JP2005306032A - Recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recorder capable of adjusting the gap between the head surface and a carrying belt while sustaining a sheet in the state parallel with the head surface. <P>SOLUTION: A gap adjusting mechanism 40 adjusts the gap on the drive roller 11 side by moving the drive roller 11 side part of a belt chassis for holding a carry belt 13 in the direction approaching/receding to/from the head surface by means of a drive side gap adjusting mechanism 41, and adjusts the gap on the driven roller side by moving the driven roller side part of the belt chassis in the direction approaching/receding to/from the head surface 2a by means of a driven side gap adjusting mechanism 42 in synchronism with the drive side gap adjusting mechanism 41. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a recording apparatus including a recording head for recording on a recording medium.

  In a recording apparatus that transports and records a sheet to a position opposite to the head surface of the recording head by a transport belt, there is a gap between the head surface of the recording head and the transport belt according to the thickness of the transported sheet. Some have a mechanism to adjust the gap. For example, in the recording apparatus described in Patent Document 1, a conveyance belt is stretched between a driving roller and a driven roller, and a gap adjustment mechanism that adjusts a gap between the head surface and the conveyance belt is a driving device. The gap is adjusted by changing the height position of the conveyor belt by swinging up and down the portion of the conveyor belt unit on the driven roller side about the rotation axis of the roller.

Japanese Patent Laying-Open No. 2003-94744 (see FIGS. 42 and 43)

  However, the gap adjusting mechanism of the recording apparatus described above is configured to adjust the height position of the conveyor belt by swinging the conveyor belt unit up and down around one axis (rotation axis of the driving roller). The paper on the conveyor belt is not parallel to the head surface. Therefore, the paper is transported to the recording head while being inclined with respect to the head surface, and particularly when the head surface is long in the paper transport direction, such as when the recording head is a line-type color inkjet head. As a result, the print quality may be deteriorated, or the paper may not be smoothly conveyed.

  An object of the present invention is to provide a recording apparatus capable of adjusting a gap between a head surface and a conveyance belt while maintaining a state in which the recording medium is parallel to the head surface.

Means for Solving the Problems and Effects of the Invention

  A recording apparatus according to a first aspect of the present invention includes a recording head for recording on a recording medium, two rollers, and a conveyance belt stretched between the two rollers, and a position facing the head surface of the recording head. And a gap adjusting mechanism for adjusting a gap between the head surface and the conveying belt, the gap adjusting mechanism paralleling the conveying belt to the head surface. The gap is adjusted by moving in a stable state.

  In this recording apparatus, the recording medium is conveyed to a position facing the head surface of the recording head by a conveying belt that is stretched between two rollers, and recording is performed on the recording medium by the recording head. Furthermore, the recording head includes a gap adjusting mechanism that adjusts the gap between the head surface of the recording head and the conveyance belt in accordance with the thickness of the recording medium. The gap adjusting mechanism is configured to adjust the gap between the head surface and the conveyor belt by moving the conveyor belt in a state parallel to the head surface. Therefore, even when the area of the head surface is large, the recording medium can be recorded on the recording medium by the recording head in a state where the recording medium is always parallel to the head surface, and the printing quality can be improved. In addition, the paper can be smoothly conveyed to the recording head.

  According to a second aspect of the present invention, there is provided a recording apparatus according to the first aspect, wherein the transport unit includes a belt chassis that holds the transport belt, a driving roller that is pivotally supported at both ends of the belt chassis in the transport direction, and a driven member. The gap adjusting mechanism moves the portion of the belt chassis on the side of the driving roller in a direction to approach / separate the head surface of the recording head. A driven-side gap adjusting mechanism, and a driven-side gap that moves the driven roller side portion of the belt chassis in a direction approaching / separating from the head surface of the recording head in synchronization with the driving-side gap adjusting mechanism. And an adjusting mechanism.

  The conveyance unit rotates the drive roller with a drive motor, thereby moving the conveyance belt stretched between the drive roller and the driven roller, and conveys the recording medium to the recording head via the conveyance belt. Furthermore, the gap adjustment mechanism adjusts the gap on the drive roller side by moving the drive roller side portion of the belt chassis holding the conveyor belt in a direction approaching / separating from the head surface by the drive side gap adjustment mechanism. In addition, the driven-side gap adjustment mechanism adjusts the driven-roller-side gap by moving the driven-roller side portion of the belt chassis in a direction approaching / separating from the head surface in synchronization with the drive-side gap adjustment mechanism. can do. In this way, the drive roller side portion and the driven roller side portion of the belt chassis can be moved in a direction approaching / separating from the head surface in synchronization with each other. It is possible to adjust the gap in a parallel state.

  According to a third aspect of the present invention, there is provided the recording apparatus according to the second aspect, wherein the drive-side gap adjusting mechanism is provided on the rotary shaft of the drive roller in a state of being eccentric with respect to the axis. A cam drive motor for rotating the first cam member, and rotating the first cam member with the cam drive motor to cause the drive roller eccentric with respect to the first cam member to move the head. It is characterized by being moved in a direction approaching / separating from the surface.

  Since the first cam member is provided in an eccentric state with respect to the rotation shaft of the drive roller, when the first cam member is rotated by the cam drive motor, the drive roller eccentric with respect to the first cam member is provided. Move in a direction approaching / separating from the head surface. Thus, the drive roller can be moved in the direction of approaching / separating from the head surface by the drive-side gap adjusting mechanism having a simple configuration.

  According to a fourth aspect of the present invention, there is provided a recording apparatus according to the third aspect, wherein the drive motor and the cam drive motor are combined with one motor. Therefore, the number of motors can be reduced, and the manufacturing cost can be reduced.

  According to a fifth aspect of the present invention, there is provided the recording apparatus according to the third or fourth aspect, wherein the first cam member provided on the rotation shaft of the precursor drive motor when the drive roller is rotationally driven by the drive motor. It has a stopper which locks so that it may not rotate. Therefore, when the driving roller rotates, the stopper can restrict the rotation of the first cam member due to the rotation of the driving roller, so that the driving roller is driven when the recording medium is conveyed. It is possible to prevent the position of the roller relative to the head surface from changing.

According to a sixth aspect of the present invention, in the recording apparatus according to any one of the third to fifth aspects, the driven-side gap adjusting mechanism is provided rotatably on the recording head side with respect to the transport belt, and the cam drive motor A camshaft connected to the camshaft, and a second cam member that is provided in an eccentric state with respect to the shaft center of the camshaft and abuts against a portion of the belt chassis on the driven roller side,
By rotating the cam shaft in synchronization with the first cam member by the driving force of the cam drive motor, the portion on the driven roller side of the belt chassis contacting the second cam member with respect to the head surface And moving in the direction of approaching / separating.

  Since the second cam member is provided eccentrically with respect to the cam shaft connected to the cam drive motor, the second cam is rotated when the cam shaft is rotated in synchronization with the first cam member by the cam drive motor. The portion of the belt chassis in contact with the member on the driven roller side moves in a direction approaching / separating from the head surface. As described above, the driven-side gap adjusting mechanism having a simple configuration can move the driven roller side portion of the belt chassis in a direction approaching / separating from the head surface in synchronization with the movement of the driving roller. .

  According to a seventh aspect of the present invention, there is provided a recording apparatus according to the sixth aspect, wherein a guide member that guides the recording medium to the recording head is provided on the cam shaft, and a pressing roller that presses the recording medium conveyed to the recording head. Is characterized by being pivotally supported. Therefore, the recording medium can be smoothly conveyed to the recording head. Further, by arranging the guide member and the pressing roller around the cam shaft, the recording apparatus can be configured compactly.

  According to an eighth aspect of the present invention, in the sixth or seventh aspect of the invention, the parallelism of the transport belt with respect to the head surface is adjusted by adjusting a position of the second cam member in a direction perpendicular to the head surface. It is characterized by having a parallelism adjusting mechanism capable of adjusting the angle. Accordingly, the parallelism adjusting mechanism can easily adjust the parallelism of the transport belt with respect to the head surface.

Embodiments of the present invention will be described. This embodiment is an example in which the present invention is applied to a line-type color inkjet printer.
The inkjet printer 1 shown in FIGS. 1 and 2 includes two sets of four inkjet heads 2 (2Y, 2C, 2M, and 2K) that discharge four colors of ink of cyan, magenta, yellow, and black, that is, eight sets. This is a color ink jet printer including the ink jet head 2. Further, the ink jet printer 1 includes a transport unit 3 that transports a sheet as a recording medium to a position facing the head surface 2 a of the ink jet head 2.

  Each inkjet head 2 is a line-type inkjet head that is long in the direction perpendicular to the paper surface of FIG. The eight inkjet heads 2 are arranged side by side along the left-right direction in FIG. Further, the two inkjet heads 2 (2Y, 2C, 2M, 2K) that discharge ink of the same color are arranged adjacent to each other in the paper transport direction. A large number of nozzles (not shown) are formed on the head surface 2 a formed on the lower surface of each inkjet head 2. Then, the paper is transported from a paper feed tray (not shown) to the position facing the head surface 2a by the transport unit 3, and ink is ejected from the nozzles to the paper to print on the paper.

  The transport unit 3 is assembled to the belt chassis 10. A pair of belt chassis 10 exist in the direction perpendicular to the paper surface of FIG. A driving roller 11 is rotatably supported on the left side of the belt chassis 10 that exists in a pair in the direction perpendicular to the paper surface. A driven roller 12 is rotatably supported on the right side of the belt chassis 10 that exists in a pair in the direction perpendicular to the paper surface. The driving roller 11 and the driven roller 12 extend between a pair of belt chassis 10 that exist in the direction perpendicular to the paper surface. An endless conveyance belt 13 is bridged between the driving roller 11 and the driven roller 12. A belt receiving member 14 for receiving the conveyor belt 13 from below is provided. The conveyor belt 13 is placed on the upper surface of the belt receiving member 14, and the belt receiving member 14 prohibits the conveyor belt 13 from being bent downward. The belt receiving member 14 is fixed to the belt chassis 10. The belt chassis 10 is urged upward by a compression spring 25 (see FIG. 1) via the belt receiving member 14. The lower end side of the compression spring 25 is supported by a cam receiving member 32 whose position is determined by the main chassis 30. The relationship among the belt chassis 10, the cam receiving member 32, the main chassis 30, and the compression spring 25 will be described later.

  As shown in FIGS. 3, 4, and 5, the rotating shaft 11 a of the driving roller 11 is connected to a driving motor 24 including a stepping motor via pulleys 20 and 21 and a belt 22. Then, when the driving force of the driving motor 24 is transmitted to the driving roller 11 and the driving roller 11 is rotationally driven, the conveying belt 13 moves between the driving roller 11 and the driven roller 12, and on the conveying belt 13. 1 is conveyed from right to left in FIG.

The ink jet printer 1 includes a swing mechanism 15 that swings the belt chassis 10 in a vertical plane about the rotation shaft 11 a of the drive roller 11. When maintenance of the transport unit 3 is performed or when a paper jam occurs in the transport unit 3, the transport unit 3 is separated from the ink ejection surface 2a of the inkjet head 2 by utilizing the swing mechanism 15.
As shown in FIG. 1, the swing mechanism 15 includes a vertically moving cam member 31, a protrusion 31a, a cam receiving member 32, and the like. The vertically moving cam member 31 is rotatably supported by the main chassis 30. The protrusion 31 a is integrally formed with the vertical movement cam member 31. The cam receiving member 32 is movable in the vertical direction in FIG. The belt chassis 10 is provided with a stopper (not shown), and the stopper prohibits the cam receiving member 32 from being further lowered with respect to the belt chassis 10. That is, when the cam receiving member 32 is lowered by a predetermined distance or more with respect to the main chassis 30, the cam receiving member 32 comes into contact with the stopper of the belt chassis 10 and lowers the belt chassis 10. A cam groove 32 a is formed at the lower end of the cam receiving member 32. The protrusion 31a is engaged with the cam groove 32a. When the vertically moving cam member 31 and the protrusion 31 a rotate with respect to the main chassis 30, the cam receiving member 32 engaged with the protrusion 31 a moves up and down with respect to the main chassis 30. The belt chassis 10 can move up and down relatively with respect to the cam receiving member 32. The belt receiving member 14 fixed to the belt chassis 10 is pushed up by the compression spring 25 and the lower end of the compression spring 25 is supported by the cam receiving member 32. Is biased relatively upward.

A motor (not shown) is connected to the vertically moving cam member 31. The vertically moving cam member 31 rotates with respect to the main chassis 30 in response to the rotational force from the motor. A columnar protrusion 31a that protrudes in a direction perpendicular to the surface of the vertical movement cam member 31 (perpendicular to the plane of FIG. 1) is provided at a position that is radially separated from the rotation center of the vertical movement cam member 31. Yes. When the vertically moving cam member 31 rotates, the protrusion 31 a moves on a concentric circle of the vertically moving cam member 31. A cam groove 32a extending in the longitudinal direction of the belt chassis 10 (left and right direction in FIG. 1) is formed at the lower end of the cam receiving member 32, and a protrusion 31a is engaged with the cam groove 32a.
When the vertically moving cam member 31 rotates and the protrusion 31a moves on the concentric circle of the vertically moving cam member 31, the cam receiving member 32 is guided by the protrusion 31a and the cam groove 32a along with the movement of the protrusion 31a. Move up and down in the vertical plane.
During printing, as shown by the solid line in FIG. 1, the upper surface of the conveyor belt 13 is maintained at an angle parallel to the ink ejection surface 2a of the inkjet head. In this state, the compression spring 25 pushes the belt chassis 10 upward via the belt receiving member 14. The lower end of the compression spring 25 is supported by the main chassis 30 via the cam receiving member 32, the protrusion 31a, and the vertically moving cam member 31. Since the belt chassis 10 is pushed up against the main chassis 30 by the compression spring 25, the belt chassis 10 is pressed against the second cam member 51.
When a paper jam occurs, the cam receiving member 32 is lowered with respect to the main chassis 30 as shown by a chain line in FIG. Then, the cam receiving member 32 comes into contact with a stopper provided on the belt chassis 10 and pushes down the belt chassis 10. As a result, the belt chassis 10 swings in the clockwise direction around the drive roller 11. Then, since the transport unit 3 is separated from the ink discharge surface 2a of the inkjet head 2, the jammed paper can be taken out.

  The cam groove 32a is formed with an arcuate recess 32b that is recessed upward. When the belt chassis 10 is in a horizontal state, the cylindrical protrusion 31a engages with the recess 32b, and the belt chassis. 10 is supported by the vertically moving cam member 31 via the protrusion 31a, so that the belt chassis 10 is prevented from rattling during conveyance of the paper. In addition, a notch 31b is formed at a predetermined position in the circumferential direction of the outer edge portion of the vertically moving cam member 31, and this notch 31b is a sensor (not shown) attached to the main chassis 30 side of the inkjet printer 1. By detecting, the rotation angle of the vertically moving cam member 31, that is, the position of the transport unit 3 can be detected.

  Incidentally, the sheet is fed from the right side to the left side in FIG. 1 through a gap (gap) between the head surface 2 a of the inkjet head 2 and the conveying belt 13. The ink jet printer 1 can print on paper of various thicknesses such as plain paper, photographic printing paper, cardboard, or envelope. Among them, when the thickness of the paper is thin, it is preferable to reduce the distance from the head surface 2a to the paper in order to increase the landing accuracy of the ink ejected from the nozzles. The same applies to a sheet on which a high quality image is generally printed. On the other hand, there is no need to narrow the gap when printing quality is not so high, such as when printing on plain paper. On the other hand, if the gap between the head surface 2a and the conveyor belt 13 is too narrow, it becomes difficult to stably convey the paper, especially when using relatively thick paper such as thick paper or envelopes. Clogging is likely to occur.

  Therefore, the ink jet printer 1 of this embodiment includes a gap adjusting mechanism 40 (see FIG. 3) that adjusts the gap between the head surface 2a of the ink jet head 2 and the transport belt 13. The gap adjusting mechanism 40 changes the state of the transport unit 3 between a state where the gap between the head surface 2a and the transport belt 13 is the narrow gap g1 shown in FIG. 1, and a wide gap g2 ( > G1) can be selectively switched to one of the states.

  The gap adjustment mechanism 40 moves the drive chassis 11 side portion (left side portion in FIG. 1) of the belt chassis 10 in a direction (vertical direction) approaching / separating from the head surface 2 a of the inkjet head 2. In synchronism with the mechanism 41 and the drive side gap adjusting mechanism 41, the portion of the belt chassis 10 on the driven roller 12 side (right side portion in FIG. 1) is moved in a direction to approach / separate from the head surface 2 a of the inkjet head 2. And a driven side gap adjusting mechanism 42 to be moved. The gap adjusting mechanism 40 adjusts the gap on the driving roller 11 side by the driving side gap adjusting mechanism 41 and synchronizes with the driving side gap adjusting mechanism 41 by the driven side gap adjusting mechanism 42. And the gap can be adjusted while the conveyor belt 13 is parallel to the head surface 2a.

First, the drive side gap adjusting mechanism 41 will be described.
The drive side gap adjusting mechanism 41 will be described. The drive side gap adjustment mechanism 41 moves the drive roller 11 up and down with respect to the main chassis 30. When the drive roller 11 moves up and down with respect to the main chassis 30, the left end of the belt chassis 10 in FIG. 1 moves up and down with respect to the main chassis 30.

  As shown in FIGS. 3 to 5, the drive side gap adjustment mechanism 41 includes a first cam member 43 and a drive motor 24 that rotates the first cam member 43. The drive motor 24 is also used as a motor that rotates the drive roller 11 and feeds the conveyor belt 13.

  As shown in FIG. 4, the first cam member 43 has a shape in which two discs 43a and 43c are overlapped, and the center of both is offset by a distance d1. The hole 43b through which the rotation shaft 11a of the driving roller 11 passes passes through the center of the disc 43a and passes through a position offset by a distance d1 from the center of the disc 43c. The disc 43 a is supported to be rotatable with respect to the belt chassis 10, and the disc 43 c is supported to be rotatable with respect to the main chassis 30. Gear teeth are formed on the outer periphery of the disc 43 c of the first cam member 43.

  Further, the pair of first cam members 43 are connected to each other via a gear 44 meshing with an outer peripheral portion thereof and a shaft member 45 concentrically fitted and fixed to a central portion of the gear 44, so that the rotating shaft 11 a A pair of first cam members 43 on both ends are configured to rotate synchronously. The rotation center of the first cam member 43 is eccentric by a predetermined amount d1 with respect to the rotation center of the rotation shaft 11a. Therefore, the pair of first cam members 43 are driven rollers from the state shown in FIG. 1 (gap g1) where the center of rotation of the first cam member 43 is eccentrically downward by d1 with respect to the center of rotation of the rotating shaft 11a. 11, the rotation center of the first cam member 43 is decentered upward by d1 with respect to the rotation center of the rotation shaft 11a (gap g2). The rotating shaft 11a moves downward by 2 × d1.

  By the way, in this embodiment, the motor for driving the drive roller 11 and the motor for driving the first cam member 43 are shared by one drive motor 24. With this configuration, the number of motors can be reduced, and the manufacturing cost of the inkjet printer 1 can be reduced. Hereinafter, a configuration for separately driving the drive roller 11 and the first cam member 43 by the drive motor 24 will be described.

  As shown in FIGS. 4 and 5, the drive roller 11 and the drive motor 24 are connected via a belt 22 and a pulley 21. A sun gear 35 meshes with the gear 34 directly connected to the drive motor 24. Further, the sun gear 35 is connected to the sun gear 35 via a gear arm 37, and the sun gear 35 is rotated. A planetary gear 36 that moves along the outer periphery of the sun gear 35 is engaged.

  When the drive motor 24 (output shaft 24a) rotates in the counterclockwise direction of FIG. 5, the driving force of the drive motor 24 is driven via the belt 22 and the pulley 21 as shown in FIG. 6 (a). The drive roller 11 is driven to rotate by being transmitted to the roller 11. At this time, the planetary gear 36 moves in the clockwise direction of FIG. 6A along the outer periphery of the sun gear 35, and the planetary gear 36 does not mesh with the first cam member 43. Is not transmitted to the first cam member 43, and the first cam member 43 is not rotated. Here, when the planetary gear 36 moves to some extent along the outer periphery of the sun gear 35, the end of the gear arm 37 that connects the sun gear 35 and the planetary gear 36 abuts against the stopper 38, and the planetary gear 36 further gears. Since the movement of the planetary gear 36 is restricted so as not to approach the position 34, the planetary gear 36 does not interfere with the gear directly connected to the drive motor 24 when the drive roller 11 rotates (when the paper is conveyed). ing.

  On the other hand, when the drive motor 24 (output shaft 24a) rotates in the clockwise direction of FIG. 5, the planetary gear 36 moves along the outer periphery of the sun gear 35 as shown in FIG. ) In the counterclockwise direction, and the planetary gear 36 meshes with the first cam member 43. Therefore, the driving force of the driving motor 24 is transmitted to the first cam member 43 through the gear 34, the sun gear 35, and the planetary gear 36, the first cam member 43 is rotated, and the rotating shaft 11a of the driving roller 11 is rotated. It will move up or down.

  Incidentally, the first cam member 43 is externally fitted to the rotation shaft 11a of the drive roller 11 so as to be relatively rotatable. However, as shown in FIG. 4, the first cam member 43 is connected to the drive roller 11 on one surface. Since the pulley 21 is close, when the driving roller 11 rotates and the sheet is conveyed, the first cam member 43 is rotated by the frictional force between the driving roller 11 and the driving roller 11. There is a risk that the height position of the will change. Therefore, the drive-side gap adjusting mechanism 41 is configured to lock the first cam member 43 provided on the rotation shaft of the drive motor 24 so as not to rotate when the drive roller 11 is rotationally driven by the drive motor 24. Have The specific configuration will be described below.

  As shown in FIG. 4, a convex portion 44 a protruding to the inner surface side is formed on the inner surface side (left side in FIG. 4) of the gear 44 for synchronizing the pair of first cam members 43. On the other hand, the main chassis 30 that supports the first cam member 43 is fixedly provided with a receiving member 46 that supports the end of the shaft member 45. The receiving member 46 is point-symmetric with respect to the shaft member 45. The upper and lower concave portions 46a and 46b with which the convex portion 44a can be engaged are formed at the position. Further, a coil spring 47 is connected to the inside of the first cam member 43, and the first cam member 43 is attracted to the main chassis 30 by the coil spring 47.

  As shown in FIG. 1, in a state where the rotation shaft 11a of the driving roller 11 is at the lower position (a state where the gap is narrow), the first cam member 43 is coil spring 47 with the convex portion 44a positioned at the upper end. As shown in FIG. 4, the convex portion 44a is engaged with the upper concave portion 46a. On the other hand, in a state where the rotation shaft 11a of the drive roller 11 is at the upper position (a state where the gap is wide), the convex portion 44a is positioned at the lower end and engages with the lower concave portion 46b. The first cam member 43 is caused by frictional force between the convex portion 44a on the first cam member 43 side and the concave portions 46a and 46b on the main chassis 30 side when the driving roller 11 is rotating. Functions as a stopper that restricts the rotation of the. The biasing force of the coil spring 47 is simply released from the engagement of the convex portion 44a and the concave portions 46a and 46b by the frictional force between the first cam member 43 and the pulley 21 when the drive roller 11 rotates. When the first cam member 43 is rotated, the rotation resistance of the first cam member 43 increases due to the engagement between the convex portion 44a and the concave portions 46a and 46b. It is set to an appropriate strength that is not too much.

  As shown in FIG. 5, the gear 44 that meshes with the first cam member 43 is formed with a notched detected portion 44 b. Then, by detecting the detected portion 44b with an optical sensor 48, for example, the reference position of the first cam member 43, that is, the reference position of the rotating shaft 11a of the drive roller 11 can be detected. Further, by appropriately setting the number of drive steps of the drive motor 24 from the reference position detected by the sensor 48, the first cam member 43 is rotated by a predetermined angle from the reference position, and the rotation shaft 11a of the drive roller 11 is rotated. The height position (gap on the drive roller 11 side) can be adjusted appropriately.

Next, the driven side gap adjusting mechanism 42 will be described.
As shown in FIG. 3, the driven side gap adjusting mechanism 42 is rotatably provided on the main chassis 30 on the upper side (inkjet head 2 side) of the conveyor belt 13, and is connected to the drive motor 24. The cam shaft 50 includes a second cam member 51 that is provided in an eccentric state with respect to the shaft center and abuts against a portion of the belt chassis 10 on the driven roller 12 side.

  As shown in FIGS. 3 and 7, the cam shaft 50 is rotatably supported by the main chassis 30 via a pair of bearing members 52 whose both ends are plate-shaped. A pair of disk-like second cam members 51 are fixedly provided at both ends of the cam shaft 50. In FIG. 3, only the second cam member 51 and the bearing member 52 on the front side in FIG. 3 are shown. The center of the second cam member 51 is eccentric with respect to the axis of the cam shaft 50 by a predetermined amount d2 (equal to the eccentric amount d1 of the first cam member 43 with respect to the rotating shaft 11a). As shown in FIG. 3, the drive motor 24 that rotates the first cam member 43 simultaneously includes a gear 53 and pulleys 54, 55, and 56, and a transmission belt that spans the gear 53 and pulleys 54 to 56. It is connected to the camshaft 50 via 57.

  Accordingly, when the first cam member 43 is rotated by the drive motor 24, the cam shaft 50 also rotates in synchronization with the first cam member 43, and the second cam fixedly provided on the cam shaft 50. The member 51 will also rotate. Here, as shown in FIGS. 1 and 2, the belt chassis 10 is urged upward by a plurality of compression springs 25 via a belt receiving member 14. Therefore, the second cam member 51 that is eccentric with respect to the cam shaft 50 rotates around the axis of the cam shaft 50, whereby the driven roller 12 side of the belt chassis 10 that contacts the second cam member 51 (FIG. 1). The right side portion is interlocked with the vertical movement of the contact portion of the second cam member 51 with the belt chassis 10 while maintaining this contact state (approaching / separating from the head surface 2a). Direction). For example, when the pair of second cam members 51 is rotated halfway from the state of FIG. 1 in which the center of the second cam member 51 is eccentric upward with respect to the axis of the camshaft 50 and the gap is narrow (gap g1), The center of the second cam member 51 is decentered downward with respect to the cam shaft 50 and has a wide gap as shown in FIG. 2 (gap g2). At this time, the driven roller 12 together with the belt chassis 10 is 2 × d2 (drive roller 11). Is equal to 2 × d1 which is the movement amount of

  The driven side gap adjusting mechanism 42 includes a parallelism adjusting mechanism 60 that can adjust the parallelism of the conveyor belt 13 with respect to the head surface 2a. As shown in FIGS. 3, 8, and 9, a plate-like bearing member 52 that supports the cam shaft 50 is formed with a bearing hole 52 a through which the cam shaft 50 is inserted. The bearing member 52 is provided so as to be rotatable in a vertical plane with respect to the main chassis 30. An arcuate groove 52b extending in the rotational direction of the bearing member 52 is formed at the upper end of the bearing member 52, and a screw 61 is inserted into the groove 52b. It is fixed in a state where it is positioned at a predetermined position with respect to 30.

  By the way, as shown in FIG. 8, the shaft center of the cam shaft 50 is eccentric by a predetermined amount d3 with respect to the center of the bearing hole 52a of the bearing member 52. Therefore, as shown in FIG. 9 (a), when the bearing member 52 is rotated in the counterclockwise direction, the cam shaft 50 rises by a predetermined amount d4. On the other hand, as shown in FIG. 9 (b), the bearing When the member 52 is rotated in the clockwise direction, the cam shaft 50 is lowered by a predetermined amount d5. Thus, by rotating the bearing member 52 in the vertical plane, the height positions of the cam shaft 50 and the second cam member 51 (head) so that the driving roller 11 and the driven roller 12 have the same height position. Position in a direction perpendicular to the surface 2a) can be adjusted, and the parallelism of the conveyor belt 13 with respect to the head surface 2a can be easily adjusted.

  As shown in FIGS. 1 and 2, the cam shaft 50 is pivotally supported by a guide member 62 that guides the paper to the inkjet head 2 and a pressing roller 63 that presses the paper conveyed to the inkjet head 2 from above. Has been. As described above, the guide member 62 and the pressing roller 63 can smoothly convey the sheet to the inkjet head 2, and the guide member 62 and the pressing roller 63 are disposed around the cam shaft 50. The ink jet printer 1 can be configured more compactly.

  Note that when the first cam member 43 is rotated by the drive motor 24 during the gap adjustment, the drive motor 24 and the camshaft 50 are moved so that the drive roller 11 and the driven roller 12 move up and down by the same amount. The number of teeth of the gear 53 for connecting the two is set. Therefore, when the gap is adjusted, the conveyor belt 13 held by the belt chassis 10 is configured to move in the vertical direction while maintaining a state of being always parallel to the head surface 2a.

Next, the operation of the ink jet printer 1 will be described.
First, when recording on a sheet by the inkjet head 2, as shown in FIGS. 1, 5, and 6A, the drive motor 24 (output shaft 24a) is rotated in the counterclockwise direction. The driving force of the driving motor 24 is transmitted to the driving roller 11 via the belt 22, and the driving roller 11 is rotationally driven. Then, the conveyance belt 13 stretched between the driving roller 11 and the driven roller 12 moves, and the conveyance belt 13 conveys the sheet from the right side of FIG. Ink is discharged. At this time, as shown in FIG. 4, a convex portion 44a formed on the gear 44 meshing with the first cam member 43 and concave portions 46a and 46b provided on the main chassis 30 side and engaged with the convex portion 44a. The rotation of the first cam member 43 fitted on the rotation shaft 11a of the drive roller 11 is restricted, and the height position of the drive roller 11 does not change while the drive roller 11 is rotating (while the paper is being conveyed). It is like that.

  On the other hand, when it is necessary to change the gap between the head surface 2a of the inkjet head 2 and the conveyor belt 13 in accordance with the type of the sheet to be conveyed, FIGS. 1, 5, and 6B are used. As shown, in the drive side gap adjusting mechanism 41, the drive motor 24 rotates in the clockwise direction opposite to that when the transport belt 13 is driven. Then, the driving force of the driving roller 11 is transmitted to the first cam member 43 and the first cam member 43 is rotated. At this time, since the rotation shaft 11a of the drive roller 11 eccentric with respect to the first cam member 43 moves up and down, the gap on the drive roller 11 side is adjusted.

At the same time, the driving force of the driving roller 11 is transmitted to the cam shaft 50 of the driven side moving mechanism 42 via the gear 53 and the transmission conveyance belt 57. Then, in synchronization with the rotation of the first cam member 43, the second cam member 51 fixed to the cam shaft 50 rotates to change the height of the lower end. Since the belt chassis 10 is biased upward by the plurality of compression springs 25, the contact state between the second cam member 51 and the belt chassis 10 is always maintained. Following the second cam member 51 changing the height of the lower end, the portion of the belt chassis 10 on the driven roller 12 side moves up and down. As a result, the gap on the driven roller 12 side is adjusted. At this time, the height of the driving roller 11 and the height of the belt chassis 10 on the driven roller 12 side are kept the same, and the belt chassis 10 moves up and down while being kept parallel to the ink discharge surface 2a.
When printing on thin paper, photographic printing paper, or the like, the state can be switched to the narrow gap state shown in FIG. On the other hand, when printing on thick paper such as thick paper and envelopes, it is switched to the wide gap state shown in FIG.

  The gap adjustment by the gap adjustment mechanism 40 described above is performed by driving the drive motor 24 by the control device (not shown) of the ink jet printer 1 based on the paper type information input by the operator. Can be configured. Alternatively, a sensor capable of detecting the type of paper conveyed from the paper feed tray to the inkjet head 2 is provided, and the control device drives the drive motor 24 to adjust the gap based on a signal from the sensor. It may be configured.

  The gap adjusting mechanism 40 of the ink jet printer 1 described above moves the portion on the driving roller 11 side of the belt chassis 10 in the vertical direction by the driving side gap adjusting mechanism 41 and synchronizes with the driving side gap adjusting mechanism 41. Since the driven-side gap adjusting mechanism 42 moves the portion of the belt chassis 10 on the driven roller 12 side in the vertical direction, the transport surface 13 is maintained parallel to the head surface 2a, and the head surface 2a and the transport belt 13 are maintained. The gap between can be adjusted. Therefore, the printing quality can be improved, and the paper can be smoothly conveyed to the inkjet head 2.

Next, modified embodiments in which various modifications are made to the embodiment will be described. In addition, about the thing which has the structure similar to the said embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted suitably.
1] The motor for rotating the first cam member 43 may be a motor different from the drive motor 24 that rotationally drives the drive roller 11. In this case, a configuration for combining the motor that rotates the drive roller 11 and the motor that rotates the first cam member 43 with one motor (drive motor) is not required. The configuration can be simplified.

  2] A motor for driving the cam shaft 50 of the driven side gap adjusting mechanism 42 is provided separately from a motor for driving the first cam member 43 of the driving side gap adjusting mechanism 41 (the driving motor 24 in the above embodiment). The drive side gap adjustment mechanism 41 and the driven side gap adjustment mechanism 42 may be synchronized by operating two motors in electrical synchronization. Furthermore, it is not always necessary to operate the drive side gap adjustment mechanism 41 and the driven side gap adjustment mechanism 42 simultaneously. For example, after the drive side gap adjustment mechanism 41 moves the drive roller 11 side of the belt chassis 10 up and down, The driven roller 12 side of the belt chassis 10 can also be moved up and down by the driven side gap adjusting mechanism 42. That is, at the stage where the adjustment of the gap is completed, it is only necessary that the conveyor belt 13 is finally parallel to the head surface 2a.

  3] In the above embodiment, the gap adjusting mechanism 40 is configured to switch the position of the conveyor belt 13 to one of a narrow gap position (see FIG. 1) and a wide gap position (see FIG. 2). However, it may be configured to select any one of the positions of three or more transport belts 13 (that is, three or more types of gaps). Further, when the driving motor is a stepping motor, the gap may be finely adjusted for each driving step of the stepping motor at the time of gap adjustment.

  4] The present invention is also applicable to recording heads other than inkjet heads such as thermal printers and dot printers.

It is a side view of the principal part of the inkjet printer (state where a gap is narrow) concerning the embodiment of the present invention. It is a side view of the principal part of an inkjet printer (a state with a wide gap). It is a figure which shows the structure of a gap adjustment mechanism. It is a figure which shows the principal part of the drive system of a drive roller, and a drive side gap adjustment mechanism. It is a principal part side view of FIG. It is a figure which shows the operation | movement of the drive system of a drive roller, and the operation | movement of a drive side gap adjustment mechanism, (a) shows operation | movement at the time of the rotational drive of a drive roller, (b) shows operation | movement at the time of gap adjustment. It is a figure which shows schematically the principal part of a driven side gap adjustment mechanism. It is a figure which shows a cam shaft and a bearing member. It is a figure which shows the effect | action of a cam shaft and a bearing member at the time of adjusting parallelism, (a) shows the state which the cam shaft raised, (b) shows the state which the cam shaft lowered.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet printer 2 Inkjet head 2a Head surface 3 Conveyance unit 10 Belt chassis 11a Rotating shaft 11 Drive roller 12 Followed roller 13 Conveyor belt 24 Drive motor 40 Gap adjustment mechanism 41 Drive side gap adjustment mechanism 42 Driven side gap adjustment mechanism 43 First cam Member 44a Convex part 46a, 46b Concave part 50 Cam shaft 51 Second cam member 52 Bearing member 60 Parallelism adjusting mechanism 61 Screw 62 Guide member 63 Pressing roller

Claims (8)

A recording head for recording on a recording medium;
A conveyance unit having two rollers and a conveyance belt spanned between the two rollers, and conveying the recording medium to a position facing the head surface of the recording head;
A gap adjusting mechanism for adjusting a gap between the head surface and the conveyor belt,
The recording apparatus according to claim 1, wherein the gap adjusting mechanism adjusts the gap by moving the transport belt in a state parallel to the head surface. The transport unit includes a belt chassis that holds the transport belt, a drive roller and a driven roller that are pivotally supported at both ends of the belt chassis in the transport direction, and a drive motor that rotationally drives the drive roller. ,
The gap adjustment mechanism is synchronized with a drive side gap adjustment mechanism that moves a portion of the belt chassis on the drive roller side in a direction approaching / separating from the head surface of the recording head, and the drive side gap adjustment mechanism. The driven-side gap adjusting mechanism is configured to move a portion of the belt chassis on the driven roller side in a direction approaching / separating from a head surface of the recording head. Recording device. The drive-side gap adjusting mechanism includes a first cam member provided on the rotation shaft of the drive roller in a state of being eccentric with respect to the shaft center, and a cam drive motor that rotates the first cam member. ,
By rotating the first cam member by the cam drive motor, the drive roller eccentric with respect to the first cam member is moved in a direction approaching / separating from the head surface. The recording apparatus according to claim 2.   The recording apparatus according to claim 3, wherein the drive motor and the cam drive motor are shared by a single motor.   4. A stopper that locks the first cam member provided on the rotation shaft of the precursor drive motor so as not to rotate when the drive roller is rotationally driven by the drive motor. Or the recording apparatus of 4. The driven-side gap adjusting mechanism is rotatably provided on the recording head side with respect to the transport belt, and is connected to the cam drive motor, and the cam shaft is eccentric with respect to the axis. A second cam member that is in contact with a portion of the belt chassis on the driven roller side,
By rotating the cam shaft in synchronization with the first cam member by the driving force of the cam drive motor, the portion on the driven roller side of the belt chassis contacting the second cam member with respect to the head surface The recording apparatus according to claim 3, wherein the recording apparatus is moved in a direction of approaching / separating.   7. A guide member for guiding the recording medium to the recording head and a pressing roller for pressing the recording medium conveyed to the recording head are pivotally supported on the cam shaft. Recording device.   7. A parallelism adjusting mechanism capable of adjusting a parallelism of the conveyor belt with respect to the head surface by adjusting a position of the second cam member in a direction perpendicular to the head surface. 8. The recording device according to 7.

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