Image forming apparatus

Abstract

This image formation device (10) comprises an ink head (20) that has a nozzle (21) capable of injecting ink onto media (Me), a heat sink (31) provided on an upper surface (20a) of the ink head (20), and dampers (40, 70) positioned directly above the ink head (20) with the heat sink (31) therebetween. The ink head (20) is capable of moving in a direction (S1) of printing on the media (Me). The heat sink (31) is capable of dissipating heat transmitted from the ink head (20) to the atmosphere. The dampers (40, 70) are integrated with the ink head (20) and can store the ink to be supplied to the ink head (20).

Description

Technical Field

[0001] The present invention relates to an improved technology of an image forming apparatus.

Background Art

[0002] Printers, facsimiles, copying machines, and image forming apparatuses having a combination of these functions are provided with dampers. These dampers are for stabilizing the ejection operation of the ink ejected from the ink head by alleviating the pressure fluctuations of the ink supplied from the ink supply line to the ink head. As a conventional technology related to such an image forming apparatus, for example, there is a technology disclosed in Patent Document 1 (see FIG. 8 of Patent Document 1).

[0003] The image forming apparatus shown in Patent Document 1 is such that a flat control board is overlapped and joined to the upper surface of an ink head (recording head), and a number of dampers (pressure control valve units) are overlapped on the upper surface of this control board. Each damper is arranged in a row in the moving direction (main scanning direction) of the ink head and is attached to this ink head. The ink outlet of each damper is directly joined to the ink inlet of the ink head. Each ink flow path from the ink outlet of each damper to the ink inlet of the ink head is vertical. Therefore, the length of each ink flow path can be shortened, and the lengths of each ink flow path can be set to be substantially uniform.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the image forming apparatus shown in Patent Document 1 does not have a heat sink for cooling the control circuit located in the ink head. This control circuit controls the ink ejection nozzle of the ink head and generates heat. In order to ensure stable operation of the control circuit, it is preferable to have a heat sink for heat dissipation.

[0006] From a heat dissipation standpoint, the heatsink must be placed above the ink head. To place both the heatsink and the damper above the ink head requires some kind of countermeasure. To cool the control circuit, the heatsink should be prioritized and placed above the ink head. In that case, it might be possible to shift the position of the damper relative to the heatsink in the direction of the ink head's movement.

[0007] However, the total length of the array of numerous dampers inevitably exceeds the length in the direction of movement of the ink head (the length of the ink head). As a result, there is a significant difference in the length of each ink flow path from the ink outlet of each damper to the ink inlet of the ink head. From the viewpoint of the stability of ink ejection from the ink head, it is preferable that the length of the ink flow path, especially the portion in the direction of movement of the ink head (the horizontal distance of the flow path portion that is long in the direction of head movement), be short.

[0008] This is because the dynamic pressure of the ink flowing into the ink head, specifically the portion of the ink flow path that is long in the direction of head movement (residual ink), is susceptible to fluctuations due to the inertia associated with the movement of the ink head. For example, if a large force acting in the opposite direction acts on the residual ink while the ink head is moving and ejecting ink, the internal pressure of the ink head decreases. As a result, ink may be ejected from the nozzles of the ink head at a slower speed. On the other hand, if a large force acting in the direction of the ink head's movement acts on the residual ink, the internal pressure of the ink head increases. As a result, the amount of ink ejected from the nozzles of the ink head may increase.

[0009] Therefore, from the standpoint of ensuring stable ink ejection from the ink head, it is necessary to maintain a more appropriate and constant internal pressure in the ink head.

[0010] The present invention aims to provide a technology that can maintain a more appropriate constant internal pressure in the ink head of an image forming apparatus equipped with a heat sink above the ink head. [Means for solving the problem]

[0011] The present invention provides an image forming apparatus comprising: an ink head having a nozzle capable of ejecting ink onto a medium and movable in the direction of printing on the medium; a heat sink provided on the upper surface of the ink head and capable of dissipating heat transmitted from the ink head to the atmosphere; and a damper located directly above the ink head via the heat sink, integrated with the ink head, and capable of storing the ink supplied to the ink head. [Effects of the Invention]

[0012] In this invention, the internal pressure of the ink head of an image forming apparatus equipped with a heat sink above the ink head can be set to a more appropriate constant pressure. [Brief explanation of the drawing]

[0013] [Figure 1] This is a perspective view of an image forming apparatus according to an embodiment. [Figure 2] Figure 1 is a schematic diagram of the carriage and ink supply system shown. [Figure 3] Figure 3A is a schematic diagram of the ink supply system shown in Figure 2, and Figure 3B is a view of Figure 3A as seen through arrow 3B. [Figure 4] Figure 2 is a perspective view of the ink ejection unit. [Figure 5] Figure 4 is an exploded perspective view of the ink ejection unit shown. [Figure 6]It is a perspective view of an assembled configuration of a base plate, a heat sink, a stand, and a cooling fan shown in FIG. 5. [Figure 7] It is a longitudinal sectional view of the ink ejection unit shown in FIG. 4. [Figure 8] It is a perspective view of the adapter shown in FIG. 5. [Figure 9] It is a perspective view of the adapter sectioned along line 9-9 in FIG. 8. [Figure 10] It is a perspective view of the first damper shown in FIG. 4. [Figure 11] It is a sectional view taken along line 11-11 in FIG. 10. [Figure 12] It is an enlarged view of part 12 in FIG. 7.

Mode for Carrying Out the Invention

[0014] Embodiments of the present invention will be described below based on the accompanying drawings. Note that the forms shown in the accompanying drawings are examples of the present invention, and the present invention is not limited to such forms.

[0015] <Example> As shown in FIG. 1, the image forming apparatus 10 is configured as an inkjet printer capable of forming a color image on a medium Me. This image forming apparatus 10 can print, for example, large-sized billboards and posters.

[0016] The medium Me as a printing target is, for example, a roll medium wound around a roll. The material of the medium Me includes, for example, papers such as ordinary paper, resins such as polyvinyl chloride resin and polyester resin, and metals such as aluminum material and iron material, and can be composed of various materials.

[0017] In this explanation, left, right, up, and down refer to the left, right, up, and down directions as viewed from the perspective of an operator standing in front of the image forming apparatus 10. Furthermore, when the operator is facing the front of the image forming apparatus 10, the direction from the rear of the image forming apparatus 10 toward the operator is defined as the front, and the direction from the operator toward the rear of the image forming apparatus 10 is defined as the rear. In the diagram, Fr indicates front, Rr indicates rear, Le indicates left, Ri indicates right, Up indicates up, and Dn indicates down.

[0018] When the rear side Rr of the image forming apparatus 10 is referred to as the upstream side and the front side Fr of the image forming apparatus 10 is referred to as the downstream side, the media Me is transported from the upstream side to the downstream side.

[0019] This image forming apparatus 10 includes a rail 12 extending from the base 11 in the left-right direction Le, Ri, and a carriage 13 that is mounted on the rail 12 so as to be movable in the left-right direction Le, Ri.

[0020] When viewing the image forming apparatus 10 from directly above, the movement direction S1 of the carriage 13 is called the "main scanning direction S1," and the transport direction S2 of the media Me is called the "sub-scanning direction S2." Here, the main scanning direction S1 corresponds to the left-right directions Le and Ri, and the sub-scanning direction S2 corresponds to the front-back directions Fr and Rr. The main scanning direction S1 and the sub-scanning direction S2 are orthogonal.

[0021] As shown in Figure 2, the carriage 13 is equipped with multiple sets of ink ejection units 14. Note that Figure 2 shows only one set of ink ejection units 14. As the carriage 13 moves in the main scanning direction S1, the ink ejection units 14 move together with the carriage 13 in the main scanning direction S1.

[0022] The ink ejection unit 14 includes one ink head 20 capable of ejecting ink, at least one heat sink 31 capable of cooling the ink head 20, one cooling fan 33 that sends cooling air to the heat sink 31, a plurality (e.g., two) of dampers 40, 70, and one adapter 150.

[0023] As the ink ejection unit 14 moves in the main scanning direction S1 together with the carriage 13, the ink head 20 becomes movable in the printing direction S1 (main scanning direction S1) on the media Me (see Figure 1). This ink head 20 has a plurality of nozzles 21 capable of ejecting droplets of various inks onto the media Me. These nozzles 21 are aligned in the main scanning direction S1 and also in the sub-scanning direction S2 (see Figure 1). The plurality of nozzles 21 are grouped into four nozzle groups 22-25 aligned in the main scanning direction S1. These nozzle groups 22-25 are arranged in a line, for example, from one side of the main scanning direction S1 to the other.

[0024] Furthermore, the ink head 20 is equipped with four ink inlets 26-29 on its upper surface 20a. The four ink inlets 26-29 are arranged in a line, for example, from one side to the other in the main scanning direction S1. The first ink inlet 26 can supply the incoming ink to the first nozzle group 22. The second ink inlet 27 can supply the incoming ink to the second nozzle group 23. The third ink inlet 28 can supply the incoming ink to the third nozzle group 24. The fourth ink inlet 29 can supply the incoming ink to the fourth nozzle group 25.

[0025] In this configuration, the image forming apparatus 10 prints on the media Me by moving the media Me in the sub-scanning direction S2 using a paper feeding means, while moving the carriage 13 in the main scanning direction S1, and ejecting ink droplets from the nozzles 21 of the ink head 20.

[0026] Furthermore, the ink head 20 incorporates a control circuit 32 that controls each nozzle 21. The area around each nozzle 21 is heated by a heater (not shown). The heat generated by the control circuit 32 and the heater is transferred to the ink head 20.

[0027] The heatsink 31 prevents overheating of the control circuit 32 and heater, and allows heat transferred from the ink head 20 to dissipate into the atmosphere.

[0028] The cooling fan 33 is positioned in the main scanning direction S1 relative to the heatsink 31, during which the ink head 20 can move. The cooling air sent from the cooling fan 33 flows in the main scanning direction S1 to cool the heatsink 31, and is then released into the atmosphere through the exhaust port 34.

[0029] Each damper 40, 70 stabilizes the ink ejection operation of each nozzle 21 by mitigating pressure fluctuations of the ink supplied to each nozzle 21. The two dampers 40, 70 correspond to the four nozzle groups 22-25. One of the two dampers 40, 70, 40 is called the "first damper 40," and the other, 70, is called the "second damper 70."

[0030] The first damper 40 comprises a first damper body 41. This first damper body 41 has two storage chambers 50 and 60 formed within it. In other words, the first damper body 41 has two storage chambers 50 and 60 (a first storage chamber 50 and a second storage chamber 60) which are partitioned by a vertical plate-shaped first partition wall 42 in the main scanning direction S1.

[0031] The first storage chamber 50 is connected to the first ink inlet 51, the first ink outlet 52, and the first return port 53. The first ink inlet 51 and the first return port 53 are located on the top plate 43 (top board 43) of the first damper body 41. The first ink outlet 52 is located on the bottom plate 44 of the first damper body 41.

[0032] The second storage chamber 60 is connected to the second ink inlet 61, the second ink outlet 62, and the second return port 63. The second ink inlet 61 and the second return port 63 are located on the top plate 43 of the first damper body 41. The second ink outlet 62 is located on the bottom plate 44 of the first damper body 41.

[0033] The second damper 70 comprises a second damper body 71. This second damper body 71 has two storage chambers 80 and 90 formed within it. In other words, the second damper body 71 has two storage chambers 80 and 90 (a third storage chamber 80 and a fourth storage chamber 90) which are partitioned by a vertical plate-shaped second partition wall 72 in the main scanning direction S1.

[0034] The third storage chamber 80 is connected to the third ink inlet 81, the third ink outlet 82, and the third return port 83. The third ink inlet 81 and the third return port 83 are located on the top plate 73 of the second damper body 71. The third ink outlet 82 is located on the bottom plate 74 of the second damper body 71.

[0035] The fourth storage chamber 90 is connected to the fourth ink inlet 91, the fourth ink outlet 92, and the fourth return port 93. The fourth ink inlet 91 and the fourth return port 93 are located on the top plate 73 of the second damper body 71. The fourth ink outlet 92 is located on the bottom plate 74 of the second damper body 71.

[0036] Each nozzle 21 of the first nozzle group 22 Ink is supplied to the ink head from the first ink supply system 110. This first ink supply system 110 is capable of supplying ink stored in the first ink tank 111 to each nozzle 21 of the first nozzle group 22 from the first ink inlet 26 of the ink head 20 via a path consisting of a first supply control valve 112, a first supply pump 113, and a first storage chamber 50 (including a first ink inlet 51 and a first ink outlet 52).

[0037] The ink in the first storage chamber 50 can be returned to the suction port of the first supply pump 113 via the first return port 53, the first return control valve 114, and the first circulation path 115. When the ink contains a pigment with a high specific gravity, the first circulation path 115 circulates the ink in the first storage chamber 50, preventing the pigment from settling into the first storage chamber 50.

[0038] Each nozzle 21 of the second nozzle group 23 is supplied with ink from the second ink supply system 120. This second ink supply system 120 can supply ink stored in the second ink tank 121 to each nozzle 21 of the second nozzle group 23 from the second ink inlet 27 of the ink head 20 via a path consisting of a second supply control valve 122, a second supply pump 123, and a second storage chamber 60 (including a second ink inlet 61 and a second ink outlet 62). The ink in the second storage chamber 60 can be returned to the suction port of the second supply pump 123 via a second return port 63, a second return control valve 124, and a second circulation path 125.

[0039] Each nozzle 21 of the third nozzle group 24 is supplied with ink from the third ink supply system 130. This third ink supply system 130 can supply ink stored in the third ink tank 131 to each nozzle 21 of the third nozzle group 24 from the third ink inlet 28 of the ink head 20 via a path consisting of a third supply control valve 132, a third supply pump 133, and a third storage chamber 80 (including a third ink inlet 81 and a third ink outlet 82). The ink in the third storage chamber 80 can be returned to the suction port of the third supply pump 133 via a third return port 83, a third return control valve 134, and a third circulation path 135.

[0040] Each nozzle 21 of the fourth nozzle group 25 is supplied with ink from the fourth ink supply system 140. This fourth ink supply system 140 can supply ink stored in the fourth ink tank 141 to each nozzle 21 of the fourth nozzle group 25 from the fourth ink inlet 29 of the ink head 20 via a path consisting of the fourth supply control valve 142, the fourth supply pump 143, and the fourth storage chamber 90 (including the fourth ink inlet 91 and the fourth ink outlet 92). The ink in the fourth storage chamber 90 can be returned to the suction port of the fourth supply pump 143 via the fourth return port 93, the fourth return control valve 144, and the fourth circulation path 145.

[0041] The adapter 150 is a so-called ink relay that adjusts the flow direction of ink supplied from each damper 40, 70 to the ink head 20. This adapter 150 has multiple ink channels 151 to 154 that supply ink from the ink outlets 52, 62, 82, and 92 of each damper 40, 70 to the ink inlets 26 to 29 of the ink head 20.

[0042] The multiple ink channels 151-154 are the first ink channel 151, the second ink channel 152, the third ink channel 153, and the fourth ink channel 154. The first ink channel 151 connects the first ink outlet 52 of the first damper 40 to the first ink inlet 26 of the ink head 20. The second ink channel 152 connects the second ink outlet 62 of the first damper 40 to the second ink inlet 27 of the ink head 20. The third ink channel 153 connects the third ink outlet 82 of the second damper 70 to the third ink inlet 28 of the ink head 20. The fourth ink channel 154 connects the fourth ink outlet 92 of the second damper 70 to the fourth ink inlet 29 of the ink head 20.

[0043] As shown in Figure 3A, the four ink inlets 26-29 of the ink head 20 are arranged in a straight line from one side (left side Le) to the other side (right side Ri) of the main scanning direction S1, in the order of the first ink inlet 26, the second ink inlet 27, the fourth ink inlet 29, and the third ink inlet 28. In other words, the positions of the third ink inlet 28 and the fourth ink inlet 29 are in reverse order. These ink inlets 26-29 are located on the front side Fr of the ink head 20 and extend upward from the upper surface 20a of the ink head 20.

[0044] In contrast, the first damper 40 and the second damper 70 are arranged in this order in a line from one side (left side Le) to the other side (right side Ri) in the main scanning direction S1. The external shape of each damper 40, 70 is a thin, flattened, roughly rectangular parallelepiped in the main scanning direction S1.

[0045] The first ink outlet 52 of the first damper 40 is located directly above the first ink inlet 26 of the ink head 20. The second ink outlet 62 of the first damper 40 is located directly behind the first ink outlet 52.

[0046] This section describes the ink channels 151-154 of adapter 150. The first ink flow path 151 extends vertically in a straight line from the first ink outlet 52 of the first damper 40 to the first ink inlet 26 of the ink head 20. The second ink flow path 152 consists of a bypass 152a that bypasses the first ink outlet 52 of the first damper 40 only in the main scanning direction S1 (horizontal direction), and a vertical path 152b that extends from the tip of this bypass 152a to the second ink inlet 27 of the ink head 20. The bypass 152a extends from the second ink outlet 62 of the first damper 40, bypassing the first ink outlet 52 in an L-shape in plan view in the horizontal direction, to directly above the second ink inlet 27 of the ink head 20. The vertical path 152b extends vertically in a straight line from the bypass 152a to the second ink inlet 27.

[0047] The third ink outlet 82 of the second damper 70 is located directly above the fourth ink inlet 29 of the ink head 20. The fourth ink outlet 92 of the second damper 70 is located directly behind the third ink outlet 82.

[0048] The third ink channel 153 extends vertically in a straight line from the third ink outlet 82 of the second damper 70 to the third ink inlet 28 of the ink head 20. The fourth ink channel 154 consists of a bypass 154a that bypasses the third ink outlet 82 of the second damper 70 only in the main scanning direction S1 (horizontal direction), and a vertical path 154b that extends from the tip of this bypass 154a to the fourth ink inlet 29 of the ink head 20. The bypass 154a extends from the fourth ink outlet 92 of the second damper 70, bypassing the third ink outlet 82 in an L-shape in plan view in the horizontal direction, to directly above the fourth ink inlet 29 of the ink head 20. The vertical path 154b extends vertically in a straight line from the bypass 154a to the fourth ink inlet 29.

[0049] The bypass 152a of the second ink channel 152 and the bypass 154a of the fourth ink channel 154 are close to each other in a plan view.

[0050] Thus, in this embodiment, the image forming apparatus 10 is configured such that the ink flow paths 151 to 154 of the adapter 150 do not intersect each other in the vertical direction, with respect to the arrangement of the ink outlets 52, 62, 82, and 92 of each damper 40 and 70, and the arrangement of the ink inlets 26 to 29 of the ink head 20.

[0051] Furthermore, in this embodiment, the image forming apparatus 10 has at least one of the multiple ink channels 151 to 154, specifically one ink channel 151, 153 (first and third ink channels 151, 153), configured to be linear in the vertical direction from the ink outlets 52, 82 of the dampers 40, 70 to the ink inlets 26, 28 of the ink head 20.

[0052] All ink channels 151-154 do not intersect each other in the vertical direction, and at least one of the multiple ink channels 151-154 is configured in a straight line. Therefore, the length of the ink channels 151-154 can be kept as short as possible.

[0053] Furthermore, by bringing the first damper 40 and the second damper 70 closer together in the main scanning direction S1, it is also possible to position the first ink outlet 52 of the first damper 40 directly above the second ink inlet 27 of the ink head 20, and the third ink outlet 82 of the second damper 70 directly above the fourth ink inlet 29 of the ink head 20.

[0054] The volume of all ink channels 151-154 is set to be the same size. For example, the diameters of the second ink channel 152 and the fourth ink channel 154 are set to be larger than the diameters of the first ink channel 151 and the third ink channel 153. Therefore, the pressure resistance (pressure loss) of the ink passing through all ink channels 151-154 can be made equal. The viscosity of the ink passing through each ink channel 151-154 is approximately the same.

[0055] Of the ink channels 151 to 154, the length of the portion in the direction of movement of the ink head 20, i.e., the main scanning direction S1 (the horizontal distance of the channel portion that is long in the direction of head movement), is particularly short. For example, as shown in Figure 3A, the first ink channel 151 and the third ink channel 153 are vertical. The portion of the bypass 152a of the second ink channel 152 that extends in the main scanning direction S1 is short because it only bypasses the first ink channel 151 in a plan view. The portion of the bypass 154a of the fourth ink channel 154 that extends in the main scanning direction S1 is short because it only bypasses the third ink channel 153 in a plan view. As a result, the internal pressure of the ink head can be kept at a more appropriate constant pressure.

[0056] The image forming apparatus 10 will be described in more detail below.

[0057] As shown in Figures 4 to 7, the ink head 20 is detachably attached to the base plate 160. This base plate 160 is a flat plate-shaped member that can be attached to the carriage 13 and has a through hole 161 into which the ink head 20 can be fitted from above.

[0058] A stand 170 is attached to the upper surface of the base plate 160. The stand 170 is composed of a pair of vertical wall plates 171 and 172 (first wall plate 171 and second wall plate 172) that rise from both ends of the base plate 160 in the main scanning direction S1, and a flat top plate 173 (top board 173) that connects the upper ends of these wall plates 171 and 172. One opening 174 of the stand 170 in the sub-scanning direction S2 (rear side Rr) is covered by a plate-shaped member 175 such as a control board. The other opening 176 of the stand 170 in the sub-scanning direction S2 (front side Fr) is covered by a plurality of vertical pipes 191 to 194 on the adapter 150. The top plate 173 has through holes 177 through which the pipes 191 to 194 of the adapter 150 can pass. Furthermore, the interior of the base plate 160 may be enclosed solely by the base plate 160.

[0059] A heatsink 31 is located inside the stand 170. An air intake 178 and a cooling fan 33 are attached to the first wall panel 171 on the left side Le. Right side Ri An exhaust port 34 is provided in the second wall panel 172. The cooling air blown by the cooling fan 33 cools the heat sink 31 as it passes through the air guide port 178 and is then released into the atmosphere through the exhaust port 34. In this way, the stand 170 acts as a duct for directing the cooling air blown by the cooling fan 33 through to the main scanning direction S1.

[0060] As shown in Figures 8 and 9, the adapter 150 is a resin molded product composed of a flat adapter body 180 (first structure 180) and four pipes 191 to 194 (second structure 191 to 194) extending downward from the adapter body 180.

[0061] The adapter body 180 includes an inlet 181 for the first ink channel 151, an inlet 182 for the second ink channel 152, an inlet 183 for the third ink channel 153, and an inlet 184 for the fourth ink channel 154, extending upward from its top surface. The inlet 181 for the first ink channel 151 faces the first ink outlet 52 of the first damper 40 shown in Figure 2. The inlet 182 for the second ink channel 152 faces the second ink outlet 62 of the first damper 40 shown in Figure 2. The inlet 183 for the third ink channel 153 faces the third ink outlet 82 of the second damper 70 shown in Figure 2. The inlet 184 for the fourth ink channel 154 faces the fourth ink outlet 92 of the second damper 70 shown in Figure 2.

[0062] Furthermore, the adapter body 180 has a bypass 152a for the second ink channel 152 and a bypass 154a for the fourth ink channel 154. Therefore, as shown in Figure 3A, when viewing the adapter 150 from above, none of the ink channels 151-154 overlap each other. Consequently, the thickness Th of the flat adapter body 180 (see Figure 3A) can be set to be small.

[0063] Furthermore, as shown in Figures 3A and 3B, each detour 152a, 154a is L-shaped in plan view. Therefore, when the detours 152a, 154a are formed from the side surface 185 of the resin adapter body 180, the detours 152a, 154a can be sealed by simply joining a single sealing sheet 186 to this side surface 185. Opening 152c, 154c (See Figure 3B) can be closed. The sealing sheet 186 can be made of, for example, a heat-sealable film.

[0064] The four pipes 191 to 194 are: the first pipe 191 having a first ink channel 151; the second pipe 192 having a vertical path 152b for a second ink channel 152; the third pipe 193 having a third ink channel 153; and the fourth pipe 194 having a vertical path 154b for a fourth ink channel 154.

[0065] Referring also to Figures 5 and 6, the adapter body 180 is placed on the top plate 173 of the stand 170 and is attached to the top plate 173 by screws 201. Therefore, the adapter 150 is located directly above the heat sink 31 and is detachably assembled to the stand 170. As a result, as shown in Figure 5, a head unit 200 (so-called sub-assembly 200) is formed on the base plate 160, in which the ink head 20, stand 170, heat sink 31, cooling fan 33, and adapter 150 are integrated. In this way, the stand 170 is cooling air In addition to serving as a duct for the wires, it also functions as an assembly stand for mounting adapter 150.

[0066] As is clear from the above explanation, a heat sink 31 is provided on the upper surface 20a of the ink head 20. The adapter 150 is located directly above this heat sink 31. Furthermore, referring to Figures 4 and 5, the first and second dampers 40 and 70 are located directly above the adapter 150. Therefore, the first and second dampers 40 and 70 are located directly above the heat sink 31. As a result, the first and second dampers 40 and 70 are located directly above the ink head 20 via the heat sink 31.

[0067] As shown in Figures 4, 5, and 8, the first and second dampers 40 and 70 are detachably mounted on the adapter 150. For example, the first and second dampers 40 and 70 are detachably fixed to the adapter 150 by a plurality of latching mechanisms 210. Each latching mechanism 210 consists, for example, a plurality of latching arms 211 provided on the adapter 150 and a plurality of latching claws 212 provided on the first and second dampers 40 and 70.

[0068] More specifically, the adapter body 180 integrally includes four locking arms 211, each having a locking hole 213. Each locking arm 211 is made up of an elastic piece that rises from the edge of the adapter body 180. The damper bodies 41 and 71 of the first and second dampers 40 and 70 are integrally equipped with four locking claws 212. They can be locked together by hooking the locking claws 212 into the locking holes 213.

[0069] The latching mechanism 210 allows the first and second dampers 40 and 70 to be attached to the adapter 150, thereby integrating them with the head unit 200. As a result, an integrated ink ejection unit 14 (see Figure 4) can be constructed. Therefore, it is easy to assemble multiple ink ejection units 14 into the carriage 13 (see Figure 2). Moreover, since the first and second dampers 40 and 70 can be removed from the head unit 200 simply by removing the latching mechanism 210, maintenance work on the first and second dampers 40 and 70 is easy.

[0070] Next, the first damper 40 will be described with reference to Figures 5, 10, and 11. The second damper 70 has the same configuration as the first damper 40, so its description will be omitted.

[0071] As shown in Figure 11, the two storage chambers 50, 60 (first storage chamber 50 and second storage chamber 60) of the first damper 40 are separate and independent spaces, with opposite sides open to each other. In other words, the first damper body 41 has openings 45, 45 that are open throughout both sides in the main scanning direction S1. These openings 45, 45 are closed by damper membranes 221, 221, respectively. As a result, the two storage chambers 50, 60 are sealed.

[0072] The damper membranes 221, 221 are made of a sheet (including a film) that is elastically deformable according to the amount of ink stored in each storage chamber 50, 60 and the pressure in each storage chamber 50, 60. For example, the damper membranes 221, 221 are preferably made of a transparent or translucent resin material. The damper membranes 221, 221 are attached to the first damper body 41 with tension such that they can bend inward and outward, respectively, of each storage chamber 50, 60.

[0073] Between the wall surface of the first partition wall 42 and the membrane surface (sheet surface) of each damper membrane 221, 221, biasing members 222, 222 are interposed, respectively, to bias the damper membranes 221, 221 outward. These biasing members 222, 222 are composed of, for example, compression coil springs. It is preferable to interpose plate-shaped pressing bodies 223, 223 between each damper membrane 221, 221 and the biasing members 222, 222.

[0074] Each damper membrane 221,221 is covered by two covers 224,224. Each cover 224,224 is made of a light-shielding and opaque material such as resin. These covers 224,224 can cover the damper membranes 221,221 from the outside of the first damper body 41 (opposite side from the storage chambers 50,60) by closing the openings 45,45.

[0075] As shown in Figure 10, the lateral base end 224a of each cover 224,224 is supported on the first damper body 41 by hinge mechanisms 225,225 so as to be able to open and close in the main scanning direction S1. Cover extensions 226,226 are integrally provided on the open ends 224b,224b of each cover 224,224, facing each other. Each cover extension 226,226 extends from the open ends 224b,224b of each cover 224,224 toward the opposite side from the hinge mechanisms 225,225. Therefore, there is a space 227 between the first damper body 41 and each cover extension 226,226. The cover extensions 226,226 are detachably hooked to each other by a latching mechanism 228.

[0076] A first pressure detection unit 231 and a second pressure detection unit 232 are arranged in the space 227. The first pressure detection unit 231 is capable of detecting the internal pressure of the first storage chamber 50. The second pressure detection unit 232 is capable of detecting the internal pressure of the second storage chamber 60.

[0077] As shown in Figures 5, 7, and 12, the ink outlets 52, 62, 82, and 92 of each damper 40 and 70 and the inlets 181 to 184 of each ink flow path 151 to 154 of the adapter 150 are sealed by a sealing member 241. The sealing member 241 is attached to the dampers 40 and 70.

[0078] More specifically, as shown in Figure 12, the ink outlets 52, 62, 82, and 92 are cylindrical portions extending from the bottom plates 44 and 74 of the damper bodies 41 and 71 toward the inlets 181 and 184 of the ink flow paths 151 and 154 of the adapter 150. The inner circumference of the tips of the ink outlets 52, 62, 82, and 92 has an annular recess 242. The sealing member 241 is an annular rubber product that is fitted into the recess 242. A cap 243 is detachably attached to the tip of the ink outlets 52, 62, 82, and 92 by a latch. This cap 243 prevents the sealing member 241, which is fitted into the recess 242, from falling out. As a result, the sealing member 241 is attached to the dampers 40 and 70.

[0079] Furthermore, the cap 243 has a through hole 243a in the center. The inlet portion 181 of the first ink flow path 151 of the adapter 150 has a tubular structure and passes through the through hole 243a of the cap 243 and the sealing member 241. Ink outlet 52 It extends into the interior. The sealing member 241 has a sealing portion that is convex around its entire circumference on both its inner and outer circumferential surfaces, and it provides a liquid-tight seal between the inner circumferential surface of the recess 242 and the outer circumferential surface of the inlet portion 181 of the first ink flow path 151.

[0080] Generally, the cost of dampers 40,70 (first and second dampers 40,70) is lower than that of the ink head 20. The adapter 150 is integrated into the ink head 20. When a damper 40,70 fails, it is preferable to replace the sealing member 241 with a new one when replacing the failed damper 40,70 in order to ensure liquid tightness.

[0081] In this embodiment, the sealing member 241 is attached to the dampers 40 and 70. Therefore, by simply replacing a faulty damper 40 or 70, the sealing member 241 can also be replaced with a new one at the same time. As a result, the cost of replacing the sealing member 241 can be reduced compared to when the sealing member 241 is attached to the adapter 150 which is incorporated into the ink head 20. Moreover, sufficient airtightness and liquid tightness of the sealing member 241 can be ensured.

[0082] To summarize the above explanation, it is as follows:

[0083] As shown in Figures 2, 3A, and 7, the image forming apparatus 10 includes an ink head 20 having a nozzle 21 capable of ejecting ink onto media Me and movable in the printing direction S1 (main scanning direction S1) onto media Me, a heat sink 31 provided on the upper surface 20a of the ink head 20, and dampers 40, 70 (first and second dampers 40, 70) located directly above the ink head 20 via the heat sink 31 and integrated with the ink head 20. The heat sink 31 is capable of dissipating heat transferred from the ink head 20 into the atmosphere. The dampers 40, 70 are capable of storing the ink supplied to the ink head 20.

[0084] Thus, the dampers 40 and 70 are positioned directly above the ink head 20 via the heat sink 31 and are integrated with the ink head 20. Therefore, the ink flow paths 151 to 154 from the ink outlets 52, 62, 82, and 92 of each damper 40 and 70 to the ink inlets 26 to 29 of the ink head 20 can be extended as far vertically as possible. Consequently, despite the presence of the heat sink 31, the length of each ink flow path 151 to 154 can be set to be as short as possible.

[0085] In particular, the length of the portion of the ink flow path 151-154 that corresponds to the direction of movement of the ink head 20, i.e., the main scanning direction S1 (the horizontal distance of the flow path portion that is long in the direction of head movement), can be set to be as short as possible. Therefore, the fluctuation in dynamic pressure when ink (residual ink) in the flow path portion that is long in the direction of head movement flows to the ink head can be reduced as much as possible.

[0086] Therefore, in an image forming apparatus 10 with a heat sink 31 placed on top of the ink head 20, the internal pressure of the ink head 20 can be set to a more appropriate constant pressure.

[0087] As shown in Figure 3A, the image forming apparatus 10 further includes an adapter 150 equipped with a plurality of ink channels 151 to 154 that supply ink from the ink outlets 52, 62, 82, 92 of the dampers 40, 70 (first and second dampers 40, 70) to the ink inlets 26 to 29 of the ink head 20. At least one of the plurality of ink channels 151 to 154, 151, 153, is configured to run in a straight line from the ink outlets 52, 82 of the dampers 40, 70 to the ink inlets 26, 28 of the ink head 20.

[0088] By configuring at least one ink channel 151, 153 in a straight line, the length of these ink channels 151, 153 can be further shortened. Furthermore, by setting the volume of each ink channel 151 to 154 to be approximately the same, for example, the ink pressure applied from the ink channels 151 to 154 into the ink head 20 can be made uniform and reduced. As a result, the internal pressure of the ink head 20 can be made a more appropriate constant pressure.

[0089] As shown in Figures 3A and 7-9, the adapter 150 has a horizontal adapter body 180 (first structure 180) and pipes 191-194 (second structure 191-194) extending vertically from the adapter body 180. The linearly configured ink channels 151 and 153 are located inside the pipes 191-194.

[0090] Therefore, positioning and fixing the section from the dampers 40 and 70 to the ink head 20 (ink ejection unit 14) to be integrated by the adapter 150 becomes easier.

[0091] As shown in Figure 3A, the image forming apparatus 10 includes an adapter 150 equipped with multiple ink channels 151 to 154 that supply ink from the ink outlets 52, 62, 82, and 92 of the dampers 40, 70 (first and second dampers 40, 70) to the ink inlets 26 to 29 of the ink head 20. The adapter 150 has a disc-shaped adapter body 180 (first structure 180) with its surface facing vertically, and pipes 191 to 194 (second structure 191 to 194) extending downward from the adapter body 180.

[0092] The first structure 180 has a plurality of inlet sections 181 to 184 on its upper surface that are connected to the ink outlets 52, 62, 82, and 92 of the dampers 40 and 70. The plurality of inlet sections 181 to 184 are arranged at positions corresponding to the four corners when the first structure 180 is viewed from above and is assumed to be the four corners of a rectangle. At least one of the plurality of inlet sections 181 to 184 is designated as a "specific inlet section 181, 183," and the rest are designated as "other inlet sections 182, 184." The ink channels 151 to 154 connected to the specific inlet sections 181, 183 (first and third ink channels 151, 153) are designated as "specific ink channels 151, 153," and the ink channels 152, 154 connected to the other inlet sections 182, 184 (second and fourth ink channels 152, 154) are designated as "other ink channels 152, 154."

[0093] The specific ink channels 151, 153 are configured in a straight line from specific inlet sections 181, 183 to the ink inlets 26, 28 of the ink head 20, 2nd structure 191,193 It passes through the interior of the other ink channels 152, 154 are configured as lateral channels 152a, 154a that pass laterally through the interior of the first structure 180 from the other inlet sections 182, 184, and as linear channels from these lateral channels 152a, 154a to the ink inlets 27, 29 of the ink head 20, 2nd structure 192,194 It consists of vertical channels 152b and 154b that pass through the interior. Specific ink channels 151 and 153 and vertical channels 152b and 154b are arranged in a single line in the horizontal direction.

[0094] Therefore, the length of the ink flow paths 151 to 154 can be shortened regardless of the positions of the ink inlets 26 to 29 of the ink head 20 or the ink outlets 52, 62, 82, and 92 of the dampers 40 and 70.

[0095] As shown in Figures 2, 4, and 7, the heat sink 31 is located within the range of the first structure 180 when viewed from above the adapter 150, that is, within the range of the projection (vertical projection) of the adapter 150 when viewed from above. Furthermore, as shown in Figures 4 and 5, the heat sink 31 is located next to the second structures 191-194.

[0096] Therefore, the section from the dampers 40 and 70 to the ink head 20 (ink ejection unit 14) can be more appropriately miniaturized and integrated. Consequently, the carriage 13 can be prevented from becoming larger.

[0097] As shown in Figure 4, the image forming apparatus 10 is further equipped with a cooling fan 33 that blows cooling air onto the heat sink 31. This cooling fan 33 is positioned in the main scanning direction S1, from which the ink head 20 can move, relative to the heat sink 31.

[0098] When printing on media Me (see Figure 1), the heatsink 31 moves in the main scanning direction S1 together with the ink head 20. In response, the cooling fan 33 blows cooling air in the same direction as the heatsink 31's movement S1 (main scanning direction S1). In other words, the direction of airflow from the cooling fan 33 toward the heatsink 31 is the same as the direction of movement S1 of the heatsink 31. Therefore, the heatsink 31 can be efficiently cooled by the cooling air.

[0099] Furthermore, the present invention is not limited to the embodiments, provided that it achieves the functions and effects of the present invention. [Industrial applicability]

[0100] The image forming apparatus 10 of the present invention is suitable for use with an inkjet printer. [Explanation of symbols]

[0101] 10 Image forming apparatus 13 Carriage 14. Ink ejection unit 20 Inkheads Top of 20a ink head 21 nozzles 26-29 Ink inlet of the ink head 31 Heatsink 32 Control circuits 33 Cooling fan 34 Ventilation outlet 40,70 damper 52, 62, 82, 92 Damper ink outlet 150 adapter 151,153 Specific ink flow paths 152,154 Other ink channels 152a, 154a Lateral channel 152b, 154b Vertical channel 180 Adapter body (First structure) 181,183 Specific entrance area 182,184 Other entrances 191-194 Pipes (Second Structure) Me Media S1 Main scanning direction S2 Sub-scanning direction

Claims

1. An ink head having a nozzle capable of ejecting ink onto media and movable in the direction of printing onto the media, A heat sink is provided on the upper surface of the ink head and is capable of dissipating the heat transmitted from the ink head into the atmosphere, A damper is located directly above the ink head via the heat sink and is integrated with the ink head, and is capable of storing the ink supplied to the ink head, The adapter comprises a plurality of ink channels that supply the ink from the ink outlet of the damper to the ink inlet of the ink head, The adapter has a first horizontal structure and a second structure extending vertically from the first structure. The aforementioned plurality of ink channels are A straight flow path is provided inside the second structure, which is configured to extend in a straight line from the ink outlet of the damper to the ink inlet of the ink head, An image forming apparatus having an L-shaped channel comprising a lateral channel passing horizontally through the interior of the first structure and a vertical channel passing through the interior of the second structure from the lateral channel to the ink inlet of the ink head.

2. An ink head having a nozzle capable of ejecting ink onto a medium and movable in the direction of printing onto the medium, A heat sink is provided on the upper surface of the ink head and is capable of dissipating the heat transmitted from the ink head into the atmosphere, A damper is located directly above the ink head via the heat sink and is integrated with the ink head, and is capable of storing the ink supplied to the ink head, The adapter comprises a plurality of ink channels that supply the ink from the ink outlet of the damper to the ink inlet of the ink head, The adapter has a first disc-shaped structure whose surface is oriented vertically, and a second structure extending downward from the first structure. The first structure has a plurality of inlets on its upper surface that are connected to the ink outlet of the damper, The aforementioned multiple entrances are arranged at positions corresponding to the four corners when the first structure is viewed from above and a rectangle is assumed to have four corners. Of the aforementioned multiple inlet sections, at least one is designated as a specific inlet section, and the rest are designated as other inlet sections. When the ink channel connected to the specific inlet of the plurality of ink channels is designated as the specific ink channel, and the ink channels connected to the other inlets are designated as other ink channels, The aforementioned specific ink flow path is configured to be linear from the aforementioned specific inlet to the ink inlet of the ink head and passes through the interior of the second structure. The other ink channel consists of a lateral channel that passes laterally through the interior of the first structure from the other inlet, and a longitudinal channel that is linearly configured from the lateral channel to the ink inlet of the ink head and also passes through the interior of the second structure. An image forming apparatus in which the aforementioned specific ink channels and the aforementioned vertical channels are arranged in a single line in the horizontal direction.

3. The image forming apparatus according to claim 1 or 2, wherein the heat sink is located within a certain range of the first structure when viewed from above the adapter, and is located next to the second structure.

4. The heatsink is further provided with a cooling fan that blows cooling air onto it. The image forming apparatus according to claim 1, wherein the cooling fan is positioned relative to the heat sink in the main scanning direction from which the ink head can move.

Images