JP2009012909A - Image recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet type line-head image recording device capable of always recording images of high quality without causing unevenness in conveyance accuracy before and after the maintenance operation. <P>SOLUTION: This image recording device 1 comprises a paper feeding section 20, a conveying section 30, an image recording section 40 and a delivery section 50. Belt rollers 32a and 32b for driving a conveying belt 31 of the conveying section 30 and the image recording section 40 are held by a main body device frame 11 and fixed relative to each other. The conveying section 30 comprises a platen unit 60 inside of the conveying belt 31. This platen unit 60 has platen rollers 64a and 64b abutting on the conveying belt 31 on sides closer to the image recording section in comparison with the belt rollers 32a and 32b, a tension roller 65 abutting on the conveying belt 31 on the opposite side to the platen rollers 64a and 64b through the belt rollers 32a and 32b, and a tension adjusting mechanism 37 for adjusting tension of the conveying belt 31, and moves inside of the conveying belt 31. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink jet line head type image recording apparatus capable of always recording a high-quality image without causing variations in conveyance accuracy before and after a maintenance operation.

  Conventionally, as an image recording apparatus, for example, an inkjet printer performs image recording by ejecting ink droplets from a plurality of nozzles of a recording head onto a recording medium held and conveyed by a conveying unit.

This ink jet printer is widely used as an office application for recording an image on, for example, a cut sheet-like recording medium (paper).
In recent years, there is also a line head type ink jet printer capable of recording images at high speed by configuring a so-called line head in which a large number of recording heads are fixedly arranged in a direction perpendicular to the recording medium conveyance direction.

  In such a line head type ink jet printer, for example, a conveyance belt is used to convey a recording medium. When the recording medium reaches just below the line head by the conveyance belt, ink is ejected from the line head, and one pass (recording) is performed. A predetermined image is recorded when the medium passes through the line head only once).

  Here, in general, in an inkjet printer, in order to obtain a good image, it is necessary to maintain a good discharge state of ink discharged from fine nozzles provided in the recording head.

For this purpose, it is necessary to perform a purge operation for discharging ink from the nozzles in order to discharge foreign matters or bubbles present in the ink flow path inside the recording head.
Furthermore, an ejection surface wiping operation for wiping the ink ejection surface is also required in order to remove excess ink droplets and foreign matters adhering to the ink ejection surface where the ink ejection port of the nozzle is provided.

  Performing these purge operations and discharge surface wiping operations is generally called a maintenance operation, and an inkjet printer is provided with a maintenance mechanism for performing such a maintenance operation.

  In order for the maintenance mechanism to perform a maintenance operation, it is necessary to form a space where the maintenance mechanism is disposed below the line head. Usually, in a line head type printer, the conveyance belt that conveys the recording medium is directly below the line head. Is provided. For this reason, at the time of maintenance operation, the conveyance belt is retracted from directly below the line head, and a space in which the maintenance mechanism can be arranged is formed below the line head.

Patent Document 1 discloses an ink jet printer that performs such a line head maintenance operation.
In the ink jet printer disclosed in Patent Document 1, the conveyor belt is stretched over a tension between the first roller and the second roller, and the conveyor belt is disposed at a position facing the line head during image recording. Has been.

When performing the maintenance operation, the first belt moves from the operating position to the retracted position, whereby the transport belt is bent and retracted from below the line head. As a result, a space is formed below the line head, and the maintenance mechanism moves into this space to perform a maintenance operation.
JP 2006-321239 A

By the way, in order to obtain a high-quality image with an ink jet printer, the conveyance accuracy of the conveyance belt must always be kept the same.
However, in the inkjet printer described in Patent Document 1, the maintenance operation is performed by moving the first roller to the retracted position and bending the transport belt. When the maintenance operation is completed, the first roller is moved to the recording operation position, and the conveying belt is returned to the original tension state.

  As described above, since the position of the first roller is different before and after the maintenance operation, not only the position of the first roller is varied due to the restoration to the recording operation position, but also the conveyance is performed between the recording operation position and the retreat position during the maintenance operation. Since the tension applied to the belt changes, the tension applied to the conveyor belt also varies.

  That is, when the tension applied to the transport belt varies as described above, the transport accuracy varies every time the maintenance operation is performed, which causes a problem that high quality image quality cannot be obtained.

  In order to solve the above-described problems, the present invention provides an ink jet line head type image recording apparatus capable of always recording a high-quality image without causing variations in conveyance accuracy before and after a maintenance operation. For the purpose.

  In order to solve the above-described problems, the present invention provides an image recording apparatus in which a belt roller rotatably supported on the apparatus main body frame, a conveyor belt stretched over the belt roller, and an inner side of the conveyor belt. A platen unit that is movably disposed, a conveyance unit that conveys the recording medium downstream, and a width equal to or greater than the width of the recording medium in a direction perpendicular to the conveyance direction of the recording medium conveyed by the conveyance unit An image recording unit for recording an image by ejecting ink from a recording head unit disposed over the head, a maintenance mechanism for performing maintenance of the recording head unit, and an image recording position for recording an image on the recording medium using the platen unit A platen unit moving mechanism for moving the recording head unit to a maintenance position where maintenance of the recording head unit is performed. A tension roller and a tension adjusting mechanism for adjusting the tension of the conveyor belt, and when the platen unit is positioned at the image recording position, the platen roller contacts the conveyor belt on the image recording unit side with respect to the belt roller, The tension roller is in contact with the conveying belt on the side opposite to the platen roller via the belt roller.

  According to the present invention, it is possible to provide an ink-jet line head type image recording apparatus capable of always recording a high-quality image without causing variations in the conveyance accuracy before and after the maintenance operation.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a schematic side view showing an image recording apparatus according to the first embodiment of the present invention. As shown in FIG. 1, the image recording apparatus 1 includes a paper feed unit 20, a transport unit 30, an image recording unit 40, and a discharge unit 50.

  FIG. 2 is a schematic top view showing the transport unit 30. In the drawings of the following description, the axis center along the conveyance direction of the recording medium is defined as the Y axis, and the axis perpendicular to the Y axis is defined as X on the surface on which the image of the recording medium 21a is formed during image recording. An axis that is orthogonal to the X-axis and the Y-axis is the Z-axis.

First, the paper feed unit 20 in FIG. 1 will be described.
The paper feed unit 20 includes a paper feed tray 21, a pickup roller 22, and a registration roller pair 23.

  The paper feed tray 21 is a medium storage unit that stores at least one recording medium 21a. In the present embodiment, the medium accommodating portion accommodates a plurality of sheets of cut sheet as the recording medium 21a.

  The pickup roller 22 is a recording medium take-out mechanism that takes out the recording medium 21 a in the paper feed tray 21 one by one. The pickup roller 22 is rotatably supported by the apparatus frame 11 shown in FIG.

The registration roller pair 23 is a conveyance direction adjusting unit that aligns the recording medium 21a taken out by the pickup roller 22 with respect to the conveyance direction during image recording.
The registration roller pair 23 is rotatably supported by the apparatus frame 11. Further, the registration roller pair 23 plays a role of feeding the recording medium 21 a after alignment to the transport unit 30.

Next, the transport unit 30 will be described.
The transport unit 30 is a transport device that transports the recording medium 21a sent from the paper feed unit 20 during image recording.

As shown in FIG. 1, the transport unit 30 includes a transport belt 31, belt rollers 32 a and 32 b, and a platen unit 60.
The conveyor belt 31 is formed in a belt-like and endless ring shape. As shown in FIG. 2, the conveying belt 31 is provided with a plurality of air suction holes 31a at predetermined intervals in the vertical and horizontal directions, for example.

  The conveyor belt 31 is stretched between belt rollers 32 a and 32 b and a platen unit 60, and is tensioned by a tension roller 65 of the platen unit 60.

  The belt rollers 32a and 32b are rotatably supported by the apparatus frame 11 as shown in FIG. As a result, the belt rollers 32a and 32b do not move during printing or maintenance, and always maintain the same positional relationship with respect to the image recording unit 40 shown in FIG.

  The belt roller 32b is connected to a belt roller drive motor 12 that is a drive source for rotating the belt 31. The belt roller drive motor 12 is also fixed to the apparatus frame 11.

  As described above, the conveyance belt 31 is rotationally driven by the belt roller drive motor 12 to constitute a belt conveyor for carrying the recording medium 21a along the Y axis. Thereby, the conveyance direction of the recording medium 21a at the time of image recording is set.

Next, details of the platen unit 60 will be described.
FIG. 3 is a perspective view showing the platen unit 60 in detail. Hereinafter, the platen unit 60 will be described with reference to FIG. 3 and FIGS. 1 and 2.

  The platen unit 60 includes a platen 61, a suction unit 63 provided below the platen 61, a platen frame 62 holding the platen 61 and the suction unit 63, a platen roller 64a rotatably supported by the platen frame 62, 64b and the tension roller 65, and a tension adjusting mechanism 37 for keeping the tension of the conveyor belt 31 always constant.

  The platen 61 is formed with a plurality of grooves 61 a extending in the Y direction over the entire region facing the conveyor belt 31. A suction hole 61b is provided in a substantially central portion of each groove 61a. The suction hole 61 b communicates with the suction unit 63.

  The suction unit 63 is a negative pressure generator that generates a negative pressure for attracting the recording medium 21 a to the conveyance surface of the conveyance belt 31. The suction unit 63 is fixed to the platen frame 62.

  Although not specifically shown, the suction unit 63 is provided with a platen chamber, and the platen chamber has a negative pressure generating source for making the inside of the chamber have a negative pressure. The negative pressure generating source is a known negative pressure generating device such as a fan.

  The platen chamber sucks air from the suction hole 61b by the negative pressure of the negative pressure generation source. With this suction force, the recording medium 21a being transported is sucked to the surface of the transport belt through the suction holes 31a of the transport belt 31.

Thereby, the recording medium 21a is prevented from being lifted from the conveyance belt 31, and the recording medium 21a is reliably adsorbed to the conveyance belt 31.
In addition, positioning holes 62 c are provided at the four corners of the platen 61 for positioning the transport unit 30 and the image recording unit 40 by fitting with positioning pins 43 of the image recording unit 40 described later.

  As shown in FIG. 1, the platen rollers 64a and 64b are rotatably held by the platen frame 62 above the belt rollers 32a and 32b. Above the platen roller 64a provided on the upstream side in the conveyance direction, a driven roller 33 that is driven and rotated via the conveyance belt 31 is provided. The driven roller 33 is provided to securely bring the recording medium 21a into close contact with the transport belt 31.

  Further, the platen rollers 64a and 64b and the platen 61 form a recording medium conveyance area 67 shown in FIG. 1 at least in an area facing the image recording unit 40. The recording medium conveyance area 67 has a flatness such that the image recording unit 40 and the conveyance belt 31 are parallel to the X axis and the Y axis. The recording medium 21 a is conveyed on the recording medium conveyance area 67 by the conveyance belt 21. As described above, the recording medium 21 a is transported by the transport belt 31.

  As shown in FIG. 1, the tension roller 65 is rotatably held by the platen frame 62 below the belt rollers 32a and 32b. Thus, by providing the platen rollers 64a and 64b and the tension roller 65 so as to sandwich the belt rollers 32a and 32b from above and below, the transport belt 31 can be always stretched by the platen unit 60.

  The tension adjusting mechanism 37 adjusts the tension applied to the transport belt 31 via the tension roller 65 so that the transport belt 31 always maintains a constant tension within a range in which the platen unit 60 moves.

  As shown in FIG. 1, for example, the tension roller sliding long hole 68 is first formed in the tension roller support portion of the platen frame 62 so that both ends of the rotating shaft of the tension roller 65 can slide up and down as shown in FIG. It is comprised so that it may be supported by.

  Next, a shaft 69 that fixedly supports both ends of the rotation shaft of the tension roller 65 at the lower end is provided. Then, a pressing and urging member 66 such as a spring mechanism or an air suspension is provided at an intermediate portion where the shaft 69 is divided into upper and lower parts.

Then, the upper end portion of the shaft 69 is fixed to a shaft holding portion 62 d fixed to the platen frame 62.
The tension roller 65 slides through the tension roller sliding long hole 68 by the tension adjusting mechanism 37 including the tension roller sliding long hole 68, the shaft 69, the pressing and urging member 66, and the shaft holding portion 62d. By moving in the Z-axis direction, a constant tension can always be applied to the conveyor belt 31.

  Further, for example, even when a change occurs such that the ambient temperature becomes high or the circumference of the conveyor belt 31 becomes longer due to wear of the conveyor belt 31 or the like, the tension adjusting mechanism 37 is connected to the conveyor belt 31 via the tension roller 65. Since the tension in the negative direction of the Z axis is always applied to the belt belt 31, the conveyor belt 31 is not loosened, and can always be bridged between the belt rollers 32 a and 32 b and the platen unit 60 with a constant tension.

  In addition, wire fixing plates 62 a for fixing one end of the wire 70 are provided at the four corners of the platen frame 62. The other ends of these wires 70 are connected to a winding mechanism (not shown) fixed to the apparatus frame 11 shown in FIG.

  The winding mechanism moves the platen unit 60 up and down by winding and holding the other ends of the four wires 70 around the winding portion and loosening or unwinding the other ends of the wires 70. The wire 70 and a winding mechanism (not shown) constitute a platen unit moving mechanism for moving the platen unit 60 up and down.

  Next, the image recording unit 40 will be described. The image recording unit 40 is an ink ejection device for ejecting ink to the recording medium 21a. The image recording unit 40 includes a recording head unit 41 and a head holding unit 42.

The recording head unit 41 is provided for each color and ejects, for example, black (K), cyan (C), magenta (M), and yellow (Y) ink.
The recording head 41 constitutes a line head with one long head or a plurality of short heads so as to have the same or larger dimension as the maximum width of the recording medium 21a to be used. In this embodiment, a plurality of short heads are arranged in a staggered manner in a direction orthogonal to the transport direction to constitute a line head.

  That is, when the image recording apparatus 1 is compatible with recording on the A3 size recording medium 21a, the width of the recording head unit 41 (the length in the depth direction in FIG. 1) is equal to or larger than the width of the A3 size recording medium 21a. Set to These recording head parts 41 are supported by a head holding part 42. The head holding part 42 is fixed to the device frame 11.

  The head holding portion 42 is provided with positioning pins 43 at positions corresponding to the positioning holes 62c provided in the platen 61 described above. The positioning pin 43 is fitted into a positioning hole 62c provided in the platen 61 at the time of image recording. Thereby, the conveyance unit 30 and the image recording unit 40 can be positioned. In this embodiment, the positioning pin 43 is provided in the head holding portion 42 and the positioning hole 62c is provided in the platen 61. However, the positioning pin 43 may be provided in the platen 61 and the positioning hole 62c may be provided in the head holding portion 42. .

  Next, the maintenance mechanism 44 will be described. The maintenance mechanism 44 is provided corresponding to each recording head unit 41, and is arranged between the recording head units 41, which is a standby position during image recording.

The maintenance mechanism 44 is provided with a known blade mechanism and cap mechanism, and the maintenance of each recording head unit 41 is performed by these mechanisms.
Next, the discharge unit 50 will be described. The discharge unit 50 is a mechanism for discharging the recording medium 21 a on which an image is recorded by the image recording unit 40. As shown in FIG. 1, the discharge unit 50 includes a discharge unit conveying roller pair 51, a discharge unit discharge roller pair 52, and a discharge tray 53.

  The discharge unit conveyance roller pair 51 plays a role of conveying the recording medium 21 a conveyed from the conveyance unit 30 into the discharge unit 50. The discharge unit discharge roller pair 52 is a conveyance roller for conveying the recording medium 21 a conveyed from the discharge unit conveyance roller pair 51 to the discharge tray 53.

Thus, the discharge unit discharge roller pair 52 takes over the conveyance of the recording medium 21 a conveyed by the discharge unit conveyance roller pair 51 and discharges the recording medium 21 a to the discharge tray 53.
Next, a method for adjusting the distance between the conveyance belt 31 and the recording head unit 41 will be described.

FIG. 4 is a diagram illustrating a state at the time of image recording in which the conveyance belt 31 and the recording head unit 41 are maintained at a narrow interval d1.
At the interval d1 during image recording shown in FIG. 4, the platen rollers 64a and 64b of the platen unit 60 are disposed above the belt rollers 32a and 32b in the Z-axis direction, and the tension roller 65 is disposed on the belt roller 32a. And 32b at a position below the Z-axis direction. That is, the platen rollers 64a and 64b are in contact with the conveyance belt 31 on the image recording unit 40 side of the belt rollers 32a and 32b, and the tension roller 65 is the belt rollers 32a and 32b in the ejection direction of the ink ejected from the recording head unit 41. The platen rollers 64a and 64b are in contact with the conveying belt 31 on the opposite side. As a result, the platen unit 60 applies a certain tension to the conveyor belt 31.

FIG. 5 is a diagram illustrating a maintenance state in which the conveyance belt 31 and the recording head unit 41 are separated by a wide distance d2.
As shown in FIG. 3, the maintenance interval d2 shown in FIG. 5 is taken up by the winding mechanism (not shown) wound around the other end of the four wires 70 wound around the winding portion. The platen unit 60 is lowered in the Z-axis direction so that the distance between the conveyance unit 30 and the image recording unit 40 is d2.

  At this time, in this embodiment, the lowering range of the platen unit 60 is such that the platen 61 and the platen rollers 64a and 64b are at the same height as the belt rollers 32a and 32b or above the belt rollers 32a and 32b. It falls in such a range.

  Until the platen unit 60 is lowered from the recording position shown in FIG. 4 to the maintenance position shown in FIG. 5, the same tension is always applied to the transport belt 31 via the tension roller 65 by the tension adjusting mechanism 37. Descend in a state.

  When the distance between the conveyance unit 30 and the image recording unit 40 reaches d2, a maintenance movement mechanism (not shown) is driven, and the maintenance mechanism 44 faces each recording head unit 41 indicated by a solid line from a standby position indicated by a broken line in FIG. Move to the position you want. Thereby, the maintenance operation of each recording head unit 41 is performed. As shown in FIG. 6, the maintenance mechanism 44 is arranged collectively on the downstream side in the recording medium transport direction from the recording head portions 41 and faces the recording head portions 41 indicated by solid lines from a standby position indicated by broken lines. You may move to a position.

  When the maintenance operation is completed, the maintenance mechanism 44 is returned to the standby position shown in FIG. 4, and the other end of the four wires 70 that the winding mechanism has loosened is further unwound to raise the platen unit 60. The recording position shown in FIG.

  4 and 5, since the belt rollers 32a and 32b and the image recording unit 40 are both installed in the apparatus frame 11, the belt roller 32a is used during the image recording shown in FIG. 4 and during the maintenance shown in FIG. And the positional relationship between 32b and the image recording unit 40 does not change.

  Further, a constant tension is always applied to the transport belt 31 by the platen unit 60. That is, the platen rollers 64a and 64b and the platen 61 held by the platen frame 62 are disposed above the belt rollers 32a and 32b, the tension roller 65 is disposed below the belt rollers 32a and 32b, and tension is applied. By providing the adjustment mechanism 37, when the platen unit 60 moves between the recording position and the maintenance position, the conveyance belt 31 can be moved with the same tension always applied.

  The positional relationship between the platen rollers 64a and 64b and the tension roller 65 in the platen frame 62 is adjusted to a position where the traveling direction of the conveyor belt 31 is stabilized during assembly.

  In order to ensure a high-quality image, the positional relationship between the belt rollers 32, the tension applied to the transport belt 31, and the positional relationship between the platen unit 60 and the image recording unit 40 must be in the same state as before cleaning. .

  In the image recording apparatus 1 of this example, the belt rollers 32 a and 32 b and the image recording unit 40 are fixed to the apparatus frame 11, and the conveying unit 30 and the image recording unit 40 are positioned by the positioning holes 62 c and the positioning pins 43. The tension applied to the conveyor belt 31 is kept constant by the tension roller 65 and the tension adjusting mechanism 37.

As a result, no change occurs in the recording medium conveyance direction of the image recording unit 40 by the conveyance unit 30, and a high-quality image can be ensured.
As described above, according to the present embodiment, the belt rollers 32a and 32b are fixed to the apparatus frame 11, and the tension between the platen unit 60 and the conveyance belt 31 is always kept the same between the recording position and the maintenance position. Because of the movement, it is possible to suppress variations in the conveyance accuracy before and after maintenance, and to perform high-quality image recording.

  The distance d1 needs to be adjusted according to the type and thickness of the recording medium 21a. In the present embodiment, the distance d1 is changed by changing the height position where the positioning pin 43 is fitted into the positioning hole 62c. Can be adjusted.

  Also at this time, the positional relationship in the platen unit 60, that is, the positional relationship between the platen rollers 64a and 64b and the tension roller 65 does not change, and the entire platen unit 60 moves, so the tension applied to the transport belt 31 does not change.

Further, since the positional relationship between the conveyance unit 30 and the image recording unit 40 does not change, the traveling direction of the conveyance belt is always stable in the same direction, and a high-quality image can be ensured.
(Modification of platen unit lifting / lowering operation)
FIG. 7 is a view showing a modification of the mechanism for moving the platen unit 60 up and down in the Z-axis direction. The platen unit moving mechanism 71 includes four guide shafts 72, a moving drive mechanism 73, and a transmission mechanism (not shown) that transmits the driving force of the moving drive mechanism 73 to the four guide shafts 72.

  Bolt-shaped male screws are formed on the surface of the guide shaft 72 so as to engage with female screw holes provided at the four corners of the platen unit 60. The guide shaft 72 is provided such that its axial direction is vertical.

  The moving drive mechanism 73 supplies a driving force for rotating the guide shaft 72 around its axis. This driving force is transmitted to the guide shaft by the transmission mechanism including gears and the like.

In the platen unit moving mechanism 71 shown in FIG. 7, the guide shaft 72 rotates in the normal direction when the moving drive mechanism 73 rotates in the normal direction, and the bolt-shaped male screw portion is screwed into the female screw hole of the platen unit 60 and slides. By doing so, the platen unit 60 is raised. On the other hand, when the moving drive mechanism 73 is reversed, the platen unit 60 is lowered.
(Tension roller modification)
In the embodiment described above, the tension roller 65 of the platen unit 60 is configured with only one arrangement, but the arrangement form of the tension roller is not limited to this.

  FIG. 8 is a view showing a modification of the arrangement form of the tension roller. In FIG. 8, the same components or functions as those shown in FIGS. 1 to 6 are denoted by the same reference numerals as those in FIGS.

  As shown in FIG. 8, a plurality (two in the example shown in FIG. 8) tension rollers 65 (65a, 65b) are arranged in the platen unit 60 of this example. The plurality of tension rollers 65 are held at both ends of an arm member 62e disposed horizontally below the suction unit 63 so as to face the suction unit 63.

  The arm member 62e supports the plurality of tension rollers 65 evenly with respect to the center of the arm member 62e. For example, when there are three tension rollers 65, the third tension roller 65 is disposed at the center of the arm member 62e.

  A tension adjusting mechanism 37 is interposed between the arm member 62e and the platen frame 62. The tension adjusting mechanism 37 is also provided with a pressing member 66 such as a spring mechanism or an air suspension.

  Also in this case, the platen unit 60 includes at least the platen rollers 64a and 64b regardless of whether the positional relationship between the conveyance unit 30 and the image recording unit 40 is the interval d1 during image recording or the interval d2 during maintenance. It is located above the belt rollers 32a and 32b in the Z-axis direction, and the plurality of tension rollers 65 move up and down in a range located below the belt rollers 32a and 32b in the Z-axis direction.

  As a result, also in this example, the conveyance belt 31 can be lowered to the maintenance interval d2 while maintaining the same tension as that applied at the interval d1 during image recording, from the maintenance position to the image recording position. When returning, it can be raised with the same tension.

  In addition, this invention is not limited to the said embodiment, In the implementation stage, it can change variously in the range which does not change the summary.

1 is a schematic side view illustrating an image recording apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic top view illustrating a conveyance unit of the image recording apparatus according to the first embodiment. FIG. 2 is a perspective view showing in detail a platen unit of the image recording apparatus in the first embodiment. FIG. 6 is a diagram illustrating a state during image recording in which the conveyance belt and the recording head unit of the image recording apparatus according to the first embodiment are maintained at a narrow distance d1. FIG. 5 is a diagram illustrating a state during maintenance in which the conveyance belt and the recording head unit of the image recording apparatus according to the first embodiment are separated by a wide distance d2. FIG. 4 is a diagram illustrating an example in which standby positions of a maintenance mechanism are collectively arranged on the downstream side in the recording medium conveyance direction from each recording head unit. It is a figure which shows the modification of the mechanism which raises / lowers a platen unit to a Z-axis direction. It is a figure which shows the modification of the arrangement | positioning form of a tension roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image recording apparatus 11 Apparatus frame 12 Belt roller drive motor 20 Paper feed part 21 Paper feed tray 21a Recording medium 22 Pickup roller 23 Registration roller pair 30 Conveyance part 31 Conveyance belt 31a Suction hole 32 (32a, 32b) Belt roller 33 Followed Roller 37 Tension applying mechanism 40 Image recording unit 41 Recording head unit 42 Head holding unit 43 Positioning pin 44 Maintenance mechanism 50 Ejecting unit 51 Ejecting unit conveying roller pair 52 Ejecting unit ejecting roller pair 53 Ejecting tray 60 Platen unit 61 Platen 61b Suction hole 62 Platen frame 62a Wire fixing plate 62c Positioning hole 62d Shaft holding part 62e Arm member 63 Suction unit 64a, 64b Platen roller 65 Tension roller 66 Biasing member 67 Recording medium Transport region 68 tension roller sliding slot 69 the shaft 70 wire 71 platen unit moving mechanism 72 guide shaft 73 moving drive mechanism

Claims (10)

A belt roller rotatably supported on the apparatus main body frame, a conveying belt stretched over the belt roller, and a platen unit movably disposed inside the conveying belt, and a recording medium A transport section for transporting downstream;
An image recording unit that performs image recording by ejecting ink from a recording head unit disposed over a width of the recording medium in a direction orthogonal to the conveyance direction of the recording medium conveyed by the conveyance unit;
A maintenance mechanism for performing maintenance of the recording head unit;
A platen unit moving mechanism for moving the platen unit to an image recording position for recording an image on the recording medium and a maintenance position for performing maintenance of the recording head unit;
With
The platen unit includes at least a platen roller, a tension roller, and a tension adjustment mechanism that adjusts the tension of the conveyance belt. When the platen unit is located at the image recording position, the platen roller is An image recording apparatus according to claim 1, wherein the image recording unit is in contact with the conveyance belt on the side of the roller, and the tension roller is in contact with the conveyance belt on the side opposite to the platen roller via the belt roller.   The platen unit has a platen at least in a region facing the image recording unit, and forms a recording medium conveyance region for conveying the recording medium downstream by the platen roller and the platen. The image recording apparatus according to claim 1. The platen unit includes at least a platen facing the image recording unit, and a suction unit that generates a negative pressure on the platen,
The image recording apparatus according to claim 1, wherein the platen and the suction unit are held by a platen frame.   The image recording apparatus according to claim 3, wherein the platen frame and the platen are integrally formed.   The image recording apparatus according to claim 3, wherein the platen frame rotatably holds the platen roller and the tension roller.   When the platen unit is moved by the platen unit moving mechanism, the movement range of the platen unit is such that the platen roller is at the same height as the belt roller, or the platen roller is closer to the image recording unit than the belt roller. The image recording apparatus according to claim 1, wherein the image recording apparatus moves within a position range of the image recording apparatus.   The tension adjusting mechanism includes a biasing member, and when the platen unit moves inside the transport belt, the biasing member biases the transport belt through the tension roller, and the transport belt. The image recording apparatus according to claim 1, wherein the image recording apparatus is moved while maintaining a constant tension.   The image recording apparatus according to claim 7, wherein the urging member includes a spring mechanism or an air suspension mechanism.   The platen unit moving mechanism includes four wires fixed at one end to the four corners of the platen unit, and winding and holding the other end of the four wires to loosen or rewind the four wires. And an image recording apparatus according to claim 1.   The platen unit moving mechanism includes a female screw hole provided at each of the four corners of the platen unit, four male screw shafts respectively screwed into the four female screw holes, and the four male screw shafts in both forward and reverse directions. The image recording apparatus according to claim 1, further comprising a drive mechanism that rotationally drives the image recording apparatus.

Images