JP2015089615A - Flatness adjustment method of platen surface in printer, adjustment jig used for flatness adjustment of platen surface and printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose a method for securing flatness of a platen surface in a printer in which spheres are disposed between a head unit and a platen unit and a platen gap is secured, and further to propose an adjustment jig.SOLUTION: A printer 1 supports each both ends of supporting rollers 85a through 85e supporting a horizontal belt portion 81a constituting a platen surface 8a by a first lateral plate 84a and a second lateral plate 84b. Platen side contact portions 89a through 89c onto which three spheres 19 for securing a platen gap are mounted are formed on the first lateral plate 84a and the second lateral plate 84b. The first lateral plate 84a is fixed to a side frame 83a of a platen unit 8, and the second lateral plate 84b is rotatably mounted to a supporting shaft 83c provided to the side frame 83a. Leading ends of protrusions 32a through 32c of an adjustment jig 30 are brought into contact with platen side contact portions 89a through 89c, and an attitude of the second lateral plate 84b is adjusted and fixed such that the platen surface 8a is parallel to an adjustment reference surface 34 of the adjustment jig 30.

Description

  The present invention relates to a technique for ensuring flatness of a surface of a platen facing a print head in a printer in which a predetermined gap (platen gap) is formed between the print head and the platen.

  In an inkjet printer, the print head mounted on the carriage is opposed to the platen, and the height of the carriage from the platen surface (the surface facing the print head) is adjusted, so that the gap between the nozzle surface of the print head and the platen surface ( The platen gap) is adjusted to an optimum dimension. For example, in a serial head type printer that performs printing by scanning a carriage equipped with a print head in the width direction of the recording paper, the carriage is mounted on a carriage shaft extending in the width direction of the recording paper, and the platen surface of the carriage shaft By providing a mechanism (platen gap adjusting mechanism) for adjusting the height of the platen using a cam mechanism or the like, the platen gap can be adjusted to an optimum dimension.

  On the other hand, in a line head type printer that includes a large print head that exceeds the width of the recording paper and that prints the print head while stopped on the recording paper, the head unit having the print head mounted on the carriage becomes large. In this case, the mechanism for supporting the large head unit has a complicated structure, and the mechanism for moving the head unit in a direction perpendicular to the platen surface is also complicated. Therefore, instead of providing a platen gap adjustment mechanism such as that used in serial head printers, a protrusion with dimensions corresponding to the optimal platen gap is provided on the head unit side, and a contact portion for contacting the protrusion is provided on the platen side. The structure which secures an optimal platen gap by providing and making a protrusion and a contact part contact is used. Patent Document 1 discloses this type of printer.

JP 2011-025479 A

  In the printer of Patent Document 1, three protrusions are formed on the head unit, three contact portions that contact the protrusions with the platen unit are formed, and by contacting these three sets of protrusions and contact portions, The projection serves as a spacer to secure the platen gap. Here, when the platen gap is ensured by such a method, the print head is positioned so as to maintain a certain distance with respect to a plane (reference surface) determined by three contact portions provided on the platen unit side. It will be. Therefore, in order to keep the platen gap at a constant size, as a premise, the flatness of the platen surface with respect to the reference surface must be ensured. However, in Patent Document 1, it is unclear whether the flatness of the platen surface with respect to the reference surface is ensured. That is, in Patent Document 1, the platen surface is configured by a conveyor belt that is stretched over a plurality of rollers. However, if the rollers have a dimensional error or are not accurately attached, the platen surface is twisted. Or may be inclined with respect to the reference plane. In such a case, there is a possibility that a certain platen gap cannot be secured.

  In view of such a point, an object of the present invention is to provide a printer configuration that can ensure flatness of a platen surface in a printer that secures a platen gap by arranging a platen gap adjusting member between a head unit and a platen unit. It is to propose a method for adjusting the flatness of the platen surface and an adjusting jig used therefor.

  In order to solve the above problems, the present invention provides a method for adjusting the flatness of a platen surface in a printer that secures a platen gap by arranging a platen gap forming member between a platen unit and a head unit. An adjustment jig in which a jig-side abutting portion capable of abutting on a place where the platen gap forming member abuts in the unit is formed is prepared, and a first member that supports a platen surface constituent member is provided as the platen unit. A first step of fixing the second member supporting the platen surface constituting member together with the first member to the other side surface of the unit main body portion so as to be swingable. And the second member for positioning the adjustment jig by bringing the jig side abutting portion into contact with the first member and the second member. And the inclination of the first member and the second member with reference to the adjustment jig, and based on the measured inclination, the posture of the second member is adjusted and fixed to the unit main body. And performing a third step.

  In this way, the flatness adjustment method of the platen surface in the printer of the present invention fixes one of the pair of members (first member) supporting the platen surface constituent member at a fixed position and the other (second member). ) Is swingable, the parallelism of the first member and the second member is measured, and the posture of the second member is adjusted and fixed. By such a method, even when there is a dimensional error or distortion in the unit main body, the parallelism of the first and second members supporting the platen surface constituting member can be ensured, and the platen surface can be prevented from being twisted to be flat. Can be secured. In the present invention, the platen unit and the platen gap forming member are provided by using an adjustment jig having a jig side contact portion that is in the same positional relationship as the contact point at which the platen gap forming member and the platen unit contact each other. The platen surface can be made parallel to a virtual surface (that is, a reference surface that is assumed to be parallel to the nozzle surface of the print head) determined by the contact position with which the nozzle contacts. Therefore, when the head unit is positioned on the platen unit with the platen gap forming member interposed therebetween, the platen gap between the print head and the platen surface can be set to a constant value.

  In the present invention, three platen gap forming members are provided, and the jig side contact portion has the same positional relationship as three contact points at which the platen gap forming member and the platen unit contact each other. It is desirable that three are provided. Since the members can be reliably positioned by bringing the members into contact with each other at three points, the contact points are preferably three points.

  In the present invention, an adjustment reference surface parallel to a virtual surface including the three jig side contact portions is formed on the adjustment jig, and in the second step, the adjustment reference surface and the first It is desirable to measure the inclination of the first member and the second member by measuring the distance between the first member and the distance between the adjustment reference surface and the second member. If it does in this way, the inclination of the 1st member and the 2nd member can be easily adjusted on the basis of the adjustment reference plane.

  In the present invention, the adjustment jig includes a jig main body portion on which the adjustment reference surface is formed, and three protrusions protruding from the jig main body portion on the same side, and the three jig sides The contact portion is the tip of the three protrusions. With such a configuration, the adjustment jig can be easily positioned.

  Furthermore, in the present invention, the platen surface constituent member is a transport belt that is stretched in the medium transport direction, and the transport belt is supported by a plurality of support rollers that extend in a direction intersecting the medium transport direction. The first member supports one end of the plurality of support rollers, and the second member supports the other end of the plurality of support rollers. In such a configuration, the flatness of the platen surface can be maintained by ensuring the parallelism of the first member and the second member.

  Next, in order to solve the above-described problems, the present invention provides an adjustment treatment used for adjusting the flatness of a platen surface in a printer that secures a platen gap by arranging a platen gap forming member between a platen unit and a head unit. A jig side abutting portion capable of abutting on a contact portion with which the platen gap forming member abuts in the platen unit and a virtual surface including the jig side abutting portion. And a reference plane for adjustment.

  With such a configuration, the adjustment jig of the present invention has a virtual plane (that is, parallel to the nozzle surface of the print head) determined by the three contact positions where the platen unit and the three platen gap forming members are in contact. The adjustment jig can be positioned such that the assumed reference plane) and the adjustment reference plane are parallel, and the parallelism between the reference plane and each part of the platen unit can be measured via the adjustment jig. Therefore, the platen unit can be configured to ensure the parallelism between the reference surface and the platen surface even when there is a dimensional error or distortion in the unit main body of the platen unit. Thus, when the head unit is positioned on the platen unit with the platen gap forming member interposed therebetween, the platen gap between the print head and the platen surface can be set to a constant value.

  In the adjustment jig of the present invention, three platen gap forming members are provided, and the jig side contact portion has the same positional relationship as three contact points at which the platen gap forming member and the platen unit contact each other. It is desirable that three are provided so that Since the members can be reliably positioned by bringing the members into contact with each other at three points, the contact points are preferably three points.

  In the adjustment jig according to the present invention, the adjustment jig includes a jig main body portion on which the adjustment reference surface is formed, and three protrusions protruding from the jig main body portion on the same side. The tip of the three protrusions is desirable. With such a configuration, the adjustment jig can be easily positioned.

  In order to solve the above problems, a printer according to the present invention includes a platen unit including a platen surface that supports a sheet-like medium, a head unit including a print head facing the platen surface, and the head unit. At least three platen gap forming members disposed between the platen units, and the platen unit supports a platen surface constituting member constituting the platen surface and a first platen surface constituting member. And a unit main body provided with one side surface to which the first member is attached and the other side surface to which the second member is attached, and the first member includes the at least three platen gaps. There are at least three platen side contact portions that contact the forming member from the side opposite to the head unit. And at least one of the at least three platen side abutting portions is formed on the second member, and a predetermined point is formed on the other side surface of the unit main body portion. A temporary fixing portion to which the second member is attached is provided in a state in which the second member can swing around the center.

  In this way, the printer of the present invention fixes one of the pair of members (first member) supporting the platen surface constituting member in a fixed position, while the other (second member) can swing. It is possible to temporarily fix it in a proper state. Therefore, even when there is a dimensional error or distortion in the unit main body, the posture of the second member can be adjusted to a posture parallel to the first member. Therefore, the parallelism of the member that supports the platen surface constituent member can be secured, and the flatness can be secured by preventing the platen surface from being twisted. Further, since the first member and the second member are provided with at least three platen side contact portions where the platen gap forming member and the platen unit are in contact with each other, a virtual surface determined by three of them. The platen surface can be made parallel to (that is, a reference surface assumed to be parallel to the nozzle surface of the print head). Therefore, when the head unit is positioned on the platen unit with the platen gap forming member interposed therebetween, the platen gap between the print head and the platen surface can be set to a constant value.

  In the printer according to the aspect of the invention, the platen surface constituent member is a transport belt that is stretched in the medium transport direction, and the transport belt is supported by a plurality of support rollers that extend in a direction intersecting the medium transport direction. The first member supports one end of the plurality of support rollers, and the second member supports the other end of the plurality of support rollers. In such a configuration, the flatness of the platen surface can be maintained by ensuring the parallelism of the first member and the second member.

  In the printer of the present invention, it is preferable that the at least three platen gap forming members are held by a holding frame arranged between the platen unit and the head unit. In this way, by holding the platen gap forming member by the holding frame separate from the head unit and the platen unit, the retracting operation and maintenance operation of the head unit are hindered by interference between the platen gap forming member and other members. Can be avoided. Further, it is possible to avoid that the operation of retracting the platen unit for removing paper jam is hindered by interference between the platen gap forming member and other members.

  According to the present invention, even when there is a dimensional error or distortion in the unit main body of the platen unit, the parallelism between the first member and the second member supporting the platen surface constituent member can be secured, and the platen surface is twisted. And the flatness can be secured. Further, the platen surface may be made parallel to a virtual surface (that is, a reference surface assumed to be parallel to the nozzle surface of the print head) determined by a contact position where the platen gap forming member and the platen unit contact each other. it can. Therefore, when the head unit is positioned on the platen unit with the platen gap forming member interposed therebetween, the platen gap between the print head and the platen surface can be set to a constant value.

1 is an external perspective view of a line inkjet printer according to an embodiment of the present invention. It is a schematic longitudinal cross-sectional view which shows the internal mechanism of the line inkjet printer of FIG. It is explanatory drawing which shows a medium conveyance mechanism typically. It is a perspective view of a platen unit. It is a perspective view of the platen unit which removed the conveyance belt. It is explanatory drawing of the platen unit which removed the conveyance belt. It is a perspective view which shows the state which has arrange | positioned the holding frame on the platen unit. It is explanatory drawing of the state which has arrange | positioned the holding frame on the platen unit. It is explanatory drawing of a holding frame main-body part. It is a perspective view of a head unit. It is the bottom view which looked at the head unit from the platen unit side. It is a perspective view of a platen unit and an adjustment jig. It is explanatory drawing of the flatness adjustment method of the platen surface using an adjustment jig.

  Embodiments of a printer to which the present invention is applied will be described below with reference to the drawings. In the following embodiments, the present invention is applied to a printer that loads and prints roll paper, but is also applicable to a printer that prints on other forms of media.

(overall structure)
FIG. 1 is an external perspective view of a line inkjet printer according to an embodiment of the present invention, and FIG. 2 is a schematic longitudinal sectional view showing an internal mechanism thereof. As shown in FIG. 1, a line inkjet printer 1 (hereinafter simply referred to as “printer 1”) includes a printer housing 2 having a rectangular parallelepiped shape as a whole. On the front surface 2a of the printer housing 2, an operation unit 3 is provided on one side in the width direction, and a paper discharge port 4 is formed on the other side. A maintenance opening / closing lid 5 is provided below the paper discharge port 4. Hereinafter, in the present specification, the front-rear direction of the printer is indicated by X, and the width direction of the printer is indicated by Y. Further, the front of the printer is denoted by reference numeral X1, and the rear of the printer is denoted by reference numeral X2.

  As shown in FIG. 2, a roll paper storage unit 6 is formed inside the printer housing 2 on the printer rear X2 side. In addition, a head unit 7 is disposed on the upper portion of the printer front X1 side, and a platen unit 8 is disposed on the lower side thereof. The head unit 7 includes a print head 71 that is a line-type inkjet head. The print head 71 is formed with an ink nozzle row that ejects ink droplets. The ink nozzle row is formed over a length including the maximum width of the continuous paper P fed from the roll paper 9 loaded in the roll paper storage unit 6. Further, the platen unit 8 includes a horizontal platen surface 8 a facing the nozzle surface of the print head 71. The platen surface 8a is configured by a horizontal belt portion 81a (a platen surface constituent member) of the conveyance belt 81 described later.

  Inside the printer housing 2, the continuous paper P drawn from the roll paper 9 of the roll paper storage unit 6 passes through the print position by the print head 71 along the medium conveyance path 10 indicated by the one-dot chain line, and the printer The paper is conveyed toward the paper discharge port 4 that opens in the front surface 2 a of the housing 2, and is discharged from the paper discharge port 4. The medium conveyance path 10 is gently lowered until the first path portion 10a extending obliquely upward toward the printer rear X2 side and the direction from the upper end of the first path portion 10a to the printer front X1 and reaching the platen surface 8a. And a third path portion 10c extending horizontally from the end of the platen surface 8a on the printer rear X2 side toward the printer front X1. The printing position by the print head 71 is provided in the middle of the third path portion 10c.

  A medium supply roller 11 is disposed at the bottom of the roll paper storage unit 6. The medium supply roller 11 is always held in contact with the roll paper 9 attached to the roll paper storage unit 6 from below. The medium supply roller 11 is driven to rotate by a supply motor (not shown), thereby feeding the continuous paper P from the roll paper 9 to the first path portion 10a. The continuous paper P can be fed out by attaching the roll paper 9 to the rotary shaft and rotationally driving the rotary shaft by a supply motor.

  A tension lever 12 that applies a back tension to the continuous paper P is disposed at a position where the direction of the medium path 10 is changed from the first path portion 10a to the second path portion 10b. An arc-shaped outer peripheral surface is formed at the tip of the tension lever 12, and the continuous paper P is stretched over this. The tension lever 12 is attached so as to be rotatable around a predetermined rotation center 13. A spring member (not shown) is attached to the tension lever 12 at a position away from the rotation center 13. The spring member is supported by the printer housing frame, and urges the tension lever 12 toward the printer rear X2. That is, the tension lever 12 is urged in a direction to increase the tension of the continuous paper P. A slide type tension lever can be used instead of the rotary type tension lever 12.

  A rotary encoder 14 is disposed at the rotation center 13 of the tension lever 12. The rotary encoder 14 can detect the rotation position of the tension lever 12 steplessly or in multiple steps. For example, an optical sensor such as an optical potentiometer or various sensors such as a magnetic sensor is used. Can do. By detecting the rotational position of the tension lever 12 by the rotary encoder 14, the tension fluctuation of the continuous paper P can be monitored and the conveyance control can be performed so as to keep the tension at an appropriate value.

  A paper guide 15 is arranged along the second path portion 10b on the printer front X1 side of the tension lever 12. The paper guide 15 has a shape that gently descends toward the front X1 of the printer, and guides the continuous paper P from the tension lever 12 toward the platen surface 8a.

  A belt-type medium transport mechanism 16 is provided in the medium transport path 10 along the third path portion 10c. FIG. 3 is an explanatory diagram schematically showing the medium transport mechanism 16. The medium transport mechanism 16 drives the transport belt 81, which is an endless belt disposed below the third path portion 10c, a plurality of guide rollers 82a to 82e around which the transport belt 81 is bridged, and the transport belt 81. A belt driving roller 82f that rotates, and a conveyance motor (not shown) that rotates the belt driving roller 82f. The conveyor belt 81 is pressed against the belt driving roller 82f by a guide roller 82a. By rotating the belt driving roller 82f, the conveyance belt 81 moves along a route passing through the guide rollers 82a to 82e. An encoder (not shown) for detecting the rotation amount is attached to the rotation shaft of the belt driving roller 82f.

  In the conveyor belt 81, a portion that is stretched between the guide rollers 82b and 82c is a horizontal belt portion 81a that extends horizontally along the third path portion 10c. Pinch rollers 17a and 17b are pressed from the same side as the head unit 7 to the upstream end and the downstream end of the horizontal belt portion 81a in the transport direction (that is, the front-rear direction X of the printer). The medium transport mechanism 16 transports the continuous paper P sandwiched between the pinch rollers 17a and 17b and the horizontal belt portion 81a.

  The platen unit 8 is equipped with a paper detector 18 that detects the continuous paper P conveyed along the platen surface 8a. The detection position by the paper detector 18 is provided upstream of the printing position by the print head 71 (that is, the printer rear X2 side) in the third path portion 10c. As shown in FIG. 2, the continuous paper P is drawn from the roll paper 9 loaded in the roll paper storage unit 6 along the first path portion 10 a of the medium transport path 10, and is stretched around the tension lever 12. The tip is set to extend along the second path portion 10b. In this state, a supply operation by the medium supply roller 11 is performed, and further, a transport operation by the medium transport mechanism 16 is performed, and a cueing operation is performed in which the top of the continuous paper P reaches the print position by the print head 71. Thereafter, the medium transport mechanism 16 performs a transport operation of continuously transporting at a constant speed in the forward feed direction from the printing position toward the paper discharge port 4. The print head 71 is driven in synchronism with this conveying operation to print on the surface of the continuous paper P passing through the printing position.

(Platen unit)
4 is a perspective view of the platen unit 8, and FIG. 5 is a perspective view of the platen unit 8 with the conveyor belt 81 removed. FIG. 6 is an explanatory view of the platen unit 8 with the conveyor belt removed. FIG. 6 (a) is a plan view, and FIGS. 6 (b) and 6 (c) are viewed from one side and the other side in the printer width direction Y. FIG. 6D is a side view of the printer as viewed from the front side of the printer. As shown in FIG. 4, in the platen unit 8, horizontal belt portions 81 a of four transport belts 81 are stretched in the front-rear direction X of the printer on the upper surface facing the head unit 7. The horizontal belt portion 81a spans between a guide roller 82b disposed at the end of the platen unit 8 on the printer front X1 side and a guide roller 82c disposed near the end of the platen unit 8 on the printer rear X2 side. This is a portion of the conveyed belt 81. Further, a guide roller 82d is disposed further to the back X2 side of the printer than the guide roller 82c. The conveyance belt 81 is stretched between the guide rollers 82c and 82d so as to be inclined from the upstream end of the horizontal belt portion 81a toward the printer lower side.

  The platen unit 8 includes a unit main body 83 that is configured by a sheet metal member or the like. The unit main body 83 includes side frames 83 a and 83 b that constitute one side surface and the other side surface of the platen unit 8 in the printer width direction Y. The side frames 83a and 83b support both ends of guide rollers 82a to 82e around which the conveyor belt 81 is stretched and a belt driving roller 82f (see FIG. 3) that drives the conveyor belt 81. In addition, a transport motor is mounted inside the unit main body 83.

  A first side plate 84a and a second side plate 84b are attached in parallel to the upper end edges of the side frames 83a and 83b. The first side plate 84a and the second side plate 84b are rectangular sheet metal members that extend horizontally in the longitudinal direction X of the printer. As shown in FIGS. 5 and 6, the first side plate 84 a and the second side plate 84 b support both ends of five support rollers 85 a to 85 e that extend parallel to the printer width direction Y. That is, each of the support rollers 85a to 85e includes a support shaft 86a whose both ends are fixed to the first side plate 84a and the second side plate 84b, and four roller bodies 86b that are rotatably attached to the support shaft 86a. ing. In each support shaft 86a, the four roller bodies 86b are attached at positions overlapping the four horizontal belt portions 81a. Each of the guide rollers 82b, 82c, and 82d has the same configuration as the support rollers 85a to 85e, and is attached to the side frame 83a and 83b with both ends fixed to the side frame 83a and 83b so as to be rotatable on the support shaft 86a. The provided roller body 86b is provided. Accordingly, on the upper surface of the platen unit 8, four rows in which a plurality of roller bodies 86b are arranged in one row in the front-rear direction X of the printer are formed, and a horizontal belt portion 81a is stretched over each row.

  The support rollers 85a to 85e are arranged at regular intervals in the front-rear direction X of the printer, and a gap is formed between the adjacent support shafts 86a and between the adjacent roller bodies 86b. A holder 87 is disposed in the gap. The holder 87 is supported by the unit main body 83. Similarly, a gap is formed between the guide roller 82c and the support roller 85e, and a holder 87 is also disposed in this gap.

  Among the four horizontal belt portions 81a, a gap is provided between the horizontal belt portion 81a disposed closest to the first side plate 84a and the adjacent horizontal belt portion 81a. The detection portion of the paper detector 18 described above is exposed at a position near X2. As the paper detector 18, an optical sensor or the like can be used. The paper detector 18 detects the continuous paper P from the gap between the horizontal belt portions 81a.

  The first side plate 84a (first member) is screwed to the side frame 83a by fixing screws 88 at two positions on both ends in the longitudinal direction (that is, the printer longitudinal direction X). On the other hand, the second side plate 84 b (second member) is rotatably attached to a support shaft 83 c (temporary fixing portion) provided in the unit main body 83. The support shaft 83c is a protrusion protruding from the resin member assembled to the side frame 83b, and is attached to a shaft hole formed at the center position in the longitudinal direction of the second side plate 84b. The second side plate 84b swings about the support shaft 83c, and its posture can be adjusted. The second side plate 84b is positioned at two positions on both ends in the longitudinal direction so as to maintain the post-positioning posture after being positioned in a posture parallel to the first side plate 84a by flatness adjustment work using an adjustment jig described later. The side frame 83b is fixed with a fixing screw 88. A support shaft may be formed on the second side plate 84b side, and a shaft hole as a temporary fixing portion may be formed on the side frame 83b side.

(Formation of platen gap)
FIG. 7 is a perspective view showing a state in which the holding frame is arranged on the platen unit 8. 8 is an explanatory view showing a state in which the holding frame is disposed on the platen unit 8. FIG. 8A is a plan view, and FIGS. 8B and 8C are one side and the other side in the printer width direction Y. The side view seen from the side, FIG.8 (d) is ZZ sectional drawing (sectional drawing of a spherical body holding | maintenance part) of Fig.8 (a). FIG. 9 is an explanatory view of the holding frame body, FIG. 9A is a perspective view, and FIG. 9B is a bottom view as seen from the platen unit 8 side. In this embodiment, three spheres 19 (platen gap forming members) are arranged between the platen unit 8 and the head unit 7. The platen unit 8 comes into contact with the spherical body 19 from the lower side and the head unit 7 comes into contact from the upper side, so that the gap (platen gap) between the nozzle surface of the print head 71 and the platen surface 8a is maintained at a constant size. ing. For this reason, the platen unit 8 is provided with three contact portions (platen side contact portions 89a to 89c described later) that contact the three spheres 19 from below. The head unit 7 also has contact portions (head-side contact portions 75a to 75c described later) that contact the three spheres 19 from above.

  On the platen unit 8 side, the contact portion with the sphere 19 is formed on the first side plate 84a and the second side plate 84b. That is, as shown in FIGS. 4 to 6, platen side abutting portions 89 a and 89 b are formed on the upper end edge of the first side plate 84 a at two locations on both ends in the longitudinal direction. The platen side abutting portions 89a and 89b are horizontal plates that are bent substantially perpendicularly from the upper end edge of the first side plate 84a and extend toward the center in the width direction of the platen surface 8a. In addition, a platen side contact portion 89c is formed at one central position in the longitudinal direction of the upper end edge of the second side plate 84b. The platen side abutting portion 89c is a horizontal plate that is bent at a substantially right angle from the upper end edge of the second side plate 84b and extends outward in the width direction of the platen surface 8a. The three spheres 19 come into contact with the platen side contact portions 89a, 89b, 89c one by one from the upper side.

  A holding frame 20 that holds the sphere 19 is disposed between the platen unit 8 and the head unit 7. As shown in FIGS. 7 to 9, the holding frame 20 has a substantially rectangular planar shape as a whole, and is disposed so as to overlap the upper surface of the platen unit 8. The holding frame 20 includes a thin holding frame main body 20A that overlaps the upper surface of the platen unit 8, and a fixed frame 20B that is attached to an end of the holding frame main body 20A on the printer rear X2 side. The holding frame 20 is fixed to the apparatus main body frame of the printer 1 via the fixed frame 20B.

  The holding frame main body portion 20A includes a pair of vertical frame portions 21a and 21b extending in parallel with the longitudinal direction X of the printer along the side frames 83a and 83b of the platen unit 8, and five support rollers 85a provided on the platen unit 8. 5 horizontal frame portions 22a to 22e arranged so as to overlap with 85e. The horizontal frame portions 22a to 22e extend in parallel to the printer width direction Y, and both ends thereof are connected to the vertical frame portions 21a and 21b. As shown in FIG. 9, the end portions of the vertical frame portions 21a and 21b on the printer rear X2 side protrude further to the printer rear X2 side than the horizontal frame portion 22e positioned closest to the printer rear X2 side, and are fixed here. A frame 20B is attached.

  The holding frame main body 20A is formed with three spherical holding parts 23a to 23c for holding the three spherical bodies 19. The spherical body holding portions 23a to 23c are formed at positions overlapping the platen side contact portions 89a to 89c. That is, the sphere holding part 23a that holds the sphere 19 that comes into contact with the platen side contact part 89a is formed at a corner on the printer front X1 side to which the horizontal frame part 22a and the vertical frame part 21a are connected. The spherical body holding portion 23b that holds the spherical body 19 that contacts the platen side contact portion 89b is formed at a corner portion on the printer rear X2 side where the horizontal frame portion 22e and the vertical frame portion 21a are connected. The spherical body holding portion 23c that holds the spherical body 19 that is in contact with the platen side contact portion 89c is formed at a position where the horizontal frame portion 22c is connected at the approximate center of the vertical frame portion 21b in the front-rear direction X of the printer. . As shown in FIG. 8D, the sphere holding part 23a is attached so as to rotatably support the penetrating part 24a penetrating the vertical frame part 21b in the vertical direction of the printer and the sphere 19 arranged in the penetrating part 24a. And a support member 24b made of wire. The structures of the sphere holding portions 23b and 23c are the same as this.

  In addition to the sphere 19, the holding frame 20 holds a star wheel 25 that suppresses the continuous paper P from being lifted from the platen surface 8 a. The star wheel 25 is attached to each of the horizontal frame portions 22a to 22e at four locations so as to overlap the four horizontal belt portions 81a.

  FIG. 10 is a perspective view of the head unit, and FIG. 11 is a bottom view of the head unit 7 viewed from the platen unit 8 side. As shown in FIGS. 2 and 10, the head unit 7 includes a print head 71, an inner carriage 72 on which the print head 71 is mounted, and an outer carriage 73 that holds the inner carriage 72 in a state in which the inner carriage 72 can be moved in the vertical direction of the printer. I have. Two carriage shafts 74 a and 74 b extending in the printer width direction Y are arranged on the printer unit X1 side and the printer rear X2 side of the head unit 7. The head unit 7 is slidably mounted on the two carriage shafts 74a and 74b. The head unit 7 slides in the printer width direction Y along the carriage shafts 74 a and 74 b, thereby causing the print head 71 and the platen unit 8 to face each other, and the print head 71 from above the platen unit 8. It is possible to move between the retracted retracted positions. Further, the inner carriage 72 on which the print head 71 is mounted moves in the vertical direction of the printer with respect to the outer carriage 73, thereby pressing the sphere 19 against the platen side contact portions 89a, 89b, 89c, and a platen gap holding position; The ink nozzle surface of the print head 71 can be moved between a retracted position where the ink nozzle surface is retracted above the holding frame main body 20A.

  As shown in FIG. 11, the print head 71 includes four heads: a first head 71a, a second head 71b, a third head 71c, and a fourth head 71d. Each head is formed with an ink nozzle that ejects one of four colors of CMYK ink. Head-side contact portions 75a, 75b, and 75c are formed on the lower end surface of the inner carriage 72 on which the first head 71a to the fourth head 71d are mounted. The head-side contact portions 75a, 75b, and 75c are formed at three locations that overlap the spherical body holding portions 23a to 23c in the holding frame 20 when the head unit 7 moves to the print execution position that faces the platen surface 8a. When the inner carriage 72 is lowered to the platen gap holding position, the three head side contact portions 75a, 75b, and 75c come into contact with the three spheres 19 held by the holding frame 20 from above, and these spheres 19 Is pressed against the platen side contact portions 89a, 89b, 89c. As a result, the distance (platen gap) between the nozzle surface of the print head 71 and the platen surface 8 a is maintained at a predetermined dimension corresponding to the diameter of the sphere 19.

(Platen surface flatness adjustment method)
FIG. 12 is a perspective view of the platen unit 8 and the adjustment jig, and FIG. 13 is an explanatory diagram of a method for adjusting the flatness of the platen surface using the adjustment jig. As described above, the horizontal belt portion 81a constituting the platen surface 8a is supported by the five support rollers 85a to 85e. One end of each of the support rollers 85a to 85e is supported by the first side plate 84a, and the other end is supported by the second side plate 84b. Accordingly, the flatness of the platen surface 8a depends on the inclinations of the support rollers 85a to 85e, in other words, the inclinations of the first side plate 84a and the second side plate 84b that support both ends thereof. Therefore, in the present embodiment, when the platen unit 8 is assembled, the first side plate 84a and the second side plate 84b are attached in parallel to the unit main body 83 by adjusting the posture of the second side plate 84b using the adjustment jig 30. As a result, the flatness adjustment work for ensuring the flatness of the platen surface 8a is performed. Hereinafter, the configuration of the adjustment jig 30 and the procedure of the flatness adjustment work will be described.

  As shown in FIG. 12, the adjustment jig 30 includes a plate-shaped jig body 31 having a predetermined thickness and three protrusions 32 a, 32 b, and 32 c that protrude from one surface of the jig body 31. ing. The protrusions 32a, 32b, and 32c have the same shape, and their tips 33a, 33b, and 33c (jig side contact portions) are when the three spheres 19 held by the holding frame 20 contact the platen unit 8. These are in the same positional relationship as the three contact points 90a, 90b, 90c on the platen side contact portions 89a, 89b, 89c. Further, in the jig main body 31, the surface opposite to the side from which the protrusions 32a, 32b, 32c project is an adjustment reference surface 34 parallel to the virtual surface A including the tips 33a, 33b, 33c. . The flatness adjustment work using the adjustment jig 30 is performed according to the following procedures (1) to (3).

(1) First, in the first step, the first side plate 84a is positioned and fixed in a posture extending horizontally in the longitudinal direction X of the printer along the upper edge of the side frame 83a of the unit main body 83. This fixing operation is performed by screwing both ends of the first side plate 84a to the side frame 83a using two fixing screws 88. Then, the other second side plate 84b is temporarily fixed to the side frame 83b. That is, the second side plate 84b is rotatably attached to the support shaft 83c protruding from the side frame 83b, and is allowed to swing around the support shaft 83c.

(2) Next, in the second step, the adjustment jig 30 is brought into contact with the platen unit 8 being assembled for positioning. Specifically, the tips 33a, 33b, and 33c of the protrusions 32a, 32b, and 32c of the adjustment jig 30 are brought into contact with the platen-side contact portions 89a, 89b, and 89c of the first side plate 84a and the second side plate 84b, respectively. Thus, the adjustment jig 30 is positioned. Although the second side plate 84b is swingable, the platen side contact portion 89 on the second side plate 84b side is disposed directly above the support shaft 83c, so that the second side plate 84b can be adjusted even if the second side plate 84b swings. The jig 30 does not wobble.

(3) Subsequently, in the third step, the inclination of the temporarily fixed second side plate 84b and the permanently fixed first side plate 84a is measured using the adjustment jig 30 as a reference. Since the fixed first side plate 84a has platen side abutting portions 89a and 89b formed at both ends thereof, the leading end 33a and 33b are brought into contact with these two points to thereby adjust the reference surface 34 for adjustment and the first side plate 84a. The first side plate 84a is in a parallel posture. Therefore, as shown in FIG. 13, the inclinations of the first side plate 84a and the second side plate 84b are measured by measuring the distances h1 and h2 between both ends of the second side plate 84b and the adjustment reference plane 34. Specifically, the dimensional difference between h1 and h2 is calculated. Thereafter, based on the measured inclination, the posture of the second side plate 84b is adjusted to a posture parallel to the first side plate 84a. Specifically, the second side plate 84b is swung around the support shaft 83c until the dimensional difference between h1 and h2 becomes zero. By setting the dimensional difference between h1 and h2 to zero, the second side plate 84b is parallel to the adjustment reference surface 34 and parallel to the first side plate 84a. Thereby, the attitude of the second side plate 84b is determined. After that, the second side plate 84b is permanently fixed to the side frame 83b. That is, both ends in the longitudinal direction of the second side plate 84 b are screwed to the side frame 83 b with the fixing screws 88.

(Main effects of this embodiment)
As described above, the flatness adjustment method for the platen surface 8a in the printer 1 according to the present embodiment determines one of the pair of members (the first side plate 84a) that supports the horizontal belt portion 81a constituting the platen surface 8a. The other side (second side plate 84b) is temporarily fixed in a swingable state about the support shaft 83c, and the inclinations of the first side plate 84a and the second side plate 84b are measured with reference to the adjustment jig 30. Then, based on the result, the second side plate 84b is adjusted to a posture parallel to the first side plate 84a and then permanently fixed. In such a method, even when there is a dimensional error or distortion in each part of the unit main body 83, the inclination of the first side plate 84a and the second side plate 84b can be secured, and as a result, the support for supporting the horizontal belt portion 81a. The inclination of the rollers 85a to 85e can be secured. Accordingly, the flatness can be ensured by preventing the platen surface 8a from being twisted.

  In particular, in this embodiment, when the three spheres 19 held by the holding frame 20 abut the tips 33a, 33b, 33c of the protrusions 32a, 32b, 32c formed on the adjustment jig 30 abut against the platen unit 8. The adjustment reference plane 34 is in the same positional relationship as the three contact points 90a, 90b, 90c on the platen side contact portions 89a, 89b, 89c, and is parallel to the virtual plane A including the tips 33a, 33b, 33c. Is formed on the adjustment jig 30. By using such an adjustment jig 30, each part of the platen unit 8 is determined by three contact points (in the case of this embodiment, contact points 90 a, 90 b, 90 c) with which the three spheres 19 contact. The inclination with respect to the virtual plane A0 (see FIG. 12) can be confirmed through the adjustment reference plane 34. Then, by making the adjustment reference surface 34, the first side plate 84a, and the second side plate 84b parallel, the platen surface 8a is assumed to be parallel to the virtual surface A0 (ie, the nozzle surface of the print head 71). Plane). Thereby, when the head unit 7 is positioned with respect to the platen unit 8 via the sphere 19, the platen gap between the nozzle surface of the print head 71 and the platen surface 8a can be set to a constant value.

  The printer 1 according to the present embodiment includes a platen unit 8 including a platen surface 8a that supports the sheet-like continuous paper P, a head unit 7 including a print head 71 facing the platen surface 8a, and the head unit 7 and the platen unit. The platen unit 8 supports the horizontal belt portion 81a via the horizontal belt portion 81a constituting the platen surface 8a and the support rollers 85a to 85e. The first side plate 84a, the second side plate 84b, a side frame 83a to which the first side plate 84a is attached, and a unit main body 83 having a side frame 83b to which the second side plate 84b is attached. The first side plate 84a has two spheres. 19, platen side contact portions 89a and 89b that contact from the opposite side of the head unit 7 are formed, The second side plate 84b is formed with a platen side contact portion 89c, and the side frame 83b is provided with a support shaft 83c to which the second side plate 84b is attached so as to be swingable around a predetermined point. Yes. With such a configuration, the flatness adjusting method described above can be applied, and the flatness of the platen surface 8a and the inclination with the virtual surface A0 can be ensured. Therefore, the platen gap can be set to a constant value.

  Furthermore, in the printer 1 of the present embodiment, the three spheres 19 are held by the holding frame 20 disposed between the platen unit 8 and the head unit 7. In this way, the sphere 19 for forming the platen gap is held by the holding frame 20 which is separate from the head unit 7 and the platen unit 8, so that the retracting operation and the maintenance operation of the head unit 7 can be performed with the sphere 19 and other members. Can be prevented from being interfered with. Further, the operation of retracting the platen unit 8 for removing paper jam can be prevented from being hindered by interference between the sphere 19 and other members.

(Other embodiments)
(1) In the above embodiment, three spheres 19 are arranged between the platen unit 8 and the head unit 7, but the number of spheres 19 may be four or more. In this case, the platen unit 8 is formed with the same number of platen side contact portions as the sphere 19, and the head unit 7 is formed with the same number of head side contact portions as the sphere 19. The adjustment jig 30 may be formed with the same number of jig-side contact portions as the platen-side contact portions so as to have the same positional relationship as the platen-side contact portion. Even in such a configuration, the adjustment jig 30 can be positioned at least at three points, and the adjustment jig 30 can be reliably positioned. Therefore, the first side plate 84a and the second side plate 84b can be installed in parallel, and the flatness of the platen surface 8a can be ensured.

(2) The form of the platen gap forming member is not limited to the sphere 19 and may be another form. The arrangement of the platen gap forming members is not limited to the arrangement as described above. Even in such a configuration, an adjustment jig provided with a jig-side contact portion capable of contacting the platen unit 8 with a platen gap forming member formed in contact with the platen gap forming member is prepared. Thus, the adjustment jig 30 can be positioned so that the virtual plane parallel to the nozzle surface of the print head 71 and the adjustment reference surface 34 formed on the adjustment jig 30 coincide with each other. Therefore, the first side plate 84a and the second side plate 84b can be installed in parallel, and the flatness of the platen surface 8a can be ensured.

DESCRIPTION OF SYMBOLS 1 ... Line inkjet printer (printer), 2 ... Printer housing, 2a ... Front surface, 3 ... Operation part, 4 ... Paper discharge port, 5 ... Open / close lid, 6 ... Roll paper storage part, 7 ... Head unit, 8 ... Platen Unit: 8a ... Platen surface, 9 ... Roll paper, 10 ... Medium transport path, 10a ... First path part, 10b ... Second path part, 10c ... Third path part, 11 ... Medium supply roller, 12 ... Tension lever, DESCRIPTION OF SYMBOLS 13 ... Center of rotation, 14 ... Rotary encoder, 15 ... Paper guide, 16 ... Medium conveyance mechanism, 17a, 17b ... Pinch roller, 18 ... Paper detector, 19 ... Sphere (platen gap formation member), 20 ... Holding frame, 20A: holding frame main body, 20B: fixed frame, 21a, 21b ... vertical frame, 22a-22e ... horizontal frame, 23a-23c ... spherical body holding unit, 24 ... Penetration part, 24b ... Support member, 25 ... Star wheel, 30 ... Adjustment jig, 31 ... Jig body part, 32a-32c ... Protrusion, 33a-33c ... Tip (jig side contact part), 34 ... Adjustment Reference surface 71: Print head, 71a: First head, 71b: Second head, 71c: Third head, 71d: Fourth head, 72: Inner carriage, 73: Outer carriage, 74a, 74b ... Carriage shaft, 75a to 75c: Head side contact portion, 81: Conveying belt, 81a: Horizontal belt portion (platen surface constituting member), 82a to 82e ... Guide roller, 82f ... Belt drive roller, 83 ... Unit main body, 83a, 83b ... Side frames, 83c ... support shafts (temporary fixing portions), 84a ... first side plates (first members), 84b ... second side plates (second members), 85a to 85e ... support rollers, 86a Support shaft, 86b ... roller body, 87 ... holder, 88 ... fixing screw, 89a to 89c ... platen side contact portion, 90a to 90c ... contact point, A, A0 ... virtual surface, P ... continuous paper, X ... front and rear of printer Direction, X1 ... Printer front, X2 ... Printer rear, Y ... Printer width direction

Claims (11)

A method for adjusting the flatness of a platen surface in a printer that secures a platen gap by arranging a platen gap forming member between a platen unit and a head unit,
Prepare an adjustment jig in which a jig side contact portion that can contact the place where the platen gap forming member contacts in the platen unit is formed,
The first member that supports the platen surface constituent member is fixed to one side surface of the unit main body of the platen unit, and the second member that supports the platen surface constituent member together with the first member is the unit. A first step of swingably attaching to the other side surface of the main body,
A second step of positioning the adjustment jig by bringing the jig-side contact portion into contact with the first member and the second member;
A third step of measuring the inclination of the first member and the second member on the basis of the adjustment jig and adjusting the posture of the second member based on the measured inclination and fixing the second member to the unit main body. A method for adjusting the flatness of a platen surface in a printer. Three platen gap forming members are provided,
The jig side abutting portion is provided with three so as to be in the same positional relationship as three abutting points where the platen gap forming member and the platen unit abut. The flatness adjustment method of the platen surface in the printer of description. A reference surface for adjustment parallel to a virtual surface including the three jig side contact portions is formed on the adjustment jig,
In the second step, by measuring the distance between the reference surface for adjustment and the first member and the distance between the reference surface for adjustment and the second member, the first member and the second member are measured. 3. A method for adjusting the flatness of a platen surface in a printer according to claim 2, wherein an inclination is measured. The adjustment jig includes a jig main body portion on which the reference surface for adjustment is formed, and three protrusions protruding from the jig main body portion on the same side,
The flatness adjustment method for a platen surface in a printer according to claim 3, wherein the three jig side contact portions are tips of the three protrusions. The platen surface constituent member is a transport belt that is stretched in the medium transport direction,
The transport belt is supported by a plurality of support rollers extending in a direction intersecting the medium transport direction,
5. The apparatus according to claim 1, wherein the first member supports one end of the plurality of support rollers, and the second member supports the other end of the plurality of support rollers. The flatness adjustment method of the platen surface in the printer of description. An adjustment jig used to adjust the flatness of a platen surface in a printer that secures a platen gap by arranging a platen gap forming member between a platen unit and a head unit,
A jig side abutting portion capable of abutting on an abutting portion with which the platen gap forming member abuts in the platen unit;
An adjustment jig used for adjusting the flatness of a platen surface, comprising: an adjustment reference surface formed in parallel with a virtual surface including the jig side contact portion. Three platen gap forming members are provided,
The three jig side contact portions are provided so as to have the same positional relationship as three contact points at which the platen gap forming member and the platen unit contact each other. An adjustment jig used for adjusting the flatness of the described platen surface. A jig body portion on which the adjustment reference surface is formed, and three protrusions protruding from the jig body portion to the same side,
The adjustment jig used for adjusting the flatness of the platen surface according to claim 7, wherein the three jig side contact portions are tips of the three protrusions. A platen unit having a platen surface for supporting a sheet-like medium;
A head unit comprising a print head facing the platen surface;
Having at least three platen gap forming members disposed between the head unit and the platen unit;
The platen unit includes a platen surface constituting member constituting the platen surface, a first member and a second member supporting the platen surface constituting member, one side surface to which the first member is attached, and the second member. A unit body provided with the other side surface to which
The first member is formed with at least two of at least three platen side contact portions that contact the at least three platen gap forming members from the side opposite to the head unit,
The second member is formed with at least one of the at least three platen side contact portions,
The printer according to claim 1, wherein a temporary fixing portion to which the second member is attached so as to be swingable about a predetermined point is provided on the other side surface of the unit main body. The platen surface constituent member is a transport belt that is stretched in the medium transport direction,
The transport belt is supported by a plurality of support rollers extending in a direction intersecting the medium transport direction,
The printer according to claim 9, wherein the first member supports one end of the plurality of support rollers, and the second member supports the other end of the plurality of support rollers. The printer according to claim 9, wherein the at least three platen gap forming members are held by a holding frame disposed between the platen unit and the head unit.

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