CN112549784A

CN112549784A - Heater unit, head module, and printing apparatus provided with same

Info

Publication number: CN112549784A
Application number: CN202010940172.2A
Authority: CN
Inventors: 鸟饲孝介; 岩间纪贵
Original assignee: Brother Industries Ltd
Current assignee: Brother Industries Ltd
Priority date: 2019-09-26
Filing date: 2020-09-09
Publication date: 2021-03-26
Anticipated expiration: 2040-09-09
Also published as: CN112549784B

Abstract

Provided are a heater unit and a head module which can make the temperature of liquid uniform and restrain the reduction of image quality, and a printing device provided with the heater unit and the head module. A heater module (30) connected to the head (50) is provided with a flow path tube (131a) which communicates with the ink inlet (51b) and extends in the vertical direction, a flow path tube (131d) which communicates with the ink inlet (51a) and extends in the vertical direction, and a heater (132). The heating surface of the heater (132) is in contact with the flow path pipe (131a, 131b) via a heat conductive grease having a heat conductivity of 1W/(m.K) or more and a rigidity lower than that of the flow path pipe.

Description

Heater unit, head module, and printing apparatus provided with same

Technical Field

The present invention relates to a heater module used in a printing apparatus that ejects ink such as UV ink.

Background

Conventionally, an ink jet printer is known in which ink before entering a head is heated by a heater to a viscosity that allows the ink to be ejected from the head. For example, patent document 1 discloses an inkjet printer including an inkjet head and an off-head ink heating device.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2015-168243

Disclosure of Invention

Problems to be solved by the invention

In the ink jet printer described in patent document 1, the ink heating device outside the head includes a heating block for heating the ink inside the tube. The heating block has an aluminum heater base body in which a groove for fitting the pipe is formed, and a heater attached to the heater base body. In this case, heat from the heater is transmitted to the ink through the heater base and the tube. Depending on the condition of contact between the heater base and the tube, heat transfer between the heater base and the tube may be impeded. When the heat transfer between the heater base and the tube is hindered, the viscosity of the ink discharged from each nozzle may vary, which may cause a reduction in image quality.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a means capable of making the temperature of a liquid uniform and suppressing the deterioration of image quality.

Means for solving the problems

The liquid ejecting apparatus of the present disclosure includes a heater module connected to a head having a first manifold, a first communication port communicating with the first manifold, a second manifold, and a second communication port communicating with the second manifold, and includes:

a first tube communicating with the first communication port and extending in a first direction;

a second tube that communicates with a second communication port, extends in the first direction, and is juxtaposed to the first tube in a second direction orthogonal to the first direction; and

a heater having a heating surface,

the heating surface of the heater is in direct contact with both the outer peripheral surface of the first tube and the outer peripheral surface of the second tube, or is in contact with the outer peripheral surface of the first tube and the outer peripheral surface of the second tube via a heat conductor having a thermal conductivity of 1W/(m · K) or more and having a rigidity lower than the rigidity of the first tube and the second tube.

In the heater module of the present invention, the heater is in direct contact with the first tube and the second tube or in thermal contact with the first tube and the second tube via a heat conductor having a thermal conductivity of 1W/(m · K) or more and having a rigidity lower than the rigidity of the first tube and the second tube. Therefore, the heat generated by the heater can be efficiently transferred to the ink flowing through the first tube and the second tube. Examples of the heat conductor include heat conductive grease, heat conductive adhesive, and heat conductive film (heat conductive sheet).

In the heater module of the present invention, the heater may include a first heater and a second heater each having a heating surface,

the first tube and the second tube may be sandwiched between a heating surface of the first heater and a heating surface of the second heater.

In this case, since 2 heaters (the first heater and the second heater) are disposed so as to sandwich the first pipe and the second pipe, the entire outer peripheral surfaces of the first pipe and the second pipe can be heated. This reduces temperature unevenness of the ink flowing through the first and second tubes.

The heater module according to the present invention may further include a metal fixture that has a surface facing a surface of the heater opposite to the heating surface and fixes the heater to the first pipe and the second pipe.

In this case, the fixture is a metal member, and therefore can uniformly heat between the first pipe and the second pipe. This can reduce the temperature difference between the ink flowing through the first tube and the ink flowing through the second tube. Further, since the fixing member is a metal member, it also functions as a heat radiation plate for radiating heat of the heater. Therefore, the heat of the heater can be prevented from losing the radiation place and the temperature of the heater can be prevented from excessively rising.

The heater module according to the present invention may further include a resin fixing member that fixes the heater, the first tube, and the second tube by sandwiching the heater, the first tube, and the second tube between the resin fixing member and the metal fixing member.

In this case, since the metal fastener and the resin fastener are combined, the manufacturing cost of the fastener can be reduced as compared with a case where the entire fastener is formed of a metal material. The metal fixing member may be formed of a metal block, and the resin fixing member may be formed of a resin block. A block means a thick plate-like member of a substantially rectangular parallelepiped (or substantially cube) shape. In this way, when the metal fastener is formed of a metal block and the resin fastener is formed of a resin block, the strength of the fastener can be improved as compared with a case where the fastener is manufactured by, for example, sheet-metal working a thin plate-like metal member. This can reliably fix the first pipe, the second pipe, and the heater.

In the heater module of the present invention, a distance between the surface of the fixing member and the outer circumferential surface of the first pipe may be equal to a distance between the surface of the fixing member and the outer circumferential surface of the second pipe.

In this case, the distance between the fixing member and the outer peripheral surfaces of the first and second pipes is substantially the same. For example, the fixing member can be formed by bending along the outer peripheral surfaces of the first and second pipes. As compared with the case where the fixing member is not bent along the outer peripheral surfaces of the first and second pipes, the heat can be uniformly heated between the first and second pipes more efficiently, and the function of the fixing member as a heat radiation plate for radiating heat from the heater can be improved.

The heater module of the present invention may further be provided with a temperature sensor,

the temperature sensor may be disposed at a position farther from the first communication port and the second communication port than the heater in the first direction,

the temperature sensor may be disposed at a position between the first communication port and the second communication port in the second direction.

In this case, the temperature sensor is disposed at a position farther from the first communication port and the second communication port than the heater in the first direction, and is disposed at a position between the first communication port and the second communication port in the second direction. That is, the temperature sensor is disposed upstream of the heater in the ink flow. Thus, the temperature sensor can detect the temperature of the ink before being heated by the heater.

In the heater assembly of the present invention, the heater may be a carbon heater. The carbon heater is flexible and has high bending resistance, and therefore can cover the first pipe and the second pipe by bending along the outer peripheral surfaces of the first pipe and the second pipe. Further, since the carbon heater is used, the output wattage can be made high (100W or more).

According to another aspect of the present invention, there is provided a head module including the heater assembly of the present invention and the head. Further, a printing apparatus including the head module is provided.

The head module according to the present invention may further include a damper unit having a damper flow path connected to the first communication port and the second communication port of the heater unit.

In this case, when the ink is transferred using the pump pressure, for example, the fluctuation of the pressure generated in the ink can be attenuated by the damper flow path.

In the head module of the present invention, the head may have an internal heater that heats the ink in the manifold,

the heater of the heater assembly may have an output wattage greater than an output wattage of the internal heater.

In this case, ink cooling in the manifold can be prevented.

Drawings

Fig. 1 is a plan view schematically showing the printer 1.

Fig. 2 is a plan view schematically showing the ink-jet head 4.

Fig. 3 (a) is a schematic view of the head unit 11, and (b) is a schematic cross-sectional view of the head unit 11.

Fig. 4 is a plan view schematically showing the head 50.

Fig. 5 is a schematic view of the flow path block 35.

Fig. 6 is a schematic view of the lower connector 31 and the spacer 31 p.

Fig. 7 (a) is a schematic view of heater unit 130, and (b) is a schematic view showing a state in which fixing member 133a is removed.

Fig. 8 (a) and (b) are schematic diagrams of the damper unit 200, and (c) is a schematic plan view of the damper unit 200.

FIGS. 9 (a) and (b) are schematic views of damper tubes 301 to 304.

Fig. 10 (a) is a schematic view of the heater unit 430, and (b) is a schematic view showing a state where the fixing member 433b is removed.

Description of the reference symbols

1 Printer

4 ink jet head

30 heater assembly

35 flow path block

50 heads

Detailed Description

< first embodiment >

The description is made based on the drawings showing the printer 1 of the first embodiment. Fig. 1 is a plan view schematically showing the printer 1. In fig. 1, the conveyance direction of the recording paper 100 (recording medium) corresponds to the front-rear direction of the printer 1. In addition, the width direction of the recording paper 100 corresponds to the left-right direction of the printer 1. The direction perpendicular to the front-rear direction and the left-right direction, i.e., the direction perpendicular to the paper surface of fig. 1 corresponds to the vertical direction of the printer 1.

< Structure of Printer 1 >

As shown in fig. 1, the printer 1 mainly includes a platen 3, four

inkjet heads

4, 2

transport rollers

5 and 6, and a controller 7, which are housed in a casing 2.

The recording paper 100 is placed on the upper surface of the platen 3. The four inkjet heads 4 are juxtaposed in the conveyance direction above the platen 3. Each ink-jet head 4 is a so-called line head. Ink is supplied to the inkjet head 4 from an ink tank not shown. The four ink-jet heads 4 are supplied with inks of different colors, respectively. In this embodiment, a UV ink that is cured by irradiation with UV light is used as the ink. The UV ink has a higher viscosity than a normal aqueous ink and cannot be ejected from the inkjet head 4 at normal temperature. Then, as will be described later, the temperature of the UV ink is raised to about 45 ℃ by using the heater unit 30 (see fig. 3 (a) and (b)) provided in the inkjet head 4.

As shown in fig. 1, the 2

transport rollers

5 and 6 are disposed rearward and forward of the platen 3, respectively. The 2

transport rollers

5 and 6 are driven by motors, not shown, respectively, and transport the recording paper 100 on the platen 3 forward.

The controller 7 includes an FPGA (Field Programmable Gate Array), an EEPROM (Electrically Erasable Programmable Read-Only Memory), a RAM (Random Access Memory), and the like. The controller 7 may include a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), and the like. The controller 7 is connected to an external device 9 such as a PC so as to be capable of data communication, and controls each part of the printer 1 based on print data transmitted from the external device 9.

Fig. 2 is a plan view schematically showing the ink-jet head 4. As shown in fig. 2, the inkjet head 4 includes a plurality of head units 11. The plurality of head units 11 are attached to the holding plate 10 in a staggered manner. The head unit 11 has a plurality of nozzles 56 aligned in the left-right direction. Fig. 2 is a schematic view, and the number of rows of nozzles in fig. 2 is different from the number of rows of nozzles in fig. 4.

The controller 7 controls a motor M (see fig. 1) that drives the

transport rollers

5 and 6, and causes 2

transport rollers

5 and 6 to transport the recording paper 100 in the transport direction. Further, the controller 7 controls the four inkjet heads 4 to eject ink from the nozzles 56 toward the recording paper 100. Thereby, an image is printed on the recording paper 100.

< Structure of head Unit 11 >

As shown in fig. 3 (a) and (b), the head unit 11 includes a frame member 20, a heater module 30, a rigid board 41, an FPC43, an internal heater unit 44, and a head 50. As described later, the head 50 includes an actuator 51 and a flow path member 55.

< frame Member 20>

The frame member 20 includes an alignment frame 21, a rear end frame 22, and a front end frame 23 which are arranged to overlap in the vertical direction. The alignment frame 21 is a plate-like member made of SUS, and has a substantially rectangular shape in a plan view. Notches for screw fastening are formed at both end portions of the alignment frame 21 in the right-left direction. The alignment frame 21 is fixed to the holding plate 10 by being screwed with the holding plate 10. A rear end frame 22 is disposed below the alignment frame 21, and a front end frame 23 is further disposed below the alignment frame. The rear end frame 22 is a frame member made of resin. The front end frame 23 is a frame member made of SUS.

At the right end of the alignment frame 21, 4 flow paths 21a extending in the vertical direction are formed (see fig. 3 (b)). Similarly, 4 flow paths 22a that communicate with the 4 flow paths 21a and extend in the vertical direction are formed at the right end of the rear end frame 22 (see fig. 3 (b)). In fig. 3 (b), only 1 of the 4 channels 21a and 1 of the 4 channels 22a are illustrated. However, as described later, 4

flow paths

21a and 22a are formed in the alignment frame 21 and the rear end frame 22, respectively, corresponding to the head 50 provided with 2

ink inlets

51a and 51b and 2

ink outlets

52a and 52b (see fig. 4).

An opening 21h is formed on the left side of the flow path 21a of the alignment frame 21, and an opening 22h is formed on the left side of the flow path 22a of the rear end frame 22. Similarly, an opening 23h is formed in the front end frame 23.

< head 50>

As shown in fig. 3 (b), the internal heater unit 44 is disposed inside the opening 22h, and the head 50 is disposed inside the opening 23 h. As shown in fig. 4, the head 50 has an actuator 51 and a flow path member 55. The flow path member 55 includes a plurality of plates in which 2

common flow paths

58a and 58b, a plurality of pressure chambers 57, a plurality of nozzles 56, and a plurality of flow paths communicating these are formed. Although not shown, a vibration plate covering the pressure chamber 57 is disposed at the uppermost layer of the plurality of plates, and a nozzle plate having the nozzles 56 formed therein is disposed at the lowermost layer of the plurality of plates.

As shown in fig. 4, the plurality of nozzles 56 and the plurality of pressure chambers 57 form 8 nozzle rows and 8 pressure chamber rows, respectively. The nozzle rows and the pressure chamber rows extend in the left-right direction, and the 8 rows of nozzle rows and the 8 rows of pressure chamber rows are arranged in the front-rear direction. In the 2 nozzle rows arranged in the front-rear direction, the positions of the nozzles 56 in the left-right direction are shifted from each other. Similarly, in the 2 pressure chamber rows arranged in the front-rear direction, the positions of the pressure chambers 57 in the left-right direction are shifted from each other.

As shown in fig. 4, the pressure chambers 57 constituting the pressure chamber rows of the first to fourth rows from the rear communicate with the common flow path 58 a. The pressure chambers 57 constituting the pressure chamber rows of the fifth to eighth rows from the rear communicate with the common flow passage 58 b. The common flow path 58a extends leftward from the ink inlet port 51a located at the right end of the flow path member 55, makes a U-turn at the left end of the flow path member 55, and extends rightward to communicate with the ink outlet port 52 a. The common flow path 58b extends leftward from the ink inlet 51b located at the right end of the flow path member 55, makes a U-turn at the left end of the flow path member 55, and extends rightward to communicate with the ink outlet 52 b.

The actuator 51 includes a plurality of individual electrodes 52 arranged in positions corresponding to the plurality of pressure chambers 57 and overlapping the pressure chambers 57, a piezoelectric layer 53, and a common electrode (not shown) arranged on the opposite side of the individual electrodes 52 (below the piezoelectric layer 53) with the piezoelectric layer 53 interposed therebetween. On the upper surface of the actuator 51, a wiring member (COF), not shown, is disposed to be electrically connected to the individual electrodes 52 and the common electrode. The driver IC provided in the wiring member (COF) is connected to the controller 7 via the FPC43, the rigid board 41, and the like. The controller 7 controls the driver IC to always apply the ground potential to the common electrode, and selectively applies the ground potential and the drive potential to the individual electrodes 52.

The ink supplied from the ink tank to the

ink inlets

51a, 51b passes through the

common channels

58a, 58b and reaches the pressure chamber 56. The controller 7 applies a drive voltage between the common electrode and the individual electrode 52, which are not shown, and drives the piezoelectric layer 53 to vibrate the vibration plate. The vibration of the vibrating plate causes the pressure in the pressure chamber 57 to become positive and ink is discharged from the nozzle 56, and the pressure in the pressure chamber 57 becomes negative and ink is supplied from the

common channels

58a and 58b to the pressure chamber 57. The ink not supplied to the pressure chamber 57 reaches the

ink outlets

52a, 52b through the

common flow paths

58a, 58 b. The ink discharged from the

ink outlet ports

52a and 52b is returned to the ink tank and is supplied to the

ink inlet ports

51a and 51b again.

< internal heater Unit 44>

As shown in fig. 3 (b), an internal heater unit 44 is disposed inside the opening 22 h. The internal heater unit 44 includes a metal heat transfer member 44a (see fig. 4) and a film heater (not shown) attached to the upper surface of the heat transfer member. The internal heater unit 44 has a function of keeping warm to prevent the ink heated in advance by the heater block 30 described later from cooling. Since the internal heater unit 44 does not actively raise the temperature of the ink, the output wattage (about 8W) of the film heater of the internal heater unit 44 is smaller than the output wattage (about 100W) of the heater 33 of the heater module 30 described later. As shown in fig. 4, the heat transfer member 44a has a flat plate-like base portion 44b having a substantially rectangular shape in plan view, and an annular projecting portion 44c projecting downward at a peripheral edge portion of the base portion 44 b. That is, the heat transfer member 44a has a thin box shape with a bottom on the upper surface, and a concave portion surrounded by the base portion 44b and the convex portion 44c is formed on the lower surface side of the heat transfer member 44 a.

As shown in fig. 4, the convex portion 44c of the heat transfer member 44a is in contact with the peripheral portion surrounding the plurality of individual electrodes 52 on the upper surface of the actuator 51 via a COF not shown. The convex portion 44c does not abut on the portion of the actuator 51 where the plurality of individual electrodes 52 are arranged. Therefore, the heat transfer member 44a does not inhibit the piezoelectric deformation of the actuator 51, and therefore does not have adverse effects such as inhibition of ink ejection.

< Heater Assembly 30>

As shown in fig. 3 (a) and (b), the heater module 30 is disposed above the right end of the alignment frame 21. The heater module 30 includes a lower connector 31, an upper connector 32, a film-like heater 33, a temperature sensor 34, and a flow path block 35. The flow path block 35 is an aluminum block, and 4 flow paths 36 to 39 extending in the vertical direction are formed inside the flow path block 35 as shown in fig. 5. In the present embodiment, the cross sections of the

flow paths

36 and 39 on the orthogonal surfaces (horizontal surfaces) orthogonal to the vertical direction are the same shape, and the cross sections of the

flow paths

37 and 38 on the orthogonal surfaces (horizontal surfaces) orthogonal to the vertical direction are the same shape. The shapes of the

flow paths

36 and 37 will be described below.

As shown in fig. 5, the flow path 37 is formed with 2

ribs

37a and 37b protruding inward in the left-right direction. The

ribs

37a and 37b extend in the up-down direction. The positions of the

ribs

37a and 37b in the front-rear direction are the same. That is, the ribs 37a and the ribs 37b are opposed in the left-right direction. A distance L1 from the front end of the flow path 37 to the rib 37a, a distance L2 from the rear end of the flow path 37 to the rib 37a, and a distance L3 in the left-right direction between the rib 37a and the rib 37b are all equal (L1 ═ L2 ═ L3). The width of the

ribs

37a and 37b in the front-rear direction is also the same as the distances L1 to L3.

As shown in fig. 5, the flow path 36 is formed with 6 ribs 36a to 36f protruding inward in the left-right direction. The ribs 36a to 36f extend in the vertical direction. The positions of the

ribs

36a and 36b in the front-rear direction are the same. Similarly, the positions of the

ribs

36c and 36d, and the

ribs

36e and 36f in the front-rear direction are the same, respectively. The ribs 36a to 37f have the same width in the front-rear direction. Similarly to the flow path 37, the distance from the front end of the flow path 36 to the rib 36a, the distance from the rear end of the flow path 36 to the rib 36e, the distance between 2 ribs adjacent in the front-rear direction, and the distance between 2 ribs facing in the left-right direction are all equal.

As shown in fig. 3 (b), film-like heaters 33 are attached to the right and left side surfaces of the flow path block 35. In the present embodiment, the heater 33 is a carbon heater, and the output wattage thereof is about 100W. Heat conductive grease is applied between the heater 33 and the flow path block 35. Although not shown in fig. 3 (a) and 5, a platen 33b made of aluminum is provided so as to sandwich the heater 33 with the flow path block 35 (see fig. 3 (b)). By fixing the pressure plate 33b to the flow path block 35 by screwing or the like, the heater 33 is fixed to the flow path block 35 in a state of thermal contact with the flow path block 35.

As shown in fig. 3 (a), 3 (b), and 5, a temperature sensor 34 is disposed above the heater 33. In the present embodiment, the temperature sensor 34 is a thermistor. The temperature sensor 34 is disposed substantially at the center of the flow path block 35 in the front-rear direction, and overlaps the

flow paths

37 and 38 in the left-right direction. As shown in fig. 3 (b), the temperature sensor 34 is disposed at a position overlapping the platen 33b in the left-right direction.

As shown in fig. 3 (a) and (b), the lower connector 31 is disposed below the flow path block 35. The lower connector 31 is screwed to the alignment frame 21. As shown in fig. 6, 4 flow paths 31a to 31d are formed inside the lower connector 31. A rubber washer 31p is disposed on the upper surface of the lower connector 31. A rectangular opening is provided in a portion of the gasket 31p overlapping the flow path 31 a. The 4 flow paths 31a to 31d are respectively communicated with 4 flow paths 36 to 39 formed in the flow path block 35 through openings of the gasket 31 p. The gasket 31p functions as a sealing member that seals between the flow path block 35 and the lower connector 31 to prevent ink from leaking. The 4 flow paths 31a to 31d communicate with the 4 flow paths 21a formed in the alignment frame 21. In the present embodiment, the flow path 36 communicates with the ink inlet 51b via the flow path 31a, 1 of the flow paths 21a, and 1 of the flow paths 22 a. The flow path 37 communicates with the ink outlet 52b via the flow path 31b, 1 of the flow paths 21a, and 1 of the flow paths 22 a. The flow path 38 communicates with the ink outlet 52a via the flow path 31c, 1 of the flow paths 21a, and 1 of the flow paths 22 a. The flow path 39 communicates with the ink inlet 51a via the flow path 31d, 1 of the flow paths 21a, and 1 of the flow paths 22 a. Although not shown, a seal member similar to the gasket 31p is also provided between the lower connector 31 and the alignment frame 21.

As shown in fig. 3 (a) and (b), the upper connector 32 is disposed above the flow path block 35. The upper connector 32 is screwed to the flow path block 35. The upper connector 32 has 4 pipe connectors 32a to 32 d. The flow paths inside the 4 pipe connectors 32a to 32d are respectively communicated with 4 flow paths 36 to 39 formed in the flow path block 35. In the present embodiment, the flow path inside the tube connector 32a communicates with the flow path 36, the flow path inside the tube connector 32b communicates with the flow path 37, the flow path inside the tube connector 32c communicates with the flow path 38, and the flow path inside the tube connector 32d communicates with the flow path 39. Although not shown, a seal member similar to the gasket 31p is also provided between the upper connector 32 and the flow path block 35. Tubes connected to the ink tanks are connected to the 4 tube connectors, respectively. This forms a circulation flow path of ink that reaches the head 50 from the ink tank through the flow path formed inside the heater block 30 and the frame member 20, and returns to the ink tank from the head 50 through the flow path formed inside the frame member 20 and the heater block 30.

< effects of the first embodiment >

The flow path block 35 of the heater module 30 is made of aluminum, and therefore has high thermal conductivity. Since the flow paths 36 to 39 are formed inside the flow path block 35, the ink flowing through the flow paths 36 to 39 contacts the flow path block 35. The heater 33 is attached to the flow path block 35, and the heater 33 and the flow path block 35 are in thermal contact with each other via thermally conductive grease. Since only the aluminum flow path block 35 and the heat conductive grease are present between the heater 33 and the ink flowing inside the flow path block 35, the heat generated from the heater 33 can be efficiently transferred to the ink. The heater 33 and the flow path block 35 may be in thermal contact without using a thermally conductive grease, for example, may be in contact with each other via a thermally conductive adhesive, a thermally conductive film (thermally conductive sheet), or the like. Alternatively, the heater 33 and the flow path block 35 may be in direct contact with each other. In either case, since the flow path block 35 and the heater 33 are in thermal contact with each other, the heat generated from the heater 33 can be efficiently transferred to the ink flowing inside the flow path block 35.

As described above, the flow paths 36 to 39 are formed with ribs such as the ribs 36 a. This can increase the surface area of the flow paths 36 to 39 as compared with the case where no ribs are formed. This increases the contact area with the ink flowing through the flow paths 36 to 39, and therefore, the heat generated by the heater 33 can be efficiently transferred to the ink. In the above embodiment, 2 or more ribs are formed in the flow paths 36 to 39, respectively. Therefore, the surface area of the flow paths 36 to 39 can be increased as compared with the case where 1 rib is formed in each of the flow paths 36 to 39. This increases the contact area with the ink flowing through the flow paths 36 to 39, and therefore, the heat generated by the heater 33 can be efficiently transferred to the ink.

In the present embodiment, the

flow paths

37 and 38 are flow paths for returning ink to the ink tank, while the

flow paths

36 and 39 are flow paths through which ink supplied from the ink tank passes. As described above, the flow paths 36 to 39 extend in the vertical direction (see FIG. 5). Since the

channels

36 and 39 have more ribs than the

channels

37 and 38, the surface areas of the

channels

36 and 39 are larger than the surface areas of the

channels

37 and 38. In other words, the length of the outer peripheries of the

flow paths

36 and 39 in the cross section of the vertical surfaces (horizontal surfaces) of the

flow paths

36 and 39 is longer than the length of the outer peripheries of the

flow paths

37 and 38 in the cross section of the vertical surfaces (horizontal surfaces) of the

flow paths

37 and 38. Accordingly, the contact area with the ink flowing through the

flow paths

36 and 39 can be made larger than the contact area with the ink flowing through the

flow paths

37 and 38, and therefore, the heat generated by the heater 33 can be efficiently transmitted to the ink supplied from the ink tank (i.e., the ink before entering the head 50).

The flow path block 35 of the present embodiment can be manufactured by a method of extrusion molding of aluminum. Thus, for example, when a flow path having an H-shaped cross-sectional shape such as the flow path 37 is formed, the distance L1 from the front end of the flow path 37 to the rib 37a, the distance L2 from the rear end of the flow path 37 to the rib 37a, the distance L3 in the left-right direction between the rib 37a and the rib 37b, and the like can be reduced to about 1 mm. This can reduce the cross-sectional area of the flow path, and thus can efficiently heat the ink. In the case of manufacturing the passage block 35 by extrusion molding, the passage block 35 can be manufactured as 1 member without a seam. This prevents air bubbles and the like in the ink from being caught in the joint. In the case of the flow path block 35 manufactured by the extrusion molding method, the cross sections of the flow paths 36 to 39 are uniform in the direction (vertical direction) in which the flow paths 36 to 39 extend. Thus, even if bubbles or the like are contained in the ink flowing through the flow paths 36 to 39, the ink is not caught in the flow paths 36 to 39.

In the above embodiment, the distance L1 from the front end of the flow path 37 to the rib 37a, the distance L2 from the rear end of the flow path 37 to the rib 37a, and the distance L3 in the left-right direction between the rib 37a and the rib 37b of the flow path having the H-shaped cross section, such as the flow path 37, are all the same. In this way, since the width of the flow path (the width in the left-right direction and the width in the front-rear direction) is the same, it is possible to suppress the flow velocity of the ink flowing through the flow path from being biased.

In the flow paths 36 to 39 of the flow path block 35, it is preferable that the cross-sectional area of the perpendicular surfaces (horizontal surfaces) of the flow paths 36 to 39 orthogonal to the vertical direction is as small as possible, from the viewpoint of efficiently transferring the heat of the heater 33 to the ink in the flow paths 36 to 39. However, if the cross-sectional area of the perpendicular surfaces (horizontal surfaces) of the flow paths 36 to 39 perpendicular to the vertical direction is too small, the flow path resistance increases, and it becomes difficult to secure a necessary flow rate of ink. According to the study of the inventors, in order to suppress the flow path resistance and to transfer sufficient heat to the ink, it is preferable that the length of the portion having the narrowest cross-sectional width in the orthogonal plane orthogonal to the direction in which the flow path extends be about 1.5 mm. For example, the distance L1 to L3 and the width of the

ribs

37a and 37b in the front-rear direction of the flow path 37 can be set to 1.5 mm. In this case, the cross section of the flow path 37 is a combination of squares having a side of 1.5 mm. Similarly, the

channels

36, 38, and 39 have a cross section in a plane orthogonal to the direction in which the channels extend, the cross section being a combination of squares having one side of 1.5mm, whereby sufficient heat can be transferred to the ink while suppressing the channel resistance.

In the above embodiment, the film-like heaters 33 are attached to the right and left side surfaces of the flow path block 35. By providing the heaters 33 on the 2 surfaces of the flow path block 35 facing each other in this way, the ink can be heated more efficiently than in the case where only 1 heater 33 is provided.

In the above embodiment, the temperature sensor 34 is disposed above the heater 33 and substantially at the center of the upstream block 35 in the front-rear direction (at a position overlapping the

flow paths

37 and 38 in the left-right direction). In the present embodiment, the

flow paths

37 and 38 are flow paths through which ink flowing from the ink tank flows, and the temperature sensor 34 is disposed upstream of the heater 33 in the ink flow. Thus, the temperature sensor 34 can detect the temperature of the ink before being heated by the heater 33. In the above embodiment, the temperature sensor 34 is disposed at a position overlapping the platen 33b in the left-right direction. The aluminum pressure plate 33b functions as a heat sink. If the platen 33b is not provided, it is considered that the heat of the heater 33 is lost and stagnated, and the temperature sensor 34 may detect a temperature higher than the actual temperature of the ink. In the present embodiment, since the platen 33b is provided and the platen 33b functions as a heat radiating plate, the temperature of the ink can be detected more accurately than in the case where the platen 33b is not provided.

< second embodiment >

Next, a second embodiment of the present invention will be described with reference to the drawings. The same reference numerals are used for the common structure with the first embodiment, and detailed description thereof is omitted.

The heater module according to the second embodiment includes heater units 130 shown in fig. 7 (a) and (b) instead of the flow path block 35 and the heater 33. The heater unit 130 includes 4 metal flow pipes 131a to 131d, 2 sheet-like heaters 132 covering the outer peripheral surfaces of the 4 flow pipes 131a to 131d, 1 set of

fixtures

133a and 133b sandwiching the 4 flow pipes 131a to 131d and the heaters 132 in the left-right direction, and a temperature sensor 34 provided on the fixture 133 a. Although not shown, the upper ends of the 4 flow pipes 131a to 131d are connected to the flow passages inside the pipe connector 32a of the upper connector 32, and the lower ends of the 4 flow pipes 131a to 131d are connected to the 4 flow passages 31a to 31d inside the lower connector 31. In the present embodiment, the flow path tube 131a communicates with the ink inlet 51b via the flow path 31a, the flow path tube 131b communicates with the ink outlet 52b via the flow path 31b, the flow path tube 131c communicates with the ink outlet 52a via the flow path 31c, and the flow path tube 131d communicates with the ink inlet 51a via the flow path 31 d.

The heater 132 is a carbon heater having a carbon sheet as a heat source. The carbon heaters are flexible and have high bending resistance, and therefore can cover the flow path pipes 131a to 131d while being bent along the outer circumferential surfaces of the flow path pipes 131a to 131 d. Thermal conductive grease is applied between the flow tubes 131a to 131d and the heater 132 to prevent gaps from being generated between the flow tubes 131a to 131d and the heater 132. The

retainers

133a and 133b are metal members bent along the outer peripheral surfaces of the 4 flow path pipes 131a to 131 d. For example, it can be formed of aluminum. The heater 132 is held by the fixing

members

133a and 133b from both sides in the left-right direction in a state where the heater 132 is along the outer peripheral surfaces of the 4 flow path pipes 131a to 131d, and thereby the heater 132 is fixed in a state of being in contact with the outer peripheral surfaces of the flow path pipes 131a to 131 d. In fig. 7 (b), the fixing member 133a is removed, and only 1 of the 2 heaters 132 is shown, but the heaters 132 are also arranged between the fixing member 133b and the flow path pipes 131a to 131 d.

The temperature sensor 34 is disposed above the heater 132 and substantially at the center of the fixing member 133a in the front-rear direction (a position between the flow path pipe 131b and the flow path pipe 131c in the front-rear direction). In the present embodiment, the

flow tubes

131b and 131c are flow paths through which ink flowing from the ink tank flows, and the temperature sensor 34 is disposed upstream of the heater 132 in the ink flow. Thus, the temperature sensor 34 can detect the temperature of the ink before being heated by the heater 132. As described later, the

fixtures

133a and 133b function as heat equalizing members that equalize heat among the flow pipes 131a to 131d, and also function as heat radiating plates that radiate heat from the heater 132. The temperature sensor 34 is disposed at a position overlapping the fixing

members

133a and 133b having the functions of heat equalization and heat dissipation in the left-right direction, and therefore can accurately detect the temperature of the ink.

< effects of the second embodiment >

The flow path pipes 131a to 131d are metal pipes, and the heaters 132 are arranged on the outer peripheral surfaces thereof. The heater 132 is curved along the outer circumferential surface of the flow path pipes 131a to 131d, and heat conductive grease is applied between the flow path pipes 131a to 131d and the heater 132 to prevent gaps from being generated between the flow path pipes 131a to 131d and the heater 132. Since only the metallic flow tubes 131a to 131d and the thermally conductive grease are present between the heater 132 and the ink flowing through the flow tubes 131a to 131d, the heat generated by the heater 132 can be efficiently transferred to the ink. The heater 132 and the flow pipes 131a to 131d may be in thermal contact without using a thermally conductive grease, for example, may be in contact with each other via a thermally conductive adhesive, a thermally conductive film (thermally conductive sheet), or the like. Alternatively, the heater 132 and the flow tubes 131a to 131d may be in direct contact with each other. In either case, since the flow tubes 131a to 131d and the heater 132 are in thermal contact with each other, the heat generated from the heater 132 can be efficiently transmitted to the ink flowing inside the flow block 35. When a heat conductor such as heat conductive grease, heat conductive adhesive, or heat conductive film (heat conductive sheet) is interposed between the heater 132 and the flow path tubes 131a to 131d, a heat conductor having a heat conductivity of 1W/(m · K) or more and being softer (lower in rigidity) than the flow path tubes 131 to 131d is used.

Since the 2 heaters 132 are disposed so as to sandwich the flow tubes 131a to 131d from both sides in the left-right direction, the entire outer peripheral surfaces of the flow tubes 131a to 131d can be heated, and therefore, the temperature variation of the ink flowing through the flow tubes 131a to 131d can be reduced. In the present embodiment, since the heater 132 uses a carbon heater, the output wattage can be increased (to 100W or more). The carbon heaters are flexible and have high bending resistance, and therefore can cover the flow path pipes 131a to 131d while being bent along the outer circumferential surfaces of the flow path pipes 131a to 131 d.

Since the heater 132 is sandwiched by the fixing

members

133a and 133b from both sides in the left-right direction in a state where the heater 132 is along the outer peripheral surfaces of the 4 flow path pipes 131a to 131d, the heater 132 can be fixed in a state of being in contact with the outer peripheral surfaces of the flow path pipes 131a to 131 d. Since the

fixtures

133a and 133b are metal members, heat can be uniformly distributed among the flow pipes 131a to 131 d. This can reduce the temperature difference of the ink flowing through the flow tubes 131a to 131 d. Since the fixing

members

133a and 133b are metal members, they also function as heat radiation plates for radiating heat from the heater 132. Therefore, the heat of the heater 132 is prevented from being lost to the radiation place and the temperature of the heater 132 is prevented from excessively increasing. In the present embodiment, since the temperature sensor 34 is disposed at a position overlapping the fixing

members

133a and 133b having the functions of heat equalization and heat dissipation in the left-right direction, the temperature of the ink can be accurately detected.

The fixing

members

133a and 133b are bent along the outer peripheral surfaces of the 4 flow path pipes 131a to 131 d. Therefore, the distance between the fixing

members

133a and 133b and the outer peripheral surfaces of the flow path pipes 131a to 131d is substantially the same. Therefore, as compared with the case where the fixing

members

133a and 133b are not bent so as to follow the outer peripheral surfaces of the 4 flow pipes 131a to 131d, the heat can be uniformly distributed between the flow pipes 131a to 131d more efficiently, and the function of the heater 132 as a heat radiation plate for radiating heat can be improved.

The temperature sensor 34 is disposed above the heater 132 and substantially at the center of the fixing member 133a (between the flow path pipe 131b and the flow path pipe 131 c) in the front-rear direction. In the present embodiment, the flow path tube 131b and the flow path tube 131c are flow paths through which ink flowing from the ink tank flows, and the temperature sensor 34 is disposed upstream of the heater 132 in the ink flow. Thus, the temperature sensor 34 can detect the temperature of the ink before being heated by the heater 33. The temperature sensor 34 is disposed on the fixing member 133 a. As described above, the aluminum fixture 133a functions as a heat sink. If the fixing member 133a is not provided, it is considered that the heat of the heater 132 is lost and stagnated, and the temperature sensor 34 may detect a temperature higher than the actual temperature of the ink. In the present embodiment, since the fixing member 133a is provided and the fixing member 133a functions as a heat radiating plate, the temperature of the ink can be detected more accurately than in the case where the fixing member 133a is not provided.

< modification >

Modifications of the first and second embodiments will be described. In the following description, the modification of the first embodiment is exemplified, but it goes without saying that the same can be applied to the second embodiment.

As shown in fig. 8 (a) and (b), a damper unit 200 may be provided above the heater module 30. The damper unit 200 has a substantially rectangular parallelepiped shape, and films 201 are attached to 4 side surfaces except the upper surface and the lower surface. As shown in FIG. 8 (c), the damper unit 200 is divided into 4 internal flow paths 206 to 209. One end of each of the 4 internal flow paths 206 to 209 is connected to an ink tank not shown through a tube not shown. The other ends of the 4 internal flow paths 206 to 209 are respectively communicated with 4 flow paths 36 to 39 of the flow path block 35 of the heater module 30. In the present embodiment, the internal flow path 206 communicates with the flow path 36, the internal flow path 207 communicates with the flow path 37, the internal flow path 208 communicates with the flow path 38, and the internal flow path 209 communicates with the flow path 39. The 4 internal channels 206 to 209 each have a substantially rectangular parallelepiped shape, and at least a part of the side surface of each of the internal channels 206 to 209 is formed by a film 201.

A pump, not shown, is provided between the ink tank and the damper unit 200, and the ink in the ink tank is transferred to the damper unit 200 by the pressure generated by the pump. The pressure generated by the pump is not always constant, but fluctuates little by little with time like pulsation. As described above, since at least a part of the side surfaces of the internal flow paths 206 to 209 of the damper unit 200 is formed by the film 201, the pressure variation of the ink passing through the internal flow paths 206 to 209 can be attenuated.

Instead of the damper unit 200, the damper tubes 301 to 304 shown in fig. 9 (a) and (b) may be used. The damper tubes 301 to 304 are tubes made of an elastic material such as rubber, and one ends of the 4 damper tubes 301 to 304 are connected to an ink tank not shown through a tube not shown. The other ends of the damper tubes 301 to 304 are respectively connected to 4 flow paths 36 to 39 of the flow path block 35 of the heater block 30. In the present embodiment, the damper tube 301 communicates with the flow path 36, the damper tube 302 communicates with the flow path 37, the damper tube 303 communicates with the flow path 38, and the damper tube 304 communicates with the flow path 39. Since the damper tubes 301 to 304 are formed of an elastic material such as rubber, pressure fluctuations of the ink passing through the damper tubes 301 to 304 can be absorbed.

Next, a modification of the second embodiment of the present invention will be described with reference to (a) and (b) of fig. 10. The same reference numerals are used for the common structure with the second embodiment, and detailed description thereof is omitted.

As shown in fig. 10 (a) and (b), the heater module according to the present modification includes a heater unit 430. The heater unit 430 includes 4 metal flow path tubes 131a to 131d, a sheet heater 132 covering the outer peripheral surfaces of the 4 flow path tubes 131a to 131d, 1 set of fixing

members

433a and 433b sandwiching the 4 flow path tubes 131a to 131d and the heater 132 in the left-right direction, and a heat conduction sheet 434 disposed between the heater 132 and the fixing

members

433a and 433 b. Although not shown in fig. 10 (a) and (b), the temperature sensor 34 is provided between the fixing member 433a and the thermally conductive sheet 434, as in the second embodiment. In addition, unlike the second embodiment, 4 flow path pipes 131a to 131d are not sandwiched by 2 heaters 132, but in the present modification, 4 flow path pipes 131a to 131d are sandwiched by one heater 132.

The fixing member 433a is formed of an aluminum block and has a substantially rectangular parallelepiped shape. 4 grooves extending in the vertical direction are formed in the right surface of the fixing member 433 a. Each groove has a substantially semicircular cross section, and the flow path pipes 131a to 131d are disposed in 4 grooves, respectively. The fixing member 433b is formed of a block of resin made of POM (polyoxymethylene) and has a substantially rectangular parallelepiped shape. The left surface of the fixing member 433b is also formed with 4 grooves extending in the vertical direction. Each cross section of the 4 grooves is substantially semicircular, as in the groove formed on the right surface of the anchor 433 a. As shown in fig. 10 (b), the fixing member 433b is screwed to the fixing member 433 a. Thus, 4 flow path pipes 131a to 131d are fixed between 4 grooves formed in the right surface of the fixing

member

433a and 4 grooves formed in the left surface of the fixing member 433 b.

In the present modification, since the fixing member 433a is formed of an aluminum block, heat from the heater 132 can be made uniform, and heat can be transmitted uniformly to the 4 flow pipes 131a to 131 d. Further, the fixing

members

133a and 133b can function as heat dissipation plates. Since the fixing member 433b is formed of a resin block made of POM, it can be manufactured at a lower cost than an aluminum block, and the manufacturing cost can be reduced. Since the fixing member 433a is formed of an aluminum block and the fixing member 433b is formed of a POM resin block, heat from the heater 132 can be uniformly dissipated, and the manufacturing cost can be reduced.

In the present modification, the fixing member 433a is formed by providing 4 grooves in an aluminum block, and the fixing member 433b is formed by performing the same processing on a POM resin block. Since both are formed by cutting out or the like from a block-shaped material, the strength can be improved as compared with the case where the plate-shaped member is subjected to sheet metal working as in the

fixtures

133a and 133b of the second embodiment. Therefore, when the heater 132 is fixed to the periphery of the flow path tubes 131a to 131d, the fixing

members

433a and 433b are not bent, and the heater 132 and the flow path tubes 131a to 131d can be reliably fixed.

In the first embodiment, the flow path block 35 of the heater module 30 has a substantially rectangular parallelepiped shape, but the present invention is not limited to such a shape, and can be changed to an appropriate shape. The same applies to the fixing

members

433a, 433b in the modification of the second embodiment. In the first embodiment, 2 heaters 33 are provided, and in the second embodiment, 2 heaters 132 are provided. However, the number of the

heaters

33 and 132 may be 3 or more, or 1.

In the first and second embodiments, the passage block 35 and the passage pipes 131a to 131d are each formed of aluminum. The fixing member 433a in the modification of the second embodiment is also formed of an aluminum block. Aluminum has high thermal conductivity and can be easily processed by extrusion molding or the like. However, the present invention is not limited to this embodiment, and the flow path block 35, the flow path pipes 131a to 131d, the fixing member 433a, and the like may be formed using a metal material other than aluminum. Further, although the fixing member 433b in the modification of the second embodiment is formed of a resin block made of POM, the present invention is not limited to this embodiment, and may be formed of a suitable resin block.

In the above embodiment, the UV ink was described as an example, but the present invention can also be applied to a printer that ejects ink other than the UV ink (for example, water-based ink). In the above embodiment, the

heaters

33 and 132 are carbon heaters, but the present invention is not limited to such an embodiment. As the heater 33 and the heater 132, other types of heaters (e.g., a film heater) can be used.

In the above embodiment, the spacer 31p is provided in the lower connector 31. The gasket 31p is 1 sealing member that covers the entire 4 flow paths 31a, but may be a sealing member provided for each flow path 31 a. The same applies to the sealing member provided between the lower connector 31 and the alignment frame 21 and the sealing member provided between the upper connector 32 and the flow path block 35.

The embodiments disclosed herein are illustrative and not restrictive in all respects. For example, the number, structure, and the like of the inkjet heads 4 can be changed. The number, arrangement, and the like of the nozzles 56 and the pressure chambers 57 can be changed as appropriate. In addition, the technical features described in the embodiments can be combined with each other. The scope of the present invention is intended to include all modifications within the scope of the claims and the scope equivalent to the claims.

Claims

1. A heater module connected to a head having a first manifold, a first communication port communicating with the first manifold, a second manifold, and a second communication port communicating with the second manifold, the heater module comprising:

a heater having a heating surface,

2. The heater assembly of claim 1,

the heater is provided with a first heater and a second heater which are respectively provided with heating surfaces,

the first tube and the second tube are sandwiched between a heating surface of the first heater and a heating surface of the second heater.

3. The heater assembly of claim 1,

the heating apparatus further includes a metal fixture having a surface facing a surface of the heater opposite to the heating surface, and fixing the heater to the first pipe and the second pipe.

4. The heater assembly of claim 3,

the heater is further provided with a resin fixture for fixing the heater, the first tube, and the second tube by sandwiching the heater, the first tube, and the second tube between the resin fixture and the metal fixture.

5. The heater assembly of claim 3,

the distance between the surface of the fixing member and the outer peripheral surface of the first pipe is equal to the distance between the surface of the fixing member and the outer peripheral surface of the second pipe.

6. The heater assembly of claim 3,

further comprises a temperature sensor disposed on the fixing member,

the temperature sensor is disposed at a position farther from the first communication port and the second communication port than the heater in the first direction,

the temperature sensor is disposed at a position between the first communication port and the second communication port in the second direction.

7. The heater assembly according to any one of claims 1 to 6,

the heater is a carbon heater.

8. A head module comprising the heater module according to any one of claims 1 to 7 and the head.

9. A head module according to claim 8,

the heater module further includes a damper unit having a damper flow path connected to the first communication port and the second communication port of the heater module.

10. A head module according to claim 8 or 9,

the head has an internal heater that heats ink within the manifold,

the heater of the heater assembly has an output wattage greater than an output wattage of the internal heater.

11. A printing apparatus, characterized in that,

a head module according to any one of claims 8 to 10.