JP2013014128A - Inkjet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a structure that strikes a balance between an increase in speed and an improvement in image quality in a carriage of an inkjet printer.SOLUTION: In this inkjet printer, preload characteristics relative to a Y-rail are intentionally deviated in a plurality of mounting structure parts provided at a carriage. The posture variation of the carriage is minimized by clarifying a main mounting structure part and a sub mounting structure part.

Description

  The present invention relates to an inkjet printer that records an image by ejecting ink.

  In order to meet the demand for higher speed and higher image quality, inkjet printers are increasingly required to improve speed and to improve the landing position accuracy of ink ejected onto a recording medium. When the machine is operated at high speed, the vibration of the carriage, which has not been a problem in the past, affects the accuracy of ink landing position. The image quality has been improved by increasing the pressure applied to the mounting structure as much as possible. The Y rail is a linear rail arranged along the main scanning direction to move the carriage linearly, and the carriage moves along the Y rail. For this reason, distortion or twisting of the Y rail affects the behavior of the carriage.

  As an example of the ink jet printer having the above-described configuration, only the print head and the print head control board are mounted on the carriage, and ink is supplied from the ink cartridge placed outside the carriage to the print head via the tube. A configuration in which the ink tank is deleted from the top is mentioned. By adopting such an ink jet printer configuration, the mass of the carriage can be reduced, and the effect of increasing the rigidity can be obtained even if the applied structure has the same pressure. As a result, carriage vibration can be suppressed, and variations in ink landing position accuracy due to this can be reduced.

  By the way, as a countermeasure against such a problem, a proposal as disclosed in Japanese Patent Application Laid-Open No. 2008-207355 has been made. In the technique of this document, an acceleration sensor is mounted on the carriage, the behavior of the carriage is detected, the ink ejection timing from the print head is corrected based on the detection result, and the deterioration of the print quality due to the behavior of the carriage is prevented. doing.

JP 2008-207355 A

  In the ink jet printer in which the portion where the carriage is coupled to the Y rail is configured by a plurality of mounting structures, the carriage is rigidly coupled to the Y rail by the plurality of mounting structures. Therefore, the positional relationship between the plurality of mounting structures is fixed, and variations in accuracy such as the dimensions, warpage, and twisting of the parts affect the linear movement of the carriage. Furthermore, in order to avoid this influence, there was one in which a movable part was provided in a part of the mounting structure part. The movable part was normally pressurized by a spring or the like, and both the movable part and the high rigidity were compatible.

  On the other hand, the components of the Y rail and carriage are manufactured with high accuracy. However, since there are cost restrictions, the components are manufactured so that the component accuracy is within a certain allowable range. As a result, for example, a characteristic peculiar to the part such as warp or twist appears on the Y rail. When the carriage scans on the Y rail, the movable parts of the plurality of attachment structure parts move according to the position where the Y rail and the attachment structure part come into contact. By doing so, the carriage moves faithfully along the shape of the Y rail. However, when the deformation amount of the Y rail is large, all of the plurality of mounting structure portions may not contact the Y rail. In such a case, the carriage cannot move along the shape of the Y rail. For example, at a certain warp position, the mounting structure part that contacts the Y rail becomes one, and when it moves further, unexpected movement of the carriage occurs, such as suddenly switching to another mounting structure part, Occasionally, it becomes a vibration, which causes the image quality to deteriorate more than the image quality deterioration caused by the shape itself such as warp or twist of the Y rail.

  However, when the speed of inkjet printers has increased and high image quality has been demanded, such deterioration in image quality has also become a problem.

  The carriage was scanned while avoiding the changing shape on the Y rail one after another by such a mounting structure. Since the carriage has a plurality of attachment structure portions, the first attachment structure portion in the advancing direction always precedes, and the remaining attachment structure portions operate with a delay depending on the position. However, since the actual carriage is composed of a plurality of mounting structure parts with respect to the Y rail, the manufacturing variation of parts is compensated for by problems such as any one mounting structure part contacting the Y rail. There was a contradiction that it was impossible.

  The present invention suppresses the influence of warpage and distortion relative to the position of the carriage relative to the warp and distortion of the Y rail and parts, and as a result, the posture change of the carriage moving along the Y rail is reduced. An object of the present invention is to provide an ink jet printer that prevents deterioration in image quality and can achieve both high speed and high image quality even when parts such as a Y rail are distorted.

  In order to achieve the above object, an ink jet printer according to the present invention is arranged in a direction intersecting with a print head for ejecting ink onto a recording medium, a carriage on which the print head is mounted, and a conveyance direction of the recording medium. A plurality of mounting structures each having a plurality of bearings, the rails being movably coupled to the rails, and scanning the carriage along the rails from the print head to the recording medium. In the ink jet printer which records the image by discharging the ink, the mounting structure portion is composed of one main mounting structure portion and another mounting structure portion, and the main mounting structure portion is the main mounting structure with respect to the rail. Provided with a pressurizing mechanism for contacting at least one of the bearings provided in the structure while pressurizing When the carriage is scanning, all of the bearings included in the main mounting structure always come into contact with the rail, and one of the bearings included in each of the other mounting structures is the pressurized pressure. When the carriage is scanning, the bearings provided in each of the other mounting structures are in contact with the rail when the carriage is scanning. It is connected to the rail so as to be separable.

  An object of the present invention is to provide an ink jet printer that can reduce carriage vibration and achieve both high speed and high image quality even in the process of avoiding image quality degradation due to warping and distortion of parts.

It is a figure explaining the state in which the carriage is attached to the Y rail. It is a figure explaining an attachment structure part. FIG. 3 is a front view of the carriage according to the first exemplary embodiment. 6 is a front view of a carriage according to Embodiment 2. FIG. It is a figure which shows an example of an inkjet printer.

(Outline of the embodiment)
Next, an embodiment of the present invention will be described. The carriage is mounted with a print head that ejects ink, and the carriage scans along the Y rail and forms an image by ejecting ink to a desired position. The carriage is held by a plurality of mounting structures on the Y rail. For example, one mounting structure is fixed to the Y rail via four bearings. Three of them are fixed relative to the Y rail, and the other one is movable relative to the Y rail. The three fixed bearings are arranged in contact with each other according to the shape of the Y rail. The remaining one bearing is rotatably arranged on the pressure arm, and the pressure arm is rotatably supported by the pressure arm shaft with respect to the mounting structure. The pressurizing arm has a bearing on one side and a pressurizing spring on the other side across the pressurizing arm shaft. The bearing is pressed against the Y rail by the force of this spring. The pressurizing spring generates a sufficiently strong force that does not rattle even when the carriage is attached to the Y rail, and holds the carriage so that it does not jump even when scanning on the Y rail.

  In order to clarify the main mounting structure part serving as a positioning reference and the subordinate mounting structure part among the plurality of mounting structure parts, the pressure characteristics of the mounting structure part are intentionally different. The mounting structure portion having the strongest pressurizing characteristic is the main mounting structure portion, and the remaining mounting structure portion having a weaker pressurizing characteristic is the subordinate mounting structure portion. As a result, even in the process of scanning on the Y rail, the posture of the carriage is held by the main mounting structure attached to the Y rail, and the subordinate mounting structure is attached to the Y rail within the range of its ability. Further, as another form, a means for changing the pressurization characteristic of the mounting structure portion can be further provided, and the force generated by the pressurization spring can be changed. Use, no pressurizing without the pressurizing spring, etc. Moreover, what is provided with the spacer which controls the movement of a bearing is also mentioned. There may be a plurality of subordinate attachment structures.

(Details of the embodiment)
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating a state where a carriage is attached to a Y rail. FIG. 2 is a diagram for explaining the mounting structure. The Y rail 1 has a length equal to substantially the entire width of the apparatus, and functions as a guide when the carriage 2 scans. In the drawing, a part of the Y rail 1 is drawn with respect to the entire length.

  One or a plurality of print heads (not shown) are mounted on the carriage 2, and ink is ejected at an appropriate timing according to the image data to form an image. The carriage 2 is attached to a belt (not shown), and the carriage 2 moves together with the belt by driving the belt. The carriage 2 is attached to the Y rail 1 via an attachment structure portion 3a and an attachment structure portion 3b. The mounting structure 3 includes a bearing a7, a bearing b8, a bearing c9, and a bearing d10 that can be scanned without being detached from the Y rail 1. Of the mounting structure 3, the bearings a7, b8, and bearing c9 are fixed to the mounting structure 3 so that their mounting positions do not change, but are mounted via the pressurizing arm 5 that can move only the bearing d10. A bearing a7 and a bearing b8 are provided so as to sandwich the top of the Y rail 1. A bearing c9 and a bearing d10 are provided so as to sandwich the lower portion of the Y rail 1. The bearing a7 and the bearing c9 are in contact with a first plane that is a plane of the Y rail 1 on the side facing the carriage 2, and the bearing b8 and the bearing d10 are in contact with a plane that intersects the first plane. Four bearings apply forces in the vertical and horizontal directions of the Y rail 1. A pressurizing arm shaft 6 is provided at the approximate center of the pressurizing arm 5, and is rotatably attached to the attachment structure portion 3 via the pressurizing arm shaft 6. Further, a pressurizing spring 4 is arranged on the pressurizing arm shaft 6 on the side opposite to the bearing d10 mounting position, and pressurizes by this. As a result, the bearing d10 can always rotate while contacting the Y rail 1.

  The attachment structure part 3a and the attachment structure part 3b have the same structure as the attachment structure part 3 described individually. In the attachment structure portion 3a, a pressurizing spring 4a is used for pressurization. Further, the pressurizing arm 5a is attached by the pressurizing spring 4a with the pressurizing arm shaft 6a as a fulcrum, that is, with the rotation center. In the attachment structure portion 3b, a pressurizing spring 4b is used for pressurization. Also, the pressurizing arm 5b is attached by the pressurizing spring 4b with the pressurizing arm shaft 6b as a fulcrum, that is, with the rotation center. The carriage 2 is attached to the Y rail 1 by the attachment structure portion 3a and the attachment structure portion 3b before and after the carriage 2 moves in the moving direction. The elastic force of the pressurizing spring 4a and the pressurizing spring 4b are different, that is, the bearing attached to the pressurizing arm 5a and the bearing attached to the pressurizing arm 5b are in contact with the Y rail with different forces. The stronger bearing contact force is positioned as the main mounting structure, and the weaker bearing force is positioned as the subordinate mounting structure.

  FIG. 3 is a front view of a carriage according to an embodiment to which the present invention is applied. An attachment structure 3c is used instead of the attachment structure 3a. A spacer 15 is used in the mounting structure 3c in place of the pressurizing spring, and the bearing d10 that moves according to the height of the spacer 15 is held in a slightly floating state without contacting the Y rail 1. ing. The spacer 15 operates rigidly and is made of metal or plastic.

  Further, the spacer 15 may be provided on the mounting structure portion 3c. Thereby, the attachment structure part 3c is in a state where no pressure is applied, and the attachment structure part 3b to which the normal pressure is applied is positioned as the main attachment structure part and the attachment structure part as the subordinate attachment structure part 3c. As a result, for example, when the carriage 2 scans in the left direction in the figure, the attachment structure portion 3c always precedes, and the attachment structure portion 3b follows. In this process, the mounting structure 3c is not pressurized, so that the mounting structure 3b always contacts the Y rail 1. As a result, the mounting structure 3b does not move away from the Y rail, can move along the Y rail 1 faithfully, and the carriage 2 does not change its posture due to the inertial force at the time of movement, and the vibration of the carriage causes the image quality to deteriorate. No tilting occurs.

  FIG. 4 is a front view of a carriage according to another embodiment to which the present invention is applied. An attachment structure portion 3d and an attachment structure portion 3e are used instead of the attachment structure portion 3a and the attachment structure portion 3b. Pressurized spring weak type 17 is used for mounting structure portion 3d, and pressurized spring strong type 16 is used for mounting structure portion 3e. It is set so that the contact of the bearing is stronger than Type 17. Further, a damper member 18 is attached to the attachment structure portion 3d in parallel with the pressurized spring weak type 17. The damper member 18 has a function of buffering the movement of the pressurizing arm 5d, and can be composed of sponge or the like in addition to rubber and elastomer. In addition, a buffer member using silicone oil or gas, a torque limiter that applies a constant load to the operation, or the like may be used. The attachment structure portion 3e becomes the main attachment structure portion, and the attachment structure portion 3d becomes the subordinate attachment structure portion. Although not shown, it is also possible to adopt a configuration in which a damper member is attached in series with the spacer 15 as shown in FIG. 3 so that pressure is applied only when the deformation of the Y rail 1 is outside a predetermined range.

  The inkjet printer has a bidirectional printing mode in which printing is performed in the forward path and the backward path during carriage scanning, and a unidirectional printing mode in which printing is performed only in the forward path or the backward path. In the present invention, since the pressurization characteristics of the plurality of mounting structures are intentionally different, the position of the main mounting structure varies depending on the scanning direction of the carriage, i.e., when positioned forward and when positioned backward. There is. In the bi-directional printing mode, the position of the main mounting structure is changed in the forward return path in the operation of the apparatus. However, in the one-way printing mode, it can always be constant, and if the subordinate mounting structure is in front, other forces are not applied to the inertial force caused by being pulled by the belt. It is desirable to lay out the main mounting structure on the trailing side of the carriage.

  As described above, in the embodiment of the present invention, the carriage 2 is attached to the Y rail 1 using the eight bearings of the attachment structure portion 3. The mounting structure 3 is suspended and connected to the Y rail 1 by the bearings a7 and b8 above the mounting structure 3. A bearing c8 and a bearing d9 are provided in contact with the plane of the Y rail 1 on the side facing the carriage 2. These three bearings have no means for pressurization. Means for applying pressure only to the bearing d10 below the mounting structure 3 is provided. Ideally, all the bearings are in contact with the Y rail 1, but the Y rail 1 may be bent or warped, and the bearing may be separated from the Y rail 1. The bearing needs to be structured to be separated from the Y rail. Since the bearings c8 and d9 that are in contact with the plane of the Y rail 1 on the side facing the carriage 2 are important bearings that determine the posture of the carriage 2, a change in position is not preferable. Further, a force is applied to the upper bearing of the mounting structure 3 so that the mounting structure 3 hangs down on the Y rail 1 due to gravity, and more force is required than the lower bearing to apply a pressure against this. It is. If the vertical direction is the downward direction, the bearing d10 is applied to the Y rail 1 obliquely upward, that is, by applying a force having a vector in the upward direction and a direction perpendicular thereto, not only in the vertical direction but also in the vertical direction. Pressure will also be applied to. Thereby, it can pressurize, without being caught in a direction.

  FIG. 5 is a diagram illustrating an example of an inkjet printer. The Y rail 1 is provided over almost the entire width of the printer. An ink jet head is mounted inside the carriage 2. The timing belt 19 is a belt wound around a pulley 20 and is connected to the carriage 2. The pulley paired with the pulley 20 is in the shadow of the carriage 2 in the figure and is not shown. The timing belt 19 rotates by changing the rotation direction. Accordingly, the carriage 2 connected to the timing belt 19 reciprocates along the Y rail 1. The platen 21 supports the recording medium conveyed by the conveyance roller 22. A plurality of conveying rollers 22 are arranged along the platen 21. The recording medium is, for example, a plastic film or paper. Ink is ejected from an inkjet head mounted on the carriage 2 that passes over the recording medium supported by the platen 21 to record an image. The recording medium is intermittently driven in the transport direction and recorded when stopped, and transport and recording are performed alternately.

1 Y rail 2 Carriage 3, 3a, 3b, 3c, 3d, 3e Mounting structure 4, 4a, 4b Pressure spring 5, 5a, 5b, 5c, 5d, 5e Pressure arm 6, 6a, 6b, 6c, 6d 6e Pressurized arm shaft 7 Bearing a
8 Bearing b
9 Bearing c
10 Bearing d
DESCRIPTION OF SYMBOLS 11 Bearing a support shaft 12 Bearing b support shaft 13 Bearing c support shaft 14 Bearing d support shaft 15 Spacer 16 Pressurized spring strong type 17 Pressurized spring weak type 18 Damper member 19 Timing belt 20 Pulley 21 Platen 22 Transport roller

Claims (7)

A print head for ejecting ink onto a recording medium; a carriage on which the print head is mounted; a rail disposed in a direction intersecting the conveyance direction of the recording medium; and the carriage movably coupled to the rail. An ink jet printer that records an image by ejecting the ink from the print head to the recording medium while scanning the carriage along the rail;
The mounting structure portion is composed of one main mounting structure portion and another mounting structure portion, and the main mounting structure portion pressurizes at least one of the bearings included in the main mounting structure portion with respect to the rail. A pressurizing mechanism that makes contact, and when the carriage is scanning, all of the bearings provided in the main mounting structure always contact the rail,
One of the bearings provided in each of the other mounting structures is provided with or without being applied to the rail with a force smaller than that of the pressurizing mechanism, and the carriage scans. In the inkjet printer, the bearings included in each of the other mounting structure portions are coupled to the rails so as to be able to contact and separate from the rails.   The bearing provided in the main mounting structure portion is in contact with a first plane on the side of the rail facing the carriage and a second plane facing the direction in which the plane intersects the plane, The inkjet printer according to claim 1, wherein the bearing that pressurizes the rail by a pressure mechanism contacts the second plane.   The main attachment structure portion is provided at one end in the moving direction of the carriage, the other attachment structure portion is provided at the other end, the carriage is connected to a belt, and the belt rotates while switching the rotation direction. The ink jet printer according to claim 1, wherein the carriage moves as the belt rotates.   The inkjet printer according to claim 1, wherein the pressurizing mechanism includes a spring.   5. The recording is performed on the recording medium when the position where the main mounting structure is provided is ahead of the other mounting structure in the traveling direction of the carriage. 6. 2. An ink jet printer according to item 1.   The ink jet printer according to any one of claims 1 to 5, further comprising a buffer member that buffers sudden movement of the bearing.   The inkjet printer according to any one of claims 1 to 6, further comprising a spacer that regulates a moving amount of the bearing.

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