JP2007045007A - Inkjet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure that a change in the angle of a carrier with paper is slight as viewed in the subscan direction and the quality of an image formed on the paper can hardly deteriorate by making the carrier hardly deflect, in whatever position its center of gravity lies, in an inkjet printer. <P>SOLUTION: The carrier 2 has a mounted printing head which is given a drive force by a drive mechanism 5 and reciprocates in the main scan direction along a shaft 3 and drips ink on paper P. The carrier 2 is constituted of a first frame 2a with the mounted printing head and a second frame 2b which is of little mass and high rigidity and connected with a connecting protuberance 24a of the first frame 2a through a connecting boss 24b. In addition, a belt 5a is connected with a driven part 25b of the second frame 2b. The second frame 2b transmits the drive force to the first frame 2a and reciprocates with the latter, without generating the deflection or deformation by providing the driven part 25b with the drive force. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet printer that forms an image on a sheet by a print head mounted on a reciprocating carrier.

  2. Description of the Related Art Conventionally, an ink jet printer that forms an image on a sheet transported in a sub-scanning direction by reciprocating a carrier mounted with a print head for ejecting ink from nozzles in the main scanning direction has been used (for example, Patent Documents). 1 to Patent Document 3). Such an ink jet printer is, for example, a shaft arranged along the main scanning direction inside the housing, a carrier slidably fitted to the shaft, and arranged along the main scanning direction, in a part of the carrier. It has a belt or the like that is engaged. The carrier is reciprocated in the main scanning direction while sliding with the shaft, for example, when the belt is rotated by a DC motor or the like.

  In such an ink jet printer, when the moving direction of the carrier changes, so-called blurring or vibration may occur in the carrier. When blurring occurs on the carrier, the angle of the carrier with respect to the paper changes, and the position where the ink ejected from the nozzles of the print head adheres to the paper changes, reducing the quality of the image formed on the paper. End up. In particular, the nozzles are ejected from the print head while the carrier reciprocates in the main scanning direction. Therefore, when the change in the angle of the carrier with respect to the paper as seen from the sub-scanning direction becomes large, the quality of the image formed on the paper deteriorates. It becomes remarkable.

  Hereinafter, a change in the angle of the carrier with respect to the sheet as seen from the sub-scanning direction, which occurs when the carrier reciprocates, will be described with reference to schematic views. 4A and 4B show the carrier of the ink jet printer. In the figure, an arrow A indicates the main scanning direction, and the sub-scanning direction is the front-rear direction of the figure. The carrier 82 is provided with a print head (not shown) on the lower surface so as to face a sheet (not shown) disposed below, and an ink cartridge (not shown) for supplying ink to the print head. ) Is installed. The carrier 82 has a cylindrical bearing portion 821 that is slidably fitted to the shaft 83 at the lower portion of the back surface. Here, as shown in FIG. 4A, the carrier 82 conceptually corresponds to a bearing portion 821 positioned at the lower portion and a portion such as an ink cartridge that is located away from the shaft 83 and has a relatively large weight. It can be understood that the weight portion 822 is connected to the bearing portion 821 and the weight portion 822 and is configured by a frame 823 corresponding to the housing of the carrier 82. As indicated by black circles in the figure, the center of gravity CG of the carrier 82 is located between the weight portion 822 and the bearing portion 821.

  As described above, for example, a belt (not shown) or the like is engaged with the carrier 82, and the carrier 82 receives a driving force from a portion with which the belt or the like is engaged, whereby the main scanning direction. Reciprocate in the direction of arrow A in the figure. FIG. 4B shows the carrier 82 when the driving force (indicated by an arrow M in the figure) is input near the weight portion 822, that is, from above the bearing portion 821 and the center of gravity CG. When the driving force is input near the weight portion 822, a moment is generated around the center of gravity CG. At this time, as shown in the figure, the carrier 82 may be inclined by an angle θ from the steady state as shown in FIG. . When the carrier 82 is tilted in this way, the angle of the carrier 82 with respect to the paper as viewed from the sub-scanning direction is changed, and the quality of the image formed on the paper is deteriorated as described above. In general, the deterioration of image quality due to such a change in angle becomes a problem when the change in angle becomes larger than about 1/100 degree. Such a tilt of the carrier 82 occurs similarly when a driving force is input to a portion closer to the bearing portion 821 than the center of gravity CG.

  Conventionally, in order to prevent the carrier 82 from being tilted in this way and causing blurring and the like, and to prevent the quality of the formed image from being deteriorated, the driving force is input from the vicinity of the center of gravity CG of the carrier 82 Sometimes it is said. When the driving force is input from a portion close to the center of gravity CG, the moment generated around the center of gravity CG is reduced. For this reason, the inclination of the carrier 82 as described above hardly occurs.

  However, the position of the center of gravity CG of the carrier 82 changes, for example, when the remaining amount of ink in the ink cartridge is reduced by continuing the image forming operation, and the driving force is at a position completely matching the center of gravity CG. It cannot be configured to be input. Further, since the printer is enlarged, it may be difficult to configure the carrier 82 so that the driving force is input near the center of gravity CG.

Patent Document 1 describes an ink jet printer that controls a motor that drives a carrier in accordance with the amount of remaining ink in order to prevent a change in the landing position of the ink on the paper due to a change in the weight of the carrier. Has been. In Patent Document 2, when the carrier reciprocates in the main scanning direction, in order to prevent the print position from being different between the forward path and the backward path, one print position is corrected based on the amount of deviation of the print pattern between the forward path and the backward path. Inkjet printers are described. Further, in Patent Document 3, in an ink jet printer in which a plurality of print heads having different configurations can be selectively mounted on a carrier, the ink ejection timing is automatically set according to the mounted print head, and the print misalignment is detected. A minimal configuration is described. However, the ink jet printers described in Patent Documents 1 to 3 cannot solve the problem that the quality of the image formed on the sheet is lowered due to the inclination of the carrier 82 as described above.
JP 2000-309110 A JP 11-286142 A Japanese Patent Laid-Open No. 10-6533

  The present invention has been made in view of the above-described problems. The carrier is less likely to be shaken regardless of the position of the center of gravity of the carrier, and the angle of the carrier with respect to the paper viewed from the sub-scanning direction. An object of the present invention is to provide an ink jet printer in which the quality of an image formed on a sheet is unlikely to deteriorate.

In order to achieve the above object, the invention according to claim 1 is a paper transport mechanism for transporting paper in the sub-scanning direction, and a shaft fixed to the printer housing so that the main scanning direction orthogonal to the sub-scanning direction is the longitudinal direction. And a cylindrical bearing portion that is slidably fitted to the shaft, and a print head that discharges ink from the nozzles to form an image on the paper is mounted, and the bearing portion and the shaft And a carrier that reciprocates in the main scanning direction while sliding, an annular belt that is arranged in the printer housing along the main scanning direction, and a DC motor that rotates the belt. In an inkjet printer provided with a drive mechanism that applies a driving force to the carrier by rotating the belt to reciprocate the carrier in the main scanning direction.
The carrier casing has a first frame that holds the print head and has one first bearing portion fitted to the shaft on the back side, and another connected to the back side of the first frame. The second frame is composed of two second bearing portions fitted to the shaft different from the first bearing portion, and the first frame. Are connected to four columnar connecting projections standing around the center of gravity at positions away from the center of gravity of the first frame on the back surface of the first frame so as to be rotatable around the axis of the connecting projection. A boss, a driven portion that is connected to the belt and serves as a portion on which a driving force by the driving mechanism acts, and a beam portion that integrally connects the second bearing portion, the connecting boss, and the driven portion. And pass through its center of gravity compared to the first frame The mass is so small that the moment of inertia around an axis parallel to the scanning direction is negligible, and a driving force in the main scanning direction is applied to the driven portion while being connected to the first frame. The belt is so rigid that the amount of deformation is within a predetermined value, and the fitting length of the second bearing portion with the shaft is longer than the fitting length of the first bearing portion with the shaft. Is connected only to the driven part, and is configured such that the driving mechanism does not directly apply a driving force to the first frame, and the second frame receives a driving force from the driving mechanism. When the carrier is reciprocated in the main scanning direction along with the reciprocating movement along the shaft, the angle of the first frame relative to the sheet as viewed from the sub scanning direction changes. Seems difficult One in which the.

  According to a second aspect of the present invention, there is provided a paper transport mechanism that transports paper in the sub-scanning direction, a shaft that is fixed to the printer housing so that the main scanning direction orthogonal to the sub-scanning direction is the longitudinal direction, and a slide on the shaft. It has a cylindrical bearing part that is movably fitted, and a print head that forms an image on the paper by ejecting ink from the nozzle is mounted, while the bearing part and the shaft slide, An ink jet printer comprising: a carrier reciprocated in a main scanning direction; and a drive mechanism that reciprocates the carrier by applying a driving force to the carrier in the main scanning direction. A first frame that holds the head and has a first bearing portion fitted to the shaft on the back surface, and a second frame of another member connected to the back surface side of the first frame. The second frame includes a second bearing portion that is fitted to the shaft different from the first bearing portion, and a plurality of carrier connecting portions that are connected to the first frame. And a driven part that is a part to which the driving force by the driving mechanism acts, a second bearing part, a carrier connecting part, and a beam part that integrally connects the driven part, Compared to the first frame, the driven portion has a small mass such that the moment of inertia around the axis parallel to the sub-scanning direction passing through the center of gravity is negligible and is connected to the first frame. The rigidity is so high that the amount of deformation when the driving force in the main scanning direction is applied is within a predetermined value, and the driving mechanism applies the driving force only to the driven part, and applies the first frame to the first frame. It is configured not to give driving force directly. When the carrier is reciprocated in the main scanning direction as the second frame reciprocates along the shaft by applying a driving force from the driving mechanism, the second frame is viewed from the sub scanning direction. The angle of the first frame with respect to the sheet is made difficult to change.

  According to a third aspect of the present invention, in the second aspect of the present invention, the carrier connecting portion surrounds the position of the center of gravity of the first frame when viewed from the sub-scanning direction at a position away from the center of gravity of the first frame. It is comprised so that it may each be connected with a position.

  According to the first aspect of the present invention, the carrier casing is configured by connecting the second frame having a small mass and high rigidity to the first frame from the back side, and the belt is covered by the second frame. The first frame is connected only to the drive unit, and the first frame reciprocates together with the second frame by the driving force applied to the second frame, and the angle of the first frame with respect to the sheet changes from the sub-scanning direction. Therefore, it is possible to make it difficult to reduce the quality of the image formed on the paper regardless of the position of the center of gravity of the carrier. Further, since the carrier connecting portion is connected to a position away from the center of gravity of the first frame and a position surrounding the position of the center of gravity of the first frame when viewed from the sub-scanning direction, It becomes difficult for rattles or the like to occur between one frame and the quality of the image formed on the paper can be made more difficult to deteriorate.

  According to the invention of claim 2, the housing of the carrier is configured such that the second frame having a small mass and high rigidity is connected to the first frame from the back side, and the first frame is the second frame. Since the driving force applied to the frame reciprocates with the second frame and the angle of the first frame with respect to the paper as viewed from the sub-scanning direction is unlikely to change, the quality of the image formed on the paper is the same as described above. Can be made difficult to decrease.

  According to the invention of claim 3, since the carrier connecting portion is connected to a position away from the center of gravity of the first frame and a position surrounding the position of the center of gravity of the first frame when viewed from the sub-scanning direction. The second frame is more reliably connected to the first frame, and the angle of the first frame with respect to the paper is less likely to change. Thereby, it becomes possible to make it difficult to lower the quality of the image formed on the paper.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an example of an inkjet printer according to this embodiment. The ink jet printer (hereinafter referred to as a printer) 1 includes a sub-head orthogonal to the main scanning direction by a print head (not shown) mounted on a carrier 2 that reciprocates in the main scanning direction (indicated by an arrow A in the figure). An image is formed on the paper P conveyed in the scanning direction (indicated by an arrow B in the figure). The printer 1 includes a carrier 2, a shaft 3 disposed inside the housing 10 of the printer 1 on the back side of the carrier 2 so that the main scanning direction is the longitudinal direction, and a paper transport mechanism that transports the paper P. 4, a drive mechanism 5 that applies a driving force to the carrier 2 to reciprocate, and an encoder scale that is used to detect the position of the carrier 2 in the main scanning direction and is arranged in the housing 10 along the main scanning direction. 6 is provided.

  The carrier 2 is equipped with a plurality of ink cartridges 20 in which, for example, a plurality of colors of ink are sealed. A print head having nozzles (not shown) serving as ink ejection holes is provided on the lower surface of each ink cartridge 20. In addition, a photocoupler (not shown) is mounted on the carrier 2, and this photocoupler can detect the position of the carrier 2 in the main scanning direction by scanning on the encoder scale 6 having a predetermined resolution. It is comprised so that. In the present embodiment, the carrier 2 is slidably fitted to the shaft 3 as will be described later, and has a contact protrusion (not shown) on the top of the carrier 2, for example. Arranged in contact with the housing 10 so as to be slidable in the main scanning direction. The carrier 2 is disposed so as to be movable in the main scanning direction while sliding with the shaft 3 in a state where the distance between the paper P and the printer head is kept substantially constant by the contact protrusion contacting the housing 10. ing.

  The drive mechanism 5 includes an annular belt 5 a disposed along the main scanning direction in the casing 10 of the printer 1, a DC motor 5 b for rotating the belt 5 a, and one drive mechanism 5 near both sides of the casing 10. One is provided with a belt 5a, and the other has a pulley 5c connected to a DC motor 5b. A part of the belt 5a is connected to the carrier 2 as described later. The drive mechanism 5 rotates the one pulley 5c by the DC motor 5b to rotate the belt 5a, thereby applying a driving force to the carrier 2 to reciprocate in the main scanning direction.

  Next, the image forming operation of the printer 1 will be described. First, the paper P placed on the paper tray 11 is transported in the sub-scanning direction by the paper transport mechanism 4. When the paper P is conveyed below the print head, a driving force is applied to the carrier 2 by the driving mechanism 5 so that the carrier 2 reciprocates in the main scanning direction. As the carrier 2 reciprocates and the print head ejects ink from the nozzles toward the paper P, a line of images is formed on the paper P in the main scanning direction. Then, the paper P is transported in the sub-scanning direction by the paper transport mechanism 4 and the print head discharges ink while the carrier 2 reciprocates to form a row of images on the paper P. An image is formed on P. When an image is formed on the paper P, the paper P is discharged onto the paper discharge tray 12, and the image forming operation is completed.

  FIG. 2 shows the back side of the carrier 2 of the printer 1. Here, in the present embodiment, the housing of the carrier 2 includes a first frame 2a that holds the print head, and a second frame 2b that is another member connected to the back side of the first frame 2a. Has been. As shown in the figure, in the present embodiment, the shaft 3 is provided so as to be located near the center of the back surface of the carrier 2, and is slidable with the shaft 3 at the approximate center of the back surface of the first frame 2 a. One first bearing portion 21a fitted to is provided. Further, four, for example, columnar connection protrusions 24a are erected on the substantially rectangular back surface of the first frame 2a. The connection protrusions 24a are formed in the vicinity of the four corners of the substantially rectangular back surface of the first frame 2a, and are arranged so as to surround the center of gravity at a position away from the center of gravity of the first frame 2a. In addition, the position and shape of these connection protrusions 24a are not restricted to this.

  The second frame 2b has two second bearing portions 21b different from the first bearing portion 21a fitted to the shaft 3, and four pieces connected to the connection protrusions 24a of the first frame 2a, respectively. A connection boss (carrier connection portion) 24b, a driven portion 25b that is connected to the belt 5a and serves as a portion where the driving force by the drive mechanism 5 acts, the second bearing portion 21b, the connection boss 24b, and the driven And a beam portion 23b that integrally connects the portion 25b. In the present embodiment, as shown in the drawing, the second bearing portion 21b is disposed on both ends of the first bearing portion 21a at both ends in the substantially central width direction of the back surface of the carrier 2. Each second bearing portion 21b is integrally provided with a driven portion 25b and connected to the belt 5a, and the driving force of the driving mechanism 5 is input to the driven portion 25b. The belt 5a is connected only to the driven part 25b, and is configured so that the driving mechanism 5 does not directly apply a driving force to the first frame 2a. The four connecting bosses 24b are respectively arranged so as to correspond to the connecting projections 24a of the first frame 2a, and these connecting bosses 24b and the second bearing portion 21b are integrally connected by the beam portion 23b. Two frames 2b are formed.

  The first bearing portion 21a and the second bearing portion 21b are molded with high accuracy in accordance with the outer diameter of the shaft 3 so that backlash or the like is not generated between the first bearing portion 21a and the second bearing portion 21b with the shaft 3. By being lubricated with grease or the like, the frictional force when sliding with the shaft 3 is reduced. And in this embodiment, it is comprised so that the fitting length with the shaft 3 of the 2nd bearing part 21b may become longer than the fitting length with the shaft 3 of the 1st bearing part 21a, and the 1st bearing part The second bearing portion 21b is configured to be less inclined in the axial direction with respect to the shaft 3 than 21a. In addition, the structure of the 1st bearing part 21a and the 2nd bearing part 21b is not restricted to this.

  The connection bosses 24b are connected to the connection protrusions 24a so as to be rotatable around the axis of the connection protrusions 24a, for example, with the contact surfaces of the connection bosses 24b and the connection protrusions 24a lubricated with grease or the like. . Each connecting boss 24b is rotatable with respect to the connected connecting projection 24a. However, since each connecting boss 24b is integrally molded as the second frame 2b, the first frame 2a and the second frame 2b are integrally formed. In a state where the frame 2b is connected, the first frame 2a cannot rotate with respect to the second frame 2b.

  Here, the second frame 2b is made of a material having a high specific rigidity as compared with a normal resin or the like, such as a plastic with glass fiber. The second frame 2b has such a small mass that the moment of inertia around the axis parallel to the sub-scanning direction passing through the center of gravity of the second frame 2b is negligible compared to the first frame 2a. In addition, it is molded into a shape having high rigidity so that it hardly deforms when a driving force is input to the driven portion 25b while being connected to the first frame 2a. Since the second frame 2b is shaped in this way, the carrier 2 is main-scanned as the second frame 2b reciprocates along the shaft 3 when a driving force is applied from the driving mechanism 5. When reciprocating in the direction, the angle of the first frame 2a with respect to the paper P viewed from the sub-scanning direction is less likely to change. This will be described below.

  FIG. 3 schematically shows the carrier 2. In the figure, an arrow A indicates the main scanning direction, and the sub-scanning direction is the front-rear direction of the figure. In the drawing, in order to schematically show the structure of the carrier 2, the first bearing portion 21 a and the second bearing portion 21 b are shown so as to be fitted to the shaft 3 positioned below the carrier 2. Further, two connecting protrusions 24a and two connecting bosses 24b are omitted. The first frame 2a of the carrier 2 includes a first bearing portion 21a, a weight portion 22a corresponding to a portion having a relatively large weight at a position away from the shaft 3, such as an ink cartridge, and the first bearing portion 21a and the weight. Suppose that it is comprised with the flame | frame 23a corresponding to the site | part which connects the part 22a. A connection protrusion 24a is provided in the vicinity of the first bearing portion 21a and the weight portion 22a.

  As shown in the figure, in the second frame 2b, two second bearing portions 21b fitted to the shaft 3 and a connection boss 24b connected to the connection protrusion 24a are integrally connected by a beam portion 23b. Configured. Although the driven portion 25b is not shown in the drawing, the driving force by the driving mechanism 5 is input to the vicinity of the second bearing portion 21b of the second frame 2b and acts only on the second frame 2b. And As described above, since the mass of the second frame 2b is small, the center of gravity CG of the carrier 2 is substantially at the same position as the center of gravity of the first frame 2a, and as shown by the black circles in the figure, the weight 22a And the first bearing portion 21a.

  When driving force is input to the carrier 2 by the driving mechanism 5, the second frame 2 b reciprocates along the shaft 3. When the second frame 2b moves, the first frame 2a also moves with the connection boss 24b and the connection protrusion 24a being connected. That is, the driving force input from the drive mechanism 5 to the second frame 2b is transmitted to the first frame 2a and indirectly input, and the first frame 2a moves. Since the driving force is transmitted from the plurality of connecting bosses 24b of the second frame 2b, the first frame 2a is reciprocated without generating a moment around an axis passing through the center of gravity CG in the sub-scanning direction. At this time, the change in the angle of the second frame 2b with respect to the paper P viewed from the sub-scanning direction of the first frame 2a connected to the second frame 2b is smaller than about 1/100 degree. However, it is configured not to be deformed. That is, the deformation amount of the second frame 2b is within a predetermined value when the carrier 2 is reciprocated in the main scanning direction. As described above, even if a driving force is input to the second frame 2b, the second frame 2b is hardly shaken or deformed due to the presence of the moment of inertia. Accordingly, the angle of the first frame 2a with respect to the paper P as viewed from the sub-scanning direction is less likely to change compared to the conventional carrier 82 as shown in FIG. 4B.

  Thus, since the angle of the first frame 2a with respect to the paper P as viewed from the sub-scanning direction is difficult to change, the position of the carrier 2 where the center of gravity is located and the position where the driving force is input is the center of gravity. Even if the position is far from the position, the quality of the image formed on the paper P can be made difficult to deteriorate. In the present embodiment, the connecting projection 24a and the connecting boss 24b that connect the first frame 2a and the second frame 2b are positioned so as to surround the center of gravity of the first frame 2a when viewed from the sub-scanning direction. In addition, since it is arranged away from the center of gravity, rattling or the like is unlikely to occur between the second frame 2b and the first frame 2a, and the quality of the image formed on the paper P is more unlikely to deteriorate. It becomes possible to do.

  In addition, this invention is not limited to the structure of the said embodiment, A various deformation | transformation is possible suitably in the range which does not change the meaning of invention. For example, the carrier connecting portion is not limited to the connecting boss 24b that is rotatably connected to the connecting protrusion 24a as described above, and is, for example, a protruding shape that is inserted into a hole provided in the first frame 2a. It may be a thing. The carrier 2 is connected to the first frame 2a through the carrier connecting portion and the second frame 2b having a small mass and high rigidity is connected to the second frame 2b, and the driving force by the driving mechanism 5 is applied to the second frame 2b. By adopting the configuration, similarly, the angle of the first frame 2a with respect to the paper P viewed from the sub-scanning direction is unlikely to change, and the quality of the image formed on the paper P can be more unlikely to be lowered. Become.

1 is a perspective view of an ink jet printer according to an embodiment of the present invention. The perspective view which shows the back surface of the carrier of a printer same as the above. The figure which shows typically the structure of the carrier of a printer same as the above. (A) is a figure which shows typically the structure of the carrier of the conventional inkjet printer, (b) is a figure which shows typically when a driving force is input into (a).

Explanation of symbols

1 Printer (inkjet printer)
2 Carrier 2a 1st frame 2b 2nd frame 21a 1st bearing part 21b 2nd bearing part 23b Beam part 24a Connection protrusion 24b Connection boss (carrier connection part)
25b Driven portion 3 Shaft 4 Paper transport mechanism 5 Drive mechanism 5a Belt 5b DC motor 10 Housing (printer housing)
P paper

Claims (3)

A paper transport mechanism for transporting paper in the sub-scanning direction;
A shaft fixed to the printer housing such that the main scanning direction orthogonal to the sub-scanning direction is the longitudinal direction;
A cylindrical bearing portion that is slidably fitted to the shaft is mounted, and a print head that forms an image on the paper by ejecting ink from the nozzle is mounted, and the bearing portion and the shaft slide. A carrier that reciprocates in the main scanning direction while moving;
An annular belt arranged along the main scanning direction in the printer casing and a DC motor for rotating the belt are provided. By rotating the belt, a driving force is applied to the carrier to In an inkjet printer comprising a drive mechanism for reciprocating a carrier in the main scanning direction,
The carrier casing has a first frame that holds the print head and has one first bearing portion fitted to the shaft on the back side, and another connected to the back side of the first frame. A second frame of the members of
The second frame is separated from the center of gravity of the first frame on the back of the first frame, and the two second bearing portions fitted to the shaft different from the first bearing portion. At the position, four columnar connecting projections standing so as to surround the center of gravity are connected to a connecting boss rotatably connected around the axis of the connecting projection, and connected to the belt by the driving mechanism. It has a driven part that is a part where a driving force acts, and a second bearing part, a connecting boss, and a beam part that integrally connects the driven part, and its center of gravity as compared with the first frame. The inertial moment about an axis parallel to the sub-scanning direction passing through is small so that the moment of inertia is negligible, and the driven portion is driven in the main scanning direction while being connected to the first frame. The amount of deformation when force is applied is within a specified value Every time the high rigidity,
The fitting length of the second bearing portion with the shaft is longer than the fitting length of the first bearing portion with the shaft,
The belt is connected only to the driven part, and the driving mechanism is configured not to give a driving force directly to the first frame,
When the carrier is reciprocated in the main scanning direction as the second frame reciprocates along the shaft as a driving force is applied from the driving mechanism, the carrier is viewed from the sub-scanning direction. An inkjet printer characterized in that the angle of the first frame with respect to the paper is less likely to change. A paper transport mechanism for transporting paper in the sub-scanning direction;
A shaft fixed to the printer housing such that the main scanning direction orthogonal to the sub-scanning direction is the longitudinal direction;
A cylindrical bearing portion that is slidably fitted to the shaft is mounted, and a print head that forms an image on the paper by ejecting ink from the nozzle is mounted, and the bearing portion and the shaft slide. A carrier that reciprocates in the main scanning direction while moving;
In an inkjet printer provided with a drive mechanism that reciprocates the carrier by applying a driving force to the carrier in the main scanning direction,
The carrier casing holds the print head, and has a first frame having a first bearing portion fitted to the shaft on the back surface, and another member connected to the back surface side of the first frame. Of the second frame,
The second frame includes a second bearing portion fitted to the shaft different from the first bearing portion, a plurality of carrier connecting portions connected to the first frame, and driving by the driving mechanism. It has a driven part that acts as a force acting part, and a beam part that integrally connects the second bearing part, the carrier connecting part, and the driven part, and its center of gravity as compared with the first frame. The mass of the inertia around the axis parallel to the sub-scanning direction passing through is small so that it can be ignored, and the driven portion is driven in the main scanning direction while being connected to the first frame. The rigidity is so high that the deformation when the force is applied is within a predetermined value,
The driving mechanism is configured to apply a driving force only to the driven part and not to apply a driving force directly to the first frame;
When the carrier is reciprocated in the main scanning direction as the second frame reciprocates along the shaft as a driving force is applied from the driving mechanism, the carrier is viewed from the sub-scanning direction. An inkjet printer characterized in that the angle of the first frame with respect to the paper is less likely to change.   The carrier connecting portion is configured to be connected to a position away from the center of gravity of the first frame and a position surrounding the position of the center of gravity of the first frame when viewed from the sub-scanning direction. The inkjet printer according to claim 2.

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