JP2007168112A - Inkjet recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate unevenness of heat between ink supply paths without disturbing soaking between head chips, and to maintain a constant amount of ink droplets to be ejected even in high duty printing in which heat generation increases, resulting in uneven density of an image. An inkjet recording head is provided.
SOLUTION: A cooling liquid cools between ink supply paths to a certain head chip and dissipates heat absorbed into a heat pipe, and then cools between ink supply paths of another head chip.
[Selection] Figure 1

Description

  The present invention relates to a cooling mechanism for a recording head used in an ink jet recording apparatus used in an image forming apparatus such as a printer, a FAX, and a copying machine, and more specifically, heat generated by a head chip mounted on a full line type recording head. The present invention relates to a layout of a coolant flow path incorporated in a head chip support member for absorbing and transporting heat.

  The ink jet recording apparatus performs image recording such as printing by ejecting ink from a recording head and adhering it to a recording medium. The recording head can be easily made compact and can record high-definition images at high speed. In addition, the running cost is low, the non-impact method is low in noise, and it is easy to record a color image using multi-colored inks. In particular, a full line type ink jet recording apparatus using a line type recording head in which a large number of ejection nozzles are arranged in the width direction of the recording medium can further increase the recording speed.

  However, as the recording speed increases, the number of times ink is ejected from one nozzle per unit time increases, resulting in an increase in the heat accumulated in the recording head as the ink is ejected. Become. Since the amount of ink discharged from the nozzles increases as the temperature rises, there is a problem that when the temperature of the recording head rises rapidly, the print density increases even in the same image, resulting in density unevenness and adversely affecting print quality.

  In addition, because the full-line type recording head is long, heat is easily trapped in the center, the temperature at both ends is lower than that at the center, and even with a uniform density image, the print density at both ends and the center is low. There was a problem that would be different.

  Therefore, in order to achieve high-speed recording with a full-line type ink jet recording apparatus, the heat concentrated in the central portion of the recording head is dispersed throughout the recording head and quickly discharged outside the recording head. Soaking and cooling means are indispensable.

  Conventionally, a soaking / cooling means for a full-line type recording head has a form in which one end of a heat pipe is joined along the recording head and the other end is joined to a heat radiating member such as a heat radiating fin or a heat sink ( For example, see Patent Literature 1 and Patent Literature 2). In these conventional full-line type recording head soaking / cooling means, the heat generated by the heat pipe is absorbed by the heat pipe and is quickly transported to the other end and dissipated to the heat radiating member. Therefore, it is possible to cool the entire recording head while keeping the temperature as uniform as possible by suppressing the local temperature rise.

  FIG. 8 shows an example in which such a heat pipe is applied to soaking and cooling a full-line type recording head that performs line-type printing by arranging a plurality of head chips in a staggered manner.

  In the figure, six head chips 2a to 2f having a plurality of nozzle arrays are mounted in a staggered arrangement on the lower surface of the base plate 1, and heat generated in the head chips 2a to 2f as a result of printing is generated in the base plate 1. Three heat pipes 3a to 3c that absorb heat via are embedded in the base plate.

  The recording medium is conveyed from the left side to the right side of the drawing by a conveying means (not shown) horizontally to the bottom surface of the base plate 1 and perpendicular to the nozzle rows of the head chips 2a to 2f. , First, ink droplets are ejected from the nozzle rows of the odd-numbered head chips 2a, 2b, 2c to form dots on the recording medium, and then the even-numbered head chips 2d so as to complement the gaps. , 2e and 2f, ink droplets are ejected from the nozzle rows to form dots on the recording medium, and an image is completed for each raster.

  FIG. 9 is a view showing in detail a part of a plan view of a surface perpendicular to the ink ejection direction of the head chip 2 and a cross-sectional structure perpendicular to the nozzle row.

  Eight nozzle rows 5a to 5h are formed in the head chip 2, and ink is supplied to the nozzle rows by two rows from the four ink supply ports 4a to 4d. Ink supplied to the nozzle arrays 5a to 5h generates bubbles due to a phase change by a pulse heating signal applied to the heaters 6a to 6h, and ink droplets are pushed out from the ejection ports.

  Nozzle rows 5a and 5c, 5b and 5d, 5e and 5g, 5f and 5h have the same nozzle arrangement and a resolution of, for example, 600 dpi. Nozzle rows 5a and 5b, 5e and 5f are arranged in one pitch, and nozzle rows 5a and 5e. Since the nozzles are arranged with a half-pitch shift, printing can be performed at a resolution of 2400 dpi, which is four times 600 dpi.

  There are 8 nozzle rows because when one nozzle is clogged and ink cannot be ejected, it is possible to substitute nozzles at the same position in another nozzle row with the same nozzle arrangement (non-discharge complementation). This is because the adjacent dots are distributed to different nozzle rows, and the adjacent dots are driven into the recording medium with a time difference between the nozzle rows, thereby preventing image quality deterioration due to the coalescence of adjacent dots.

  FIG. 10 is a view of the recording head as viewed from the ink supply side.

  Ink is supplied from the ink holding tank (not shown) to the head chips 2a to 2f through the ink supply paths 7a to 7l. That is, the ink that has passed through the ink supply path 7a is supplied to the four nozzle rows 5e to 5h through the ink supply ports 4c and 4d of the head chip 2a. Similarly, the ink that has passed through the ink supply path 7b is supplied to the four nozzle rows 5a to 5d through the ink supply ports 4a and 4b of the head chip 2a. Ink supply to other head chips is performed in the same manner.

In order to prevent the heat pipes 3a to 3c from interfering with these ink supply paths 7a to 7l, the heat pipe 3b is located between the ink supply paths 7b, 7d and 7f and 7g, 7i and 7k, and the heat pipe 3a is connected to the ink supply path. The heat pipe 3c is embedded next to the ink supply paths 7a, 7c, and 7e next to 7h, 7j, and 7l. The heat generation of the head chips 2a to 2c is caused by the heat pipes 3b and 3c, and the heat from the head chips 2d to 2f. Heat is absorbed by the heat pipes 3a and 3b through the base plate 1, and is instantaneously transported and dissipated to the non-heat generating portion, so that the entire recording head is heated.
Patent registration 2683112 (page 9, Fig. 1) Japanese Patent Registration No. 2768507 (page 7, Fig. 1)

  However, in the case of a base plate having a plurality of ink supply paths for one head chip, heat tends to be trapped in the beam portions between the ink supply paths, which may hinder soaking. For example, in the head chip 2a, the heat generated by the heaters 6d and 6e is diffused between the ink supply ports 4b and 4c of the head chip 2a and transmitted to the beam portion between the ink supply paths 7a and 7b. In this case, the ink supply paths 7a and 7b filled with ink having a thermal conductivity far lower than that of 32 W / mK (for example, 0.68 W / mK) serve as heat insulating walls to transfer heat to the heat pipes 3b and 3c. Therefore, there is a problem that the heat of the beam part has to bypass both sides having high thermal resistance and be transmitted to the heat pipes 3b and 3c, resulting in excessive temperature rise of the nozzle rows 5d and 5e. . The same applies to other head chips.

  Therefore, a means for escaping the heat trapped in the beam portion between the ink supply paths is necessary. However, in order to reduce the size of the head chip, the interval between the ink supply ports 4b and 4c must be reduced as much as possible. There is no space to embed even the smallest diameter heat pipe in the beam portion of the base plate 1 in accordance with the interval, and instead a liquid cooling pipe is provided in the beam portion of the base plate 1 so that the cooling liquid flows in the nozzle row direction. The cooling liquid heated after cooling adjacent head chips flows into the next head chip, so the temperature of the head chip increases as it goes downstream of the liquid cooling tube, and the soaking temperature between the head chips is increased. On the other hand, there is a problem that it becomes a factor to worsen.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ink jet recording head having a base plate having a configuration that minimizes a temperature difference between head chips while quickly diffusing heat generated in the head chips.

The present invention has been conceived in order to achieve the above-described object, and an ink jet recording head according to the present invention includes a head chip in which one or more nozzle rows each including a plurality of nozzles for ejecting ink are formed. An ink jet recording head comprising: a plurality of head chips mounted; and a base plate in which at least one ink supply path for supplying ink to the nozzle row is formed for each head chip.
The base plate has one or more systems of first heat transporting means on the inside or a side surface, and has a heat transporting capability lower than that of the first heat transporting means, and has at least one heat exchanging part with the first heat transporting means. A plurality of second heat transporting means corresponding to each of the plurality of head chips for absorbing heat generated by the head chip during ejection. With an endothermic part
After the heat transport medium in the second heat transport means absorbs heat in one of the heat absorption sections, the heat transport medium is transferred to the heat exchange section to dissipate heat to the first heat transport section, and thereafter The second heat transporting means is arranged so as to be transferred to the heat absorption part of the head chip.

  In addition, the heat transport medium in the second heat transport means absorbs heat from the first heat transport means before absorbing heat in the first heat absorption section of the plurality of heat absorption sections. The second heat transporting means is arranged so as to pass through the exchange part.

Further, in an ink jet recording head comprising a head chip in which a plurality of nozzle rows are formed and a base plate in which a plurality of ink supply paths are formed for each head chip,
The heat absorption part has a structure in which a heat transport medium in the second heat transport means passes in the nozzle row direction between adjacent ink supply paths among the plurality of ink supply paths. .

  According to the present invention having the above-described configuration, the heat transport medium in the second heat transport means, which is a coolant, cools the heat between the ink supply paths to a certain head chip and absorbs heat by the heat pipe. Since heat is dissipated to the first heat transporting means and the ink supply path of another head chip is cooled, the heat buildup between the ink supply paths is eliminated without disturbing the soaking between the head chips. In addition, it is possible to provide an ink jet recording head in which the amount of ink droplets to be discharged is kept constant even in high duty printing in which heat generation increases, and image density unevenness does not occur.

  In addition, after the second heat transporting means, which is a cooling liquid, flows into the recording head, first the heat received by the heat pipe is absorbed, and each head chip is heated by the second heat transporting means whose temperature has been raised to some extent. This is an inkjet recording head that does not require a separate cooling means for the heat pipe and does not overcool the head chip that is cooled first, and that does not cause uneven image density. can do.

  Next, details of the present invention will be described in accordance with the description of the embodiments.

(First embodiment)
FIG. 1 is a perspective view showing the appearance and head chip arrangement of an ink jet recording head according to a first embodiment of the present invention. The ink jet recording head of this embodiment is mainly composed of a base plate 1, head chips 2a to 2f, and heat pipes 3a to 3c.

  In order to form a three-dimensional liquid-cooled tube, the base plate 1 has a five-layer structure from the first layer 1a to the fifth layer 1e, and the heat pipes 3a to 3c are formed on the second layer 1b. Each is incorporated in a groove space.

  On the lower surface of the base plate 1, six head chips 2a to 2f having eight nozzle rows are bonded and fixed in a staggered arrangement, and heat generated in the head chips 2a to 2f as a result of printing is generated. The three heat pipes 3a to 3c absorb more heat in the high temperature part and soak.

  FIG. 2 is a perspective view showing the ink supply path 7 and the coolant inlet / outlet of the base plate 1 of the ink jet recording head according to the first embodiment of the present invention.

  The ink supply paths 7a to 7l pass through all layers of the base plate 1, and ink is supplied to the head chips 2a to 2f from an ink holding tank (not shown) via the ink supply paths 7a to 7l. That is, the ink that has passed through the ink supply path 7a is supplied to the four nozzle rows 5e to 5h through the ink supply ports 4c and 4d of the head chip 2a in FIG. Similarly, the ink that has passed through the ink supply path 7b is supplied to the four nozzle rows 5a to 5d through the ink supply ports 4a and 4b of the head chip 2a. Ink supply to other head chips is performed in the same manner.

  In order to prevent the heat pipes 3a to 3c from interfering with these ink supply paths 7a to 7l, the heat pipe 3b is located between the ink supply paths 7b, 7d and 7f and 7g, 7i and 7k, and the heat pipe 3a is connected to the ink supply path. The heat pipe 3c is embedded next to the ink supply paths 7a, 7c, and 7e next to 7h, 7j, and 7l. The heat generation of the head chips 2a to 2c is caused by the heat pipes 3b and 3c, and the heat from the head chips 2d to 2f. Heat is generated by the heat pipes 3a and 3b through the base plate 1 from the bottom and side surfaces of the heat pipe, and instantaneously transported and radiated to the non-heat generating portion, so that the entire recording head is heated.

  Three liquid cooling tubes 8, 9, and 10 are formed inside the base plate 1 to avoid interference between the ink supply paths 7a to 7l and the heat pipes 3a to 3c. A coolant such as water cooled to normal temperature or below normal temperature is injected from the inlets 8a, 9a and 10a, respectively, and the heated coolant is discharged from the outlets 8b, 9b and 10b.

  FIG. 3 is a perspective view showing a state where the layers 1a to 1e of the base plate 1 are separated.

  The heat-absorbing portions 8d, 9d, 10d and 8f, 9f, 10f of the liquid-cooled tubes 8, 9, 10 are formed on the second layer 1b of the base plate 1 close to the head chips 2a-2f, similar to the heat pipe 3, and the heat pipe 3b Since the heat exchanging parts 8c, 9c, 10c and 8e, 9e, 10e with the heat exchange through the upper surface of the heat pipe 3b that does not absorb heat from the head chip 2, the heat exchange part 8c, 9c, 10c is directly above the heat pipe 3b of the fourth layer 1d. It is formed.

  The openings that serve as the flow paths for the ink and the cooling liquid provided in each of the layers 1a to 1e are formed, for example, by molding such as a press on a ceramic sheet before firing, and then the layers are laminated and fired to form a hard ceramic plate. As a result, it is possible to easily form the liquid cooling tubes 8, 9, and 10 having a complicated three-dimensional structure inside the base plate.

  Next, an operation process in which the coolant flowing through the liquid cooling tubes 8, 9, and 10 sequentially cools the head chips 2a to 2f will be described with reference to FIG.

  FIG. 4 is a perspective view showing the positional relationship between the ink supply paths 7a to 7l formed in the base plate 1, the liquid cooling tubes 8, 9, and 10, the heat pipes 3a to 3c, and the head chips 2a to 2f.

The cooling liquid in the liquid cooling tube 8 flows from the inlet 8a at a temperature T ₀ (for example, 25 ° C.), absorbs heat from the heat pipe 3b at the heat exchanging portion 8c, and rises to a temperature T ₁ (for example, 27 ° C.). (Primary cooling), it flows into the heat absorption part 8d of the head chip 2d. Then, after the temperature is raised to a temperature T ₂ (for example, 29 ° C.) through the ink supply paths 7g and 7h (secondary cooling), the heat exchange section 8e dissipates heat to the heat pipe 3b and decreases to near the temperature T ₁ . the following flows into the heat absorbing portion 8f of the head chip 2c, the ink supply passage 7e, through the inter-7f are discharged from the outlet 8b after raising to the vicinity of temperature T ₂ again.

Similarly, in the liquid cooling tube 9, the coolant flowing in from the inlet 9 a at the temperature T ₀ absorbs heat from the heat pipe 3 b at the heat exchanging portion 9 c and rises to the temperature T _1, and the heat absorbing portion of the head chip 2 b. after raising further up temperature T ₂ flows into 9d, dissipating the heat pipe 3b in the heat exchange portion 9e. And if dropped to around the temperature T _1, then flows into the heat absorbing portion 9f of the head chip 2f, and is discharged from the outlet 9b after raising to the vicinity of temperature T ₂ again.

The cooling liquid in the liquid cooling tube 10 is desirably introduced from the opposite side to the liquid cooling tubes 8 and 9 as shown in FIG. However, in this embodiment, heat exchange is performed with the heat pipe 3b in the same manner as the cooling liquid in the liquid cooling tubes 8 and 9. That is, the cooling fluid flowing from the inlet 10a at a temperature T ₀ is raised to temperatures T ₁ absorbs heat from the heat pipe 3b in the heat exchange portion 10c, further temperature flows into the heat absorbing portion 10d of the head chip 2e until T ₂ after raising, dissipates heat to the heat pipe 3b in the heat exchange portion 10e. And if dropped to around the temperature T _1, then flows into the heat absorbing portion 10f of the head chip 2a, is discharged from the outlet 10b after raising the temperature to near the temperature T ₂ again.

  As described above, with the configuration shown in the present embodiment, even if the temperature of the coolant rises after cooling a certain head chip, the coolant temperature recovers when the next head chip is cooled. It is possible to cool the space between the ink supply paths of the base plate 1 where heat is easily generated while maintaining the same temperature range.

  Further, in the present embodiment, since all the heat exchange portions of the coolant are provided directly above the central heat pipe 3b, the heat transport capacity of the heat pipes 3a, 3c on both sides is lower than that of the heat pipe 3b, This is suitable when only the heat pipe 3b is provided in the base plate 1.

  In this embodiment, the case where six head chips are bonded and fixed to the base plate in a staggered arrangement has been dealt with, but seven or more head chips may be used. Further, not only two rows of staggered arrays but also three or more rows of staggered head chips may be used.

(Second embodiment)
FIG. 5 shows the positional relationship between the ink supply paths 7a to 7l formed in the base plate 1 of the second embodiment of the present invention, the liquid cooling tubes 11 and 12, the heat pipes 3a to 3c, and the head chips 2a to 2f. It is a perspective view.

  In this embodiment, there are two liquid cooling tubes, the head chips 2d, 2e, 2f in the even number row by the combination of the liquid cooling tube 11 and the heat pipe 3a, and the heads in the odd number row by the combination of the liquid cooling tube 12 and the heat pipe 3c. Chips 2a, 2b, and 2c were structured to soak and cool, respectively. Since the configuration of the liquid-cooled tubes 11 and 12 other than the channel structure conforms to that of the first embodiment, the description thereof is omitted.

  Hereinafter, an operation process in which the coolant flowing through the liquid cooling tubes 11 and 12 sequentially cools the head chips 2d, 2e, and 2f and the head chips 2a, 2b, and 2c will be described with reference to FIG.

The cooling liquid in the liquid cooling tube 11 flows from the inlet 11a at a temperature T ₀ (for example, 25 ° C.), absorbs heat from the heat pipe 3a at the heat exchanging portion 11c, and rises to a temperature T ₃ (for example, 29 ° C.). (Primary cooling), it flows into the heat absorption part 11d of the head chip 2e. Then, after the temperature is raised to the temperature T ₄ (for example, 31 ° C.) through the ink supply paths 7i and 7j (secondary cooling), the heat exchange unit 11e dissipates heat to the heat pipe 3a and decreases to near the temperature T ₃ . then flows into the heat absorbing portion 11f of the head chip 2f a U-turn, an ink supply path 7k, after raising to near the temperature T ₄ again through the inter-7l, turn radiates heat to the heat pipe 3a in the heat exchange portion 11g after cooled to near the temperature T ₃ again Te, then flows into the heat absorbing portion 11h of the head chip 2d, it is discharged from the outlet 11b after raising to around a third time temperature T ₄ through the ink supply path 7 g, between 7h .

The cooling liquid in the liquid cooling tube 12 is desirably introduced from the opposite side of the liquid cooling tube 11 as shown in FIG. That is, the cooling fluid flowing from the inlet 12a at a temperature T ₀ is heated to a temperature T ₃ by absorbing heat from the heat pipe 3c in the heat exchange portion 12c, further temperature flows into the heat absorbing portion 12d of the head chip 2b until T ₄ after raising, dissipates heat to the heat pipe 3c in the heat exchange portion 12e. And if dropped to near the temperature T _3, flows into the heat absorbing portion 12f of the head chip 2a and then U-turn after raising to near the temperature T ₄ again, this time with the heat dissipation to the heat pipe 3c in the heat exchange portion 12g after cooled to near the temperature T ₃ again, then it flows into the heat absorbing portion 12h of the head chip 2c, and is discharged from the outlet 12b after raising to around a third time temperature T _4.

  As described above, with the configuration as shown in the present embodiment, only the two heat pipes on both sides and the two liquid-cooled tubes can be used to heat the base plate 1 while maintaining all the chips at substantially the same temperature range. The space between the ink supply paths can be cooled.

(Third embodiment)
FIG. 6 shows the positional relationship between the ink supply paths 7a to 7l formed in the base plate 1 of the third embodiment of the present invention, the liquid cooling tubes 13 and 14, the heat pipes 3a to 3c, and the head chips 2a to 2f. It is a perspective view.

  In this embodiment, a structure in which even-numbered head chips 2d, 2e, 2f and odd-numbered head chips 2a, 2b, 2c are soaked and cooled by a combination of two liquid cooling tubes 13, 14 and a heat pipe 3b, respectively. It was. Further, in order to avoid interference between the liquid cooling tubes 13 and 14 and the ink supply paths 7a to 7l, both ends of the third, fourth, and fifth layers of the ink supply paths 7a to 7l of the base plate 1 are slightly shortened to have openings. However, sufficient ink can be supplied to the head chips 2a to 2f. Since the configuration other than the flow path structures of the liquid cooling tubes 11 and 12 and the ink supply paths 7a to 7l conforms to the first embodiment, the description thereof is omitted.

  Hereinafter, an operation process in which the coolant flowing in the liquid cooling tubes 13 and 14 sequentially cools the head chips 2d, 2e, and 2f and the head chips 2a, 2b, and 2c will be described with reference to FIG.

The cooling liquid in the liquid cooling tube 13 flows from the inlet 13a at a temperature T ₀ (for example, 25 ° C.), absorbs heat from the heat pipe 3b at the heat exchanging portion 13c, and rises to a temperature T ₃ (for example, 29 ° C.). (Primary cooling), it flows into the heat absorption part 13d of the head chip 2d. Then, after the temperature is raised to the temperature T ₄ (for example, 31 ° C.) through the ink supply paths 7g and 7h (secondary cooling), the heat exchange unit 13e dissipates heat to the heat pipe 3b and decreases to near the temperature T ₃ . then flows into the heat absorbing portion 13f of the head chip 2e, the ink supply path 7i, after the temperature was raised to near the temperature T ₄ again through the inter-7j, again the temperature T in the heat radiation to the heat pipe 3b is now in the heat exchange portion 13g after cooled to around _3, and then flows into the heat absorbing portion 13h of the head chip 2f, the ink supply path 7k, and is discharged from the outlet 13b after raising to around a third time temperature T ₄ through the inter-7l.

The cooling liquid in the liquid cooling tube 14 is desirably introduced from the opposite side to the liquid cooling tube 13 as shown in FIG. That is, the cooling fluid flowing from the inlet 14a at a temperature T ₀ is heated to a temperature T ₃ by absorbing heat from the heat pipe 3b in the heat exchange portion 14c, further temperature flows into the heat absorbing portion 14d of the head chip 2c until T ₄ after raising, dissipates heat to the heat pipe 3b in the heat exchange portion 14e. And if dropped to near the temperature T _3, then flows into the heat absorbing portion 14f of the head chip 2b, again the temperature T ₄ to the vicinity after raising the temperature T ₃ again by releasing heat to the heat pipe 3b is now in the heat exchange portion 14g after cooled to near, then flows into the heat absorbing portion 14h of the head chip 2a, it is discharged from the outlet 14b after raising to around a third time temperature T _4.

  As described above, with the configuration shown in the present embodiment, the ink of the base plate 1 that easily generates heat while maintaining all the chips at substantially the same temperature range with only one central heat pipe and two liquid-cooled tubes. The space between the supply paths can be cooled.

(Fourth embodiment)
FIG. 7 shows the positional relationship between the ink supply paths 7a to 7l formed in the base plate 1 of the fourth embodiment of the present invention, the liquid cooling tubes 15 and 16, the heat pipes 3a to 3c, and the head chips 2a to 2f. It is a perspective view.

  In this embodiment, the head chips 2a to 2f are soaked and cooled by a combination of the two liquid cooling tubes 15 and 16 and the heat pipes 3a and 3c. In order to intensively cool the central part of the nozzle row of each head chip whose temperature rises most, the heat-absorbing part of the liquid cooling tubes 15 and 16 crosses the center of the nozzle line in a direction perpendicular to the nozzle row on the upper layer of each head chip. So that the coolant flows. Therefore, the heat absorption part of the liquid cooling pipes 15 and 16 is provided in the fourth layer 1d of the base plate 1 like the heat exchange part, and the ink supply paths 7a to 7l avoid the interference with the liquid cooling pipes 15 and 16, so that the base plate 1 The 3rd, 4th, and 5th layer openings can be separated into two locations on both ends, and ink can be supplied to each head chip from two paths. Since the configuration other than the flow path structures of the liquid cooling tubes 11 and 12 and the ink supply paths 7a to 7l conforms to the first embodiment, the description thereof is omitted.

  Hereinafter, an operation process in which the coolant flowing through the liquid cooling tubes 15 and 16 sequentially cools the head chips 2a to 2f will be described with reference to FIG.

The cooling liquid in the liquid cooling tube 15 flows from the inlet 15a at a temperature T ₀ (for example, 25 ° C.), absorbs heat from the heat pipe 3c at the heat exchanging portion 15c, and rises to a temperature T ₃ (for example, 29 ° C.). (Primary cooling), it flows into the heat absorption part 15d of the head chip 2a. Then, after the temperature is raised to a temperature T ₄ (for example, 31 ° C.) (secondary cooling), the heat exchange part 15e dissipates heat to the heat pipe 3a and falls to near the temperature T _3. flows, after raising to near the temperature T ₄ again, this time after lowering to the vicinity of the temperature T ₃ again by releasing heat to the heat pipe 3c in the heat exchange portion 15 g, and then flows into the heat absorbing portion 15h of the head chip 2b, a third time to near the temperature T ₄ is discharged from the outlet 15b after raising.

Similarly, in the liquid cooling pipe 16, the coolant flowing in from the inlet 16 a at the temperature T ₀ absorbs heat from the heat pipe 3 a at the heat exchanging portion 16 c and rises to the temperature T _3, and the heat absorbing portion of the head chip 2 f. after raising further to a temperature T ₄ flows in 16d, dissipating the heat pipe 3c in the heat exchange portion 16e. And if dropped to near the temperature T _3, then flows into the heat absorbing portion 16f of the head chip 2c, again the temperature T ₄ to the vicinity after raising the temperature T ₃ again by releasing heat to the heat pipe 3a is now in the heat exchange portion 16g after cooled to near, then flows into the heat absorbing portion 16h of the head chip 2e, it is discharged from the outlet 16b after raising to around a third time temperature T _4.

  As described above, with the configuration shown in the present embodiment, the ink of the base plate 1 that easily generates heat while keeping all the chips at substantially the same temperature range with the two heat pipes and the two liquid-cooled tubes on both sides. It is possible to cool between the supply paths and the center of the nozzle row.

The perspective view showing the appearance and head chip arrangement of the recording head of the first embodiment The perspective view showing the ink supply path of the base plate of 1st Example, and a cooling fluid outflow inlet. Exploded perspective view of the base plate of the first embodiment The perspective view showing the positional relationship of the ink supply path, heat pipe, and coolant flow path of the first embodiment. The perspective view showing the positional relationship of the ink supply path, heat pipe, and coolant flow path of the second embodiment. The perspective view showing the positional relationship of the ink supply path, heat pipe, and coolant flow path of the third embodiment. The perspective view showing the positional relationship of the ink supply path of 4th Example, a heat pipe, and a coolant flow path. Perspective view showing appearance and head chip arrangement of conventional recording head Schematic diagram showing ink supply path and nozzle arrangement in the head chip The perspective view showing the ink supply path of the base plate of a prior art example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base plate 2 Head chip 3 Heat pipe 4 Ink supply port 5 Nozzle 6 Heater 7 Ink supply path 8-16 Coolant flow path

Claims (6)

A head chip in which one or more nozzle rows each composed of a plurality of nozzles for ejecting ink are formed, and a plurality of the head chips are mounted, and ink for supplying ink to the nozzle row for each head chip In an inkjet recording head comprising a base plate on which one or more supply paths are formed,
The base plate has one or more systems of first heat transporting means on the inside or a side surface, and has a heat transporting capability lower than that of the first heat transporting means, and has at least one heat exchanging part with the first heat transporting means. A plurality of second heat transporting means corresponding to each of the plurality of head chips for absorbing heat generated by the head chip during ejection. With an endothermic part
After the heat transport medium in the second heat transport means absorbs heat in one of the heat absorption sections, the heat transport medium is transferred to the heat exchange section to dissipate heat to the first heat transport section, and thereafter An ink jet recording head characterized in that the second heat transporting means is disposed so as to be transferred to the heat absorbing portion of the head chip.   The heat transfer medium for absorbing heat from the first heat transporting means before the heat transport medium in the second heat transporting means absorbs heat in the first heat absorbing part of the plurality of heat absorbing parts. 2. The ink jet recording head according to claim 1, wherein the second heat transporting means is disposed so as to pass through.   The heat absorption part has a structure in which a heat transport medium in the second heat transport means passes in the nozzle row direction between adjacent ink supply paths among the plurality of ink supply paths. The ink jet recording head according to claim 1.   3. The ink jet recording head according to claim 1, wherein the first heat transporting means is a heat pipe or a coolant flow path.   3. The ink jet recording head according to claim 1, wherein the second heat transporting means is a coolant flow path.   The said base plate is a thing which laminated | stacked and baked the ceramic sheet | seats, and the said cooling fluid flow path is formed in each sheet | seat in the process before laminating | stacking the said ceramic sheet | seats. Or an ink jet recording head according to claim 5.

Images