JP2010241091A - Inkjet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the disturbance of images in a simple constitution, in such a manner that at scanning wherein the entrance distance of a carriage is shorter, the stretching of a driving belt is made smaller by making the length of a tension-applied-section of the driving belt shorter, and in the meantime, at scanning wherein the stretching of the driving belt becomes larger, the margin of time until the stretching of the driving belt is stabilized is extended by making the entrance distance of the carriage longer. <P>SOLUTION: This inkjet recording apparatus 1 includes: the carriage 32; a driving motor 511 for making the carriage 32 scan; and an end-less driving belt 53 which is stretched in a manner to extend in the main scanning direction X and makes the carriage 32 scan by transmitting the driving force of the driving motor 511 to the carriage 32 as a tension. The carriage 32 can move to a printing region T, a home position P<SB>1</SB>, and a maintenance position P<SB>2</SB>which is arranged on the opposite side from the home position P<SB>1</SB>to the printing region T, and at the same time, of which the distance in the main scanning direction X to the printing region T is longer than that of the home position P<SB>1</SB>. The driving motor 511 is connected with the driving belt 53 through a driving pulley 515 on the same side as the maintenance position P<SB>2</SB>to the printing region T. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus.

  2. Description of the Related Art Conventionally, an image recording apparatus using an inkjet method is known as an image recording unit that can record an image easily and inexpensively. An image recording apparatus using the ink jet method (hereinafter referred to as an ink jet recording apparatus) scans a carriage on which an ink jet head is mounted and ejects minute ink droplets from a nozzle of the ink jet head onto a recording medium. The image is recorded.

  In recent years, especially in this ink jet recording apparatus, printing (image recording) has been speeded up, and accordingly, the number of ink jet heads mounted on the carriage has been increased and the weight of the carriage tends to increase. As the number of inkjet heads mounted on the carriage increases, it is necessary to add a mechanism for adjusting the landing position with other inkjet heads in addition to the ink supply members and nozzle drive boards. Will increase more and more.

  By the way, in the so-called shuttle type ink jet recording apparatus, generally, a carriage is connected to an endless driving belt stretched around two pulleys, and the carriage is scanned by running the driving belt. In such a carriage drive configuration, the drive belt stretches when the carriage is scanned. The elongation of the driving belt becomes constant after an unstable behavior such that the elongation of the driving belt increases during the acceleration of the carriage and returns a little when moving to a constant speed.

  When the ink jet head performs a printing operation in a state where the above-described unstable elongation occurs in the drive belt, an error corresponding to the elongation occurs in the position control of the carriage, resulting in a disturbance in the recorded image. . The unstable elongation of the drive belt becomes larger as the carriage is heavier. Therefore, when the carriage with the increased weight is used as described above, the image is distorted. Further, the unstable elongation of the drive belt is increased even when the portion where the tension is applied is longer.

  Therefore, there is a method (for example, refer to Patent Document 1) that detects the length of the drive belt and adjusts the driving force of the drive source according to the detected length to stabilize the driving operation of the drive belt. Proposed.

JP 2002-172824 A

  However, in the method described in Patent Document 1, it is necessary to newly provide components such as a detecting unit for detecting the length of the driving belt and a driving force adjusting unit, which complicates the configuration of the apparatus. .

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an ink jet recording apparatus capable of suppressing image disturbance with a simple configuration.

In order to solve the above-mentioned problem, the invention according to claim 1
A carriage mounted with an inkjet head for ejecting ink droplets and scanned in a predetermined scanning direction;
A scanning drive source for scanning the carriage;
Endless driving force transmission that is stretched so as to extend in the scanning direction and is connected to the carriage and the scanning driving source, and transmits the driving force of the scanning driving source to the carriage as tension. Members,
An inkjet recording apparatus comprising:
The carriage is
A print area for discharging the ink droplets onto the recording medium, a first movement start position, and the first movement start position disposed on the opposite side of the print area from the first movement start position. A second movement start position having a longer distance in the scanning direction to the print area than the print area,
The scanning drive source is
The driving force transmission member is connected to the print area on the same side as the second movement start position.

Invention of Claim 2 is the inkjet recording device of Claim 1, Comprising:
The driving force transmission member is
The first portion where the main tension acts when scanning the carriage from the first movement start position toward the second movement start position is different from the second portion other than the first portion. Formed by material,
The second portion is formed of a material that is less likely to extend than the first portion.

Invention of Claim 3 is an inkjet recording device of Claim 1 or 2, Comprising:
The first movement start position is a position in the scanning direction corresponding to a carriage standby unit that makes the carriage wait.
The second movement start position is a position in the scanning direction corresponding to a head maintenance unit that performs maintenance of the inkjet head.

Invention of Claim 4 is an inkjet recording device as described in any one of Claims 1-3, Comprising:
The driving force transmission member is a belt or a wire rope.

According to the first aspect of the present invention, the scanning drive source is the same as the second movement start position where the distance in the scanning direction to the print area is longer than the two movement start positions of the carriage with respect to the print area. Since, on the side, it is connected to an endless driving force transmission member (driving belt), the second is more than in the case of scanning A in which the carriage is scanned from the first movement start position to the second movement start position. In the scan B in which scanning is performed from the movement start position toward the first movement start position, the length of the tension acting portion on which the main tension acts on the drive belt is increased, and the printing area is shifted from each movement start position. The run-up distance of the carriage becomes longer.
As a result, when the carriage A has a shorter run distance, the length of the tension acting portion of the drive belt is shortened to reduce the extension of the drive belt, while the extension of the drive belt is increased. In this case, it is possible to increase the margin for the time required for the extension of the drive belt to be stabilized by increasing the run distance of the carriage. Therefore, the driving belt can be made smaller or more stable during the run of the carriage from each movement start position to the printing area, and recorded in the printing area as compared with the conventional case. Image disturbance can be suppressed.

  In addition, since the above effect can be obtained only by selecting the side on which the scanning drive source is connected to the drive belt, unlike the prior art, a detection means for detecting the length dimension of the drive belt, a drive force adjustment means, etc. There is no need to newly provide parts, and a simple configuration can be achieved.

  According to the second aspect of the present invention, the driving belt is formed of a material different between the first portion where the main tension acts during the scanning A and the second portion other than the first portion. Since the second portion is formed of a material that is less likely to extend than the first portion, the tension acting portion is not detected during the scanning B in which the length of the tension acting portion of the drive belt is longer than that during the scanning A. The second portion is included. Therefore, the extension of the drive belt in the scan B, which tends to be larger than that in the scan A, can be further reduced, and the disturbance of the image recorded in the print area can be further suppressed.

1 is a perspective view of an ink jet recording apparatus according to the present invention. It is a front view of a carriage. It is a perspective view of a head maintenance part. It is a perspective view of a drive part. It is (a) perspective view of a driven part, (b) It is a top view. FIG. 3 is a schematic diagram illustrating a main part of an ink jet recording apparatus when a carriage is scanned from a home position toward a maintenance position. FIG. 3 is a schematic diagram illustrating a main part of an ink jet recording apparatus when a carriage is scanned from a maintenance position toward a home position. It is a graph which shows the scanning speed of the carriage at the time of a run. It is a schematic diagram which shows another example of an inkjet recording device. It is a schematic diagram which shows the other another example of an inkjet recording device.

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

FIG. 1 is a perspective view of an ink jet recording apparatus 1 according to the present invention.
As shown in this figure, the ink jet recording apparatus 1 mainly includes a transport unit 2 and a main scanning unit 3.

  An endless transport belt 21 for transporting a recording medium (not shown) from the back side in the direction of arrow Z (hereinafter referred to as transport direction Z) is disposed above the transport unit 2. As the recording medium, in addition to paper and fabric, resin films, metals, and the like can be used, and are not particularly limited.

  The main scanning unit 3 is disposed above the conveyance belt 21 of the conveyance unit 2. The main scanning unit 3 includes a CPU (not shown) that controls the operation of each unit of the inkjet recording apparatus 1. Inside the main scanning unit 3, rod-shaped guide rails 31, 31 are arranged so as to extend in the direction of arrow X (hereinafter referred to as main scanning direction X). A substantially casing-like carriage 32 is supported so as to be reciprocally movable in the main scanning direction X. A carriage drive mechanism 5 for scanning the carriage 32 is provided inside the main scanning unit 3. The carriage drive mechanism 5 will be described in detail later.

  As shown in FIG. 2, the carriage 32 is provided with a plurality of nozzles 321 for discharging ink droplets I of each color such as yellow (Y), magenta (M), cyan (C), and black (K) during image recording. A plurality of recording heads 320 are provided, and in this embodiment, only one row and two rows arranged in the direction of arrow Y (hereinafter referred to as sub-scanning direction Y) are alternately subjected to main scanning. A total of 24 units (8 colors × 3 sets) are mounted so as to be arranged in 16 rows in the direction X. The lower surface of the recording head 320 is exposed from the carriage 32, and forms a nozzle surface 320a in which a plurality of nozzles 321 are arranged in the sub-scanning direction Y.

As shown in FIG. 1, the central portion of the movable range of the carriage 32 is a print region T in which an ink droplet I is ejected and an image is recorded on a recording medium. One end side (the left side in FIG. 1) outside the printing area T is a home position P ₁ (see FIG. 6) of the carriage 32. At the home position P ₁ , a carriage standby unit 33 that waits for the carriage 32 is provided. The carriage 32 is moved to the home position P ₁ when the operation is stopped, and the nozzle 321 is covered with a moisture retention cap (not shown) of the carriage standby unit 33 so that the nozzle 321 is prevented from drying. Further, the distance L ₁ (see FIG. 6) in the main scanning direction X from the home position P ₁ to the printing area T can accelerate the carriage 32 to a predetermined scanning speed in the printing area T, and the apparatus can be made compact. The predetermined distance is shortened as much as possible in order to configure.

A head maintenance unit 4 that performs maintenance of the recording head 320 is disposed on the other end side (the right side in FIG. 1) outside the print region T, which is a movable range of the carriage 32. The head maintenance unit 4 is disposed below the height at which the carriage 32 is scanned, and the carriage 32 moves to a maintenance position P ₂ (see FIG. 7) above the head maintenance unit 4 to perform predetermined maintenance. Work is to be done. The home position P ₁ and the maintenance position P ₂ are juxtaposed in the main scanning direction X so as to sandwich the print area T at different distances from the print area T, as will be described later.

  As shown in FIG. 3, the head maintenance unit 4 includes a flushing unit 41, a nozzle missing detection unit 42, a head cleaning unit 43, and a suction unit 44 in this order along the main scanning direction X. . These are arranged so as to be separated from the print region T in order from the one with the highest use frequency at the time of image recording, and the arrangement shortens the image recording time.

  Among these, the flushing unit 41 includes a waste liquid receiver 411 and an ink absorber (not shown) provided in the waste liquid receiver 411. In the flushing section 41, the nozzle 321 of the carriage 32 moved vertically above the waste liquid receiver 411 is flushed by idlely discharging the ink droplet I with a pressure higher than a normal value by a predetermined value. Drying of 321 is prevented. This flushing is performed on the nozzles 321 of all the recording heads 320 for each scan in which the carriage 32 crosses the print region T once during image recording.

  The nozzle missing detection unit 42 includes a light emitting unit 421 that emits laser light, a light receiving unit 422 that receives the laser light, and an ink receiver 423 disposed below the laser light. In this nozzle missing detection unit 42, an ink droplet I is ejected toward the laser beam from the nozzle 321 of the carriage 32 moved vertically upward, and the light receiving unit 422 determines whether the laser beam is blocked by this ink droplet I. By detecting at, ejection / non-ejection of the ink droplet I from the nozzle 321 is detected. The ink droplet I that has passed through the laser light lands on an ink absorber (not shown) in the ink receiver 423 and is absorbed. The detection of the ink droplet I by the nozzle missing detection unit 42 is periodically performed at the time of image recording in order to check the clogging of the nozzle 321.

  The head cleaning unit 43 includes a cleaning roller 431 whose lower part is immersed in a cleaning liquid. In the head cleaning unit 43, the cleaning roller 431 contacts and rotates on the nozzle surface 320a of the carriage 32 moved vertically upward, so that the cleaning roller 431 wipes off dirt on the nozzle surface 320a while scooping up the cleaning liquid. The nozzle surface 320a is cleaned. The cleaning of the nozzle surface 320a by the head cleaning unit 43 is performed mainly when a slight ejection curve or weak emission of the ink droplet I is confirmed.

  The suction unit 44 includes a plurality of cap members 441 for covering the nozzle surfaces 320a of the recording heads 320. In this suction part 44, after covering all the nozzle surfaces 320a of the carriage 32 moved vertically upward with the cap members 441, the suction pumps (not shown) communicated with the cap members 441 are driven to drive the nozzles 321. The ink and foreign matter inside are removed by suction. The suction in the nozzle 321 by the suction unit 44 is performed when the nozzle 321 is clogged.

Next, the configuration of the carriage drive mechanism 5 will be described with reference to FIGS.
4 is a perspective view of a drive unit 51 described later, FIG. 5A is a perspective view of a driven unit 52 described later, and FIG. 5B is a top view of the driven unit 52. 4 shows only the drive unit 51 with the cover removed, and the drive belt 53 is not shown in FIG. 5B.

  As shown in FIG. 1, the carriage drive mechanism 5 includes a drive unit 51 provided at the other end of the guide rails 31 and 31 (right side of FIG. 1) and one end of the guide rails 31 and 31 (left side of FIG. 1). A driven unit 52 provided, a drive unit 51 extending in the main scanning direction X, and a drive belt 53 stretched around the driven unit 52 are provided.

  4, the drive unit 51 includes a drive motor 511 that is a scanning drive source of the carriage 32, and a motor pulley (not shown) fixed concentrically to a motor shaft (not shown) of the drive motor 511. A primary reduction pulley 512 disposed above the motor pulley, a secondary reduction pulley 513 having a smaller diameter than the primary reduction pulley 512 and concentrically fixed to the primary reduction pulley 512, and a secondary reduction pulley A final reduction pulley 514 disposed above 513, and a drive pulley 515 fixed concentrically to the final reduction pulley 514 and having a drive belt 53 stretched thereon. Further, a primary rotary belt 516 is stretched between the motor pulley of the drive motor 511 and the primary reduction pulley 512, and a secondary rotation belt 517 is stretched between the secondary reduction pulley 513 and the final reduction pulley 514. .

  In the drive unit 51, when the motor shaft of the drive motor 511 is rotationally driven by the above configuration, the driving force is transmitted from the motor pulley to the primary reduction pulley 512 via the primary rotation belt 516. The secondary reduction pulley 513 fixed to the secondary reduction pulley 512 is transmitted to the final reduction pulley 514 via the secondary rotary belt 517. Thus, the drive pulley 515 fixed to the final deceleration pulley 514 is rotationally driven, and the drive belt 53 stretched around the drive pulley 515 is caused to travel.

  The drive unit 51 is configured to be able to move the drive motor 511 and the secondary reduction pulley 513 in the vertical direction. As a result, the tension of the primary rotary belt 516 can be adjusted by moving the drive motor 511 in the vertical direction, and the tension of the secondary rotary belt 517 can be adjusted by moving the secondary reduction pulley 513 in the vertical direction. ing.

  As shown in FIGS. 5A and 5B, the driven unit 52 covers the driven pulley 521 over which the drive belt 53 is stretched and the lower half of the driven pulley 521 and supports the driven pulley 521. A first cover member 522 and a second cover member 523 that covers the outside of the first cover member 522 are provided. Among these, the first cover member 522 is supported by the second cover member 523 by a fulcrum shaft 524 inserted in the vertical direction, and is configured to be swingable in the sub-scanning direction Y around the fulcrum shaft 524. Yes. In addition, a tension adjusting screw 525 disposed along the main scanning direction X is screwed into the second cover member 523 along the side wall on one end side in the main scanning direction X, and is arranged along the sub scanning direction Y. The provided bias adjusting screws 526 and 526 are screwed onto the front side wall.

  In the driven portion 52, the bottom surface of the tension adjusting screw 525 is abutted against the first cover member 522, and the position of the driven pulley 521 in the main scanning direction X is moved together with the first cover member 522, thereby driving belt 53. The tension can be adjusted. Further, the bottom surfaces of the bias adjusting screws 526 and 526 are abutted against the first cover member 522, and the driven pulley 521 is swung in the sub-scanning direction Y together with the first cover member 522 around the fulcrum shaft 524. The deviation of the driving belt 53 in the sub-scanning direction Y can be adjusted.

  4 and 5, the drive belt 53 is an endless belt stretched between a drive pulley 515 of the drive unit 51 and a driven pulley 521 of the driven unit 52, and is fixedly connected to the carriage 32. Yes. The drive belt 53 is connected to a drive motor 511 via a drive pulley 515, and transmits the drive force of the drive motor 511 to the carriage 32 as a tension to scan the carriage 32 in the main scanning direction X.

Moreover, the drive belt 53, second belt portion of the first belt portion 53a to which the main tension acts, other than the first belt portion 53a when scanning the carriage 32 toward the maintenance position P ₂ from the home position P ₁ The second belt portion 53b is formed of a material that is less likely to extend than the first belt portion 53a (see FIGS. 6 and 7). As materials for the first belt portion 53a and the second belt portion 53b, for example, combinations shown in Table 1 below can be used. In Table 1, the belt core body is a plurality of cords that form the core of the drive belt 53, and the belt base material covers the surface of the belt core body.

Next, the operation of the ink jet recording apparatus 1 according to the present invention will be described with reference to FIGS.
FIG. 6 is a schematic diagram showing a main part of the ink jet recording apparatus 1 when the carriage 32 is scanned from the home position P ₁ toward the maintenance position P _2. FIG. 7 is a schematic view showing the carriage 32 from the maintenance position P _2. FIG. 2 is a schematic diagram illustrating a main part of the inkjet recording apparatus 1 when scanned toward a home position P ₁ .

In the ink jet recording apparatus 1, as shown in FIGS. 6 and 7, it is necessary to accelerate the carriage 32 to a predetermined scanning speed in the print region T, not only when the image recording is not performed, but also during the image recording. Therefore, the carriage 32 is moved to the home position P ₁ or the maintenance position P ₂ . Accordingly, when image recording is performed, the carriage 32 starts to move from the home position P ₁ or the maintenance position P ₂ toward the print region T.

Here, the distance L _{1 in} the main scanning direction X from the home position P ₁ to the print area T is a predetermined distance for mainly accelerating the carriage 32 as described above. On the other hand, the minimum distance L _{2 in} the main scanning direction X from the maintenance position P ₂ to the print area T is that at least flushing is performed for each scan with respect to all the nozzles 321 as described above, so that the carriage 32 is accelerated. The distance from the flushing portion 41 to the print area T is added to the above predetermined distance. Therefore, the home position P ₁ and the maintenance position P _2, are different and the distance L ₁ and the distance L ₂ to the print area T, respectively, longer towards the distance L ₂ from the maintenance position P ₂ to the print region T It has become.

When the carriage 32 starts to move from the home position P ₁ to the maintenance position P ₂ , the carriage 32 is scanned by the main tension acting on the first belt portion 53a of the drive belt 53 (scan A). When the movement from the maintenance position P ₂ to the home position P ₁ is started, scanning is performed by main tension acting on the second belt portion 53b and a part of the first belt portion 53a in the drive belt 53. (Scan B). The main tension is a tension for pulling the carriage 32 among the tensions acting on the drive belt 53, and indicates a tension larger than the tension acting on the other drive belt 53 portions.

At this time, since the drive belt 53 is connected to the drive motor 511 via the drive pulley 515 on the same side as the maintenance position P ₂ with respect to the print area T, the scan belt 53 is more likely to scan than the scan A. In addition, the length of the tension acting portion where the main tension acts on the driving belt 53 becomes longer, and the running distance of the carriage 32 from each movement start position of the home position P ₁ and the maintenance position P ₂ to the printing area T becomes longer. (Distance L ₂ > Distance L ₁ )

  As a result, when the traveling distance of the carriage 32 is shorter, the length of the tension acting portion of the drive belt 53 is shortened to reduce the extension of the drive belt 53 while the extension of the drive belt 53 is further increased. When scanning B is increased, the run-up distance of the carriage 32 can be lengthened to increase the time margin until the extension of the drive belt 53 is stabilized.

  The scanning speed of the carriage 32 at this time reaches a predetermined scanning speed in a shorter time in the case of scanning A than in the case of scanning B as shown in FIG. There is also less variation due to slow growth.

  As described above, according to the ink jet recording apparatus 1 of the present invention, when the traveling distance of the carriage 32 is shorter, the length of the tension acting portion of the drive belt 53 is shortened to extend the drive belt 53. On the other hand, during scanning B in which the extension of the drive belt 53 becomes larger, the run-up distance of the carriage 32 can be made longer, and the time margin until the extension of the drive belt 53 becomes stable can be extended. Therefore, during the run of the carriage 32 from the respective movement start positions to the print area T, the extension of the drive belt 53 can be made smaller or more stable, and the print area T can be made easier than before. It is possible to suppress the disturbance of the image recorded in

  Further, since the above-described effect can be obtained only by selecting the side where the drive motor 511 is connected to the drive belt 53, unlike the conventional case, the detection means for detecting the length dimension of the drive belt 53 and the adjustment of the drive force There is no need to newly provide parts such as means, and a simple configuration can be achieved.

  Further, the drive belt 53 is formed of different materials for the first belt portion 53a and the second belt portion 53b to which the main tension acts during the scanning A, and the second belt portion 53b extends more than the first belt portion 53a. Since the length of the tension acting portion of the drive belt 53 is longer than that in the scanning A, the tension acting portion is a portion including the second belt portion 53b. Therefore, the extension of the drive belt 53 in the scan B, which tends to be larger than that in the scan A, can be further reduced, and the disturbance of the image recorded in the print region T can be further suppressed.

  It should be noted that the present invention should not be construed as being limited to the above-described embodiment, and of course can be modified or improved as appropriate.

For example, in the above embodiment has been described as being disposed on different sides with respect to the print area T at a home position P ₁ and the maintenance position P _2, as shown in FIG. 9, the home position P ₁ and a maintenance position P ₂ may be arranged on the same side with respect to the print area T, and as shown in FIG. 10, the home position P ₁ is included in the maintenance position P ₂ because the suction part 44 also serves as the carriage standby part 33. May be arranged. Even in these cases, since the running distance of the carriage 32 is set with respect to the left and right of the printing area T, the driving motor 511 is connected to the driving belt 53 on either the left or right side of the longer running distance. (Drive pulley 515) may be connected.

  Further, the drive belt 53 is not limited to a belt shape, and may be a wire rope, for example.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 4 Head maintenance part 32 Carriage 33 Carriage standby part 53 Drive belt (drive force transmission member)
53a First belt portion (first portion)
53b Second belt portion (second portion)
320 Recording head (inkjet head)
511 Drive motor (scanning drive source)
I Ink droplets L ₁ and L ₂ distance (distance in scanning direction)
P ₁ home position (first movement start position)
P ₂ maintenance position (second movement start position)
T Print area X Main scanning direction (scanning direction)

Claims (4)

A carriage mounted with an inkjet head for ejecting ink droplets and scanned in a predetermined scanning direction;
A scanning drive source for scanning the carriage;
Endless driving force transmission that is stretched so as to extend in the scanning direction and is connected to the carriage and the scanning driving source, and transmits the driving force of the scanning driving source to the carriage as tension. Members,
An inkjet recording apparatus comprising:
The carriage is
A print area for discharging the ink droplets onto the recording medium, a first movement start position, and the first movement start position disposed on the opposite side of the print area from the first movement start position. A second movement start position having a longer distance in the scanning direction to the print area than the print area,
The scanning drive source is
An ink jet recording apparatus connected to the driving force transmission member on the same side as the second movement start position with respect to the printing area. The driving force transmission member is
The first portion where the main tension acts when scanning the carriage from the first movement start position toward the second movement start position is different from the second portion other than the first portion. Formed by material,
The inkjet recording apparatus according to claim 1, wherein the second portion is formed of a material that is less likely to extend than the first portion. The first movement start position is a position in the scanning direction corresponding to a carriage standby unit that makes the carriage wait.
The inkjet recording apparatus according to claim 1, wherein the second movement start position is a position in the scanning direction corresponding to a head maintenance unit that performs maintenance of the inkjet head.   The inkjet recording apparatus according to claim 1, wherein the driving force transmission member is a belt or a wire rope.

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