Inkjet printing device

Abstract

To facilitate attachment and detachment of a head part and preventing printing accuracy from varying when attaching the head part.SOLUTION: An inkjet printing device comprises: a plurality of head parts constituted of a head main body part and a base part 21; a line block frame 22 for supporting the base part from below; and an energizing device 23 for attaching the base part to the line block frame while energizing the base part toward the line block frame. The energizing device has: a shaft part 30 attached to the line block frame; a bracket part 31 attached through a bearing part 30a1 so that the part can move up and down along the shaft part; a spring part 32 for energizing the bracket part downward; and a lock pin 33 protruding downward from the bracket part. During the energization, a lock pin is arranged on an upper surface of the base part, and when the energization is released, the lock pin is lifted upward, which can facilitate attachment and detachment of the head part and can prevent printing accuracy from varying.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an inkjet printing device having a head unit capable of ejecting ink. [Background technology]

[0002] In a line head type inkjet printing device, a head unit is fixed, and printing is performed by ejecting minute droplets of ink from the head unit onto a print medium that passes below the head unit. Generally, a plurality of head parts are used at the same time, and there are various mounting structures for them.

[0003] For example, there is known an inkjet recording device (inkjet printing device) in which a head substrate 12 having a line head consisting of multiple short heads 11 arranged in a staggered pattern is attached to a carriage 9, and inkjet recording is performed on a recording medium 2 positioned below the carriage using the line head (see, for example, Patent Document 1). In such an inkjet printing device, each short head 11 (head portion) is attached to a head mounting surface 27 by fastening flanges 29a, 29b provided on both longitudinal sides of the short head with fixing screws 30, 30 that are screwed into the head mounting surface 27.

[0004] Also known is an inkjet printing device in which a plurality of line heads, each of which has a number of inkjet nozzles arranged in a row, are arranged in the printing direction (see, for example, Patent Document 2). In such an inkjet printing device, first and second fixing pins 17, 18 are provided to press and fix the upper surfaces of the flanges 5, 7 on both sides of the line head 3 (head portion), and brackets 19, 20 to which the fixing pins 17, 18 are fixed are fixed to the line head frame 2 with fixing bolts 21, 22. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2010-173232 A [Patent Document 2] JP 2011-152708 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the inkjet printing devices described in Patent Documents 1 and 2 above, the head unit is attached with fixing screws or bolts, which means that it is time-consuming to attach and detach the head unit, and maintenance work and the like is extremely inefficient. Another drawback is that the tightness of the bolts changes each time the head is attached, which causes variations in printing accuracy.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide an inkjet printing device that allows the head unit to be easily attached and detached, and that minimizes variations in printing accuracy each time the head unit is attached. [Means for solving the problem]

[0008] The inventors conducted intensive research to solve the above problems and discovered that the above problems could be solved by having a biasing device for attaching the head unit to the line block frame while the printing unit biases the base unit toward the line block frame, thereby completing the present invention.

[0009] The present invention is an inkjet printing device having a printing unit capable of ejecting ink, the printing unit having a plurality of head units consisting of a head main body unit and a base unit provided on the periphery of the head main body unit, a line block frame for supporting the base units from below, and a biasing device for attaching the base units to the line block frame while biasing them toward the line block frame, the biasing device having an axle unit extending in the vertical direction attached to the line block frame, a bracket unit attached to the axle unit via a bearing unit so as to enable vertical movement along the axle unit, a spring unit attached to the axle unit for biasing the bracket unit downward, and a lock pin attached to the bracket unit and protruding downward from the bracket unit, and when biased, the lock pin is positioned on the upper surface of the base unit, and when biased, the lock pin is lifted upward.

[0010] In the inkjet printing device of the present invention, it is preferable that the urging device further has a gripping portion attached to the bracket portion and protruding upward from the bracket portion, and that by lifting the gripping portion, the gripping portion, the bracket portion and the lock pin are lifted together.

[0011] In the inkjet printing device of the present invention, the bracket portion is attached to the shaft portion via a bearing portion so as to be capable of vertical movement along the shaft portion and rotational movement around the shaft portion, and when biased, a lock pin is arranged on the upper surface of the base portion, and when biased, it is preferable that the lock pin is lifted upward and the bracket portion is rotated so that the lock pin is arranged in a standby position provided on the upper surface of the line block frame. In this case, it is more preferable that the standby position is a blind hole provided on the upper surface side of the line block frame, and that the upper end surface of the blind hole is positioned above the lower end surface of the lock pin when placed in the standby position.

[0012] In the inkjet printing device of the present invention, it is preferable that the urging device is provided on the bracket portion and further has a block portion protruding downward from the bracket portion, and when the lock pin is placed in the standby position, the block portion is placed on the upper surface of the line block frame.

[0013] In the inkjet printing device of the present invention, it is preferable that the shaft portion has a cylindrical small diameter shaft portion and a large diameter shaft portion that is provided on top of the small diameter shaft portion and has a larger diameter than the small diameter shaft portion, the spring portion is inserted into the small diameter shaft portion and is sandwiched between the large diameter shaft portion and the bracket portion, and the spring portion consists of a coil spring and a disc spring that is arranged below the coil spring so as to be continuous with the coil spring.

[0014] In the inkjet printing device of the present invention, it is preferable that the base portion is positioned by abutting against a reference pin provided on the line block frame, and the biasing device is attached in a positioned state.

[0015] In the inkjet printing device of the present invention, the base portion is rectangular when viewed from above, and the line block frame is attached with a first eccentric pin at a position capable of abutting one long side surface of the base portion, a first pressure pin at a position capable of abutting the other long side surface, a second eccentric pin at a position capable of abutting one short side surface, and a second pressure pin at a position capable of abutting the other short side surface, wherein the first pressure pin biases the base portion in the short direction and the second pressure pin biases the base portion in the long direction, and it is preferable that the position of the base portion is fine-tuned by rotating the first eccentric pin and / or the second eccentric pin. At this time, it is more preferable that the force with which the spring portion urges the base portion downward is smaller than the force with which the first pressure pin or the second pressure pin urges the base portion laterally. Effect of the Invention

[0016] In the ink jet printer of the present invention, since the printing unit has a biasing device, it is possible to attach the base portion of the head unit to the line block frame in a state in which the base portion is biased toward the line block frame. That is, in the biasing device, the bracket portion is biased downward by the spring portion, so that the base portion is biased downward by disposing the lock pin attached to the bracket portion on the upper surface of the base portion. Furthermore, in the inkjet printer, the bracket portion is capable of moving up and down along the shaft portion, so that the biasing force on the base portion is released by lifting the lock pin together with the bracket portion. For these reasons, in an inkjet printing device, the head unit can be easily attached and detached by simply moving the lock pin up and down via the bracket unit. Furthermore, since the force biasing the bracket portion is provided by the spring portion, the same degree of biasing force is applied to the base portion every time the head portion is attached. Therefore, it is possible to minimize variations in printing accuracy that occur each time the head unit is attached.

[0017] In addition, in the inkjet printer, when the bracket part is rotatable about the shaft part, the biasing is released by lifting the lock pin upward from the biasing position and rotating the bracket part to a standby position provided on the upper surface of the line block frame. In this case, in the inkjet printer, the bracket part can be rotated to the side, making it easier to attach and detach the head part.

[0018] In addition, in this case, the standby position is a blind hole provided on the upper surface side of the line block frame, and the upper end face of the blind hole is positioned higher than the lower end face of the lock pin when placed in the standby position. Therefore, the rotation of the lock pin placed in the standby position is prevented by the walls surrounding the blind hole, thereby preventing it from accidentally rotating and moving onto the base portion.

[0019] In addition, in an inkjet printing device, if the biasing device further has a block portion provided on the bracket portion, when the lock pin is positioned in the standby position, the block portion is placed on the upper surface of the line block frame, thereby preventing the lower surface of the lock pin from being damaged due to friction, etc.

[0020] In the ink jet printing device of the present invention, since the biasing device has a gripping portion, it becomes easy to lift the bracket portion and the lock pin, so that the head portion can be easily attached and detached. Incidentally, the head unit is a precision machine, and generally, multiple head units are arranged close together, so when attaching or detaching any one head unit, there is a risk of touching the other head units. If the other head units are touched, the head unit may be misaligned or may be damaged. For this reason, being able to lift the bracket unit and the lock pin via the grip unit is extremely effective in attaching or detaching the head units.

[0021] In the inkjet printing device of the present invention, the spring portion is not only a coil spring, but also a disc spring is arranged below the coil spring so as to be continuous with the coil spring, which makes it possible to easily adjust the spring force. That is, the coil spring that expands and contracts sufficiently in the vertical direction ensures a sufficient amount of vertical movement of the bracket portion, and the disc spring that can exert a sufficient biasing force (spring force) can apply a sufficient downward biasing force to the bracket portion. Note that the biasing force of the disc spring can be easily adjusted by changing the number and type of disc springs. Furthermore, by placing the disc spring below the coil spring, the coil spring biases the bracket portion via the disc spring, so that the coil spring directly biases only the bearing portion, thereby preventing the bearing portion from shifting in the vertical direction relative to the bracket portion.

[0022] In the inkjet printer of the present invention, the base portion is positioned by abutting against the reference pin, and a biasing device is attached to the base portion, so that the base portion can be biased toward the line block frame at a desired position. This prevents the base portion from being significantly misaligned, and therefore significantly reduces the time required for fine adjustment of the base portion's position.

[0023] In the inkjet printing device of the present invention, the first pressure pin and the first eccentric pin allow easy fine adjustment of at least the short-side position of the base portion, and the second pressure pin and the second eccentric pin allow easy fine adjustment of at least the long-side position of the base portion. At this time, by making the force with which the spring portion urges the base portion downward smaller than the force with which the first pressure pin or the second pressure pin urges the base portion laterally, it is possible to fine-tune the position of the base portion while maintaining the state in which the urging device urges the base portion. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a side view showing a schematic diagram of an example of an ink jet printing device according to the present embodiment. [Diagram 2] FIG. 2 is a transparent plan view showing one printing unit of the inkjet printing device shown in FIG. [Figure 3(a)] FIG. 3(a) is an enlarged plan view showing a state in which a biasing device biases and a state in which the biasing device releases bias in one head unit of the printing section shown in FIG. [Figure 3(b)] FIG. 3(b) is an enlarged side view showing a state in which a biasing device biases and a state in which the biasing device releases bias in one head unit of the printing section shown in FIG. [Figure 4] FIG. 4 is an enlarged side view showing a pressure pin used for positioning in the head unit shown in FIG. [Diagram 5]FIG. 5 is a cross-sectional view showing the first biasing device in a biased state taken along line A1-A1 in FIG. 3(a) and the first biasing device in a released state taken along line A2-A2. [Figure 6] FIG. 6 is a cross-sectional view showing the second biasing device in a biased state taken along line B1-B1 in FIG. 3(a) and the second biasing device in a released state taken along line B2-B2. [Figure 7] FIG. 7 is an explanatory diagram for explaining the operation of the first biasing device of the head unit shown in FIG. 3(a) and FIG. 3(b) when biased and when released. [Figure 8] FIG. 8 is an explanatory diagram for explaining the operation of the second biasing device of the head unit shown in FIG. 3(a) and FIG. 3(b) when biased and when released. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are given the same reference numerals and duplicated explanations are omitted. In addition, unless otherwise specified, positional relationships such as up, down, left, right, etc. are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to those shown in the drawings. In this specification, the transport direction of the print-receiving medium is referred to as the X direction, and the width direction of the print-receiving medium is referred to as the Y direction.

[0026] The inkjet printing device according to the present invention is a device for printing by ejecting ink from a head unit onto a transported print-receiving medium. Such an ink jet printing device is of an on-demand type, and the ejection method may be a piezoelectric method, a thermal method, or the like. The printing method may be a serial method or a one-pass method. Incidentally, in the embodiment described below, a one-pass method using a line head is adopted. The print medium is not particularly limited, and examples of the print medium that can be used include paper, film, fabric, nonwoven fabric, and metal foil. The ink is not particularly limited, and may contain, for example, a coloring material such as a pigment or dye, or a magnetic material, a water-based solvent, and known additives that are added as necessary.

[0027] FIG. 1 is a side view showing a schematic diagram of an example of an inkjet printing device 100 according to the present embodiment. As shown in FIG. 1, the inkjet printing device 100 has a paper feeding section 11 for feeding the printable medium 10, a plurality of guide rolls for guiding the fed printable medium 10, four printing sections 12 for printing on the printable medium 10, a drying section 13 for drying the printed printable medium 10, and a recovery section 14 for recovering the dried printable medium 10. In the inkjet printing device 100, the paper feeding section 11, printing section 12, drying section 13 and recovery section 14 are connected in series, making it possible to carry out the entire process from feeding the print-receiving medium 10 to printing, drying and recovery in a single flow. The paper feed section 11, the guide rolls, the drying section 13 and the recovery section 14 may be appropriately selected from known components, and therefore detailed description thereof will be omitted.

[0028] In the inkjet printing device 100, four printing units 12 are arranged in series along the transport direction of the print-receiving medium 10. Each printing unit 12 is capable of independently ejecting ink onto the print-receiving medium 10 being transported below it. In the inkjet printing device 100, for example, by assigning each printing section 12 to handle one different color of ink out of CMYK, full-color printing is possible.

[0029] In the inkjet printing device 100, the four printing units 12 have the same configuration. Fig. 2 is a transparent plan view showing one printing unit 12 of the inkjet printing device 100 shown in Fig. 1. Fig. 2 is a plan view of the printing unit 12 with the top plate portion of the head box 24 seen through. As shown in FIG. 2, the printing section 12 has a box-shaped head box 24, a line block frame 22 supported by a bottom plate portion 24b of the head box 24, and a plurality of head units supported by the line block frame 22. That is, the inkjet printing device 100 has four printing sections 12, each of which has a head box 24, a line block frame 22, and a plurality of head units. As described below, the head unit refers to one consisting of one head part H and two biasing devices 23 for biasing the base part 21 of the head part H. Also, having a plurality of head units refers to having the head unit as one unit and having this unit repeatedly.

[0030] In the printing unit 12, the head box 24 is a rectangular parallelepiped box made up of an upper top plate (not shown), a lower bottom plate 24b, and four side plates 24a connecting the two. The head box 24 accommodates a plurality of head parts H (head units) therein. In the printing unit 12, by having the head box 24, foreign matter such as ink mist and dust from the outside can be prevented from entering the inside of the head box 24 and adhering to the head part H and the like. In addition, the head box 24 may house a distribution tank (not shown) for temporarily storing ink and distributing the ink to the head main body portion 20 of the head portion H, a tube (not shown) for circulating the ink, etc.

[0031] In the head box 24, a line hole 24c having a rectangular shape when viewed from above is formed in the approximate center of the bottom plate portion 24b. The line block frame 22 is attached to the bottom plate portion 24b so as to close the line holes 24c. That is, the line block frame 22 is supported from below by the peripheral portion of the line holes 24c of the bottom plate portion 24b. As a result, the lower surface of the line block frame 22 is exposed except for the portion that abuts against the bottom plate portion 24b.

[0032] In the head box 24, the bottom plate portion 24b is provided with pins and the like for positioning the line block frame 22. That is, in the bottom plate portion 24b, a first positioning pin 24b1 and a second positioning pin 24b2 are provided at positions on both sides of the line hole portion 24c in the Y direction. Moreover, the second positioning pin 24b2 is attached to a direction adjustment device 25, which will be described later.

[0033] The head box 24, together with the head portion H housed therein, is capable of reciprocating along a rail (not shown) extending in the Y direction. Therefore, in the inkjet printing device 100, the head box 24 can be moved at any time to a printing position for printing, a maintenance position for performing maintenance on the head unit H, a storage position for storing the head unit H, etc., which are provided along the rails. For such movement, a linear motion mechanism such as an air cylinder or a ball screw is preferably used.

[0034] In the printing unit 12, the line block frame 22 is a rectangular plate-like frame on which a plurality of head units H are mounted. The line block frame 22 has a frame main body portion 22a, a plurality of head hole portions (not shown) provided in the frame main body portion 22a, and support portions 22b provided on the periphery of the head hole portions and protruding inward from the frame main body portion 22a into the head hole portions. Here, the upper surface of the support portion 22b and the upper surface of the frame main body portion 22a are approximately parallel to each other, and the upper surface of the support portion 22b is located lower than the upper surface of the frame main body portion 22a. That is, in the line block frame 22, the frame main body portion 22a and the support portion 22b are stepped in a side view.

[0035] In the line block frame 22, a frame main body portion 22a is provided with pin holes and the like for positioning with respect to a bottom plate portion 24b. That is, in the frame main body 22a, a positioning pin hole 22a1 is provided at a position corresponding to the first positioning pin 24b1, and a positioning pin receiving portion 22a2 is attached at a position corresponding to the second positioning pin 24b2. Therefore, when attaching the line block frame 22 to the bottom plate portion 24b, it is possible to roughly position the line block frame 22 relative to the bottom plate portion 24b by inserting the first positioning pin 24b1 into the positioning pin hole 22a1 of the line block frame 22 and fitting the second positioning pin 24b2 attached to the direction adjustment device 25 into the positioning pin receiving portion 22a2 of the line block frame 22. As a result, the time required for fine adjustment of the position of the line block frame 22 relative to the bottom plate portion 24b can be significantly shortened.

[0036] The direction adjustment device 25 is Z-shaped and has a plate-shaped adjustment main body 25a, an attachment portion 25b arranged to protrude from one end of the adjustment main body 25a toward the line block frame 22, and a direction adjustment knob 25c arranged at the other end to protrude on the side opposite the line block frame 22. Here, a second positioning pin 24b2 is attached to the attachment portion 25b, and the direction adjustment knob 25c is supported by the side plate portion 24a of the head box 24 so as to be exposed to the outside of the head box 24. Moreover, one end of the adjustment main body 25a is rotatably attached to the upper end of a central shaft 25e that extends vertically. The central shaft 25e has a lower end portion fixed to the bottom plate portion 24b. In addition, the adjustment main body portion 25a has a center positioning pin hole 25d at approximately its center, and the adjustment main body portion 25a is positioned relative to the bottom plate portion 24b by using a pin or the like to position it so that it matches with the pin hole provided in the bottom plate portion 24b.

[0037] In the direction adjustment device 25, by operating the direction adjustment knob 25c, it is possible to slightly rotate the attachment portion 25b about the central shaft 25e. At this time, since the positioning pin receiving portion 22a2 of the line block frame 22 is fitted into the second positioning pin 24b2 attached to the mounting portion 25b of the direction adjustment device 25, the positioning pin receiving portion 22a2 side of the line block frame 22 also rotates slightly together with the mounting portion 25b of the direction adjustment device 25. That is, in this case, the positioning pin receiving portion 22a2 side of the line block frame 22 rotates slightly around the first positioning pin 24b1 as an axis. Therefore, in the printing unit 12, the direction adjustment device 25 makes it possible to finely adjust the position of the line block frame 22 with respect to the bottom plate portion 24b.

[0038] In the printing section 12, the head section H (head unit) is attached to the support section 22b of the line block frame 22 so as to cover the head hole section. That is, the base section 21 of the head section H is supported from below by the support section 22b, which is the peripheral portion of the head hole section of the line block frame 22. As a result, the lower surface of the head portion H is exposed except for the portion that abuts against the support portion 22b of the line block frame 22.

[0039] Here, in the line block frame 22, the head holes and support parts 22b are provided at seven locations in a staggered manner when viewed from above, and a head part H is attached to each of the support parts 22b. Specifically, in the line block frame 22, the head parts H are arranged in two rows in the X direction, one row has four head parts H arranged side by side in the Y direction, and the other row has three head parts H arranged side by side in the Y direction, and the head parts H in one row and the head parts H in the other row are arranged so that their X-directional positions are staggered.

[0040] Fig. 3(a) is an enlarged plan view showing a state where the biasing device 23 is biased (upper side of Fig. 3(a) and Fig. 3(b)) and a state where the biasing device 23 is released (lower side of Fig. 3(a) and Fig. 3(b)) in one head unit of the printing section 12 shown in Fig. 2, and Fig. 3(b) is an enlarged side view corresponding to Fig. 3(a). Note that the illustration of the positioning pins is omitted in Fig. 3(b). 3(a) and 3(b), the head unit has a head part H consisting of a head main body part 20 and a plate-shaped base part 21 provided on the periphery of the head main body part 20, and a biasing device 23 for attaching the base part 21 to the line block frame 22 while biasing the base part 21 toward the line block frame 22. In other words, the printing unit 12 has a plurality of head parts H, a line block frame 22 for simultaneously supporting each of the base parts 21 of the head parts H from below, and a biasing device 23 for attaching each base part 21 to the line block frame 22 while biasing the base part 21 toward the line block frame 22. In the printing unit 12, the head body 20 and the base 21 of the head unit H are integrally formed. Moreover, the head portions H of the multiple head units have the same configuration. That is, the seven head portions H shown in FIG. 2 have the same configuration.

[0041] In the head unit, the base portion 21 of the head part H is positioned relative to the line block 22 by a reference pin 41 , a pressure pin 42 and an eccentric pin 43 attached to the support portion 22 b of the line block frame 22 . Here, the reference pin 41 is a normal pin, the eccentric pin 43 is a pin that is rotatable and has its pin center at an eccentric position relative to the center of rotation, and the pressure pin 42 is a pin that can exert a spring force in the lateral direction. Incidentally, the eccentric pin 43 may also be referred to as a first eccentric pin 43 or a second eccentric pin 43, as necessary. Similarly, the pressure pin 42 may also be referred to as a first pressure pin 42 or a second pressure pin 42.

[0042] FIG. 4 is an enlarged side view showing a pressure pin used for positioning in the head unit shown in FIG. As shown in FIG. 4, the pressure pin 42 used for positioning the base portion 21 is made up of a head portion 42a and a body portion 42b. In the pressure pin 42, a coil spring is built into the body portion 42b, and when the head portion 42a is pressed laterally by the base portion 21, stress is generated based on the spring force of the coil spring. At this time, since the head 42a of the pressure pin 42 is egg-shaped, the stress acting in an arc direction centered on the lower end of the head 42a is not only a force toward the base portion 21, but is also able to fully exert a force that urges the base portion 21 downward.

[0043] Returning to Figure 3(a), a reference pin 41 and a first eccentric pin 43 are attached at a fixed distance to the support portion 22b of the line block frame 22 at positions where they can abut against one of the long side surfaces of the base portion 21, and two first pressure pins 42 are attached at a fixed distance to positions where they can abut against the other long side surface. The reference pin 41 and one of the first pressure pins 42, and the first eccentric pin 43 and the other of the first pressure pins 42 are disposed at positions facing each other with the base portion 21 interposed therebetween. Therefore, in the base portion 21, the first pressure pin 42 biases the base portion 21 in the X direction (short side direction), and by rotating the first eccentric pin 43, it is possible to fine-tune the rotational position of the base portion 21 around the reference pin 41 on the XY plane, i.e., at least the position of the base portion 21 in the short side direction.

[0044] In addition, a second eccentric pin 43 is attached to the support portion 22b of the line block frame 22 at a position where it can abut against one of the short side surfaces of the base portion 21, and a second pressure pin 42 is attached to a position where it can abut against the other short side surface. Therefore, in the base portion 21, the second pressure pin biases the base portion 21 in the Y direction (longitudinal direction), and by rotating the second eccentric pin 43, it is possible to fine-tune at least the longitudinal position of the base portion 21. In addition, to fine-tune the position of the base part 21, first, the first eccentric pin 43 is rotated to fine-tune the position of the base part 21 in the short side direction. At that time, the position of the base part 21 in the long side direction is also shifted, so it is preferable to then rotate the second eccentric pin 43 to fine-tune the position of the base part 21 in the long side direction.

[0045] In addition, the line block frame 22 is provided with a stopper 44 attached next to the eccentric pin 43 to prevent the eccentric pin 43 from rotating, for example. The stopper 44 is configured to hold down the upper surface of the eccentric pin 43 from above by tightening a lock screw. This makes it possible to prevent the eccentric pin 43 from accidentally rotating after fine adjustment of the position by the eccentric pin 43 has been completed, for example.

[0046] In the head part H, it is preferable that the base part 21 is attached to the line block frame 22 by the biasing device 23 in a state where the base part 21 is positioned to a certain extent relative to the line block frame 22. This prevents the position of the base part 21 from being significantly shifted, and therefore the time required for fine adjustment of the position of the head part H can be significantly shortened. In addition, it is preferable that the force with which the spring portion 32 of the biasing device 23 biases the base portion 21 downward is smaller than the force with which the pressure pin 42 biases the base portion 21 laterally, as described below. In this case, it is possible to fine-tune the lateral position of the base portion 21 while maintaining the state in which the biasing device 23 biases the base portion 21.

[0047] Returning to Figures 2, 3(a) and 3(b), in the head unit H, the head main body 20 is generally rectangular and serves to temporarily store ink and eject the ink. In the head main body 20, a plurality of nozzles are formed on the bottom surface, and ink supplied to the inside can be ejected from the nozzles. The nozzles formed on the underside of the head main body 20 are exposed through the head hole of the line block frame 22 and the line hole 24c of the head box, as described above. This allows the head main body 20 to eject ink onto the print-receiving medium 10 being transported below the printing unit 12.

[0048] In the head unit, the biasing device 23 is a device for attaching the base portion 21 to the line block frame 22 while biasing the base portion 21 toward the line block frame 22. In the head unit, the biasing by the biasing device 23 is maintained even after the head portion H is attached to the line block frame 22 by the biasing device 23. On the other hand, the biasing device 23 can also forcibly release the biasing force, which allows the head portion H to be easily removed.

[0049] Two biasing devices 23 are provided for each base portion 21. Specifically, the biasing devices 23 are disposed at diagonal positions of the base portion 21. In this way, the base portion 21 is biased downward by the biasing devices 23 with as uniform a force as possible over the entire base portion 21. The two biasing devices 23 have the same configuration except that the bracket portions 31 have different shapes.

[0050] Hereinafter, for convenience, the biasing device 23 having the bracket portion 31 that is L-shaped when viewed from above (the biasing device at the top right of the head unit shown in FIG. 3(a)) will be referred to as the "first biasing device 23," and the biasing device 23 having the bracket portion 31 that is rectangular when viewed from above (the biasing device at the bottom left of the head unit shown in FIG. 3(a)) will be referred to as the "second biasing device 23." Note that when the term "biasing device 23" is used simply, it refers to both the first biasing device 23 and the second biasing device 23.

[0051] FIG. 5 is a cross-sectional view showing the first biasing device in a biased state taken along line A1-A1 in FIG. 3(a) (left side of FIG. 5), and the first biasing device in a released state taken along line A2-A2 (right side of FIG. 5). FIG. 6 is a cross-sectional view showing the second biasing device in a biased state taken along line B1-B1 in FIG. 3(a) (left side of FIG. 6), and the second biasing device in a released state taken along line B2-B2 (right side of FIG. 6). As shown in Figures 5 and 6, the biasing device 23 has an axle portion 30 extending in the vertical direction attached to the frame main body portion 22a of the line block frame 22, a bracket portion 31 attached to the axle portion 30 via a bearing portion 30a1 so as to enable vertical movement along the axle portion 30, a spring portion 32 attached to the axle portion 30 for biasing the bracket portion 31 downward, a gripping portion 34 attached to the bracket portion 31 and protruding upward from the bracket portion 31, a lock pin 33 attached to the bracket portion 31 and protruding downward from the bracket portion 31, and a block portion 35 provided on the bracket portion 31 and protruding downward from the bracket portion 31.

[0052] In the biasing device 23, the shaft portion 30 has a cylindrical small diameter shaft portion 30a extending in the vertical direction, and a large diameter shaft portion 30b provided on the upper portion of the small diameter shaft portion 30a and having a larger diameter than the small diameter shaft portion 30a. In the shaft portion 30, the smaller diameter shaft portion 30a has a threaded portion at its lower end, and is screwed into a threaded hole provided in the frame main body portion 22a of the line block frame 22. Further, a bearing portion 30a1 (oil-free bushing) is attached to the lower portion of the small diameter shaft portion 30a, and a bracket portion 31 is attached via the bearing portion 30a1. A spring portion 32 is attached to the middle portion of the small diameter shaft portion 30a so as to surround the middle portion, and the spring portion 32 is sandwiched between the large diameter shaft portion 30b and a bracket 31.

[0053] In the first biasing device 23, the bracket portion 31 is a plate-like shape that is L-shaped when viewed from above and has a surface that extends horizontally, and in the second biasing device 23, the bracket portion 31 is a plate-like shape that is rectangular when viewed from above and has a surface that extends horizontally. The biasing device 23 is provided with a gripping portion 34, a lock pin 33, and a block portion 35. That is, the bracket portion 31 is integrated with the bearing portion 30a1, the grip portion , the lock pin 33 and the block portion . In addition, the bracket portion 31, together with these, is capable of moving up and down along the length direction of the shaft portion 30 (small diameter shaft portion 30a), and of rotating about the axis of the shaft portion 30 (small diameter shaft portion 30a). At this time, since the bracket portion 31 is attached to the small diameter shaft portion 30a of the shaft portion 30 via the bearing portion 30a1, the bracket portion 31 is able to move up and down and rotate smoothly.

[0054] In the biasing device 23, as described above, the spring portion 32 is inserted into the small diameter shaft portion 30a and is sandwiched between the large diameter shaft portion 30b and the bracket portion 31. Therefore, the spring portion 32 can expand and contract by the length of the small diameter shaft portion 30a. In addition, since the spring portion is sandwiched between the large diameter shaft portion 30b and the bracket portion 31 in a contracted state, it constantly exerts a downward spring force (biasing force) on the bracket portion 31, starting from the large diameter shaft portion 30b.

[0055] Here, as the spring portion 32, a coil spring (a coil-shaped compression spring), a leaf spring, a disc spring, or the like can be used. Among these, it is preferable that the spring portion 32 be a coil spring or a disc spring, and it is more preferable that the spring portion 32 be a coil spring and a disc spring. Specifically, it is more preferable that the spring portion 32 is composed of a coil spring 32a and a disc spring 32b disposed below the coil spring 32a so as to be continuous with the coil spring 32a. In this case, the spring force of the spring portion 32 can be easily adjusted. Furthermore, by arranging the disc spring 32b below the coil spring 32a, the coil spring 32a biases the bracket portion 31 via the disc spring 32b, so that the coil spring 32a directly biases only the bearing portion 30a1, thereby preventing the bearing portion 30a1 from shifting in the vertical direction relative to the bracket portion 31.

[0056] In the biasing device 23, the lock pin 33 is cylindrical, and its upper end is attached and fixed to the bracket portion 31 by a fastener such as a bolt. The lock pin 33 has a flat lower end and is disposed at a biased position 21a on the base portion 21 when biased, and is disposed at a standby position 22c on the line block frame 22 when released.

[0057] Here, the standby position 22c is provided in the line block frame 22 (see FIG. 3(a) and FIG. 3(b)), and is a blind hole provided on the upper surface side of the line block frame 22. At the standby position 22c, an upper end surface 22c1 of the blind hole is positioned higher than a lower end surface 33a of the lock pin 33 when the lock pin 33 is disposed at the standby position 22c. As a result, the lock pin 33 disposed at the standby position 22c abuts against the wall surrounding the blind hole, thereby making it possible to prevent the bracket portion 31 from accidentally rotating.

[0058] In the biasing device 23, the grip portion 34 is cylindrical and disposed between the shaft portion 30 and the lock pin 33, and its lower end portion is a threaded portion that is screwed into a screw hole provided in the bracket portion 31. Therefore, by lifting the grip portion 34, the grip portion 34, bracket portion 31, bearing portion 30a1, lock pin 33, and block portion 35 are lifted together. The grip portion 34 is provided so as to protrude upward from the bracket portion 31, and its upper end portion is located higher than the large diameter shaft portion 30b. Therefore, in the biasing device 23, the grip portion 34 is easy to grip. In the biasing device 23, the bracket portion 31 and the lock pin 33 can be easily lifted by the gripping portion 34, making it easy to move the bracket portion 31 up and down relative to the shaft portion 30, and to rotate the bracket portion 31 around the shaft portion 30.

[0059] In the biasing device 23, the block portion 35 is molded integrally with the bracket portion 31. The block portion 35 is block-shaped and is disposed on the upper surface of the frame main body portion 22a when the lock pin 33 is disposed in the standby position 22c. As a result, the entire biasing device 23 is supported by the block portion 35. At this time, it is preferable that the lower surface of the lock pin 33 is not in contact with the bottom surface of the blind hole of the standby position 22c, but is in a floating state at a certain distance, which can prevent the lower surface of the lock pin 33 from being damaged due to friction or the like.

[0060] FIG. 7 is an explanatory diagram for explaining the operation of the first biasing device of the head unit shown in FIGS. 3(a) and 3(b) when biased (left side of FIG. 7) and when released (right side of FIG. 7), and FIG. 8 is an explanatory diagram for explaining the operation of the second biasing device of the head unit shown in FIGS. 3(a) and 3(b) when biased (left side of FIG. 8) and when released (right side of FIG. 8). As shown in FIGS. 7 and 8, when biased, the lock pin 33 of the biasing device 23 is disposed at the biasing position 21a on the base portion 21. As shown in FIG. At this time, the bracket portion 31 is biased downward by the spring portion 32, and therefore biases the base portion 21 downward, via the lock pin 33, toward the support portion 22b of the line block frame 22. That is, in the inkjet printing device 100, the lock pin 33 of the biasing device 23 is disposed on the upper surface of the base portion 21 of the head portion H, so that the head portion H is biased downward.

[0061] From this state, by lifting the gripping portion 34 of the biasing device 23 upward, the bracket portion 31 moves upward along the shaft portion 30, and the lock pin 33 is also lifted at the same time. This releases the biasing force. That is, in the inkjet printing device 100, the biasing force is released by lifting the lock pin 33 of the biasing device 23. In this case, since the bracket portion 31 is biased downward by the spring portion 32, the bracket portion 31 is forcibly lifted by a force exceeding this bias.

[0062] Next, by rotating the grip portion 34 of the biasing device 23, the bracket portion 31 rotates about the shaft portion 30, and the lock pin 33 is also rotated at the same time. This rotational movement is performed from a position where the lock pin 33 is above the biasing position 21a to a position where the lock pin 33 is above the standby position 22c.

[0063] Then, by lifting the gripping portion 34 of the biasing device 23 downward, the bracket portion 31 moves downward along the shaft portion 30, and the lock pin 33 is disposed at the standby position 22c. Note that, as described above, the lock pin 33 is not in contact with the bottom surface of the standby position 22c, which is a blind hole. At this time, the block portion 35 provided on the bracket portion 31 is placed on the upper surface of the frame main body portion 22a of the line block frame 22. As a result, the biasing device 23 is in a state of being supported by the frame main body portion 22a. In order to move the lock pin 33 from the standby position 22c to the biasing position 21a, the above-mentioned operations may be carried out in reverse.

[0064] In this manner, in the inkjet printing device 100, simply by moving the lock pin 33 up and down via the bracket portion 31, the head portion H can be easily attached and detached. Furthermore, since the force biasing the bracket portion 31 is provided by the spring portion 32, the base portion 21 is provided with a biasing force of the same magnitude each time the head portion H is attached. Therefore, it is possible to minimize variations in printing accuracy in the head unit H each time the head unit H is attached. Furthermore, since the bracket portion 31 can be rotated about the shaft portion 30 to release the lock pin 33 to the lateral standby position 22c, the head portion H can be more easily attached and detached.

[0065] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

[0066] The inkjet printing device 100 according to this embodiment has a paper feed unit 11, a printing unit 12, a drying unit 13 and a recovery unit 14, but the paper feed unit 11, the drying unit 13 and the recovery unit 14 may be separate entities.

[0067] In the inkjet printing device 100 according to this embodiment, one line block frame 22 equipped with a head unit H is attached to the bottom plate portion 24b of the head box 24, but multiple line block frames equipped with a head unit H may also be attached.

[0068] In the inkjet printing device 100 according to this embodiment, the head units H are attached to the line block frame 22 at seven locations in a staggered pattern when viewed from above, but the number of head units H and the positions at which the head units H are attached are not limited to this.

[0069] In the inkjet printing device 100 according to this embodiment, the line block frame 22 is positioned relative to the bottom plate portion 24b of the head box 24 using the positioning pins, the direction adjustment device 25, and the like, but the positioning method is not limited to this. Similarly, the reference pin 41, pressure pin 42, eccentric pin 43, etc. are used to position the base portion 21 relative to the line block frame 22, but the positioning method is not limited to this.

[0070] In the head unit of the inkjet printing device 100 according to this embodiment, two urging devices 23 are provided for each base portion 21, but this is not limited to this and one or three or more urging devices may be provided. Furthermore, the position where the biasing device 23 is provided is not limited to the diagonal position of the base portion 21.

[0071] In the inkjet printer 100 according to this embodiment, when the lock pin 33 is placed on the base portion 21 and biased, a space is formed between the side surface of the block portion 35 and the side surface of the frame main body portion 22a of the line block frame 22, but they may be in contact with each other. In this case, the contact between the two can be used to position the biasing device 23 at the biasing position 21a.

[0072] In the biasing device 23 of the inkjet printing device 100 according to this embodiment, the shaft portion 30 has a threaded portion at its lower end, and is screwed into a threaded hole provided in the frame main body portion 22a of the line block frame 22, but the attachment method is not limited to this. Similarly, the grip portion 34 has a threaded lower end and is screwed into a threaded hole provided in the bracket portion 31, but the attachment method is not limited to this.

[0073] In the biasing device 23 of the inkjet printer 100 according to this embodiment, the block portion 35 is molded integrally with the bracket portion 31, but may be a separate body. Further, the upper end of the lock pin 33 is attached and fixed to the bracket portion 31 by a fastener such as a bolt, but the attachment method is not limited to this. Further, the lock pin 33 and the gripping portion 34 are both cylindrical, but are not limited to this and may be polygonal or the like. [Industrial Applicability]

[0074] The inkjet printing device of the present invention can be used as a device capable of forming patterns and the like by applying ink to a print-receiving medium. According to the inkjet printing device of the present invention, the head unit can be easily attached and detached, and variations in printing precision caused each time the head unit is attached can be minimized. [Explanation of symbols]

[0075] 10...Print medium 100 Inkjet printer 11...Paper feed section 12 Printing section 13...Drying section 14. Recovery section 20 Head body 21 Base section 21a...Biasing position 22···Line Block Frame 22a Frame body 22a1···Locating pin hole 22a2···Locating pin receiving part 22b...Support part 22c...Standby position 22c1: Upper end surface of blind hole 23... Actuating device 24 Head box 24a...Side plate part 24b...Bottom plate part 24b1···First positioning pin 24b2...Second positioning pin 24c···Line hole 25...Direction adjustment device 25a...Adjustment main body 25b...Mounting part 25c···Direction adjustment knob 25d···Centering pin hole 25e...Central axis 30... Shaft section 30a...Small diameter shaft part 30b...Large diameter shaft part 30a1···Bearing part 31 Bracket part 32 Spring part 32a···Coil spring 32b... Disc spring 33 Lock pin 33a...Lower end face of lock pin 34...grip part 35 Block section 41 Reference pin 42 Pressure pin 42a...Head 42b... Body 43 Eccentric pin 44 Stopper H... Head

Claims

1. In an inkjet printing device having a printing unit capable of ejecting ink, the printing unit has a plurality of head units each consisting of a head main body unit and a base unit provided on a periphery of the head main body unit, a line block frame for supporting the base units from below, and a biasing device for attaching the base units to the line block frame while biasing the base units toward the line block frame, The biasing device has a shaft portion that is attached to the line block frame and extends in the vertical direction, a bracket portion that is attached to the shaft portion via a bearing portion so as to enable vertical movement along the shaft portion, a spring portion that is attached to the shaft portion and biases the bracket portion downward, and a lock pin that is attached to the bracket portion and protrudes downward from the bracket portion, When biased, the lock pin is disposed on the upper surface of the base portion, When the biasing force is released, the lock pin is lifted upward.

2. the biasing device further includes a gripping portion attached to the bracket portion and protruding upward from the bracket portion, 2. The ink jet printing device according to claim 1, wherein the grip portion, the bracket portion and the lock pin are lifted together by lifting the grip portion.

3. the bracket portion is attached to the shaft portion via a bearing portion so as to be capable of vertical movement along the shaft portion and rotational movement around the shaft portion; When biased, the lock pin is disposed on the upper surface of the base portion, 2. The inkjet printing device according to claim 1, wherein, when the biasing force is released, the lock pin is lifted upward and the bracket portion is rotated so that the lock pin is placed in a standby position provided on an upper surface of the line block frame.

4. The standby position is a blind hole provided on the upper surface side of the line block frame, 4. The ink jet printing device according to claim 3, wherein an upper end surface of the blind hole is positioned higher than a lower end surface of the lock pin when the ink jet printing device is disposed at the standby position.

5. The biasing device further includes a block portion provided on the bracket portion and protruding downward from the bracket portion, 4. The ink jet printing device according to claim 3, wherein when the lock pin is disposed at the standby position, the block portion is disposed on an upper surface of the line block frame.

6. The shaft portion has a cylindrical small diameter shaft portion and a large diameter shaft portion provided on an upper portion of the small diameter shaft portion and having a larger diameter than the small diameter shaft portion, the spring portion is inserted through the small diameter shaft portion and is sandwiched between the large diameter shaft portion and the bracket portion, 2. The ink jet printing device according to claim 1, wherein the spring portion comprises a coil spring and a disc spring disposed below the coil spring so as to be continuous with the coil spring.

7. The base portion is positioned by abutting against a reference pin provided on the line block frame, 2. The ink jet printing apparatus according to claim 1, wherein the biasing device is attached in the positioned state.

8. The base portion has a rectangular shape when viewed from above, a first eccentric pin is attached to the line block frame at a position capable of contacting one long side surface of the base portion, a first pressure pin is attached to a position capable of contacting the other long side surface, a second eccentric pin is attached to a position capable of contacting one short side surface, and a second pressure pin is attached to a position capable of contacting the other short side surface, The first pressure pin biases the base portion in a short direction, The second pressure pin biases the base portion in a longitudinal direction, 2. The ink jet printing device according to claim 1, wherein the position of the base portion is finely adjusted by rotating the first eccentric pin and / or the second eccentric pin.

9. 9. The ink jet printing device according to claim 8, wherein a force with which the spring portion urges the base portion downward is smaller than a force with which the first pressure pin or the second pressure pin urges the base portion laterally.

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