JPH03275359A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To always conduct recording in an ideal state by providing a temperature control means for controlling the temperature of a capping means for preventing the evaporation of ink from a recording head. CONSTITUTION:In a non-recording state, the surfaces with delivery ports 30 of recording heads 1A-1D are covered and capped by a recovery device 14. However, 1f recording heads 1A-1D are respectively controlled high in temperature, a relatively large amount of ink is evaporated from the delivery ports 30, resulting in a high temperature in a nearly colosed space formed by the surfaces of the delivery ports 30 and the recovery device 14. At this time, if the inner surface of the delivery device 14 is low in temperature, a dew may be generated on the inner surface and become a water drop, which wets the delivery ports 30. When a cap temperature sensor 42 detects a temperature lower than a predetermined temperature, a cap heater 41 heats the recovery device 14 to prevent the generation of a dew under temperature control.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ink sheet recording apparatus used as a copying machine, a facsimile machine, a computer, a word processor, or a composite device thereof.

[Conventional technology]

2. Description of the Related Art Inkjet recording apparatuses that perform recording by ejecting ink onto a recording material have been known. Inksheet recording devices are non-impact type recording devices with features such as low noise and the ability to easily record color images by using multicolored inks, and have rapidly become popular in recent years. It's coming.

However, many inksheet recording devices have a configuration in which ink is ejected directly from fine ejection ports in the print head to perform printing, and devices with such a configuration are capable of consistently stable ejection. In some cases, various configurations were added to maintain the state.

For example, in order to prevent ink constituents from evaporating from the ejection ports during non-printing, capping has been performed to cover the ejection port surface of the print head with a cap means.

(Problems to be Solved by the Invention) However, in the above conventional example, when the capping means is at a low temperature relative to the surrounding environment, dew condensation occurs on the capping means, and water droplets adhere to the ejection port surface of the recording head. There was a flash.

The present invention was made in view of these circumstances,
The purpose is to provide an ink jet recording apparatus that can prevent dew condensation on the cap means.

[Means to solve the problem]

An inkjet recording apparatus of the present invention includes: a recording head that ejects ink for recording; a cap means for preventing evaporation of ink from the recording head disposed outside the recording area of the recording head; and temperature control means for controlling the temperature of the cap means.

A cap means for preventing ink from evaporating from the recording head may be arranged integrally with a recovery device provided at the home position.

The temperature control means may include a temperature detection means for detecting the temperature of the cap means, and a heating means for heating the cap means.

Furthermore, the temperature control means may have a relationship such that T, -72=constant, where T1 is the temperature of the recording head and T2 is the temperature of the cap means.

The recording head uses thermal energy to eject ink from the ejection ports, and may include an electrothermal converter as a means for generating thermal energy.

(Function) In the inkjet recording apparatus of the present invention configured as described above, the temperature of the cap means is controlled by the temperature control means, so that the cap means can be maintained at a temperature at which dew condensation does not occur.

〔Example〕

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

FIG. 1 shows an example of a bubble jet type inkjet recording apparatus to which the present invention is applied. Here, the case of a multicolor printing apparatus using the printing head of the first embodiment of the present invention shown in FIG. 2 will be explained as an example.

As shown in FIG. 2, the recording head unit 1 consists of four recording heads IA to ID, and each recording head I
Self-recording liquids of different colors are ejected from A to ID. Also,
Each of the recording rads IA to ID is provided with an electrothermal transducer 40 that generates thermal energy and is supplied with an applied voltage in order to eject the recording liquid from the plurality of ejection ports 30 provided in a row. It is arranged for each liquid path. By applying a drive signal, the electrothermal transducer 40 generates thermal energy to cause film boiling and form bubbles in the ink liquid path. The growth of this bubble causes ink droplets to be ejected from the ejection port 30 (see FIG. 5). 3 is a carriage on which the recording head unit 1 is mounted and moves along the kite rail 4 (in the direction of the arrow); 5 is a timing belt that moves the carriage 3; and 6 is a drive motor that drives the carriage 3. Further, the recording sheet 7, which is the recording material, is held at the recording position by a pair of sheet feed rollers 9 driven by a sheet feed motor 8, and a pair of holding rollers 10 that cooperate with the pair of sheet feed rollers 9. Each time one line of recording is completed, the sheet is fed in the direction of arrow F. 11 is a supply pipe that supplies ink to each of the recording heads IA to ID, 12 is a return pipe that returns ink from the recording heads IA to ID to a tank 13, and 14 is a pipe that moves the carriage 3 out of the recording area of each recording spatula FIA to ID. When the recording head unit 1 is guided to the set main position H, it faces the recording head unit 1 and performs ejection failure recovery, and also changes the ink composition from each ejection port 30 of each recording head unit 1A to ID during non-printing. This is a recovery device for multiple recording heads that is integrally provided with a cap means for preventing evaporation of components.

FIG. 2 is a perspective view of the recording head unit 1, and as shown in the figure, each of the recording heads IA to ID has temperature detecting means 20A to 20D disposed on the side thereof and substantially in front. As the temperature detecting means 20A to 20D, known means such as a thermistor or a temperature IC1 thermocouple can be used. Further, 21A to 21D are each recording head IA to I.
The heating elements 21A to 21D are respectively disposed on the sides of D and approximately below the center, and heaters, power transistors, etc. can be used as the heating elements 21A to 21D.

As shown in FIGS. 3 and 4, the recovery device 14 has a cap temperature sensor 42 on the bottom surface as a temperature detection means for detecting the temperature of the recovery device 14, and a cap temperature sensor 42 on both sides that heats the recovery device 14. Two cap heaters 41 are provided as heating means, and the bottom surface, both side surfaces, and the front plate 43 are made of metal members.

Further, in FIG. 4, reference numeral 31 is a liquid chamber that temporarily stores ink supplied from the tank 13 through the supply pipe 11 by the ink pressure feeding means 24, and the ink is transferred from the liquid chamber 31 to each discharge port 30. The supply takes place by capillary action.

Next, temperature control in this embodiment will be explained.

In the non-recording state of each of the recording heads IA to ID, as shown in FIG. 4, the surface of each ejection port 30 is covered and capped by the recovery device 14.

However, if each of the print heads IA to ID is temperature-controlled to a high temperature, a relatively large amount of ink evaporates from each ejection port 30, and the temperature of each print head IA to ID is
The air temperature in the substantially closed space formed by the surface of the discharge port 30 and the recovery device 14 becomes high. At this time, recovery device 1
If the inner surface of the recovery device 14 is at a low temperature, dew condensation will occur on the inner surface of the recovery device 14, and water droplets due to the condensation will fall onto each of the recording heads IA to
It may adhere to the discharge ports 30 of the ID and wet each discharge port 30. Therefore, when the cap temperature sensor 42 detects a temperature below a predetermined temperature, the cap heater 41 heats the recovery device 14 and performs temperature control to prevent dew condensation.

As a result of repeated experiments and studies by the present inventors, when the temperature of each recording head IA to ID is controlled at about 45°C, the temperature of the recovery device 14 including the front plate 43 is controlled at 30°C or more and 50°C or less. That is appropriate. More specifically,
If the temperature of the recovery device W14 is raised too much, it may accelerate the evaporation of the ink at the ejection port 30, so the dye concentration should be 2% by weight.
When using a water-based ink, it was appropriate to control the temperature of the recovery device 14 to 30°C or higher and 35°C or lower.

In this embodiment, the front plate 43 of the recovery device 14 is made of metal, but instead, it may be made of a material that does not easily condense, for example, a polymeric material such as ABS resin.

Further, in this embodiment, the cap means for preventing ink from evaporating from each of the recording heads IA to ID is shown as being disposed integrally with the recovery device 14 provided at the home position H. The invention is not limited to this. That is, the capping means may be located at a position other than the home position as long as it is located outside the recording area of the recording head, and therefore may be located separately from the recovery device 14. In this case, the capping means may be located close to the recovery means 14, or may be disposed outside the recording area on the opposite side to the recovery means 14 (on the right side in FIG. 1).

Further, in this embodiment, the temperature of the recovery device 14, that is, the cap means is controlled within a predetermined temperature range, but the present invention is not limited to this. for example,
When capping the recording head in a state where the temperature of the recording head is higher than a preset temperature, such as immediately after recording ends, the temperature of the capping means is increased accordingly. If the recording head temperature is TI and the temperature of the character pink member is T2, it may be controlled so that T, -72=constant.

The present invention brings about excellent effects particularly in bubble-shed recording heads and recording apparatuses among inkjet recording systems.

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) corresponding to the sheet and liquid path. By applying at least one drive signal that corresponds to recorded information and causes a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, the electrothermal transducer generates thermal energy, and the recording head This is effective because it causes film boiling on the heat acting surface of the liquid (ink), resulting in the formation of bubbles in the liquid (ink) in one-to-one correspondence with this drive signal. The growth and contraction of the bubble causes liquid (ink) to be ejected through the ejection opening to form at least one drop. When this drive signal is in the form of a pulse, the growth and contraction of bubbles can be carried out immediately and appropriately, so that ejection of liquid (ink) with particularly excellent responsiveness can be achieved, which is more preferable. As this pulse-shaped drive signal, those described in US Pat. No. 4,463,359 and US Pat. No. 4,345,262 are suitable. Furthermore, U.S. Patent No. 4 relates to the temperature increase rate of the working surface of the upper J.
If the conditions described in No. 313124 are adopted, even better recording can be achieved.

The configuration of the recording head includes, in addition to the combined 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. US Pat. No. 4,558,333 and US Pat. No. 4,459,600 disclose a configuration in which the
The configurations described in the respective specifications may be used. In addition,
Japanese Unexamined Patent Publication No. 123670 of 1981 discloses a configuration in which a common slit is used as a discharge part of a plurality of electrothermal converters, and an aperture that absorbs pressure waves of thermal energy is used as a discharge part. The present invention is also effective as a configuration based on Japanese Unexamined Patent Application Publication No. 138461 of 1981, which discloses a configuration corresponding to.

Furthermore, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length can be increased by combining multiple recording heads as disclosed in the above-mentioned specification. The present invention can more effectively exhibit the above-mentioned effects.

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 a cartridge type recording head is used.

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

In the embodiments of the present invention described above, the ink is described as a liquid, but it may be an ink that solidifies at room temperature or below, but softens or becomes a liquid at room temperature, or an ink that is used for boat fishing with an inkjet. It may be one that becomes soft or liquid in the temperature range of 30° C. or higher and 70° C. or lower, which is the temperature range for temperature adjustment. That is, it is sufficient if the ink is in a liquid state when the recording signal is applied. In addition, it is possible to actively prevent temperature rise due to thermal energy by using it as energy to transform the ink from a solid state to a liquid state, or to use ink that solidifies when left in order to prevent ink evaporation. Iruka,
In any case, the property of liquefying only by thermal energy, such as ink that is liquefied by application of thermal energy in accordance with a recording signal and ejected as liquid ink, or that has already begun to solidify by the time it reaches the recording medium. The use of ink is also applicable to the present invention. In such a case, the ink is held in a liquid or solid state in the recesses or through holes of the porous sheet, as described in JP-A-54-56847 or JP-A-60-71260. It may also be in a form that faces the electrothermal converter. In the present invention, the most effective method for each of the above-mentioned inks is to implement the above-mentioned film boiling method.

〔Effect of the invention〕

As explained above, the present invention can prevent dew condensation on the cap means by controlling the temperature of the cap means. As a result, it is possible to eliminate the influence of water droplets adhering to the ejection orifice surface of the recording head, and it is possible to always perform recording under good conditions.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the main parts of an embodiment of an inkjet recording apparatus to which the present invention is applied, FIG. 2 is an exploded perspective view of an enlarged recording head, and FIG. 3 is a front view of a recovery device.
Figure 4 is an explanatory diagram of the ink supply/recovery system of this embodiment;
The figure is a perspective view showing a section of the recording head cut away. DESCRIPTION OF SYMBOLS 1... Recording head unit, IA, IB, IC, ID-... Recording head, 14-. Recovery device, 20... Front plate, 21... Cap heater, 31-. Discharge port, 32-. Electrothermal converter, 42--Cap temperature sensor.

Claims (1)

[Scope of Claims] 1) A recording head that discharges ink for recording, a cap means for preventing evaporation of ink from the recording head disposed outside the recording area of the recording head, and An inkjet recording apparatus comprising: a temperature control means for controlling the temperature of the cap means. 2) The ink jet recording apparatus according to claim 1, wherein the cap means for preventing evaporation of ink from the recording head is disposed integrally with a recovery device provided at the home position. 3) The inkjet recording apparatus according to claim 1 or 2, wherein the temperature control means includes a temperature detection means for detecting the temperature of the cap means and a heating means for heating the cap means. 4) If the temperature of the recording head is T_1 and the temperature of the cap means is T_2, then the temperature control means has a temperature of T_1.
The inkjet recording apparatus according to claim 1, 2 or 3, wherein -T_2=constant. 5) The recording head uses thermal energy to eject ink from the ejection ports, and has an electrothermal converter as a means for generating thermal energy.
or 4. The inkjet recording device according to 4.