JP4854553B2 - Heat exchanger and image forming apparatus having the same - Google Patents

Description

  The present invention relates to a heat exchanger that exchanges heat with a liquid flowing in a flow path, and an image forming apparatus including the heat exchanger.

  Ink jet printers having an ink supply path for supplying ink to a recording head, cooling water and lubricating oil in an internal combustion engine of a vehicle, liquid seasonings in a processed food production line, or blood or infusion for supplying blood to a body, such as a dialysis machine In the liquid supply apparatus, it is necessary to control the temperature of the liquid to be supplied in order to stabilize characteristics and cool the body.

  For example, Patent Document 1 is disclosed as an invention related to a liquid temperature adjusting means. The present invention has an inlet portion through which liquid flows in, a main body portion made of a metal shell having a space through which the liquid flows, and an outlet portion through which liquid that has passed through the inside of the main body portion flows out. In the inner direction of the shell, one or more flow path guide walls projecting like a bowl are provided.

In addition, a liquid channel that guides the flow of liquid is formed inside the main body by a channel guide wall, and the overall length of the liquid channel is set longer than the length of the longest side of the metal shell. Has been. That is, the temperature of the liquid can be adjusted by providing a temperature adjusting unit on one or both sides of the flow path that is spread in a plane.
JP 2001-211853 A

  By the way, in a color ink jet printer, typically, inks of a plurality of colors such as cyan (Cyan, C), magenta (Magenta, M), yellow (Yellow, Y), and black (Black, K) are mounted. ing.

Since these four color inks usually have similar physical properties, it is desirable that they be at substantially the same temperature in order to obtain uniform ejection characteristics when ejected from an inkjet head.
However, when the technique described in Patent Document 1 is applied to a color ink jet printer, channels corresponding to the number of ink colors, typically four channels, are required, which increases the number of components and increases the cost. Further, since it is necessary to control the temperature of each color ink, the control becomes complicated.

  In addition, in an inkjet printer, the amount of ink that can be absorbed by the paper is less than the capacity that can be absorbed per unit time. For example, assuming that the ink absorbable capacity is 100%, when C is ejected by 50%, the remaining M, Y and K are ejected only by 50% at the maximum.

  The amount of heat generated by driving the head is substantially proportional to the ink ejection amount. That is, the calorific value is not determined independently for each color, and the sum is always below a certain level. Conventionally, the temperature of each color ink has not been controlled focusing on this point.

  In addition, forced air or running wind at atmospheric temperature has been used as a cooling means for cooling water and lubricating oil in the internal combustion engine of vehicles, but because of instability due to changes in climate and environment, it was prepared for the worst environment It was over-equipped.

  The present invention has been made to solve such a problem, and provides a heat exchanger capable of adjusting the temperature of liquid flowing in a plurality of flow paths to substantially the same temperature in a compact configuration, and an image forming apparatus including the heat exchanger. With the goal.

In order to achieve the above object, the heat exchanger of the present invention comprises:
A plurality of flow paths that are branched from each other and extend substantially in parallel; a heat conduction part that exchanges heat with the liquid flowing in the plurality of flow paths; and a temperature adjustment unit that adjusts the temperature of at least a part of the heat conduction part , Wherein the plurality of flow paths are formed around the center of the heat conducting portion.

The image forming apparatus according to the present invention includes:
A recording head for ejecting ink to a recording medium based on a drive signal;
An ink supply path for supplying ink to the recording head having at least a plurality of flow paths;
A recording medium transport unit that transports the recording medium relative to the recording head;
And a heat exchanger according to claim 1 disposed in the ink path.

  According to the present invention, it is possible to adjust the temperature of liquids flowing through a plurality of flow paths to a substantially same temperature with a compact configuration.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram showing the configuration of an ink jet printer equipped with a heat exchanger.

  The ink jet printer 500 is an image forming apparatus that forms an image using four types of color inks (C, M, Y, and K). FIG. 1 shows a configuration for forming an image of a certain color in the ink jet printer 500. Other than the heat exchanger 1, the recording medium 530, and the medium conveying means 540 shared by four colors, FIG. In addition, a similar configuration for three colors exists in the inkjet printer 500. The ink jet printer 500 includes an image forming unit such as an ink jet head 510, an upper tank 550, and a lower tank 551.

  The ink jet printer 500 ejects ink 520 that is a liquid toward the recording medium 530 from the ink jet head 510 based on an external signal. In synchronization with the ink ejection, the medium transport unit 540 transports the recording medium 530 in a predetermined direction, whereby an image is formed on the recording medium 530.

  In the ink jet printer 500, one heat exchanger 1 is disposed in the ink circulation path. The four color inks (C, M, Y, K) pass through the heat exchanger 1 without being mixed with each other, and the temperature is controlled.

  The ink jet printer 500 has an ink supply path in an ink circulation manner in the ink jet head 510. When the main power supply of the ink jet printer 500 is on, the ink circulates regardless of whether the image is formed or not.

Here, the ink circulation path will be described.
Ink flows in order from the inkjet head 510 through the lower tank 551, the heat exchanger 1, the pump 560, and the upper tank 550 along the ink supply path (in the direction of the arrow in FIG. 1), and then returns to the inkjet head 510 again. The arrangement of these members is a lower tank 551, an ink jet head 510, and an upper tank 550 in ascending order in the vertical direction. Moreover, the height of the heat exchanger 1 and the pump 560 is arbitrary.

  That is, at the time of ink circulation, the electromagnetic valves 570 and 571 for releasing the atmosphere are opened, and the ink flows down from the upper tank 550 to the lower tank 551 via the inkjet head 510 by gravity. In parallel with this, the pump 560 pumps ink from the lower tank 551 to the upper tank 550 through the heat exchanger 1.

  Even if the amount of ink in the circulation path decreases due to ink ejection, the electromagnetic valve 572 for releasing the atmosphere of the ink tank 555 and the electromagnetic valve 573 for opening and closing the ink path from the ink tank 555 to the upper tank 550 are appropriately used. The ink tank opens and closes and ink flows from the ink tank 555 to the upper tank 550. For this reason, the amount of ink in the circulation path is kept substantially constant.

  Since the inkjet head 510 gives heat generated by the liquid ejecting operation to the ink, the temperature of the ink is higher downstream than the upstream of the inkjet head 510. Then, when the ink passes through the heat exchanger 1, the heat received by the inkjet head 510 is taken away. As a result, the temperature of the ink entering the inkjet head 510 is always suitably maintained.

  Next, FIG. 2A is a top view of the heat exchanger 1, and FIG. 2B is a cross-sectional view taken along A-A 'of FIG. 2A. 2C is a top view of the heat exchanger 1 excluding the upper lid member 140 and the lower lid member 145, and FIG. 2D is a cross-sectional view of the main body 100 taken along B-B '.

  The main body 100 of the heat exchanger 1 is made of a metal lump made of a material having good thermal conductivity such as aluminum or copper. The periphery of the main body 100 is covered with a bottomed cylindrical upper lid member 140 and a lower lid member 145.

  In addition, the main body 100 has gaps 130C, 130M, 130Y, and 130K formed at positions away from the substantially cylindrical central axis by a predetermined distance in the radial direction. The gaps 130C, 130M, 130Y, and 130K are formed in three (12 in total) for each ink color substantially in parallel with the central axis of the cylinder.

  In the present embodiment, a virtual cylindrical portion surrounded by the gaps 130C, 130M, 130Y, and 130K in the main body 100 is referred to as a heat flow path 110 as a heat conducting portion. The gap 130C (M, Y, K) forms part of an ink flow path 160C (M, Y, K) described later.

  Note that, for example, a part of the gap 130 </ b> K and the like may be provided in the center of the heat flow path 110. Further, the heat flow path 110 and a temperature adjusting means 120 described later are connected by a contact portion 110A that protrudes beyond the width of the gap 130 (the direction of ink flow). This contact portion 110 </ b> A forms part of the main body 100.

  The dimensions of the air gaps 130C, 130M, 130Y, and 130K and the heat flow path 110 are determined from the ability of the temperature adjusting means 120, the specific heat of the ink, the physical properties such as the thermal conductivity of the ink, the maximum heat generation amount per unit time of the inkjet head 510, and the like. Is done.

  The upper lid member 140 and the lower lid member 145 described above are made of a heat insulating material with low thermal conductivity such as acrylic. In the upper lid member 140, ink outlets 141C, 141M, 141Y, and 141K are formed. The lower lid member 145 has ink inlets 146C, 146M, 146Y, and 146K. Furthermore, a hole 140H slightly larger than the cross-sectional area of the contact portion 110A is formed at the center of the upper lid member 140.

  And the main body 100 is thermally insulated except the surface of 110 A of contact parts by pinching the main body 100 with the upper cover member 140, the lower cover member 145, and sealing members 150, such as rubber | gum. The ink flow path 160C (M, Y, K) is formed by the ink inlet 146C (M, Y, K), the gap 130C (M, Y, K), and the ink outlet 141C (M, Y, K). Has been.

  In this way, the ink that has passed through the inkjet head 510 enters the heat exchanger 1 from the ink inlet 146C (M, Y, K), and exchanges heat with the wall surface of the gap 130C (M, Y, K). Ink is discharged from the ink outlet 141C (M, Y, K). When the main body 100 is eroded by ink, for example, surface treatment such as anodizing may be applied to the liquid contact portion of the main body 100.

  A temperature adjusting means 120 such as a Peltier element is installed in the contact portion 110A. A heat sink 121 and a fan 122 are stacked on the temperature adjusting means 120. In this case, in order to improve the thermal conductivity between the contact portion 110A, the temperature adjusting means 120, and the heat sink 121, it is more preferable to apply thermal conductive grease or the like in the middle.

  Thus, the current flowing through the temperature adjusting unit 120 is adjusted based on the ink temperature, the environmental temperature, the temperature of the inkjet head 510, the drive duty of the inkjet head 510, and the like. By this current adjustment, a heat flow is generated from one surface of the Peltier element as the temperature adjusting means 120 to the other surface, and the ink temperature is suitably maintained.

  A temperature sensor 170 made of a thermistor is installed at the bottom center of the main body 100. The resistance measurement lead of the temperature sensor 170 is drawn out from a small hole 145H formed in the lower lid member 145 that does not affect the heat insulation. The temperature adjustment unit 120 operates based on the detection value of the temperature sensor 170.

  The installation position of the temperature sensor 170 is not limited to the center of the bottom of the main body 100. For example, a thin hole that does not affect heat conduction from the bottom to the center of the main body 100 may be provided and installed at the tip of the hole. Further, the temperature sensor 170 may be installed in the ink flow paths 160C, M, Y, and K. Further, regarding the temperature sensor 170, a plurality of means may be arbitrarily selected. Thereby, the temperature distribution of the main body 100 can be estimated appropriately.

  In addition, if the information regarding temperature is obtained, the place and number in which the temperature sensor 170 is installed are not ask | required. Further, the temperature sensor 170 is not limited to the thermistor, and may be a thermocouple or a Pt resistance thermometer, for example.

Next, heat transfer and heat conduction in the heat exchanger 1 will be described.
The temperature adjustment unit 120 adjusts the temperature of the main body 100 based on the detection value of the temperature sensor 170 so that a predetermined amount of heat can be exchanged with the ink while the ink passes through the heat exchanger 1. Specifically, the average temperature of all four colors of ink is set as a representative temperature related to heat transfer. Further, in the heat exchanger 1, the temperature adjusting means 120 is controlled so that the total amount of heat taken from each color ink becomes a predetermined amount.

  The ink that has entered the heat exchanger 1 from the ink inlet 146 </ b> C (M, Y, K) transfers heat to the wall surface of the gap 130. This heat is released to the environment through the temperature adjusting means 120 and the heat sink 121 through the heat flow path 110 by heat conduction.

  When the printing duty of a specific ink color, for example, C ink is higher than the other colors, the ink temperature at the ink inlet 146C is higher than the ink temperature at the other ink inlet 146M (Y, K). At this time, the temperature difference between the C ink and the main body 100 is larger than the temperature difference between the M, Y, K ink and the main body 100.

  For this reason, the amount of heat transferred from the ink to the main body 100 is larger for the C ink than for the M, Y, and K inks. As a result, even if the temperature of the ink inlet 146C (M, Y, K) is different for each color, the ink outlet 141C (M, Y, K) has substantially the same temperature.

  This effect is because the heat flow path 110 as the heat conducting portion is made common to all color inks. Thereby, even if the ink of arbitrary colors enters the heat exchanger 1 at an arbitrary temperature, the heat exchanger 1 not only adjusts the ink temperature of each color but also realizes averaging of the ink temperatures.

  In this embodiment, the main body 100 has a cylindrical shape, and the ink channel 160 has a cross-sectional shape that has a trapezoidal shape. However, the shape is not limited to this. For example, as shown in FIGS. 3A and 3B, the shape of the main body 10O may be a quadrangular pyramid, and the ink flow path 160 may be a quadrangular section. Further, the ink flow path 160C (M, Y, K) may be formed in a spiral shape around the central axis of the main body 100, as shown in the cross-sectional view of FIG. If the ink flow path 160C (M, Y, K) is spiral, the flow path becomes long and heat exchange is easy.

  Further, the heat flow path 110 plays a role of quickly carrying the heat transferred from the ink to the temperature adjusting means 120. In general, the heat transfer coefficient between the liquid and the solid is relatively high, and the heat resistance between the liquid and the solid can be lowered relatively easily by devising the shape of the solid-liquid interface. The factor that most affects the efficiency is the thermal conductivity from the ink to the temperature adjusting means 120. Therefore, it is important that the size, shape, and material of the heat flow path 110 are determined based on the maximum heat generation amount per unit time of the inkjet head 510, the ink physical properties, the ability of the temperature adjusting means 120, and the like.

  Assume that the heat flow path 110 is very narrow and the ink flow paths 160C (M, Y, K) are arranged very close to each other. Then, the amount of heat conducted from the portion covered with the lower lid member 145 at a position away from the temperature adjusting means 120 becomes very small, and the efficiency becomes very bad. For this reason, in this embodiment, the heat flow path 110 having a necessary and sufficient cross-sectional area is arranged.

  In the present embodiment, a Peltier element is used as the temperature adjusting means 120, but a different configuration may be used. For example, a configuration in which the heat sink 121 is directly attached to the contact portion 110A without installing a Peltier element is conceivable.

  In this case, although it is difficult to control the temperature of the heat transfer system, the ink temperatures of the respective colors are averaged, and the ink temperature is suppressed to a level slightly higher than the environmental temperature by the heat radiation from the heat sink 121. Therefore, the configuration is effective when the environmental temperature is close to a temperature suitable for ink ejection of the inkjet head 510.

  In this embodiment, the ink has four colors of C, M, Y, and K. However, any number of colors may be used as long as there are a plurality of colors, for example, a total of six colors including light cyan and light magenta. In this case, if the ink flow path is divided into six colors, the same effect can be obtained.

  In the present embodiment, the case where the gap 130C (M, Y, K) that is a part of the heat channel 110 and the ink channel 160C (M, Y, K) is integrally formed has been described. However, for example, an ink flow path 160C (M, Y, K) formed separately from a metal pipe may be disposed around the cylindrical heat flow path 110.

  In the present embodiment, since the heat flow path from the plurality of ink flow paths to the heat radiating portion is shared, the ink temperature can be averaged and optimized with a compact configuration. The ink jet printer is set so that only an amount smaller than the ink absorbable capacity of paper is ejected per unit time.

  For example, assuming that the ink absorbable capacity of paper is 100%, when ink C is ejected by 50%, the remaining inks M, Y, and K are combined and ejected only by 50% at maximum. It is known that the amount of heat generated by driving the head is substantially proportional to the ink ejection amount.

  That is, the amount of heat generated by driving the head is not determined independently for each ink color, and the sum is always set to be a certain value or less. On the other hand, when a heat radiating portion is provided for each ink color, a heat radiating portion corresponding to the maximum heat radiating amount of each ink color is required. For this reason, in this case, the sum total of the heat dissipating ability of the heat dissipating parts of the four color inks becomes excessive.

  On the other hand, in the present embodiment, the heat flow path from the ink flow paths of a plurality of colors to the heat radiating section is made common over the plurality of flow paths, and the heat radiation capability is able to cope with the total amount of heat generated by head driving. For this reason, the sum total of heat dissipation capability can be reduced, and the temperature adjusting means 120 such as a Peltier element can be small.

  In the present embodiment, the liquid to be temperature-controlled is ink, but any fluid that appropriately flows in the ink flow path 160C (M, Y, K) may be used. For example, a jelly-like material other than ink is not a problem as long as it can flow properly.

  In the present embodiment, as shown in FIGS. 2C and 2D, the heat exchanger 1 has a flow path in which three gaps 130 for one color of ink are connected in parallel by the upper lid member 140 and the lower lid member 145. It was. For this reason, the heat transfer area is large, the cooling efficiency is high, and the flow path resistance is small at the same time.

In the present embodiment, the ink cooling has been described, but the case of heating is exactly the same as the case of cooling. When a Peltier element is used as the temperature adjusting means 120, the ink can be selectively heated or cooled depending on the direction of the current.
(Second Embodiment)
FIG. 5 is a cross-sectional view of the heat exchanger 1 for explaining the second embodiment. Also, description of the same parts as those of the first embodiment described above will be omitted, and only different points will be mainly described.

  In the present embodiment, six of the twelve voids formed in the main body 100 are used for the ink flow path 160K, and the rest are equally divided by the ink flow paths 160C, M, and Y. Thereby, the heat exchanger 1 has a configuration in which the black ink flow paths 160K are arranged between the three color ink flow paths 160C, M, and Y, respectively. At this time, three ink inlets 146K and three ink outlets 141K are located at locations separated from each other. These flow paths branch or merge outside the heat exchanger 1.

That is, the black ink flow paths 160K are dispersedly arranged. Accordingly, heat flows from the ink flow path 160K to the other ink flow paths 160C, M, and Y.
According to this embodiment, when the heat generation amount of ink K per time is larger than that of other colors, the heat transfer area between ink K and heat flow path 110 can be increased. Further, the heat dissipation amount of the ink K can be increased by making the flow path of the ink of the other color having a relatively low temperature adjacent to the flow path of the ink K.

  Further, according to the present embodiment, for example, it is also effective when the specific heat of the ink K is larger than the specific heat of the inks of other colors. For example, when the apparatus is started at a high temperature, the amount of heat necessary for cooling to an appropriate ink temperature is larger for ink K than for other colors.

  Furthermore, this embodiment is suitable for increasing the heat dissipation amount of a specific liquid. For example, when the heat generation amount of ink other than ink K is large, it is necessary to relatively increase the heat transfer area of the ink.

In order to further improve the heat transfer efficiency, it is conceivable to form protrusions or protrusions on the walls of the gap 130. Furthermore, a method of increasing the heat transfer area or inducing a secondary flow by complicating the shape of the flow path, such as a spiral flow path, is also effective.
(Third embodiment)
FIG. 6 is a cross-sectional view of the heat exchanger 1 for explaining the third embodiment. Also, description of the same parts as those of the first embodiment described above will be omitted, and only different points will be mainly described.

  In the present embodiment, in the heat exchanger 1 of the second embodiment, the ink flow path 160K is disposed on the inner side (center side of the heat flow path 110) than the other ink flow paths 160C (M, Y). It is.

  For example, when the heat generation amount of K ink per hour is larger than that of other color inks, the heat transfer rate from the K ink to the heat flow path 110 is improved by positioning the K ink on the center side of the heat flow path 110. Is planned. Accordingly, the heat dissipation amount of the K ink can be increased more than the heat dissipation amount of the other color inks.

According to the present embodiment, the configuration of the heat exchanger 1 is more complicated than that of the second embodiment, but has an advantage that the heat dissipation amount of a specific liquid can be increased.
(Fourth embodiment)
FIG. 7 is a cross-sectional view of the heat exchanger 1 for explaining the fourth embodiment. Also, description of the same parts as those of the first embodiment described above will be omitted, and only different points will be mainly described.

  In the present embodiment, a fluid is used as the heat channel 110, and the fluid is filled in the container 143. As the fluid to be used, a liquid having good thermal conductivity such as water or liquid metal is typically preferable. In addition, this fluid is required to have poor chemical reactivity at the contact portion with other members. Except for the contact part 110A of the temperature adjusting means 120, the container 143 is preferably a highly heat-insulating material such as an acrylic resin.

  Further, the contact portion 110A between the fluid (the heat flow path 110) and the temperature adjusting means 120 is preferably a material having high thermal conductivity such as aluminum or copper. Further, the ink flow path 160C (M, Y, K) is a solid tube that passes through the container 143, and preferably has a good thermal conductivity such as a thin metal pipe made of aluminum or copper.

  Further, cooling fins may be formed in the ink flow path 160C (M, Y, K). At this time, a fin shape that does not disturb convection, for example, a pin fin, a plate fin formed in a vertical direction, or the like is suitable.

  According to the present embodiment, convection is induced in the fluid by the temperature difference between the fluid and the wall surface temperature of the ink flow path 160 </ b> C (M, Y, K) and the temperature difference between the fluid and the contact portion 110 </ b> A of the temperature adjusting unit 120. Thereby, since this convection contributes to heat transfer, it is efficient. However, convection is likely to be induced when the temperature adjusting means 120 is at the top and the ink is cooled, and conversely, when the ink is heated, convection hardly occurs. For this reason, the temperature adjusting means 120 may be provided at the bottom of the container 143 when the ink is heated.

  In the present embodiment, since the heat flow path 110 is a fluid, manufacturing and processing are easy. In addition, since the ink flow path 160C (M, Y, K) can be made of a metal tube or the like, it can be easily made even with a complicated shape such as a spiral or a turn.

  Further, although the Peltier element is used as the temperature adjusting unit 120, for example, instead of the temperature adjusting unit 120, the ink may be directly cooled by using a fluid as a refrigerant such as chlorofluorocarbon.

  In the present embodiment, the case where the heat exchanger 1 is used for ink temperature control of the ink circulation type ink jet printer 500 has been described. However, instead of the ink circulation type, for example, the heat exchanger 1 may be interposed between the one-way flow path connected from the ink tank 555 to the inkjet head 510.

  Moreover, the heat exchanger 1 of this Embodiment can also be mounted, for example in a vehicle handle, and can be utilized for the heating or cooling of the cooling water or lubricating oil in an internal combustion engine. Furthermore, it can also be used for temperature adjustment of liquid seasonings, for example, in processed food production lines.

1 is a block diagram of an ink jet printer according to a first embodiment. It is a top view of the heat exchanger which concerns on 1st Embodiment. It is sectional drawing which follows A-A 'of the heat exchanger which concerns on 1st Embodiment. It is a top view of what remove | excluded the upper cover member, the lower cover member, etc. from the heat exchanger which concerns on 1st Embodiment. It is sectional drawing in B-B 'of the main body which concerns on 1st Embodiment. It is sectional drawing which follows B-B 'of the main body which concerns on the modification of 1st Embodiment. It is sectional drawing which follows A-A 'of the heat exchanger which concerns on the modification of 1st Embodiment. It is sectional drawing which follows A-A 'of the heat exchanger which concerns on the modification of 1st Embodiment. It is sectional drawing in alignment with B-B 'of the main body which concerns on 2nd Embodiment. It is sectional drawing which follows B-B 'of the main body which concerns on 3rd Embodiment. It is sectional drawing which follows A-A 'of the heat exchanger which concerns on 4th Embodiment.

Explanation of symbols

1 heat exchanger 100 main body 100F fluid 110 heat flow path (heat conduction part)
110A Contact portion 120 Temperature adjustment means 121 Heat sink 122 Fan 130C, M, Y, K Air gap 140 Upper lid member 141C, M, Y, K Ink outlet 143 Container 145 Lower lid member 146C, M, Y, K Ink inlet 150 Seal member 160C, M, Y, K Ink channel (channel)
500 Inkjet printer 510 Inkjet head 520 Ink 530 Recording medium 540 Medium transport means 550 Upper tank 551 Lower tank 555 Ink tank 560 Pumps 570, 571, 572, 573 Electromagnetic valve

Claims (8)

A plurality of flow paths extending substantially parallel are branched from each other, and a heat conducting portion for performing liquid heat exchange flowing through the plurality of flow passage, a temperature adjusting means for adjusting the temperature of at least a portion of the heat conducting portion In a heat exchanger comprising:
The plurality of flow paths are formed around the center of the heat conducting portion, the heat exchanger being characterized in that The heat exchanger according to claim 1, wherein the plurality of flow paths are formed at a predetermined distance from the heat conducting portion. The heat exchanger according to claim 1, wherein the plurality of flow paths are formed integrally with the heat conducting unit. The heat exchanger according to claim 1, wherein the plurality of flow paths are formed separately from the heat conducting unit. The heat transfer area of a relatively high temperature or high specific heat liquid channel among the liquids flowing in the plurality of channels and the heat conducting part is formed to be relatively large. Item 2. The heat exchanger according to Item 1. 2. The flow path of a liquid having a relatively high temperature or high specific heat among the liquid flowing in the plurality of flow paths is formed closer to the heat conducting unit than the other flow paths. The described heat exchanger. A relatively low temperature liquid flow path is formed adjacent to a relatively high temperature or high specific heat liquid flow path among the liquid flowing in the plurality of flow paths. The heat exchanger according to claim 1. A recording head for ejecting ink to a recording medium based on a drive signal;
An ink supply path for supplying ink to the recording head having at least a plurality of flow paths;
A recording medium transport unit that transports the recording medium relative to the recording head;
An image forming apparatus comprising: the heat exchanger according to claim 1 disposed in the ink path.