JPS62113560A - Clogging-prevention device of liquid jet recorder - Google Patents

Abstract

PURPOSE:To prevent clogging of a nozzle due to increased viscosity of an ink by loading a liquid holding member impregnated with a volatile component of ink on a capping member and properly regulating the heating of the capping member with a heating means. CONSTITUTION:A capping member 18 is pressed against an orifice surface during non-recording time, and a detection signal from a temperature sensing element 23 is input to a control circuit 28. Then a switch is turned ON/OFF through a driver 32 to properly regulate the temperature of the capping member 18. A solution 24 is stored into a container-type space 25 of the capping member 18, and also a liquid holding member 26 to be impregnated with the solution 24 is internally fitted in said member 18. The evaporated component of the solution 24 is allowed to fill the space 25 so that evaporation of the volatile component of ink 13 from an orifice at the tip of a recording head nozzle 10 may be prevented. Thus it is possible to maintain a stable discharge even in circumstances where evaporation and drying can easily occur or in a low- temperature environment where ink in the nozzle 10 can easily become more viscous.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a clogging prevention device 11 for a liquid jet recording device that prevents clogging of the recording head portion by attaching a lid member to the recording head portion during non-printing. - Regarding equipment.

[Conventional technology]

In general liquid jet recording devices, if the nozzle holes of the recording head that eject ink droplets of the recording device are left in the atmosphere, the ink filled in the nozzles dries, solidifies, or the density of the ink decreases. There was a problem in that the viscosity of the ink increased and so-called clogging occurred, making it impossible to eject ink droplets. Therefore, in order to prevent the orifice surface of the recording head from coming into contact with external air during non-recording times such as before the start of recording or after the end of recording, an apparatus has been proposed in which a crowning member is brought into close contact with the orifice surface.

However, there are two types of ink used in liquid jet recording devices: water-based and oil-based. Factors that increase the viscosity of these inks include the evaporation and drying of volatile components in the ink, as described above. In addition, there is an increase in ink viscosity due to a decrease in ink temperature, and even if the orifice surface of the print head is sealed with a crowning member to prevent the ink in the nozzles of the print head from drying, the orifice surface of the print head may increase. If the ink droplets are cooled by the cap member, ink droplets may not be ejected due to increased ink viscosity. In other words, in general, the temperature dependence of ink viscosity has a characteristic curve that differs depending on the solvent that makes up the ink, the concentration of dye contained in the ink, etc., but the viscosity increases as the ink temperature decreases, regardless of whether the ink is water-based or oil-based. .

Therefore, if the ink temperature decreases and the ink viscosity increases too much, the ejection power from the inkjet recording head becomes insufficient.

FIG. 6 shows the relationship between ink viscosity and ink temperature in the case of water-based ink, and the shaded area indicates the limit at which the ink can be properly ejected. In this way, in a low-temperature environment, the print head temperature T)l becomes the ink ejection lower limit temperature T)11
Even if the temperature is sufficiently higher than that of the capping member, the temperature T
When CL is lower than the minimum ink ejection temperature TH1, the ink inside the nozzle of the recording head is cooled, and the ink temperature TN inside the nozzle becomes lower than the minimum ink ejection temperature TH1, causing ink droplets to drop. It becomes impossible to discharge.

Conversely, the ink temperature rises too much and the ejection upper limit temperature TH! If it exceeds 1, the ink viscosity will drop too much, making it impossible to obtain a stable ejection condition when ejecting from the orifice of the recording head, resulting in problems such as the generation of many satellites. Therefore, it is necessary to maintain the ink temperature between temperatures TH1 and TH2, as in TH magazine, for example.

In other words, simply pressing the crowning member against the orifice surface of the recording head to seal it or controlling the temperature of the recording head will not completely eliminate the clogging of the recording head, and the sealing by the crowning member will not completely eliminate the clogging. Even if the ink is in a state of fQ, it is necessary to always control the temperature of the ink in the nozzle to an appropriate range and maintain its viscosity at an appropriate level.

[Problem that the invention seeks to solve]

In view of the above-mentioned points, it is an object of the present invention to provide a recording head that prevents evaporation and drying of the volatile components of the ink in the nozzles, and that prevents ink from being ejected even in a low-temperature environment where ink tends to thicken at low temperatures. An object of the present invention is to provide a clogging prevention device for a recording device.

[Means for solving problems]

In order to achieve such an object, the present invention solves the problem of clogging in a liquid jet recording apparatus in which a capping member can cover the nozzle hole of a recording head that performs recording by ejecting droplets of recording liquid from a nozzle hole. In the prevention device, a means for heating the recording head, a means for detecting the temperature of the recording head, a means for heating the capping member, a means for detecting the temperature of the capping member, and a means for heating the recording head, a means for detecting the temperature of the capping member, and a device adjacent to a nozzle hole of the capping member. Based on the information from the means for retaining the volatile component solution in the recording liquid and the temperature sensing means of the recording head and the temperature sensing means of the crowning member, the heating means and the crowning member of the recording head are The apparatus is characterized by comprising means for controlling the temperature of the recording head and the crowning member to predetermined temperature conditions through the heating means.

[For production]

In the clogging prevention device configured in this way, the liquid retaining member impregnated with the volatile components of the ink in the nozzle is loaded with the liquid retaining member, which causes viscosity increase due to evaporation of the volatile components of the ink inside the nozzle. In addition to preventing clogging, by appropriately controlling the heating of the capping member using the heating means, it is possible to prevent clogging due to low-temperature thickening.

〔Example〕

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

FIG. 1 shows an embodiment of the present invention, where 1 is a carriage on which a recording head 2 is mounted, and 3 is an idle rail that movably holds the carriage 1. In FIG. Both ends of an endless belt 4 are connected to the carriage l, which is driven by a drive motor 5 and moves along the recording surface of the recording paper 6. 7 is a roller for feeding the recording paper 6, 8A and 8B are guide rollers, and 9 is a paper feeding motor.

On the other hand, the recording head 2 is provided with a plurality of nozzles 10 arranged in a vertical line for ejecting ink droplets toward the recording paper 6.
Ink tank in nozzle 10! l to supply tube 12
Ink 13 is supplied to the nozzle 10 via the flexible cable 12A, and an ink ejection signal is selectively supplied via the flexible cable 12A. Furthermore, the recording head 2 is provided with a head heating means C (hereinafter referred to as a head heater) 14 and a means 15 for detecting the temperature of the heater 2, and a detection signal from the temperature detecting means 15 is sent to a controller having a microprocessor. By inputting it to the circuit 28, the switch 17 connected to the power supply 16 via the driver 30 is turned on and off,
Heating by the head heater 14 can be controlled.

Reference numeral 18 denotes a capping member that is mounted on the orifice surface of the recording head 2 during non-recording, and when the carriage 1 is not recording, the carriage 1 is moved in the direction of arrow B and the capping member 18 is pressed against the orifice surface. 19 is an elastic body attached to the crown attachment side of the crown attachment member 18, 20 is a heating means for the crown attachment member 18 (hereinafter referred to as a cap heater), and 21 is a 7ff for heating.
Source, 22 is Swift. Furthermore, 23 is a temperature detection element, and here as well, by inputting the detection signal from the temperature detection element 23 to the control circuit 28, the switch 22 is turned on and off via the driver 32, and the temperature of the crowning member 18 is adjusted appropriately. can be controlled.

In this example, the crown attachment member 18 is constructed as shown in FIG. 2B. That is, 24 is a solution of volatile components in the ink, and the capping member 18 has a container-shaped space 25 to be sealed.
The space 25 is filled with the volatile vapor of the solution 24, and the recording head nozzle l
The volatile components of the ink 13 are prevented from being emitted from the tip orifice IOA of the ink 13 in the nozzle 10.
This prevents the ratio of volatile components from changing.

This means that when the container-shaped space 25 does not contain any solution 24 or liquid holding member 26 as shown in FIG. If the nozzle 10 is sealed while keeping the nozzle 10 elevated, the evaporation of the volatile components of the ink 13 in the nozzle 10 toward the space 25 will be promoted, creating a concentration gradient in the ink 13 in the nozzle 10 as shown in this figure. occurs.

Therefore, assuming that the volume ratio of volatile components to the total in normal ink is a%, as the volume approaches the orifice IOA, it increases to a/2%, 874%, and a/8%.
As a result, the nozzle lO
At the tip of the ink, that is, near the orifice IOA, the viscosity increases due to evaporation, so that the viscosity becomes higher than the ink ejection limit viscosity ρM1 (see FIG. 4), and there is a possibility that ink droplets may not be ejected. In contrast, by adopting the configuration shown in FIG. 2B, the viscosity of the ink 13 in the nozzle IO is maintained in a good state so that stable ejection can be obtained without generating a concentration gradient of volatile components. can do.

Here, as the volatile component solution 24 in the ink used, it is effective to use the ink 13 itself or a solution that does not contain the dye contained in the ink, or in the case of aqueous ink, distilled water, etc. As the material 26, a sponge-like porous member, a plastic sintered body, or the like is effective.

Next, the operation of the liquid jet recording apparatus constructed in this way and its clogging prevention 1h stirrup will be described. In Figure 1,
First, during recording, the carriage 1 is driven and travels in the direction of arrow A from the illustrated recording start position, and each nozzle 10 of the recording head 2 is selectively driven, and ink droplets are ejected from each nozzle 10 to face each nozzle 10. Ink droplets adhere to the diagonally shaded recording width portion P of the recording paper 6 in the so-called scanning direction, whereby recording is performed in a dot matrix pattern. In this way, when the recording of the character is completed, the carriage 1 is driven in the direction of arrow B and returns to the position shown in the figure, and the recording paper 6 is fed in the direction of arrow C by the width of the recording width portion P described above. , the above operation is repeated again.

On the other hand, during non-recording, the carriage l is driven in the direction of arrow B from the illustrated position, and the recording head 2 is moved to the crowning member 1.
8, the crowning member 18 is displaced in the direction of the arrow by a driving means (not shown), and the member 18 is pressed against the orifice surface of the recording head 2, as shown in FIG. 2B. and capping is performed. In this case, the elastic body 18 of the crown attachment member 18 is attached to the orifice surface.
Due to this close contact, the space 25 is sealed and the individual orifices IOA are kept in direct contact with the solution vapor within this limited space 25.

In this case, as mentioned above, if the temperature of the capping member 18 is lower than the lower limit temperature T)+1 which is the ink ejection limit, the ink 13 at the tip of the nozzle lO
The head heater 14 attached to the recording head 2 is controlled based on the signal from the head temperature detection means 15, because the recording head 2 is cooled and becomes incapable of being ejected as a result of low-temperature thickening.
Furthermore, the cap heater 20 attached to the crown ti member 18 is controlled based on the signal from the temperature detection element 23 thereof.

An example of the control operation will be explained with reference to FIG. first,
When the key switches (not shown) of the power supplies 16 and 21 are turned on in step S1 and it is confirmed in step S2 that the clogging prevention 1F device is in operation,
Proceeding to step S3, it is determined whether the temperature TH of the recording pad 2 is higher than a predetermined ink ejection lower limit temperature TH, and if the temperature TH is higher than the lower limit temperature TH1, the switch 17 is activated in step S4. and head heater 14.
The recording head is turned on so that the temperature TH of the recording head is equal to or higher than the lower limit temperature T)11.

Next, proceed to step S5, and record the temperature TH of the rad 2.
is the upper limit temperature for ink ejection TH! If the upper limit temperature THQ is exceeded, the switch 17 is deenergized in step S6 to turn off the head heater 14.
state. Next, the process proceeds to step S7, where it is determined whether the temperature Tc of the crown attachment member 18 is maintained at a temperature Ts or higher of the recording head 2, and if it is determined that the head temperature Tc is not maintained at a level T)1 or higher, Switch 22 in step S8
is energized to bring the cap heater 20 into the "ON" state.

If the temperature Tc is maintained at the head temperature Tn or higher in step S7, the process advances to step S9, where the capping member temperature Tc
is lower than the ink ejection upper limit temperature TO, and the head temperature T)
It is determined whether the temperature is in the temperature range α℃ (α=O℃~30℃) higher than l, and here the cap temperature Tc is higher than the temperature (α=O℃~30℃).
If the temperature is not lower than T H+α), the stay and the valve 510 turn the gap heater 20 off.

Further, in step S9, the cap temperature Tc is changed to the temperature TH+α
If it is determined that the following is not maintained, further step Sl
It is determined whether or not to continue operating the clogging prevention device. If it continues, the process returns to step S3 and the same operation is repeated. If not, the power is turned off at step S512. is “off”.

Note that the cap temperature Tc is controlled by the control described above.

The reason why the ink ejection upper limit temperature T s Q, is controlled to be lower than the head temperature TH and a temperature 30° C. higher than the head temperature TH is to prevent clogging of the inkjet recording device. The conditions have been experimentally confirmed by the inventor of the present application.

FIG. 5A shows an example of the state of temperature change when temperature control is performed by the sequence operation procedure described above. First, the head temperature T)I is changed to the discharge lower limit temperature T
Same upper limit temperature as H! While controlling the cap salt 1fTC to maintain it between the head temperature TH and the temperature L, the upper limit temperature If is higher than the head temperature TH, but not more than 30℃ higher than the temperature TO.
By controlling the temperature to be lower than T Hz, the temperature of the capping member 18 can be maintained in a temperature range suitable for ink ejection as indicated by hatching.

Next, another embodiment of the control operation by the clogging prevention device of the present invention will be described with reference to FIG. Also in this example,
The operating procedure from step 31 to step S12 remains the same, but in this example, steps 57 to 510
In this method, the cap temperature Tc is controlled so as to keep the limit range narrow, and the cap temperature Tc is set to a temperature (β=θ℃~30℃) higher than the head temperature T)l.
It is controlled to have a lower L width of (γ=θ°C to 5°C) with respect to TH+β).

FIG. 5B shows an example of the state of temperature change when such temperature control is performed. In this example, the cap temperature Tc is maintained between the lower limit temperature TH and the upper limit temperature TH. With respect to the head temperature TH, γ rises above and below the temperature holding line of (T o + β), which is at a higher level than this temperature.
It is possible to maintain the temperature within a range of .

〔Effect of the invention〕

As is clear from the above description, according to the clogging prevention device for the liquid jet recording apparatus of the present invention, the capping member of the recording head has a container-like space, and the volatile component solution in the ink and the A liquid holding member impregnated with a volatile component solution is housed, and the recording head and the capping member are individually provided with heating means and means for detecting temperature, so that the temperature of the capping member is appropriately higher than the temperature of the recording head. By controlling the temperature so that the ink inside the nozzle of the recording head is not lowered by the capping member, it is possible to prevent the ink in the nozzle in an environment where it is easy to dry due to evaporation of the solution in the capping member due to saturated vapor. It has become possible to provide a clogging prevention device for a liquid jet recording device that can maintain stable ejection without causing ink non-ejection even in a low-temperature environment where ink tends to increase in viscosity.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of the configuration of a clogging prevention device for a liquid jet recording apparatus according to the present invention, and FIG. 2A is a perspective view showing an example of the structure of a clogging prevention device for a liquid jet recording apparatus according to the present invention. An explanatory diagram schematically showing changes in ink concentration, FIG. 2B is an explanatory diagram showing a state in which a capping member holding a volatile component solution according to the present invention is attached to the nozzle tip, and FIGS. 3 and 4 are illustrations of the present invention. A flowchart showing the operating procedure of the invention device, and FIGS. 5A and 5B are temperature curves showing the state of temperature change of the crowning member when controlled by the operating procedure shown in FIGS. 3 and 4, respectively. 6 are characteristic curve diagrams showing the relationship between ink temperature and its viscosity in the stirrup of the liquid jet recording device. l... Carriage 2... Recording head, 3... Guide rail, 4... Endless belt, 5... Drive motor, 6... Recording paper, 7... Roller, 8A, 8B ...Guidance roller. 9... Paper feed motor, lO... Nozzle, 10A... Orifice, 11... Ink tank, 12... Feeding tube, 12A... Flexible cable, 13... Ink, 14 .20...Heating means, 15...Temperature detection means, 16...Power supply, 17.22...Switch, 18...Cap attachment member, 19...B column body. 21...Power source, 23...Temperature detection element, 24...Solution, 25...Space, 2G...Liquid holding member, 2nd...Control circuit, 30.32...Driver. Figure 1 Figure 2B Figure 5A

Claims (1)

[Scope of Claims] 1) A clogging prevention device for a liquid jet recording device, in which the nozzle hole of a recording head that performs recording by ejecting droplets of recording liquid from a nozzle hole can be covered with a capping member, means for heating the recording head; means for detecting the temperature of the recording head; means for heating the capping member; means for detecting the temperature of the capping member; and the nozzle hole of the capping member. means for retaining a volatile component solution in the recording liquid; and a means for detecting the temperature of the recording head based on information from the temperature sensing means of the recording head and the temperature sensing means of the capping member. Preventing clogging of a liquid jet recording apparatus, characterized in that the apparatus further comprises means for controlling the temperatures of the recording head and the capping member to a predetermined temperature condition through heating means and heating means for the capping member. Device. 2) In the clogging prevention device for a liquid jet recording apparatus according to claim 1, the predetermined temperature condition is such that the temperature of the recording head is T_H, and the temperature of the crowning member is T_H.
C. A clogging prevention device for a liquid jet recording apparatus, characterized in that T_H_1<T_H≦T_C<T_H_2, where T_H_1 and T_H_2 are the droplet ejection limit upper and lower temperature limits of the recording liquid. 3) In the clogging prevention device for a liquid jet recording device according to claim 1 or 2, the predetermined temperature condition is T_H_1<T_H≦T_C=T_H+α<T_H_2.
(α is a set value within the range of 0° C. to 30° C.) A clogging prevention device for a liquid jet recording device. 4) In the clogging prevention device for a liquid jet recording device according to claim 1 or 2, the predetermined temperature condition is T_H<T_H≦T_C≠T_H+β<T_H|T_C
-(T_H+β)|≦γ However, β is a set value within the range of 0°C to 30°C. A clogging prevention device for a liquid jet recording device, characterized in that γ is in a range of 0°C to 5°C.