Mounting structure of inkjet head

Abstract

To provide a mounting structure of an inkjet head that does not require a position of a replaced inkjet head to be adjusted.SOLUTION: A mounting structure of an inkjet head comprises a support member 31 arranged to oppose to an ink discharge surface, and a head holder 34 positioned at the support member 31 by a positioning structure 43. The positioning structure 43 has first-third positioning parts 62-64 for the support member 31, and first-third positioning surfaces 65-67 for the head holder 34. The first-third positioning surfaces 65-67 are formed to be perpendicular to a positioning direction, at positions separated by predetermined distances in three positioning directions from a predetermined reference position of the inkjet head. At least two positioning parts of the first-third positioning parts 62-64 restrict the head holder 34 from moving so that the head holder 34 can move in parallel only in a direction in which the head holder contacts and separates from other positioning part.SELECTED DRAWING: Figure 13

Description

[Technical field]

[0001] The present invention relates to a mounting structure for an inkjet head used in a digital printer. [Background technology]

[0002] Conventional digital printers often use ready-made inkjet heads. In this case, an intermediate part may be used between the inkjet head and a support member on the printer side, as described in Patent Document 1, for example. Patent Document 1 discloses an attachment structure in which the inkjet head is fixed to a holder as an intermediate part that fits the support member on the printer side, and the holder is attached to the support member.

[0003] In order to fix the inkjet head to the holder, Patent Document 1 discloses a method in which the inkjet head is aligned with an alignment mark on the holder, and then the two are fastened together using a screw member. Incidentally, in an inkjet head, the ink ejection holes of the ejection nozzles may become clogged, and in such a case the inkjet head is replaced with a new one. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-212667 A Summary of the Invention [Problem to be solved by the invention]

[0005] In a printer that performs inkjet printing, high accuracy is required for the position of the inkjet head, so when replacing the inkjet head, time must be spent to adjust the position in addition to the time required for the installation work. If the positioning of the inkjet head includes the tightening work of a screw member as disclosed in Patent Document 1, the position may be shifted due to elastic deformation caused by the tightening, and the precision of the position adjustment is likely to be low. In such a case, the position adjustment requires a lot of time.

[0006] An object of the present invention is to provide an inkjet head mounting structure that eliminates the need for position adjustment after replacing an inkjet head. [Means for solving the problem]

[0007] In order to achieve this object, the inkjet mounting structure of the present invention comprises a support member arranged opposite an ink ejection surface, and a head holder to which an inkjet head is fixed and which is removably attached in a state in which it is positioned on the support member by a positioning structure, the positioning structure having first to third positioning portions provided on the support member and which determine a position by restricting movement of the head holder in three mutually perpendicular positioning directions, and first to third positioning surfaces formed on the head holder so as to individually contact the first to third positioning portions, the first to third positioning surfaces being formed at positions away from a predetermined reference position of the inkjet head in the three positioning directions by a distance determined for each direction, and being perpendicular to the positioning directions, and at least two of the first to third positioning portions are structured to restrict movement of the head holder so that the head holder can move parallel only in directions in which it approaches and moves away from the other positioning portions.

[0008] The present invention may provide a mounting structure for the inkjet head, in which the head holder is mounted to the support member at two mounting portions, and one of the two mounting portions is configured to use a first mounting bolt that penetrates an exposed portion that is exposed on the side opposite the support member when the inkjet head is fixed in the head holder and is screwed into the support member, and the other mounting portion is configured to use a second mounting bolt that penetrates the support member and is screwed into the head holder.

[0009] The present invention relates to a mounting structure for an inkjet head, wherein the positioning structure is provided on one side and the other side of the support member in a direction parallel to the direction of movement of the ink ejection surface, and a groove-shaped cutout portion is formed at the end of the support member close to the ink ejection surface, the cutout portion opening toward the ink ejection surface and extending in a direction perpendicular to the direction in which the ink ejection surface moves and along the ink ejection surface, and the second mounting bolt may pass through a plate-shaped portion of the support member that constitutes the side of the cutout portion.

[0010] The present invention may provide a mounting structure for the inkjet head, wherein a groove is formed on a side of the support member in the direction of movement of the ink ejection surface, the groove having a width sufficient to accommodate the head holder and extending in a direction perpendicular to the ink ejection surface, the groove having an opening end consisting of an opening close to the ink ejection surface and a terminal end face located on the opposite side of the ink ejection surface from the opening end, and the first to third positioning portions may be constituted by a bottom surface of the groove, one side surface of the groove in the width direction of the groove, and the terminal end face of the groove.

[0011] The present invention relates to a mounting structure for an inkjet head, wherein a first flat surface extending in a direction perpendicular to the movement direction of the ink ejection surface and perpendicular to the ink ejection surface, and a second flat surface parallel to the ink ejection surface are formed on a side of the support member in a direction parallel to the movement direction of the ink ejection surface, and a protrusion is provided on the first flat surface or the second flat surface, and the first to third positioning portions may be constituted by the first flat surface, the second flat surface, and the protrusion.

[0012] The present invention may provide a mounting structure for an inkjet head, wherein a side portion of the support member in a direction parallel to the movement direction of the ink ejection surface is provided with a first flat surface extending in a direction perpendicular to the movement direction of the ink ejection surface and perpendicular to the ink ejection surface, and a plurality of protrusions protruding from the first flat surface, and the first to third positioning portions may be formed by the first flat surface and the plurality of protrusions.

[0013] The present invention relates to a mounting structure for an inkjet head, wherein the support member is formed to extend in a direction perpendicular to the movement direction of the ink ejection surface and along the ink ejection surface, and is configured to be movable between a use position facing the ink ejection surface and a retracted position away from the ink ejection surface in a direction perpendicular to the movement direction of the ink ejection surface, and the positioning structure and the head holder to which the inkjet head is fixed are respectively provided at a plurality of positions aligned in the direction in which the support member extends, and the positioning structure is configured so that the head holder can slide and be removed from the support member in a direction perpendicular to the ink ejection surface. Effect of the Invention

[0014] According to the present invention, it is possible to provide an inkjet head mounting structure that eliminates the need for position adjustment after replacing an inkjet head. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a side view showing the configuration of a printing machine that employs an inkjet head mounting structure according to the present invention. [Diagram 2] FIG. 2 is a front view of multiple inkjet devices arranged near the periphery of a print cylinder. [Diagram 3] FIG. 3 is a bottom view of a part of the inkjet device as seen from the printing cylinder side. [Figure 4] FIG. 4 is a cross-sectional view showing the mounting structure of the inkjet head. [Diagram 5] FIG. 5 is a perspective view showing a plurality of ink-jet heads and a part of a support member. [Figure 6] FIG. 6 is an exploded perspective view showing a part of the ink-jet head, the head holder, and a part of the support member. [Figure 7] FIG. 7 is an exploded perspective view showing a part of the ink-jet head, the head holder, and a part of the support member. [Figure 8] FIG. 8 is a front view of the mounting structure for the inkjet head. [Figure 9] FIG. 9 is an enlarged cross-sectional view showing a part of the mounting structure of the inkjet head. [Figure 10] FIG. 10 is an enlarged cross-sectional view showing the attachment portion of the support member and the head holder. [Figure 11] FIG. 11 is an enlarged cross-sectional view showing a part of the mounting structure of the ink-jet head. [Figure 12] FIG. 12 is a perspective view showing the mounting structure of the ink-jet head. [Figure 13] FIG. 13 is an exploded perspective view showing the mounting structure of the inkjet head. [Figure 14] FIG. 14 is a flow chart showing the procedure for machining the first to third positioning surfaces. [Figure 15] FIG. 15 is a bottom view of the assembly consisting of the mounting member and the head holder. [Figure 16] FIG. 16 is a side view of an assembly consisting of the mounting member and the head holder. [Figure 17]FIG. 17 is a perspective view showing a modified example of the mounting structure of the ink-jet head. [Figure 18] FIG. 18 is a perspective view showing a modified example of the mounting structure of the ink-jet head. [Figure 19] FIG. 19 is a side view showing the configuration of a printing press showing another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] (First embodiment) BEST MODE FOR CARRYING OUT THE DISCLOSURE One embodiment of an inkjet head mounting structure according to the present invention will now be described in detail with reference to FIGS. The inkjet head mounting structure according to the present invention can be used in a printing machine 1 as shown in FIG. (Explanation of the printing machine) The printing press 1 shown in Fig. 1 transports a sheet 4 from a feeder section 2 located at the far right in Fig. 1 to a printing unit 3, where printing is performed on the sheet 4. The sheet 4 on which printing has been performed in the printing unit 3 is sent to a delivery section 5 and discharged to a delivery pile 6.

[0017] The feeder section 2 is structured to transfer the sheet 4 from the feeder pile 7 to the feeder board 9 by means of a sucker 8. The printing unit 3 includes a supply side transfer cylinder 11 to which the sheet 4 supplied from the feeder section 2 is transported by a swing device 10, a printing cylinder 12 to which the sheet 4 is fed from the supply side transfer cylinder 11, and a transport mechanism 13 that transports the sheet 4 after printing. The supply-side transfer cylinder 11 supplies the sheet 4 to the printing cylinder 12 at a supply position P1.

[0018] The printing cylinder 12, which adsorbs and transports the sheet 4, rotates around an axis extending in a direction perpendicular to the paper surface of FIG. 1. The printing cylinder 12 according to this embodiment is a so-called triple cylinder, and has three transport surfaces 14 at three locations in the rotation direction, as shown in FIG. 1. These transport surfaces 14 are formed by the outer circumferential surface of the printing cylinder 12, and are provided at positions that divide the printing cylinder 12 into three equal parts in the rotation direction as viewed from the axial direction. In this embodiment, the transport surfaces 14 correspond to the "ink ejection surface" as defined in the present invention. The axial direction of the printing cylinder 12 corresponds to the "direction perpendicular to the direction in which the ink ejection surface moves and along the ink ejection surface" as defined in the present invention. Furthermore, the radial direction of the printing cylinder 12 corresponds to the "direction perpendicular to the ink ejection surface" as defined in the present invention. Furthermore, the transport direction of the sheet 4 transported by the printing cylinder 12 corresponds to the "movement direction of the ink ejection surface" as defined in the present invention. Between the adjacent conveying surfaces 14, a peripheral cutout portion 15 is provided, and a gripper device 16 is also provided.

[0019] Near the periphery of the printing cylinder 12 and downstream of the supply-side transfer cylinder 11 in the sheet transport direction, an inkjet device 17 and an ink drying lamp 21 are arranged in this order. The inkjet device 17 performs printing by ejecting ink droplets onto the sheet 4. The inkjet device 17 will be described later. The ink drying lamp 21 is for curing the ink applied to the sheet 4 by the inkjet device 17 .

[0020] The transport mechanism 13 includes a discharge-side transfer cylinder 22 that receives the sheet 4 from the printing cylinder 12 at receiving position P2, and a delivery belt 23 that receives the sheet 4 from the discharge-side transfer cylinder 22. The above-mentioned supply-side transfer cylinder 11 and discharge-side transfer cylinder 22 are equipped with gripper devices 24, 25 to transfer the sheet 4. These gripper devices 24, 25 are equivalent to the gripper device 16 of the printing cylinder 12. The delivery belt 23 discharges the printed sheet 4 onto a delivery pile 6 .

[0021] (Description of the inkjet device) As shown in FIG. 2, the inkjet device 17 is attached to a frame (not shown) of the printing press 1 by a mounting structure 32 including a support member 31 arranged opposite the conveying surface 14 of the printing cylinder 12. The inkjet device 17 includes inkjet heads 33 arranged in pairs on both sides of the support member 31. The two sides of the support member 31 referred to here are both sides of the support member 31 in a direction perpendicular to the axial direction of the printing cylinder 12 and perpendicular to the radial direction of the printing cylinder 12 (direction perpendicular to the axial direction and radial direction of the printing cylinder 12: direction parallel to the moving direction of the ink ejection surface). In the following, of the sides of the support member 31 on which the inkjet heads 33 are provided, the side located downstream in the sheet conveying direction (left side in FIG. 2) is simply referred to as "one side 31a," and the side located upstream in the sheet conveying direction is simply referred to as "the other side 31b."

[0022] (Explanation of supporting members) Support member 31 is formed in a rectangular column shape extending in the axial direction of printing cylinder 12, and is supported in a state where it is positioned with high precision on the frame of printing press 1 via a support mechanism (not shown). Support member 31 is formed to have a length extending from one end of printing cylinder 12 to the other end in the axial direction of printing cylinder 12. The support mechanism supports the support member 31 so that the support member 31 can move between a use position facing the printing cylinder 12 and a retracted position away from the printing cylinder 12 in the axial direction of the printing cylinder 12 .

[0023] (Explanation of inkjet head) As shown in Fig. 4, the inkjet head 33 includes a mounting member 35 that is attached to the support member 31 via a head holder 34, which will be described later, and an ink discharge device 36 assembled to the mounting member 35. As shown in Fig. 5, the inkjet heads 33 are provided at a plurality of positions aligned in the axial direction of the support member 31 (the axial direction of the printing cylinder 12). Fig. 5 omits a portion of the ink discharge device 36. The inkjet heads 33 are arranged in the longitudinal direction of the support member 31 so that the adjacent inkjet heads 33 are as close to each other as possible, as shown in FIG.

[0024] As shown in Figures 6 and 7, the mounting member 35 of the inkjet head 33 has an L-shaped cross section and includes a plate-shaped mounting portion 35a that is mounted to the support member 31 via a head holder 34 described later, and a nozzle support portion 35b that protrudes from one end of the mounting portion 35a close to the printing cylinder 12 (the lower end in Figures 6 and 7) to the opposite side to the support member 31. Only a portion of the support member 31 in the longitudinal direction is depicted in Figures 6 and 7. The mounting member 35 is made of a metal material. The nozzle support portion 35b shown in Figures 6 and 7 is depicted with a nozzle portion 37 of the ink ejection device 36 attached thereto.

[0025] As shown in Fig. 3, the nozzle section 37 is formed to have a parallelogram shape when viewed from the printing cylinder 12 side. When arranging the multiple inkjet heads 33 side by side on the support member 31, the adjacent nozzle sections 37 are arranged as close as possible to each other, as shown in Fig. 3. A strip-shaped nozzle plate 37a is provided at the end of the nozzle section 37 facing the printing cylinder 12. The nozzle plate 37a is formed in a shape that extends in the longitudinal direction of the support member 31 (the left-right direction in Fig. 3, that is, the axial direction of the printing cylinder 12). Although not shown, the nozzle plate 37a has a large number of ink ejection holes formed therein.

[0026] 6 and 7, mounting portion 35a of mounting member 35 is formed in a plate shape extending in the axial direction and radial direction of printing cylinder 12. Mounting portion 35a has a first screw hole 38 and a second screw hole 39 formed in it and aligned in the longitudinal direction of mounting portion 35a (radial direction of printing cylinder 12). Fixing bolts 40 for fixing head holder 34 to mounting member 35 are screwed into first and second screw holes 38, 39.

[0027] (Description of head holder) Head holder 34 cooperates with support member 31 to form mounting structure 32 described above, and is formed in a plate shape from a metal material. Head holder 34 in this embodiment is plate-like extending in the axial direction and radial direction of printing cylinder 12, and is formed in a shape that is long in the radial direction of printing cylinder 12. Furthermore, a mounting seat 34a consisting of a protrusion extending in the radial direction of printing cylinder 12 is formed in the portion of head holder 34 to which mounting member 35 is connected. First and second through holes 41, 42 for passing therethrough two fixing bolts 40 described above are drilled in the portion of head holder 34 where mounting seat 34a is formed.

[0028] In addition, the head holder 34 is positioned on the support member 31 by a positioning structure 43 described later as shown in Figure 4, and is removably attached to the support member 31 at two mounting portions 44, 45 located on the upper and lower sides in Figure 4 (two locations located on one radial side and the other radial side of the printing cylinder 12). Of the two mounting portions 44, 45, the first mounting portion 44, which is located at the upper side, is configured to use a first mounting bolt 46 that penetrates the end of the head holder 34 opposite the printing cylinder 12.

[0029] The first mounting bolt 46 is passed through a third through hole 47 formed in the head holder 34, and screwed into a third screw hole 48 formed in the support member 31. The third through hole 47 is formed in an exposed portion 49 of the head holder 34 that is exposed on the side opposite to the support member 31 when the inkjet head 33 is fixed, as shown in Fig. 8. The hole diameter of the third through hole 47 is set so that an anti-interference gap d1 is formed between the third through hole 47 and the first mounting bolt 46, as shown in Fig. 9.

[0030] Of the two mounting portions 44, 45, the second mounting portion 45 located on the lower side has a configuration that uses a second mounting bolt 52 that screws into a fourth screw hole 51 formed in end portion 31c of head holder 34 that is adjacent to printing cylinder 12, as shown in Fig. 4. As shown in Fig. 10, end portion 31c of support member 31 that is adjacent to printing cylinder 12 has a groove-shaped cutout portion 53 that opens toward printing cylinder 12 when viewed in the axial direction of printing cylinder 12. Cutout portion 53 is formed so as to extend without interruption from one end to the other end of support member 31 in the longitudinal direction.

[0031] The second mounting bolt 52 penetrates the plate-like portion 54 of the support member 31 constituting the side surface of the cutout portion 53, and is screwed into the fourth screw hole 51 of the head holder 34. The fourth screw hole 51 passes through a fourth through hole 55 formed in the plate-like portion 54. The diameter of the fourth through hole 55 is set so that an interference prevention gap d2 is formed between the second mounting bolt 52 and the fourth through hole 55, as shown in Fig. 11. The fracture position in Fig. 11 is the position indicated by the line XI-XI in Fig. 10.

[0032] (Description of positioning structure) As shown in Figure 12, positioning structure 43, which positions head holder 34 relative to support member 31, is configured to perform positioning in the positioning directions indicated by the three arrows A to C in Figure 12. Note that Figure 12 is drawn when mounting member 35 is not attached to head holder 34. The first positioning direction A is a direction perpendicular to the axial and radial directions of printing cylinder 12. The second positioning direction B is the axial direction of printing cylinder 12. The third positioning direction C is the radial direction of printing cylinder 12.

[0033] The positioning structure 43 according to this embodiment is configured using a groove 61 formed in the support member 31 and the outer surface of the head holder 34. The grooves 61 are formed at a plurality of positions aligned in the longitudinal direction of the support member 31 (the axial direction of the printing cylinder 12) on one side portion 31a and the other side portion 31b of the support member 31. More specifically, as shown in Fig. 13, the groove 61 is formed so as to extend in the radial direction of the printing cylinder 12 with a width capable of accommodating the head holder 34, with the axial direction of the printing cylinder 12 being the groove width direction. The groove 61 has an opening end 61a formed by an opening close to the printing cylinder 12, a terminal end surface 61b located on the opposite side of the opening end 61a from the printing cylinder 12, and side surfaces 61c and 61d that define the groove width.

[0034] The groove 61 has three positioning portions 62 to 64 to determine the position by restricting the movement of the head holder 34 in the above-mentioned three positioning directions A to C. The first positioning portion 62 is a bottom surface 61e of the groove 61. The second positioning portion 63 is one side surface 61c of the groove 61. The third positioning portion 64 is an end surface 61b of the groove 61. In this embodiment, the bottom surface 61e of the groove 61 is connected to the side surfaces 61c and 61d at a right angle, and the bottom surface 61e is connected to the end surface 61b at a right angle.

[0035] The outer surface of the head holder 34 constituting the positioning structure 43 is a surface formed so as to contact the first to third positioning portions 62 to 64 individually. That is, this outer surface is a first positioning surface 65 formed so as to contact the bottom surface 61e of the groove 61 which is the first positioning portion 62, a second positioning surface 66 formed so as to contact one side surface 61c of the groove 61 which is the second positioning portion 63, and a third positioning surface 67 formed so as to contact the terminal surface 61b of the groove 61 which is the third positioning portion 64.

[0036] These first to third positioning surfaces 65 to 67 are formed so as to be perpendicular to the above-mentioned first to third positioning directions A to C. That is, the first positioning surface 65 is formed so as to be perpendicular to the first positioning direction A. The second positioning surface 66 is formed so as to be perpendicular to the second positioning direction B. The third positioning surface 67 is formed so as to be perpendicular to the third positioning direction C. These first to third positioning surfaces 65 to 67 are formed at positions perpendicular to the positioning directions A to C at distances determined for each of the positions from a predetermined reference position. The reference position may be, for example, the position of a predetermined ink ejection hole of the inkjet head 33.

[0037] The first to third positioning surfaces 65-67 are formed in the head holder 34 in the correct positions in the order shown in the flow chart of Fig. 14. First, the inkjet head 33 is mounted on the mounting member 35 with only the nozzle portion 37 attached thereto, and the mounting member 35 to which the nozzle portion 37 is attached is prepared (step S1). Next, the head holder 34 is fixed to the mounting member 35 with the first and second fixing bolts 40 (step S2). After that, the assembly consisting of the head holder 34 and the mounting member 35 is set in a processing machine (not shown) (step S3). Then, the first to third positioning surfaces 65-67 are formed in the head holder 34 by machining (step S4).

[0038] The first positioning surface 65 is machined at a position that is a directional distance L1 away in the first positioning direction A from the ink ejection hole 71 at the reference position, as shown in Fig. 15. The ink ejection hole 71 shown in Fig. 15 is drawn larger than it actually is to make the reference position easier to understand. The second positioning surface 66 is machined at a position that is a directional distance L2 away in the second positioning direction B from the ink ejection hole 71 at the reference position. The third positioning surface 67 is machined at a position that is a directional distance L3 away in the third positioning direction C from the ink ejection hole 71 at the reference position, as shown in Fig. 16.

[0039] (Explanation of operation and effects of this embodiment) In order to attach the head holder 34 having the first to third positioning surfaces 65-67 thus formed to the support member 31, first, the first to third positioning surfaces 65-67 are brought into contact with the first to third positioning portions 62-64. For example, the first positioning surface 65 is brought into contact with the first positioning portion 62 consisting of the bottom surface 61e of the groove 61, and the head holder 34 is translated along the bottom surface 61e of the groove 61 to bring the second positioning surface 66 into contact with the second positioning portion 63, and the third positioning surface 67 into contact with the third positioning portion 64. In a state in which the head holder 34 is in contact with the first positioning portion 62 and the second positioning portion 63, it is only possible to translate in the direction toward and away from the third positioning portion 64. That is, at least two of the first to third positioning portions 62 to 64 restrict the movement of the head holder 34 so that the head holder 34 can move in parallel only in a direction approaching or separating from the remaining positioning portions.

[0040] The first to third positioning surfaces 65-67 of the head holder 34 come into contact with the first to third positioning portions 62-64, whereby the head holder 34 and the mounting member 35 of the inkjet head 33 are positioned relative to the support member 31. Positioning here means that the ink ejection holes 71, which are the reference positions of the nozzle portion 37, are positioned at the designed position of the printing machine 1.

[0041] To attach the head holder 34 integrated with the mounting member 35 to the support member 31, the first and second mounting bolts 46, 52 are fastened in a state in which the first to third positioning surfaces 65-67 are in contact with the first to third positioning portions 62-64. Since the first and second mounting bolts 46, 52 are not involved in positioning, the positioning state does not change after the first and second mounting bolts 46, 52 are fastened. After the mounting member 35 is fixed to the support member 31, other components of the ink discharge device 36 are attached to the mounting member 35, thereby completing the assembly of the inkjet head 33 to the support member 31.

[0042] The inkjet head 33 may need to be replaced due to clogging of the ink ejection holes. In such a case, the inkjet head 33 is removed from the support member 31, and the mounting member 35 having the nozzle portion 37 and the head holder 34 are replaced with new ones. This replacement work is performed with the support member 31 moved to the retracted position. With the support member 31 moved to the retracted position, the first and second mounting bolts 46, 52 are loosened and removed, and the target inkjet head 33 together with the head holder 34 can be slid downward (toward the radial inside of the printing cylinder 12) from the opening end 61a of the groove 61 and pulled out.

[0043] As described above, the first to third positioning surfaces 65-67 are formed in advance on the new head holder 34 while it is fixed to the mounting member 35 having the nozzle portion 37. Therefore, by fastening the first and second mounting bolts 46, 52 with the first to third positioning surfaces 65-67 of the new head holder 34 in contact with the first to third positioning portions 62-64 of the existing support member 31, the ink ejection holes 71 in the reference position are positioned at the designed position without performing any special positioning work. Thereafter, the head holder 34 is attached to the support member 31, and then other parts are attached to the mounting member 35 to complete the inkjet head 33. Therefore, according to this embodiment, it is possible to provide an inkjet head mounting structure that eliminates the need for position adjustment after replacing an inkjet head.

[0044] The head holder 34 according to this embodiment is attached to the support member 31 at two attachment portions (a first attachment portion 44 and a second attachment portion 45). Of the two attachment portions 44, 45, the first attachment portion 44 is configured to use a first attachment bolt 46 that penetrates an exposed portion 49 that is exposed on the opposite side of the support member 31 in the head holder 34 with the inkjet head 33 fixed thereto, and is screwed into the support member 31. The other, the second attachment portion 45, is configured to use a second attachment bolt 52 that penetrates the support member 31 and is screwed into the head holder 34. For this reason, when the head holder 34 is attached to the support member 31, the first and second mounting bolts 46, 52 do not interfere with the nozzle portion 37. Also, in the direction in which the multiple inkjet heads 33 are lined up, the first and second mounting bolts 46, 52 are disposed inside the head holder 34, so the distance between adjacent inkjet heads 33 can be minimized.

[0045] Positioning structure 43 according to this embodiment is provided on each of one side portion 31a and the other side portion 31b of support member 31, and a groove-shaped cutout portion 53 that opens toward printing cylinder 12 when viewed in the axial direction of printing cylinder 12 is formed in the end of support member 31 that is adjacent to printing cylinder 12. Second mounting bolt 52 passes through plate-shaped portion 54 of support member 31 that constitutes the side surface of cutout portion 53. Therefore, even though the ink-jet heads 33 are attached to both sides of the support member 31, the second mounting bolts 52 can be screwed into the head holder 34 from the side opposite the ink-jet heads 33.

[0046] In this embodiment, a groove 61 is formed in one side portion 31a and the other side portion 31b of the support member 31, the groove 61 extending in the radial direction of the printing cylinder 12 with a width sufficient to accommodate the head holder 34. The groove 61 has an opening end 61a formed by an opening adjacent to the printing cylinder 12, and a terminal end surface 61b located on the opposite side of the opening end 61a from the printing cylinder 12. The first to third positioning portions 62 to 64 are formed by a bottom surface 61e of the groove 61, one side surface 61c of the groove 61 in the axial direction of the printing cylinder 12, and the terminal end surface 61b of the groove 61. The second positioning portion 63 can also be formed by a side surface 61d of the groove 61. Therefore, the first to third positioning portions 62 to 64 can be formed with high precision by machining, and the positioning structure 43 with even higher positioning precision can be realized.

[0047] The support member 31 in this embodiment is formed to extend in the axial direction of the printing cylinder 12, and is configured to be movable between a use position facing the printing cylinder 12 and a retracted position away from the printing cylinder 12 in the axial direction of the printing cylinder 12. The positioning structures 43 and the head holders 34 to which the inkjet heads 33 are fixed are provided at multiple positions aligned in the axial direction of the support member 31. The positioning structures 43 are configured so that the head holders 34 can slide from the support member 31 radially inward of the printing cylinder 12 and be removed. Therefore, even though multiple inkjet heads 33 are attached to a single support member 31, parts of the inkjet heads 33 can be easily replaced.

[0048] (Modification of positioning structure) The positioning structure 43 can be configured as shown in Figures 17 and 18. In Figures 17 and 18, members that are the same as or equivalent to those described with reference to Figures 1 to 16 are given the same reference numerals and detailed description thereof will be omitted as appropriate. One side 31a and the other side 31b of the support member 31 shown in Figure 17 are provided with a first flat surface 81 as a first positioning portion 62, a first protrusion 82 as a second positioning portion 63, and a second flat surface 83 as a third positioning portion 64.

[0049] First flat surface 81 is formed so as to extend in the axial direction and radial direction of printing cylinder 12. First protrusion 82 is constituted by a bolt in this embodiment. This bolt is screwed into a screw hole 84 that opens into first flat surface 81. The head of the bolt constitutes first protrusion 82 that is provided in a protruding manner on first flat surface 81. The second flat surface 83 is formed so as to be perpendicular to the first flat surface 81 and extend in the axial direction of the printing cylinder 12 .

[0050] In this way, when the second positioning portion 63 is configured by the first protrusion 82, the head holder 34 can move parallel only in the direction of approaching and moving away from the first protrusion 82 (second positioning portion 63) by bringing the head holder 34 into contact with the first flat surface 81 and the second flat surface 83. Therefore, the head holder 34 can be positioned with respect to the support member 31 by sliding the head holder 34 along the first flat surface 81 and the second flat surface 83 and bringing it into contact with the first protrusion 82.

[0051] One side 31a and the other side 31b of the support member 31 shown in Figure 18 are provided with a first flat surface 81 as a first positioning portion 62, second and third protrusions 85, 86 as a second positioning portion 63, and a fourth protrusion 87 as a third positioning portion 64. The first flat surface 81 is formed so as to extend in the axial direction and radial direction of the printing cylinder 12 . In this embodiment, the second to fourth protrusions 85 to 87 are formed by bolts. These bolts are screwed into respective screw holes 88 to 90 opening in the first flat surface 81. The heads of these bolts form the second to fourth protrusions 85 to 87 protruding from the first flat surface 81. The second and third protrusions 85 and 86 constituting the second positioning portion 63 are arranged side by side in the radial direction of the printing cylinder 12 .

[0052] In this way, when the second positioning portion 63 and the third positioning portion 64 are configured by a plurality of protrusions (second to fourth protrusions 85 to 87), the head holder 34 is brought into contact with the first flat surface 81 and the second and third protrusions 85, 86 constituting the second positioning portion 63, so that the head holder 34 can move in parallel only in the direction approaching and separating from the fourth protrusion 87 (third positioning portion 64). Therefore, the head holder 34 can be positioned with respect to the support member 31 by sliding the head holder 34 along the first flat surface 81 and the second and third protrusions 85, 86 and bringing it into contact with the fourth protrusion 87.

[0053] Even when some of the first to third positioning portions 62-64 are formed by protrusions (first protrusion 82 and second to fourth protrusions 85-87) as shown in Figures 17 and 18, the positioning of the head holder 34 can be easily performed in the same manner as when the first to third positioning portions 62-64 are formed by grooves 61. By adopting a configuration in which a protrusion made of a bolt is provided on the first flat surface 81 as shown in Figures 17 and 18, the area of ​​the support member 31 that is subjected to surface machining is reduced, making it easier to machine the support member 31. In addition, when the third positioning portion 64 is formed by the second flat surface 83 as shown in Figure 17, the bolt that serves as the second positioning portion 63 can also be provided on the second flat surface 83 instead of the first flat surface 81.

[0054] (Second embodiment) In the above-described embodiment, an example has been shown in which the present invention is applied to a printing press 1 configured to transport a sheet 4 by a printing cylinder 12. However, the present invention can also be applied to a printing press equipped with a transport system using a belt, or a printing press that uses a cylinder or a belt as an intermediate transfer member. A printing press using a belt transport system can be configured, for example, as shown in FIG. 19. In FIG. 19, members that are the same as or equivalent to those described with reference to FIGS. 1 to 18 are given the same reference numerals, and detailed description thereof will be omitted as appropriate.

[0055] A belt-type conveying printing machine 100 shown in Fig. 19 includes a belt-type conveying device 101 that conveys a sheet 4. This belt-type conveying device 101 has a sheet-conveying belt 102 that is stretched across a pair of sprockets 103, 104 and extends horizontally, and conveys the sheet 4 by rotating this belt 102 counterclockwise in the figure. An inkjet device 17 is disposed above the belt 102. In this embodiment, the upper surface of the belt 102 facing the inkjet device 17 corresponds to the "ink ejection surface" of the present invention.

[0056] The sheet 4 is placed on the belt 102 by a sheet transfer device (not shown) in the feeder unit 2 depicted at the right end in Fig. 19, and is sent by the belt 102 to below the inkjet device 17. The inkjet device 17 sprays ink onto the sheet on the belt 102 to perform printing. The printed sheet is transported by a belt 102 to a delivery section 5 and discharged onto a delivery pile 6 . By applying the present invention to the printing machine 100 equipped with the belt-type conveying device 101 in this way, it is possible to eliminate the need for position adjustment after replacing the inkjet head. [Explanation of symbols]

[0057] 1,100...printing press, 12...printing cylinder, 31...support member, 31a...one side portion, 31b...other side portion, 32...mounting structure, 33...inkjet head, 34...head holder, 43...positioning structure, 44...first mounting portion, 45...second mounting portion, 46...first mounting bolt, 49...exposed portion, 52...second mounting bolt, 53...notched portion, 54...plate-shaped portion, 61...groove, 61a...opening end, 61b...terminal surface, 61c...side surface, 61e...bottom surface, 62-64...first to third positioning portions, 65-67...first to third positioning surfaces, 81...first flat surface, 82...first protrusion, 83...second flat surface, 85...second protrusion, 86...third protrusion, 87...fourth protrusion, 102...belt.

Claims

1. a support member disposed opposite to the ink ejection surface; a head holder to which an inkjet head is fixed and which is detachably attached to the support member in a state where the head holder is positioned by a positioning structure; The positioning structure includes: first to third positioning parts provided on the support member for restricting movement of the head holder in three mutually orthogonal positioning directions to determine a position; a first positioning surface formed on the head holder so as to come into contact with the first positioning portion, a second positioning surface formed on the head holder, and a third positioning surface formed on the head holder so as to come into contact with the first positioning portion, the first to third positioning surfaces are formed at positions spaced apart from a predetermined reference position of the inkjet head in the three positioning directions by distances determined for each of the three positions, and are formed so as to be perpendicular to the positioning directions; An inkjet head mounting structure, characterized in that at least two of the first to third positioning portions are structured to restrict the movement of the head holder so that the head holder can move parallel only in the direction of approaching and moving away from the other positioning portions.

2. 2. The inkjet head mounting structure according to claim 1, The head holder is attached to the support member at two attachment portions, one of the two mounting portions is configured to use a first mounting bolt that penetrates an exposed portion of the head holder that is exposed on a side opposite to the support member when the inkjet head is fixed thereto, and is screwed into the support member; The inkjet head mounting structure is characterized in that the other mounting portion is configured to use a second mounting bolt that passes through the support member and is screwed into the head holder.

3. 3. The inkjet head mounting structure according to claim 2, the positioning structure is provided on one side and the other side of the support member in a direction parallel to a moving direction of the ink ejection surface, a groove-shaped notch portion is formed at an end portion of the support member adjacent to the ink ejection surface, the groove-shaped notch portion being open toward the ink ejection surface and extending in a direction perpendicular to the direction in which the ink ejection surface moves and along the ink ejection surface; 2. An ink jet head mounting structure, comprising: a support member having a plate-like portion that constitutes a side surface of the notch, the support member having a plate-like portion that extends through the plate-like portion;

4. 2. The inkjet head mounting structure according to claim 1, a groove is formed on a side of the support member in the direction of movement of the ink ejection surface, the groove having a width capable of accommodating the head holder and extending in a direction perpendicular to the ink ejection surface; the groove has an opening end formed by an opening adjacent to the ink ejection surface, and a terminal end surface located on the opposite side of the opening end from the ink ejection surface, An inkjet head mounting structure, characterized in that the first to third positioning portions are formed by a bottom surface of the groove, one side surface of the groove in the width direction of the groove, and the terminal surface of the groove.

5. 2. The inkjet head mounting structure according to claim 1, a first flat surface extending in a direction perpendicular to the movement direction of the ink ejection surface and perpendicular to the ink ejection surface, and a second flat surface parallel to the ink ejection surface are formed on a side portion of the support member in a direction parallel to the movement direction of the ink ejection surface, and a protrusion is provided on the first flat surface or the second flat surface, an inkjet head mounting structure, wherein the first to third positioning portions are constituted by the first flat surface, the second flat surface, and the protrusion;

6. 2. The inkjet head mounting structure according to claim 1, a first flat surface extending in a direction perpendicular to the movement direction of the ink ejection surface and perpendicular to the ink ejection surface, and a plurality of protrusions protruding from the first flat surface are provided on a side portion of the support member in a direction parallel to the movement direction of the ink ejection surface, The inkjet head mounting structure is characterized in that the first to third positioning portions are constituted by the first flat surface and the plurality of protrusions.

7. In the inkjet head mounting structure according to any one of claims 1 to 6, the support member is formed to extend in a direction perpendicular to a moving direction of the ink ejection surface and along the ink ejection surface, and is configured to be movable between a use position facing the ink ejection surface and a retracted position away from the ink ejection surface in the direction perpendicular to the moving direction of the ink ejection surface, the positioning structure and the head holder to which the inkjet head is fixed are provided at a plurality of positions aligned in a direction in which the support member extends, 13. An inkjet head mounting structure, wherein the positioning structure is configured so that the head holder can slide and be removed from the support member in a direction perpendicular to the ink ejection surface.

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