JPH0358849A - inkjet recording device - Google Patents

Abstract

PURPOSE:To achieve reduction of cost by removing electric power loss by a method wherein a first heat pipe established as an annex to each recording head is extended outside a recording area of the recording head, and a second heat pipe connected to each of a plurality of extended first heat pipes outside the recording area is provided. CONSTITUTION:Temperatures of heat pipes 16 of recording head units 11A to 11D are mutually equalized via second heat pipes 18, 19. This temperature is detected by a detection means 21, and heating means 20 and a cooling means 23 are operated by a control means 26 based on this detection value. Thereby temperatures of all recording head units 11A to 11D are controlled under same condition. As a result, electric power loss is removed, and its structure can be simplified.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is characterized in that line-type recording head units arranged parallel to each other are disposed orthogonally to the feeding direction of a recording material, and each recording head is moved at a predetermined timing. The present invention relates to an inkjet multicolor recording device that performs color recording by ejecting ink from a unit to a predetermined location.

(Prior art) Inkjet recording devices that eject ink from a recording head to record characters, images, etc. on a recording material (e.g. continuous paper or cut paper) produce less noise than other types of recording devices. , has the advantage that the mechanical structure is basically simple and low cost, and is widely used as a multicolor recording device. Especially in recent years, in order to increase the recording speed,
An inkjet multicolor recording apparatus has been proposed in which a line type recording head unit is disposed over the entire width of a recording material and ink is ejected from orifices corresponding to required locations. Here, since the ink ejection status sensitively responds to changes in the temperature of the head base, control is required to maintain a constant temperature over the entire print area of the print head unit. In particular, in a line-type recording head unit that uses an inkjet method that uses thermal energy, such as thermal bubble inkjet, which utilizes the night phase change of ink using thermal energy, the recording head performs localized printing or image recording. However, it is necessary to control the temperature to maintain a uniform and constant temperature state so that temperature unevenness and temperature changes over time do not occur throughout the head.

(Problems to be Solved by the Invention) Therefore, the present inventors proposed a recording head unit having a structure in which a heat pipe 2 is attached to a line type recording head 1, as shown in FIG. Here, the recording head 1 has a large number of orifices arranged in parallel in the width direction toward the recording material A, and is equipped with an element that applies thermal energy to the ink supplied to each orifice. In order to balance the temperature as a whole, the attached heat pipe 2 is provided with heating means 3, heat radiation means and cooling means 4, temperature detection means 5, etc., and the detection result of the temperature detection means 5 is Based on this, the control means 6 operates to drive the heating means 3 or the cooling means 4.

However, in a multicolor recording apparatus, a large number of such recording head units must be arranged in parallel on the recording material A. As a result, the overall configuration becomes complicated, resulting in high costs. In particular, the heat dissipation means and the cooling means 4
The recording head unit is large due to the use of heat dissipation fins, a blower, etc., which not only increases cost but also requires widening the distance between the recording head units. For this reason, it is difficult to perform highly accurate registration (positional misalignment when recording colors in an overlapping manner), and there is a problem in that the overall size of the apparatus increases.

Therefore, as shown in FIG. 6, in a multicolor recording apparatus, each of the heat pipes 2a to 2d has extension portions 2a' to 2d outside the recording area.
A heat radiation means 41 common to d' and a cooling means 42 for cooling the heat radiation means 41 are provided to form a single block of forced heat radiation means 4o. Here, the heat pipes 2a to 2 are connected to each of the recording heads 1a to 1d, respectively.
In addition, within the recording area, the heat pipes 2a to 2d are provided with heating means 3a to 3d and temperature detection means 5a to 5d, respectively. In this way, the relative spacing between the recording head units can be made as narrow as possible, which is advantageous in terms of registration. However, the problem here is that each recording head 1a
1d is unevenly used, for example, when monochromatic black recording is performed, the control signal for the cooling means 42 is controlled based on the detected temperature of the recording head, and the corresponding control signal is also controlled for the recording head that is not in use. This results in the heat pipe being cooled. At this time, these temperature detection means detect the temperature drop of the corresponding recording head and send it to the control means 6, while the heating means is activated for them, and overall cooling and heating are performed at the same time. However, there remains the problem that the electric charge loss increases.

(Object of the Invention) The present invention has been made based on the above circumstances, and has a simple overall configuration, heating and cooling are performed in common for all heat pipes, and there is no power loss.
It is an object of the present invention to provide an inkjet type multicolor recording device that is devised so that the relative spacing between each recording head unit can be made as narrow as possible.

(Means for Solving the Problem) Therefore, in the present invention, in an inkjet recording apparatus that performs recording by discharging ink at a predetermined location at a predetermined timing from a plurality of print head units arranged parallel to each other, each of the above-mentioned A first heat pipe attached to a recording head extends outside the recording area of the recording head, and a second heat pipe connects with each of the plurality of extended first heat pipes outside the recording area. A pipe is installed.

(For I) In such a configuration, the temperatures of the heat pipes of each recording head unit are averaged with each other via the second heat pipe, and this temperature is detected to operate the heating means or cooling means. By doing so, temperature control can be realized under the same conditions for all recording heads, there is no power loss, and
The structure is also simple, and the spacing between each recording head can be set relatively narrow, making registration easier.

(Example) Hereinafter, an example of the present invention will be specifically described with reference to the drawings. In FIG. 1, reference numerals 11A to 11D are recording head units for color inks such as black, cyan, magenta, and yellow, and the elongated direction thereof is oriented in a direction perpendicular to the feeding direction of the recording material A. , are arranged in parallel with each other at predetermined intervals. As shown in FIG. 2, each head unit includes a recording head 15 provided with an ink chamber 13 on a substrate 14, which is provided with a large number of pores 12 arranged in the width direction of the recording material A, and a recording head 15. It consists of a flat type I heat pipe 16 connected to the ink chamber 13 at a first region 16a, and is attached to an apparatus frame (not shown) via a support member 17. There is. The orifice 12 also includes at least one element (not shown) that applies thermal energy to the ink.
The temperature of these elements is controlled to eject ink. And the orifice 12
is communicated with an ink supply means (not shown) via an ink chamber l3. The heat pipe 16 has a wick made of wire mesh or the like on its inner wall surface, and has a second area 16b extending outside the recording area of the recording head.
Both are formed flat so that they are perpendicular to each other, that is, in directions with a 90 degree phase difference (see FIG. 3).

A flat second heat pipe 18, 19 is disposed across the heat pipes 16 of all the recording head units IIA to LID so as to sandwich the second region 16b. It is connected to the flat surface of the heat pipe l6.

A plate-shaped heating means 20 such as a heater is provided on the heat pipe 18, and a temperature detection means 2l is provided on the lower surface thereof between the first heat pipes 16. Furthermore, a heat radiating means 22 having comb-like heat radiating fins is provided below the heat pipe 19, and a cooling means 23 for forcibly radiating heat by air cooling such as a blower is disposed correspondingly to this heat radiating means 22.

As shown in FIG. 4, the heat pipe 18 or 19 has a known configuration in which wire mesh wicks 27, 27' are arranged on the upper and lower surfaces of the inside, and sintered metal wicks 24 are arranged in the middle at predetermined intervals. The upper and lower heat plates 25 and 25' are respectively connected to the flat surface of the first heat pipe 16 (i.e., the second region 16b), the heating means 2o, and the heat radiation means 2.
It is connected to 2. Further, the output signal of the temperature detection means 21 is taken into the control means 26, and an operation signal is given to the heating means 20 or the cooling means 23 accordingly.

The recording head includes a thermal energy generating element (electrothermal converter) as an ejection energy generator that generates thermal energy used to eject ink,
@ caused by bubbles generated by the thermal energy.
Ink is ejected by making use of pressure changes. With such a configuration, each recording head unit IIA to LID
The temperature change at is brought to the heat pipes 18 and 19 via each heat pipe 16 and is equalized by heat transfer. Then, the temperature of the heat pipe l8 is detected, and the heat pipe 18 is heated or the heat pipe l9 is cooled, and the temperature change is transmitted to each heat pipe 16 to control the temperature of each recording head l5. Serve. Because of this function, there is no power loss, and the structure is simple because the heating means 20, heat radiation means 22, cooling means 23, etc. are shared, and the mutual spacing between the recording head units IIA to 11D can be adjusted. This has the advantage of making registration easier because it can be made as narrow as possible.

In addition, in a multi-color recording apparatus like this embodiment, three or more colors are not recorded simultaneously (because the combination of three colors only requires one color, black), and therefore, the recording head unit The simultaneous ejection of two colors or less is advantageous in terms of power design for heat dissipation. Further, one of the heat pipes 18 and 19 may be replaced with a metal material having good thermal conductivity. Or the heat pipe 18
Alternatively, 19 may be constructed by arranging a plurality of flat vibrator-like objects in parallel.

Furthermore, although the inkjet method in which ink is ejected under thermal energy control has been described, the technology of the present invention can of course be applied to other types of inkjet multicolor recording devices.

As described above, the present invention brings about excellent effects particularly in bubble jet recording heads and recording apparatuses among ink jet recording systems. For typical configurations and principles, see US Patent No. 47231, for example.
Preferably, the method is carried out using the basic principles disclosed in Japanese Patent No. 29 and Japanese Patent No. 4,740,796.

This method can be applied to both the so-called on-demand type and the continuous type, but especially in the case of the on-demand type, the ink is placed in correspondence with the sheet holding the liquid (ink) and the liquid path. By applying at least one drive signal to the electrothermal transducer corresponding to the recorded information and providing a rapid temperature rise to obtain nucleate boiling, the electrothermal transducer generates thermal energy and heats the recording head. This is effective because it causes nucleate boiling on the working surface, resulting in the formation of bubbles in the liquid (ink) in one-to-one correspondence with this drive signal. Due to the growth and contraction of this gas, liquid (ink) is ejected through the ejection opening to form at least one liquid.

When this drive signal is in the form of a pulse, the bubbles are immediately and appropriately lengthened and contracted, so that ejection of liquid (ink) with particularly excellent responsiveness can be achieved, which is more preferable. As this pulse-shaped drive signal, US Pat. No. 4,463,359
Suitable materials are those described in No. 4,345,262. In addition, US Patent No. 43 1 3 1 2 relates to the temperature increase rate of the heat acting surface.
By adopting the conditions described in Specification No. 4, even more excellent recording can be achieved. The configuration of the recording head includes a combination of an ejection port and a liquid path electrothermal converter (straight liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned specification, as well as a structure in which a heat acting part is bent. The present invention also includes configurations using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose configurations arranged in regions. In addition, Japanese Patent Laid-Open No. 123670 of 1982 discloses a configuration in which a slit common to a plurality of electrothermal converters is used as a discharge part of the electrothermal converter, and a discharge opening that absorbs pressure waves of thermal energy is disclosed. The effects of the present invention are also effective even in a structure based on Japanese Patent Application Laid-Open No. 138461 of 1982, which discloses a horizontal structure corresponding to the section. Furthermore, as a full-line type recording head having a length corresponding to the maximum recording medium that can be recorded by the recording device, the length can be increased by combining multiple recording heads as disclosed in the above-mentioned specification. A configuration that satisfies
Either configuration as a single recording head integrally formed may be used, but the present invention more effectively exhibits the above-mentioned effects. I can do it. In addition, a replaceable chip-type recording head that is attached to the device body enables electrical connection to the device body and ink supply from the device body, or a chip-type recording head that is installed integrally with the recording head itself. The present invention is also effective when using a cartridge type recording head. Further, it is preferable to add recovery means, preliminary auxiliary means, etc. to the recording head provided as a configuration of the recording apparatus in the present invention, since this can further stabilize the effects of the present invention. Specifically, these include capping means for the recording head, cleaning means, pressure or suction means, preheating means using an electrothermal transducer or a heating element other than this, or a combination of these, and a means separate from recording. It is also effective to perform a preliminary ejection mode in which ejection is performed in order to perform stable recording.

Furthermore, the recording mode of the recording device is not limited to a recording mode for only mainstream colors such as black, but may also be configured by integrally configuring the recording head or by a combination of multiple heads, or by using multiple colors of different colors or by mixing colors. The present invention is also extremely effective for devices equipped with at least one full color image.

(Effects of the Invention) The present invention has been described in detail above, and since the heating means, heat radiation means, cooling means, etc. are common as a whole, the configuration is simple, power loss is eliminated, and costs can be reduced. The relative spacing between each recording head unit can be narrowed, which provides benefits such as easier registration.

[Brief explanation of drawings]

FIG. 1 is a perspective view of essential parts showing an embodiment of the present invention, FIG. 2 is a perspective view of a recording head, FIG. 3 is a perspective view of a first heat pipe, and FIG. 4 is a cross-section of a second heat pipe. 5 and 6 are perspective views of essential parts showing each structure of the previously proposed inkjet type multicolor recording apparatus. 1lA to 11D...recording head unit, l2...
Orifice, 13... Ink chamber, 14... Substrate, 15... Recording head, 16... First heat pipe, 16a... First region, 16b... Second region, 17... Supporting member, 18. 19... Second heat vip, 20... Heating means, 21... Temperature detection means, 22... Heat radiation means, 23... Cooling means, 26.
...control means.

Claims (5)

[Claims] (1) In an inkjet recording device that performs recording by ejecting ink at a predetermined location at a predetermined timing from a plurality of recording heads arranged parallel to each other, a first heat pipe attached to each of the recording heads is connected to the recording head. An inkjet recording apparatus comprising: a second heat pipe that extends outside the recording area of the head and connects each of the plurality of extended first heat pipes outside the recording area. (2) A pair of the second heat pipes are provided so as to sandwich each of the plurality of first heat pipes, and one of the second heat pipes includes a heating means and a second heat pipe. A temperature detection means for detecting temperature is provided,
The inkjet recording apparatus according to claim 1, wherein the other second heat pipe is provided with a heat radiation means. (3) The first heat pipe is of a flat type, and has a first region that contacts the recording head unit and a second region that contacts the second heat pipe, and the first heat pipe has a first region that contacts the recording head unit and a second region that contacts the second heat pipe.
The inkjet recording apparatus according to claim 1, wherein the area and the second area are perpendicular to each other. (4) The recording head is equipped with a thermal energy generating element as an ejection energy generator that generates thermal energy used to eject ink, and rapid pressure changes caused by air conditions generated by the thermal energy The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus ejects ink by utilizing. (5) The inkjet recording apparatus according to any one of claims 2, 3, and 4, wherein the inkjet recording head is provided with the ejection ports over the entire width of the recording member.