JPH03227651A - Temperature adjusting member and ink jet recording head unit provided with same temperature adjusting member and ink jet recording apparatus loading same unit - Google Patents

Abstract

PURPOSE:To shorten the extending length of a condensing part while maintaining the regenerating efficiency enough thereby to make the apparatus compact by making the width of a second regenerating part (condensing part) in a direction perpendicular to a longitudinal direction of a temperature adjusting member along a recording head larger than that of a first regenerating part. CONSTITUTION:In a condensing part 30 having an extension of a heat pipe 6 of a recording head 1 and cooled by a cooling fan 11, there are provided a plurality of cooling fins 7 along a direction of the air flow from the fan 11. The width L3 of the heat pipe 6 of the condensing part 30 is made larger than the width L2 where the heat pipe 6 is in touch with the recording head 1 to receive and transmit the heat, and the length L1A in a longitudinal direction of the heat pipe 6 at the condensing part 30 is set smaller. The width L2 is preferably 1.3 to 5 times the width L3 from the viewpoint of the improvement of the regenerating characteristics. The length L1A of the condensing part is also influenced by the relation between L2 and L3. If the length of the condensing part in the longitudinal direction of the heat pipe is reduced while the radiation efficiency at the condensing part 30 is maintained equivalent, the recording apparatus becomes compact in size.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a temperature adjusting member for an inkjet recording head that can be applied to a recording section of a high-speed recording type device as a recording means of a copying machine, a fax machine, etc., and the adjusting member. Regarding an inkjet recording head unit equipped with an inkjet recording head unit and an inkjet recording apparatus equipped with this unit, specifically, for a recording head that performs recording using thermal energy, a temperature adjustment member for controlling the temperature of the recording head and the adjustment member are provided. The present invention relates to an inkjet recording head unit and an inkjet recording apparatus equipped with the unit.

[Background technology] Traditionally, recording methods that utilize thermal energy, such as thermal type and thermal transfer type, have been used for recording facsimiles, copying materials, etc. because they provide highly reliable and high-quality images. It has been widely used in equipment. In recent years, it has become increasingly possible to achieve even higher speeds, higher reliability, and higher quality, by heating the recording liquid using a thermal energy generating means and using the change in the state of the recording liquid due to the film boiling phenomenon to generate flying liquid. Bubble jet type (BJ) recording apparatuses that perform recording by landing droplets on a recording material are attracting attention.

However, recording devices that utilize such thermal energy generally use a multi-head in which a plurality of thermal recording elements are arranged to form recording dots using thermal energy, in order to increase speed. When using a thermal head, the temperature rise of the entire head is large, and the temperature distribution tends to vary among the recording elements used, resulting in a temperature distribution that varies in the direction in which the thermal recording elements are arranged (this causes density unevenness in the recorded image). There were cases where this was a contributing factor.

Therefore, in order to solve this problem, a recording device equipped with a heat pipe that exchanges heat with the recording head is used as a means to adjust the temperature of the recording head along the arrangement direction of the thermal recording elements of the multi-head. The present inventors proposed this at the development stage. FIG. 4 shows an example of the configuration of a recording apparatus having such a recording head 1, in which the recording head 1 and the heat vibro are integrally constructed via a support member 2 and fixed. Reference numeral 9 denotes a recording material (hereinafter referred to as a sheet) that is fed in the direction of the arrow by a conveyance means (not shown) along the ink ejection surface IA of the recording head unit 10 integrated in this way; 12 is a heater 8 and a fan 11 for cooling the heat vibro.
A controller 13 is a temperature sensor provided at the connection between the heat vibro and the support member 2.

Now, in the above-described recording apparatus, when the switch to start the recording operation is turned on, first, the temperature of the support member 2 is detected by the temperature sensor 13. If the temperature of the controller 12 is lower than a predetermined temperature (hereinafter referred to as the specified temperature) that must be maintained during recording operation, the controller 12 turns on the heater 8.
“ON” L, the support member 2 is heated. in this case,
The first one located on the adhesive surface with the support member 2 of the heat vibro.
On the heat exchange section side, in order to uniformly spread and condense the working liquid in the heat vibro that has been evaporated by the heating from the heater 8, and to uniformly release the heat, the support member 2 receives a uniform heat flow rate and is uniformly heated. The temperature rises to .

Furthermore, when the temperature detected by the temperature sensor 13 reaches the specified temperature or higher than the allowable value, the controller 12 activates the fan 11 to send air to the fins 7 and start dissipating heat from the recording head l via the heat vibro. . In this case, the contact surface between the heat vibro and the support member 2 (first heat exchange section)
, a large amount of working fluid evaporates from the portion where the heat flow rate from the support member 2 is large, and a small amount of working fluid evaporates from the portion where the heat flow rate is small, and the temperature increases depending on the amount of evaporation. Therefore, a large amount of heat and a small amount of heat are absorbed into steam. Also, for a part where there is no inflow of total heat flow rate, -
The working liquid, which has become vapor, condenses there and releases latent heat.
Provides heat. Since there is almost no thermal resistance in the steam part and the amount of heat transfers instantaneously, the interface temperature is maintained almost uniformly even if the heat flow rate flowing into the heat vibro is uneven.

Therefore, even if heat flows into the support member 2 with uneven heat flow velocity depending on the recording signal, the support member 2 can be kept at a substantially uniform temperature by the temperature equalization effect inside the heat vibro. (Thus, even if the interface temperature is made uniform, the remaining amount of heat is instantaneously conducted to the part where the fins 7 are provided (hereinafter referred to as the condensing part (second heat exchange part)) 20, where it is It condenses and generates heat, which is transmitted to the air flow sent from the fan 11 via the fins 7 and released into the air.

In this way, during the recording operation, the temperature of the recording head l is always kept uniform and maintained at the specified temperature via the support member 2. Since the recording head can be held nearby, stable recorded images can be formed regardless of the length of the recording head.

[Problem to be solved by the invention]

However, in an inkjet recording apparatus equipped with a long multi-head recording head using the above-mentioned thermal energy generating means, in order to ensure that sufficient heat exchange is performed with respect to the recording head 1, The length Ll of the heat vibro (hereinafter referred to as the second heat exchanger condensing section) 20 in the extending direction is formed to be sufficiently longer than the width L2 of the heat vibro, as shown in FIG. This was a major factor in increasing the size of the entire recording device.

To give a specific example, if the metering head l shown in Fig. 4 is an A3 size BJ type multi-head with a density of 400 dpi, in order to keep the temperature at 50°C or less during recording operation, it is necessary to The length Ll of the condensing section 20# is approximately 200m+
+m, and it was necessary to install the radiation fins 7 between them.

The purpose of the present invention is to focus on such problems to be solved,
In order to solve this problem, we developed a thermal energy-based recording system that does not require an increase in the size of the device, and that efficiently and sufficiently adjusts the temperature of the recording head via a heat vibrator to obtain good recorded images. The goal is to provide equipment.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a method of contacting a recording head portion having an array of ejection ports for ejecting ink and exchanging heat with the recording head portion. In the temperature adjusting member, the temperature adjustment member includes a first heat exchange section that performs heat exchange and a second heat exchange section that extends outside of the recording head section and performs heat exchange. It is characterized by having a relationship of Ll<L3, where Ll is the length of the droplet in the direction along the discharge direction, and L3 is the length of the second heat exchanger in the same direction. be.

Further, a recording head configured by arranging ejection ports for ejecting ink, a first heat exchange section that contacts a side surface of the recording head and exchanges heat with the recording head section, and the recording head and a second heat exchange section extending outward from the head to perform heat exchange. In the recording head unit, the temperature adjustment member includes a second heat exchange section extending outside the head and performing heat exchange, wherein the recording head of the first heat exchange section of the temperature adjustment member It is characterized by having a relationship of Ll<L3, where Ll is the length of the droplets along the ejection direction from the heat exchanger, and L3 is the length of the second heat exchanger along the same direction. be.

Furthermore, a recording head configured by arranging ejection ports for ejecting ink, a first heat exchange section that contacts a side surface of the recording head and exchanges heat with the recording head section, and the recording head. a temperature adjusting means including a second heat exchange section extending outward from the head and performing heat exchange; and a conveyor for conveying a recording material on which an image is formed by the ink ejected from the ejection port. In the inkjet recording apparatus, Ll is the length of the first heat exchanger of the temperature adjustment member in a direction along the ejection direction of droplets from the recording head, and The length along the same direction is L3
It is characterized by having the relationship Ll<L3.

[Function J] According to the present invention, the width of the condensing part in the direction perpendicular to the longitudinal direction of the heat vibrator is made wider than the width of the heat vibrator in the same direction. It is possible to secure the same heat dissipation area even if the length is shortened (to implement efficient head temperature control) without increasing the longitudinal width of the recording head in the recording device.
be able to.

〔Example〕

Embodiments of the present invention will be described in detail and specifically below based on the drawings.

FIG. 1 shows an example of a recording head using thermal energy to which the present invention is applied. Here, reference numeral 30 is provided at the extension of the heat vibro attached to the recording head l, and the cooling fan 11
The condensing section is cooled by The condensing section 30 is provided with a plurality of cooling fins 7 along the flow direction of the air from the fan 11. In this embodiment, the condensing section 3
The width L3 of the heat vibro at 0 is made sufficiently larger than the width L2 at the contact portion of the heat vibro where heat is exchanged with the recording head l, and instead, the length of the condensing portion 30 in the extending direction is Short (form) LIA.

In this example, Ll and L3 are as described above <Ll<L3
However, from the viewpoint of improving heat exchange characteristics, it is preferable that L3 is about 1.3 to 5 times longer than L1, and preferably about 1.5 to 3 times longer than L1. More preferred. However, the relationship between Ll and L3 is also influenced by the length of the condensing section Ll, and LI
The length of L3 relative to Ll is determined within a range that allows the surface area indicated by AXL3 to satisfy the desired heat exchange characteristics and the relationship with the storage space of the installation part, and is not necessarily limited to the above-mentioned value range. (Selected as appropriate.

(Thus, the heat radiation area L in the condensing section 20 shown in FIG.
By setting the heat dissipation area LIAXL3 in the condensing section 30 in FIG. 1 to correspond to IXL2, the condensing section 3
The length in the extending direction can be shortened while maintaining the same heat dissipation capacity at zero, and the recording apparatus can be made smaller.

FIG. 2 is a schematic side view showing an example of an inkjet recording apparatus equipped with an inkjet recording head unit equipped with the temperature adjustment member described above.

In Fig. 2, 1Bk, ly, 1m, and lc are bubble jet recording heads corresponding to black, yellow, magenta, and cyan ink colors, respectively.
A heating resistor is used as a built-in ejection energy generator, and ink droplets are ejected from an ejection port using bubbles generated in the ink when electricity is applied as a pressure source, and is fixed to a block 22. Each recording head has 4473 ejection ports arranged at a density of 400 dpi. A heat pipe as a temperature adjustment means as shown in FIG. 1 is attached to this recording head.

23 is a capping unit, during standby etc.
At the time of non-recording, the block 22 is pulled up to the position shown by the dashed line in the figure, and the units 23 are faced and capped. Further, during circulation recovery, the capping unit 23 serves as a tray for receiving waste ink fed from a recovery pump and an ink supply system (not shown) and pushed out from an ejection port. The waste ink is led to a waste ink tank (not shown).

Reference numeral 24 denotes an endless charged adsorption belt which is disposed facing each of the recording heads 1Bk, ly, 1m and lc at a predetermined interval for conveying the recording sheet, and 25 is connected to each recording head via the charged adsorption belt 4. These are back platens arranged opposite to each other.

26 is a paper feed cassette which stores recording sheets 7 such as plain paper and is removably attached to the main body of the apparatus, and 28 is a pickup roller that feeds and feeds only one recording sheet 27 on the uppermost surface. A conveyance roller 29 conveys the recording sheet 27 sent out from the pickup roller 28 to a conveyance path 30, and a conveyance roller 31 is disposed on the exit side of the conveyance path 30.

33 and 34 are heaters and fans that use hot air to dry and fix ink droplets attached to the recording sheet 27 during recording; 35 is a discharge roller that discharges the fixed recording sheet 27 out of the apparatus; and 36 is a discharged recording sheet. 2
This is a tray that stores items 7 in sequence.

Next, we will discuss application examples used in actual experiments.

In the experiment, an inkjet recording head using a bubble jet method was used as the thermal recording head 1, and in particular, 400 dpi,
A full multi-head for A3 size paper having a total of 4473 ejection ports was used. Further, as the heat vibrator 6, one having a tube material of 1, a working fluid of Freon 11, and a maximum heat transport capacity of 70 W was used. At this time, the heat vibro has a width L2
= 17mm, condensing part width L3 = 34mm, thickness both 8ma
I used one with a + square shape. By forming the heat vibrator in this way, the length of the condensing section, which conventionally required about 200 mm, can be reduced to 50 mm, and the device can be made smaller without impairing its heat dissipation ability.

FIG. 3 shows another embodiment of the invention. This example shows a suitable example when recording is performed with the recording head 1 facing downward on the recording material 9. In this example as well, the length CIA in the extending direction of the heat vibro is made as short as possible (the width L3 of the condensing part is changed to the width L2 of the portion of the heat vibro that maintains contact with the recording head l).
Making it wider is the same as in FIG. 1, but in this example, by configuring the condensing section 40 with the lower surface of the first heat exchange section as shown by arrow A, it is assumed that L3 is made wider. Compared to the case where the condenser section 40 is extended and expanded, it is possible to prevent the working fluid cooled and liquefied in the condensing section 4o from accumulating at the bottom of the condensing section 40 due to gravity and making it difficult to circulate, thereby allowing efficient heat dissipation. be able to.

(Others) The present invention brings about excellent effects particularly in a bubble jet type recording head and recording apparatus among inkjet recording types.

This is because such a system can achieve higher recording density and higher definition.

As for typical configurations and principles thereof, it is preferable to use the basic principles disclosed in, for example, US Pat. No. 4,723,129 and US Pat. No. 4,740,796. This method can be applied to both the so-called on-demand type and continuous type, but especially in the case of the on-demand type, it is necessary to arrange the liquid (ink) in accordance with the sheet and liquid path that hold it. The electrothermal converter that is
Generating thermal energy in the electrothermal transducer and producing film boiling on the thermally active surface of the recording head by applying at least one drive signal that corresponds to recorded information and provides a rapid temperature rise above nucleate boiling. This is effective because, as a result, bubbles in the liquid (ink) can be formed in pairs corresponding to the drive signals. The growth and contraction of the bubble causes liquid (ink) to be ejected through the ejection opening to form at least one droplet. If this drive signal is in the form of a pulse, bubble growth and contraction will occur immediately and appropriately.
Particularly responsive liquid (ink) ejection can be achieved,
More preferred. This pulse-shaped drive signal is described in U.S. Pat. Nos. 4,463,359 and 4,345,262.
Those described in the specification are suitable. Furthermore, if the conditions described in US Pat. No. 4,313,124 concerning the invention regarding the temperature increase rate of the heat acting surface are adopted, even more excellent recording can be performed.

The configuration of the recording head includes, in addition to the combination configuration of ejection ports, liquid paths, and electrothermal converters (straight liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned specifications, a heat acting section. The present invention also includes configurations using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose configurations in which the wafer is placed in a bending region. In addition, Japanese Patent Application Laid-Open No. 1989-5 discloses a configuration in which a common slit is used as a discharge part of a plurality of electrothermal converters.
No. 9-123670 and Japanese Patent Application Laid-Open No. 59/1989 which discloses a configuration in which a discharge portion is made to correspond to an opening that absorbs pressure waves of thermal energy.
The effects of the present invention are also effective even if the structure is based on the publication No.-138461. In other words, regardless of the form of the recording head, recording can be performed reliably and efficiently.

Further, the present invention can be particularly effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium that can be recorded by a recording apparatus. Such a recording head may have a configuration in which the length is satisfied by a combination of a plurality of recording rads, or a configuration in which one recording head is formed in one direction.

In addition, even if it is a serial type, it may be a replaceable chip type print head that can be attached to the main body of the device to enable electrical connection with the main body of the device or supply of ink from the main body of the device, or the print head itself. It is also possible to apply the present invention when using a cartridge type recording head that is integrally provided with the recording head.

Further, it is preferable to add recovery means for the recording head, preliminary auxiliary means, etc., which are provided as a configuration of the recording apparatus, to the present invention, because the effects of the present invention can be further stabilized. Specifically, these include capping means for the recording head, cleaning means, pressure or suction means, preheating means using an electrothermal transducer or another heating element, or a combination thereof; It is also effective to perform a preliminary ejection mode in which ejection is performed separately from printing in order to perform stable printing.

Also, with regard to the type and number of recording heads mounted, for example, only one recording head is installed corresponding to monochromatic ink.
In addition to the above, a plurality of inks may be provided corresponding to a plurality of inks having different recording colors and densities.

In addition, the inkjet recording apparatus of the present invention may take the form of an image output terminal for information processing equipment such as a computer, a copying apparatus combined with a reader, etc., or a facsimile apparatus having a transmitting/receiving function. It may be something.

〔Effect of the invention〕

As explained above, according to claim 1 of the present invention,
The second heat exchange section (condensing section) is connected to the width L2 of the first heat exchange section along the recording head in a direction perpendicular to the longitudinal direction of the temperature adjustment member.
Since the width L3 in the same direction is widened, the extension length LIA of the condensing section can be shortened while the heat exchange capacity is sufficiently maintained, and a temperature adjustment member that can be miniaturized can be provided. Further, according to claim 3, it is possible to provide an inkjet recording unit that is similarly small in size, can perform sufficient heat exchange and temperature adjustment, and always performs stable ejection at a uniform temperature.Furthermore, according to claim 8, For example, it is possible to provide an inkjet recording device that can reduce the size of the device, increase heat exchange efficiency, accurately adjust the temperature of the recording head (uniformly), and achieve stable ink ejection and high-quality recording. can.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of the configuration of a recording head and its temperature control means according to the present invention; FIG. 2 is a schematic side view showing an example of an inkjet recording apparatus in which the recording head unit of the present invention can be installed; The figure is a perspective view showing the configuration of another embodiment of the present invention. FIG. 4 is a perspective view showing the structure of a conventional example, and FIG. 5 is an explanatory diagram showing the structure of a conventional recording head and its temperature control means. l...Recording head, 6...Heat pipe, 7...Fin, 8...Heater, 9...Recording material, 11...Fan, 13...Temperature sensor, 20...・Condensing part, Ll, LIA...Condensing part length, Ll...Heat vibe width, L3...Condensing part width.

Claims (1)

[Scope of Claims] 1) A first heat exchange section that contacts a recording head section having an array of ejection ports for discharging ink and exchanges heat with the recording head section, and an external part of the recording head section. and a second heat exchange section extending in the direction to perform heat exchange, the length of the first heat exchange section in the direction along the ejection direction of droplets from the recording head section. L2 is the length of the second heat exchange section along the same direction, and L3 is the length of the second heat exchange section in the same direction. 2) A claim characterized in that the length L3 of the second heat exchange part has a relationship within a range of 1.1 times or more and 5 times or less with respect to the length L2 of the first heat exchange part. Item 1. Temperature adjustment member according to item 1. 3) A recording head configured by arranging ejection ports for ejecting ink, a first heat exchange section that contacts a side surface of the recording head and exchanges heat with the recording head section, and the recording head. A recording head unit comprising: a temperature adjusting member including a second heat exchanger extending outward from the head and performing heat exchange; the recording head of the first heat exchanger of the temperature adjusting member; Inkjet recording characterized by having a relationship such that L2<L3, where L2 is the length of the droplets along the ejection direction from the second heat exchanger, and L3 is the length of the second heat exchanger in the same direction. head unit. 4) The length L3 of the second heat exchange part with respect to the length L2 of the first heat exchange part has a relationship in a range of 1.3 times or more and 5 times or less. The inkjet recording head unit described. 5) The recording head is of a full-line type in which the ejection openings are formed corresponding to the entire recording width of a recording material on which ink is ejected to form an image. inkjet recording head unit. 6) The inkjet recording head unit according to claim 3, wherein there are a plurality of recording heads, and each recording head is provided with the temperature adjusting means. 7) The recording head is of a type that discharges ink using thermal energy, and has an electrothermal converter as a thermal energy generating means.
or 6. The inkjet recording head unit according to any one of 6. 8) A recording head configured by arranging ejection ports for ejecting ink, a first heat exchange section that contacts a side surface of the recording head and exchanges heat with the recording head section, and the recording head. a temperature adjusting means including a second heat exchange section extending outward from the head and performing heat exchange; and a conveyor for conveying a recording material on which an image is formed by the ink ejected from the ejection port. means and
In the inkjet recording apparatus, the length of the first heat exchange section of the temperature adjustment member in the direction along the ejection direction of droplets from the recording head is L2, and the length of the second heat exchange section is in the same direction. An inkjet recording apparatus characterized by having a relationship of L2<L3, where L3 is the length along the line. 9) The length L3 of the second heat exchange part with respect to the length L2 of the first heat exchange part has a relationship in a range of 1.3 times or more and 5 times or less. The inkjet recording device described above. 10) The recording head is of a full-line type in which the ejection openings are formed corresponding to the entire recording width of a recording material on which ink is ejected to form an image. inkjet recording device. 11) The inkjet recording apparatus according to claim 8 or 10, wherein there is a plurality of recording heads, and each recording head is provided with the temperature adjustment means. 12) The inkjet recording according to claim 11, wherein the plurality of temperature adjustment means provided for the plurality of recording heads are in communication with each other in a part of the second heat exchange section. Device. 13) The recording head is of a type that discharges ink using thermal energy, and has an electrothermal converter as a thermal energy generating means.
12. The inkjet recording device according to any one of 10, 11, and 12. 14) The inkjet recording apparatus according to any one of claims 11, 12, and 13, wherein the plurality of recording heads are capable of performing full-color recording by ejecting different colors respectively.