JP2009132024A - Inkjet recording head and inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a temperature rise of a head due to the speeding-up and the densifying of recording. <P>SOLUTION: This inkjet recording head is equipped with: a recording element board 1 arranged with a plurality of recording element trains composing of a plurality of recording elements 103 for delivering ink; and a supporting plate 210 for supporting the recording element board. In this case, heat exhausting means 201 and 401 are respectively provided in the portions of the supporting plate corresponding to ones between the recording element trains. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an inkjet recording apparatus that performs a recording operation by discharging ink, and an inkjet recording head used in the recording apparatus.

  2. Description of the Related Art Conventionally, ink jet recording apparatuses are widely used and commercialized for computer-related output devices and the like because the running cost of color images is low and the apparatus can be miniaturized.

  In recent years, in order to realize high-definition image recording at higher speed, it is also desired to realize a recording head having a longer recording width (discharge port array length). Specifically, a head having a length of 4 inches to 13 inches or the like has been required.

  As the head becomes longer and faster in this way, the energy input to the head increases and the head temperature rises during recording. As a result, it is necessary to cope with recording reliability, such as a variation in ejection amount for each page, unstable ejection at high temperatures, and a decrease in continuous recording performance.

Conventionally, the head is cooled by air cooling from the outside of the head or mounting a cooling pipe on the head. However, since these methods do not provide a sufficient cooling effect, a method for suppressing the temperature rise of the head by providing a cooling liquid flow path for circulating a cooling liquid such as water along the ejection port array of the head is proposed. (Patent Documents 1 and 2).
Japanese Patent Application Laid-Open No. 08-150711 Japanese Patent Laid-Open No. 08-276574

  In the conventional method, since a heat pipe and a heat radiating member are externally attached to the completed recording head, there is a problem that the recording element substrate serving as a heat source and the heat pipe cannot be brought close to each other. In addition, since it is externally attached, the contact area between the heat pipe and the recording head is limited, and the heat exchange efficiency between the recording head and the heat pipe is poor. In particular, in the case of an ink jet recording head as shown in FIG. 6, there are the following problems.

  FIG. 6A shows an ink jet recording having an ejection port array group N1 in which two rows of ejection ports 106 from which ink is ejected are arranged in parallel, and another ejection port array group N2 having the same configuration arranged side by side. 1 is a perspective view of a recording element substrate 1 of a head. FIG. 6B is a cross-sectional view taken along the line AA in FIG.

  The recording element substrate 1 is, for example, a Si substrate 101 having a thickness of 0.5 to 1 mm, and an ink supply port 102 including a rectangular through-hole is formed as an ink flow path. On both sides of the ink supply port 102, one row of electrothermal conversion elements 103 are arranged. The ink supply port 102 is formed by etching at an angle of about 54.7 degrees by anisotropic etching using the crystal orientation of the Si substrate 101.

  On the Si substrate 101, a flow path forming member 104 made of a photosensitive resin, which includes an ink flow path 105 and an ejection port 106 corresponding to the electrothermal conversion element 103, is formed. Here, the discharge port 106 is provided so as to face the electrothermal conversion element 103. The ink supplied from the ink supply port 102 is ejected from the ejection port 106 using thermal energy generated by the electrothermal conversion element 103 as ejection energy.

The support plate 110 is made of an alumina (Al ₂ O ₃ ) material having a thickness of 4 to 10 mm, for example. An ink channel 111 for supplying ink to the recording element substrate 1 is formed in the support plate 110. The recording element substrate 1 is bonded and fixed to the support plate 110 with high positional accuracy so that the ink supply port 102 of the recording element substrate 1 corresponds to the ink flow path 111 of the support plate 110.

  The ink supply member 112 includes a liquid chamber 113 that stores ink. The opening of the ink supply member 112 and the support plate 110 are connected and fixed in communication so that ink can be supplied.

  Ink supply to the liquid chamber 113 may be performed by an ink supply system (not shown) including a tube, or may be a form in which a recording head and an ink tank are directly mounted.

Here, the heat generated in the electrothermal conversion element 103 of the recording element substrate 1 first spreads in the Si substrate 101. However, since the electrothermal conversion elements 103 are further arranged in one row on both sides of each of the two ink supply ports 102, the electrothermal conversion elements disposed at positions inside the two ink supply ports 102 with respect to each other. The heat generated in the elements 103b and 103c is difficult to dissipate. As a result, the vicinity of the electrothermal conversion elements 103b and 103c of the recording element substrate 1 is harder to cool than the other parts. That means
In general, it has been found that, in an ink jet recording head that ejects ink droplets using thermal energy, the amount of ejected ink droplets increases as the temperature near the electrothermal transducer increases. Therefore, when a large number of images are continuously recorded at a high speed, there is a problem that the amount of ink droplets changes due to such a temperature difference and density unevenness of the image occurs.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an ink jet recording head and a recording apparatus using the recording head that can suitably perform thermal diffusion of a recording element substrate and suppress a temperature difference.

  The present invention that achieves the above-described object provides an ink jet recording comprising: a recording element substrate having a plurality of recording element arrays each composed of a plurality of recording elements for ejecting ink; and a support plate that supports the recording element substrate. In the head, heat exhausting means is provided at a portion of the support plate corresponding to the space between the recording element arrays.

  According to the present invention, by dissipating the heat of the region between the ejection port array groups, the temperature disparity of the recording element substrate of the inkjet recording head can be suppressed, and the amount of ink droplets ejected from each ejection port can be reduced. Variations can be suppressed and occurrence of density unevenness in images can be suppressed.

  Next, embodiments of the present invention will be described with reference to the drawings.

  The printing element substrate of each embodiment described below has an ejection port array group N1 in which two rows of ejection ports 106 are arranged in parallel, and another ejection port array group N2 having the same configuration arranged in parallel to the side. It is. However, the present invention can achieve the same effect even with a recording element substrate having a single ejection port array N1 and another ejection port array N2 arranged in parallel therewith.

  Further, as shown in FIG. 6B, the discharge port 106 and the electrothermal conversion element 103 are vertically opposed to each other. Therefore, the discharge port array group in the present invention is synonymous with the electrothermal conversion element array group as it is. Can be treated as Similarly, the discharge port array can be directly used as a synonym for the electrothermal conversion element array.

(First embodiment)
FIG. 1 is a diagram illustrating an ink jet recording head according to a first embodiment of the present invention. 1A is a plan view as viewed from the recording element substrate side, FIG. 1B is a cross-sectional view taken along a plane perpendicular to the recording element array, and FIG. 1C is a side view. Since the structure of the recording element substrate 1 is the same as that described with reference to FIG. 6, the corresponding members are given the same numbers and the details are omitted.

The material of the support plate 210 is preferably a material having ink resistance and good thermal conductivity, and is formed of, for example, an alumina (Al ₂ O ₃ ) material having a thickness of 4 to 10 mm. An ink channel 211 for supplying ink to the recording element substrate 1 is formed in the support plate 210. The ink supply port 102 of the recording element substrate 1 communicates with the ink flow path 211 of the support plate 210, and the recording element substrate 1 is fixed to the support plate 210.

  The opening of the ink supply member 112 and the support plate 110 are connected and fixed in communication so that ink can be supplied.

  Ink supply to the liquid chamber 113 may be performed by an ink supply system (not shown) including a tube, or may be a form in which a recording head and an ink tank are directly mounted.

  The partition part 210 a, which is a region sandwiched between the two ink flow paths 211 of the support plate 210, is provided with a flow path 201 as heat exhausting means for allowing the coolant to flow through the support plate 210. Yes. A cooling liquid such as water is supplied to the flow path 201 by a cooling liquid circulation system as shown in FIG.

  Therefore, the heat generated between the discharge port array group N1 in which two rows of the discharge ports 106 are arranged in parallel and the other discharge port array group N2 of the same configuration arranged in parallel to the side of the discharge port 106 passes through the support plate 210. The heat is transferred to the coolant flowing through the flow path 201 disposed in the close position, and quickly discharged outside the head. Here, since the discharge port 106 and the electrothermal conversion element 103 are in a positional relationship facing each other as shown in FIG. 6B, the discharge port array group is directly an electrothermal conversion element array group. With such a configuration, even when a large number of images are continuously recorded at a high speed, the temperature difference between the two portions of the recording element substrate 1 and the central portion can be extremely reduced.

  FIG. 2 is a schematic diagram showing an ink and cooling liquid supply system of an ink jet recording apparatus used in other embodiments in addition to the present embodiment.

  As shown in FIG. 2, the supply system of the ink jet recording apparatus includes an ink tank 8 containing ink 15, and two tubes 216 and 217 are disposed in the ink tank 8. One of the tubes 217 is connected to one end of the recording head 14 and communicates with the common liquid chamber of the recording head 14. The other tube 216 is connected to the other end of the recording head 14 via the pump 9 and communicates with the common liquid chamber of the recording head 14.

  The recording head 14 ejects ink droplets by a recording head drive circuit (not shown) during recording.

  Even if bubbles exist in the ink flow path, the bubbles can be discharged from the ink tank 8 by driving the pump 11 to circulate the ink.

  When ink is ejected from the recording head 14 such as during recording, ink is supplied from the ink tank 8 to the recording head 14 via the tube 217 or tube 216 by capillary force.

  Reference numeral 10 denotes a coolant tank, and two tubes 218 and 219 are disposed in the coolant tank 10. One of the tubes 218 is connected to one end of the recording head 14 and communicates with a coolant flow path in the support plate 210 of the recording head 14. The other tube 219 is connected to the other end of the recording head 14 via the pump 11 and communicates with the coolant flow path in the support plate 210 of the recording head 14. When the temperature of the recording head 14 rises, the pump 11 is driven, and the cooling liquid in the cooling liquid tank 10 circulates in the order of the tube 218, the support plate 210, and the tube 219, and the recording head 14 is cooled. In addition, sensors that detect detection data such as the flow rate of cooling water, inlet temperature, outlet temperature, head temperature (recording element substrate built-in sensor, etc.), environmental temperature, etc., the amount of heat exhausted from the head by the coolant, etc. are provided. The head temperature may be controlled by setting a cooling condition.

(Second Embodiment)
FIG. 3 is a diagram illustrating an ink jet recording head according to the second embodiment of the present invention. 3A is a plan view viewed from the recording element substrate side, FIG. 3B is a cross-sectional view taken along a plane perpendicular to the recording element array, and FIG. 3C is a side view. Except for the configuration of the flow path of the coolant, such as the recording element substrate 1 and the ink supply member 212, the configuration is the same as in the first embodiment.

  The partition portion 310a, which is a region sandwiched between the two ink flow paths 311 of the support plate 310, is provided with a coolant flow path 301 as heat exhausting means so as to pass through the support plate 310, and water or the like. The coolant is caused to flow by a coolant circulation mechanism (not shown).

  In the present embodiment, the coolant flow path 301 is bent so as to approach the recording element substrate 1, whereby the central portion 301 a approaches or contacts the back surface of the recording element substrate 1 (the back surface of the Si substrate 101).

With this configuration, the heat in the region between the two ejection port array groups (electrothermal conversion element array groups) N1 and N2 of the recording element substrate 1 is less than that through the support plate 210. The heat is transferred to the coolant flowing through the flow path 201 and is quickly discharged outside the head. Therefore, when a large number of images are continuously recorded at high speed, the temperature difference between the both ends and the center of the recording element substrate can be further reduced.
Note that a heat pipe may be used as the exhaust heat means instead of the coolant flow path.

(Third embodiment)
FIG. 4 is a diagram illustrating an embodiment using a heat pipe as another heat exhausting means instead of the cooling flow path. 4A is a plan view viewed from the recording element substrate side, FIG. 4B is a cross-sectional view taken along a plane perpendicular to the recording element array, and FIG. 4C is a side view.

  The configuration other than the configuration of the flow path of the coolant, such as the recording element substrate 1 and the ink supply member 212, is the same as that in the first embodiment.

  One end of the heat pipe 401 is inserted into the partition 410 a that is a region sandwiched between the two ink flow paths 411 of the support plate 410 so as to penetrate the support plate 410. The other end of the heat pipe 401 is connected to the heat sink 402.

  The heat sink is made of a metal material having a high thermal conductivity such as an aluminum alloy or a copper alloy, for example, and the cooling efficiency is enhanced by a shape having a surface area as large as possible so as to have a cross-sectional shape as shown in FIG. A commercially available heat pipe can be used as the heat pipe. The material that fills the gap between the heat pipe 401 and the support substrate 1 and the gap between the heat pipe 401 and the heat sink 402 can be used as long as it has a high thermal conductivity and is stable. For example, a silicon-based adhesive can be used.

  According to the ink jet recording head of this embodiment, the heat in the region between the two ejection port array groups (electrothermal conversion element array groups) N1 and N2 of the recording element substrate 1 is located close to the support plate 410. It is transmitted to the heat pipe 401 arranged at. The heat transmitted to the heat pipe 401 is transported through the heat pipe 401 and quickly radiated from the heat sink 402 to the atmosphere. Therefore, when a large number of images are continuously recorded at high speed, the temperature difference between the both end portions and the central portion of the recording element substrate can be reduced.

  Further effects can be obtained by arranging the heat sink 402 in an air flow generated by a fan or the like.

(Fourth embodiment)
In the present embodiment, a case will be described in which the present invention is applied to an ink jet recording head in which ejection openings are arranged over the entire recording area in order to realize high-definition image recording at a higher speed.

  FIG. 5 is a diagram illustrating a configuration in which the present invention is applied to an ink jet recording head in which a plurality of recording element substrates 1 are arranged in a zigzag pattern and discharge ports are disposed substantially corresponding to the entire width of the recording area. The top view seen from the 1 side is shown. The recording element substrate 1 is exactly the same as that used in the embodiment of FIG.

  The recording element substrates 1 are arranged in a zigzag pattern on the support plate 510 and enable wide recording with the same color. For example, six recording element substrates 1 each having a discharge port array group length of 0.7 inches are arranged in a staggered manner to enable recording with a width of 4 inches.

  Further, the end portion of the ejection port array of each recording element substrate 1 is provided with an area overlapping with the end portion of the ejection port array of the other recording element substrate 1 adjacent in a staggered manner in the recording direction, and the image This prevents a gap in which no recording is performed from occurring in the area.

  A coolant flow path 501 is provided so as to penetrate through the portions corresponding to the central portions of the recording element substrates 1a, 1b, and 1c of the support plate 510, and the central portions of the recording element substrates 1d, 1e, and 1f of the support plate 510 are provided. A coolant flow path 502 is provided so as to penetrate a portion corresponding to the portion. A coolant such as water is caused to flow through the two flow paths 501 and 502 by, for example, a coolant circulation system as described with reference to FIG.

By adopting such a configuration, it is possible to simplify the configuration of the coolant circulation by providing the coolant flow path so as to pass between each of the two ejection port array groups of the plurality of recording element substrates. it can. Furthermore, the cooling liquid circulation system can be simplified by combining the plurality of cooling liquid flow paths at one end.
Note that a heat pipe may be used as the exhaust heat means instead of the coolant flow path.

(Other embodiments)
For the ink jet recording head of each of the above-described embodiments, a heat exhausting means such as a cooling liquid flow path or a heat pipe may be provided outside the ejection port array group, and a higher cooling effect can be obtained. it can.

It is a figure explaining the inkjet recording head which concerns on the 1st Embodiment of this invention. It is a model diagram which shows the supply system of the ink of the inkjet recording device used for each other embodiment other than this embodiment, and a cooling fluid. It is a figure explaining the inkjet recording head which concerns on the 2nd Embodiment of this invention. It is a figure explaining the inkjet recording head which concerns on the 3rd Embodiment of this invention. It is a figure explaining the inkjet recording head which concerns on the 4th Embodiment of this invention. It is a figure explaining the inkjet recording head of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording element board | substrate 103 Electrothermal conversion element 106 Discharge port 201 Flow path 210 Support plate 401 Heat pipe

Claims (7)

In an ink jet recording head comprising: a recording element substrate having a plurality of recording element arrays each composed of a plurality of recording elements for ejecting ink; and a support plate for supporting the recording element substrate.
An ink jet recording head, characterized in that heat exhausting means is provided at a portion of the support plate corresponding to the space between the recording element arrays.   The support plate includes a plurality of ink flow paths for supplying ink to the recording elements, and the heat exhausting means is provided along the recording element array between the ink flow paths. 2. An ink jet recording head according to 1.   The ink jet recording head according to claim 1, wherein the exhaust heat unit is in contact with the recording element substrate.   4. The ink jet recording head according to claim 1, wherein the exhaust heat means is a flow path through which a cooling liquid flows.   4. The ink jet recording head according to claim 1, wherein the exhaust heat means is a heat pipe.   An ink jet recording comprising: the ink jet recording head according to claim 4; and a control device that causes the cooling liquid to flow through the flow path of the ink jet recording head and suppresses temperature rise of the ink jet recording head. apparatus.   An ink jet recording apparatus comprising a heat sink for dissipating heat from the heat pipe according to claim 5.

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