other. To do.

  In other words, the curvature of the imaginary curve 32 connecting the ink ejection surface of the head unit 27 at the cleaning position and the curvature of the imaginary curve 38 connecting the cleaning execution surface of the cleaning unit 35 of the cleaning unit 34 are formed in advance to coincide with each other. Yes.

  In this way, during the rotational movement during cleaning, the cleaning unit 34 moves its cleaning execution surface in a direction away from the surface of the drum 21, and when it is positioned at the cleaning position, the imaginary curve of the head unit 27. The position of the rotation shaft 37 of the cleaning unit 34 is set so that the imaginary curve 38 of the cleaning execution surface coincides with 32.

In other words, it can also be said that the rotation shaft 37 serving as the rotation center of the cleaning unit 34 of this example is provided at a position different from the rotation center shaft 26 of the drum 21.
In any case, in FIGS. 1A and 1B, the setting position of the rotation shaft 37 of the cleaning unit 34 is the curvature (arc) of the imaginary curve 32 connecting the ink ejection surfaces of the head unit 27 when in the cleaning position. ) And the center of curvature (arc) of a virtual curve 38 connecting the cleaning execution surface of the cleaning unit 34 are set to coincide with each other.

  Thus, when the cleaning execution surface rotates to the cleaning position, the rotation locus drawn by the cleaning execution surface moves along an arc of a virtual curve 32 connecting the ink ejection surfaces of the head unit 27 at the cleaning position. To do.

  Therefore, even if the cleaning unit 34 rotates and moves into the cleaning position while the head unit 27 remains set at the head cleaning position, the head unit 27 and the cleaning unit 34 collide and interfere with each other. There is nothing.

Of course, even when the cleaning unit 34 rotates from the cleaning position to the retracted position, the head unit 27 and the cleaning unit 34 do not collide with each other due to collision contact.
As described above, the head unit and the cleaning unit do not interfere when moving from the image recording state to the cleaning state and when moving from the cleaning state to the image recording state, so there is no need to temporarily retract the head unit as in the prior art. Therefore, the head unit can be efficiently cleaned with a simple structure.

  FIG. 2 is a diagram schematically illustrating the operation of the recording head and the cleaning unit at the time of cleaning of the inkjet image recording apparatus according to the second embodiment by taking up only the configuration of the main part.

  The configuration shown in the figure is the same as that of the first embodiment except that the holding unit of the cleaning unit and the position of its rotation center are different from those of the first embodiment. Therefore, only the components necessary for the explanation are given the same numbers as in the first embodiment, and the others are omitted.

  In the first embodiment, as shown in FIG. 1B, the rotation center (rotary shaft 37) of the cleaning unit 34 is the curvature of a virtual curve 38 that connects the cleaning execution surfaces when the cleaning unit 34 is at the cleaning position ( In this example, as shown in FIG. 2, the rotation center (rotation shaft 37 a) of the cleaning unit 34 is more than the position of the rotation shaft 37 of the first embodiment. It is set in the area 39 that becomes the side.

In other words, the rotation shaft 37 a serving as the rotation center of the cleaning unit 34 of this example is provided at a position different from the rotation center shaft 26 of the drum 21.
Thus, in this example, the rotation shaft 37a of the cleaning unit 34 is closer to the head unit 27 than the center of the curvature (arc) of the imaginary curve 38 connecting the cleaning execution surfaces when the cleaning unit 34 is at the cleaning position. Since it is set closer, the rotation trajectory drawn by the cleaning execution surface becomes a shape that is narrower than the curved surface of the virtual curve 38.

  Therefore, even if the cleaning unit 34 rotates and moves into the cleaning position while the head unit 27 remains set at the head cleaning position, the head unit 27 and the cleaning unit 34 collide and interfere with each other. There is nothing.

  Also in this case, the curvature of the imaginary curve 32 connecting the ink ejection surfaces of the head unit 27 and the curvature of the imaginary curve 38 connecting the cleaning execution surface of the cleaning unit 35 of the cleaning unit 34 are made to coincide with each other. When the ink enters the cleaning position and is positioned at the cleaning position, the ink ejection surface of the head unit 27 and the cleaning execution surface of the cleaning unit 34 are exactly aligned and face each other.

  In the setting of the position of the rotation shaft 37a serving as the rotation center of the cleaning unit 34, the position of the rotation shaft 37a is set when the cleaning unit 34 is in the retracted position, that is, the retracted position is downstream of the head unit in the transport direction. 2 (the position of the chain double-dashed line shown in FIG. 2), or although not shown, the area is on condition that the cleaning unit 35 does not contact the surface of the drum 21 when the retracted position is upstream of the head unit in the transport direction. 39 can be set to an appropriate point.

As described above, in the configuration of this example, the distance between the virtual curve 38 of the cleaning unit 34 and the rotation shaft 37a is shorter than that in the case of the first embodiment.
Therefore, the head cleaning position of the head unit 27 corresponding to the cleaning position of the cleaning unit 34 can be set to a lower position than in the case of FIG. Thereby, it can contribute to size reduction of the whole apparatus.

  FIGS. 3A and 3B are diagrams schematically illustrating operations of the recording head and the cleaning unit at the time of image recording and cleaning of the inkjet image recording apparatus according to the third embodiment by taking up only the configuration of the main part. is there.

  The configurations shown in FIGS. 4A and 4B are different from the first embodiment only in the positions of the holding unit of the cleaning unit and the rotation shaft serving as the rotation center thereof. There is no big difference from the case of Example 1. Therefore, only the components necessary for the explanation are given the same numbers as in the first embodiment, and the others are omitted.

  Also in this example, the curvature of the imaginary curve 32 connecting the ink ejection surfaces of the head unit 27 and the curvature of the imaginary curve 38 connecting the cleaning execution surfaces of the cleaning unit 35 of the cleaning unit 34 are formed to coincide with each other. Yes.

  As shown in FIGS. 3A and 3B, the rotation shaft 37 b serving as the rotation center of the cleaning unit 34 of this example is an imaginary line connecting the center of the head unit 27 and the rotation center axis 26 of the drum 21. 42 is set as a region 43 (see FIG. 3B) opposite to the region in the direction in which the cleaning unit 34 retracts from the head unit 37 (the state in FIG. 3A).

  In other words, in this example as well, it can be said that the rotation shaft 37 b serving as the rotation center of the cleaning unit 34 is provided at a position different from the rotation center shaft 26 of the drum 21.

  In the example shown in FIGS. 3 (a) and 3 (b), the arrangement position of the rotation shaft 37 b of the cleaning unit 34 is more specifically rotated with respect to an imaginary line 42 passing through the rotation center axis 26 of the drum 21. It is set at an appropriate position of a line 44 orthogonal to the central axis 26.

  Unlike the first embodiment, the rotating shaft 37b performs the cleaning of the cleaning unit 34 at the center of the curvature (arc) of the virtual curve 32 connecting the ink ejection surfaces of the head unit 27 at the head cleaning position and the cleaning position. The centers of curvatures (arcs) of the virtual curve 38 connecting the surfaces do not coincide.

For this reason, when the cleaning unit 34 rotates, the virtual curve 38 of the cleaning unit 34 does not move along the virtual line 32 of the head unit 27.
That is, in this configuration, when the cleaning unit 34 rotates and enters the cleaning position while the head unit 27 remains set at the head cleaning position, the rotation shaft 37b of the cleaning unit 34 is positioned as described above. Thus, the cleaning execution surface approaches the ink ejection surface of the head unit 27 while the cleaning unit 35 is lifted from below.

  Therefore, the head unit 27 and the cleaning unit 34 do not collide and interfere with each other until the cleaning unit 34 is positioned at the cleaning position.

  Also in this case, the curvature of the imaginary curve 32 connecting the ink ejection surfaces of the head unit 27 and the curvature of the imaginary curve 38 connecting the cleaning execution surface of the cleaning unit 35 of the cleaning unit 34 are made to coincide with each other. When positioned at the cleaning position, the ink ejection surface of the head unit 27 and the cleaning execution surface of the cleaning unit 34 exactly coincide and face each other.

  Also in this example, when the position of the rotation shaft 37b of the cleaning unit 34 is set, the position of the rotation shaft 37b is when the cleaning unit 34 is at the retracted position indicated by the two-dot chain line in FIG. An appropriate point in the region 43 can be set on condition that the cleaning unit 35 does not contact the surface of the drum 21.

  Further, when the cleaning unit 34 is retracted from the head unit 37 in the direction opposite to the drawing, that is, upstream of the head unit 37 in the transport direction, the position of the rotation shaft 37b is the virtual line 42. Can be set as appropriate in the region opposite to the region 43.

  FIG. 4 is a diagram schematically illustrating the operation of the recording head and the cleaning unit during the cleaning of the inkjet image recording apparatus according to the fourth embodiment by taking up only the configuration of the main part.

  The configuration shown in the figure is the same as that in FIG. 1 except for the mounting position of the rotation shaft of the cleaning unit, which is different from that in the first embodiment. Therefore, only the components necessary for the explanation are given the same numbers as in the first embodiment, and the others are omitted.

  As shown in FIG. 4, the rotation shaft 37 c serving as the rotation center of the cleaning unit 34 of the present example is a lower support formed continuously from the head unit positioning unit 28 that supports and positions the head unit 27. It is provided in the portion 28d.

According to this configuration, the same effects as those of the first embodiment shown in FIG. 1 can be obtained, and the number of members interposed between the head unit 27 and the cleaning unit 34 can be reduced.
Further, since the head unit 27 and the cleaning unit 34 are attached to the same support member that also serves as a positioning member, the relative positions of the head unit 27 and the cleaning unit 34 during cleaning can be accurately positioned.

  As described above, according to the present invention, the rotational movement center of the cleaning unit for cleaning the recording head of the head unit is provided at a position different from the rotational center of the drum that conveys the recording medium. Even if the cleaning unit is rotated to the cleaning position in the state where it is moved to the position, the cleaning unit has the surface shape of the cleaning portion having the same curvature as the arcuate surface on which the ink discharge surface of the recording head is continuously provided. There is no interference.

(a), (b) is a figure which illustrates typically operation | movement of the recording head and the cleaning unit at the time of the image recording of the inkjet image recording apparatus in Example 1 and a cleaning taking up only the structure of the principal part. FIG. 10 is a diagram schematically illustrating the operation of the recording head and the cleaning unit during cleaning of the inkjet image recording apparatus according to the second embodiment by taking up only the configuration of main parts. (a), (b) is a figure which illustrates typically operation | movement of the recording head and the cleaning unit at the time of the image recording of the inkjet image recording device in Example 3 and a cleaning taking up only the structure of the principal part. FIG. 10 is a diagram schematically illustrating the operation of a recording head and a cleaning unit at the time of cleaning of an inkjet image recording apparatus according to Example 4 by taking up only the configuration of main parts.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 Inkjet image recording apparatus 21 Drum 22 Feed guide roller 23 Recording medium 24 Discharge guide roller 25 Recording head 26 Drum rotation center axis 27 Head unit 28 Head unit positioning unit 28d Lower support part 29 Butting part 31 Lower stopper 32 Ink discharge surface D Drum diameter H Platen gap 33 Upper stopper 34 Cleaning unit 35 Cleaning unit 36, 36a, 36b, 36c Cleaning holding unit 37, 37a, 37b, 37c Rotating shaft 38 Virtual curve 39 connecting cleaning execution surface 39 Rotating Axis setting area 42 Drum center virtual line 43 Rotating axis setting area 44 Orthogonal line

Claims (5)

A cylindrical drum for conveying a recording medium;
A plurality of recording heads are arranged in a direction along the circumference of the drum, and an imaginary curve connecting the ink ejection surfaces of the plurality of recording heads is separated from the drum surface by a platen gap with respect to the central axis of the drum. A head unit configured to have a large curvature,
A head unit moving mechanism for moving the head unit between an image recording position for image recording and a head cleaning position for cleaning the ink discharge nozzles;
A head unit positioning unit for positioning the head unit at the head cleaning position for performing the cleaning;
A cleaning unit that performs cleaning on the head unit, and a curvature of a virtual curve that connects a cleaning execution surface of the cleaning unit is substantially the same as a curvature of the virtual curve that connects the ink ejection surface of the recording head Cleaning unit,
A cleaning unit moving mechanism for rotating the cleaning unit between a retracted position for image recording and a cleaning position for cleaning;
Have
In an inkjet image recording apparatus that performs cleaning by moving the head unit from the image recording position to the head cleaning position and rotating the cleaning unit from the retracted position to the cleaning position.
When the rotational movement of the cleaning unit from the retracted position to the cleaning position, the cleaning execution surface moves in a direction away from the surface of the drum, and the cleaning unit is moved to the cleaning position. An inkjet image recording apparatus, wherein the center of rotation of the cleaning unit is set so that the virtual curve of the head unit coincides with the virtual curve of the cleaning execution surface when positioned.   The rotation center of the cleaning unit is set to coincide with the center of curvature of the virtual curve of the cleaning execution surface when the cleaning unit is at the cleaning position. The inkjet image recording apparatus according to 1.   The rotation center of the cleaning unit is set on the head unit side with respect to the center of curvature of the virtual curve of the cleaning execution surface when the cleaning unit is at the cleaning position. Item 2. An inkjet image recording apparatus according to Item 1.   The rotation center of the cleaning unit is set to an area opposite to an area in a direction in which the cleaning unit retracts from the head unit, with a virtual line connecting the center of the head unit and the center of the drum as a boundary. The inkjet image recording apparatus according to claim 1, wherein:   The inkjet image recording apparatus according to claim 1, wherein a rotation center axis of the cleaning unit is provided in the head unit positioning unit.