JPS60219059A - Liquid injection recorder - Google Patents

Abstract

PURPOSE:To make a recording head replaceable and to eliminate a requirement for a non-discharge recovery mechanism of liquid droplets by providing portions to be caught in front and in the rear of the bottom portion of the recording head and by providing hook portions on a carriage side that engages with the portions to be caught. CONSTITUTION:A portion 1c to be caught, pulls 1d and 1e are provided at the edges of this side of recording heads 1a and 1b that have an identical construction with the only difference in colors of liquids being used. A carriage 2 is provided with a hook portion 2a and the recording heads 1a and 1b are interlinked with the hook portion 2a at the portion 1c to be caught, and the heads are fixed to the carriage 2 in such a manner as to be replaceable. Multicolor recording is feasible.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a liquid jet recording device, and more specifically [Prior Art] A liquid jet recording device has a simple structure of a recording head, can easily perform color recording, or can perform high-speed recording. Its use has increased in recent years due to its recordability and unequal reasons.

On the other hand, disadvantages of the liquid jet recording method include ejection failure and clogging of the feeder ejection port due to volatile components of the liquid in the liquid ejection port emitting during a pause in the recording operation.

In conventional liquid jet recording devices, in order to compensate for the drawbacks mentioned above, devices such as providing a camp means to cover the liquid ejection port or providing a recovery pump means to remove the highly viscous liquid near the liquid ejection port have been taken. are doing.

However, in a recording device in which the cap means and recovery pump means are manually operated by the user, the user is required to carry out the operations before starting the recording operation, making the recording device very inconvenient to use. There was a drawback.

On the other hand, a device in which the operation is electrically controlled using a power source such as a motor or an electromagnetic plunger is more convenient than the above device, but at least a moving cuff source and a control circuit are added to the recording device. Furthermore, there is a drawback that the cost of the recording device increases.

In addition, there is a technology that prevents the liquid in the liquid ejection port from increasing in viscosity by performing idle ejection unrelated to printing at regular intervals just before the printing device starts the printing operation and while the printing operation is paused. has been proposed in the past, but this technique has the disadvantage that liquid consumption increases regardless of recording.

[Purpose] The present invention has been made to eliminate the above-mentioned drawbacks of the conventional technology, and by making the recording head replaceable, multi-color recording can be easily performed, and a droplet failure recovery mechanism is provided. The purpose of the present invention is to provide a liquid jet recording device that eliminates the need for liquid jet recording.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

FIG. 1 is a perspective view showing the configuration of a liquid jet recording apparatus according to the present invention, in which the recording heads indicated by numerals 1a and 1b are the same recording head except for the color of the liquid. For example, head la contains black ink, and head ib contains red ink. A hook portion 1c is provided at the front end of the heads la and lb.

Handle portions 1d and le are provided.

The one indicated by reference numeral 2 is provided with a hook portion 2a in the carry ring, and the recording heads 1a and lb are provided with a hook portion 1c.
is engaged with the hook portion 2a and is fixed to the carriage 2 in a replaceable manner. .

To remove the recording head from the carriage 2, it is sufficient to rotate the hook part 2a in the six directions of the arrows, raise the handle part 1d upward with your fingertips, grasp the handle part 1e, and lift it upward.

The one indicated by code 3 is a flexible cable connected to head 1a.
and lb are electrically connected to an electric control circuit (not shown).

The carriage 2 is slidably attached to guide shafts 4 and 5, and drives a drive pulley 7 provided on the shaft of a motor 6 provided at one end of the device and a pulley 8 provided at the other end. It is connected to the wire 8 stretched between them at the end 2b.

Therefore, the rotation of the motor 6 is transmitted to the carriage 2 via the pulleys 7 and 8 and the wire 9, and the carriage 2 is moved left and right by the motor 6.

A platen 10 provided parallel to the guide shaft 4.5 feeds the recording paper 11 in the sub-scanning direction, and the platen 10 is rotated via a drive gear of a motor 15 and an intermediate gear 13.14.

Next, the recording operation will be explained.

The carriage 2 moves rightward in FIG. 1 by the rotation of the motor 6, and the recording head 1a records on the recording paper 11 based on a print signal sent via the flexible cable 3 while the carriage 2 is moving. A recording signal "g" for the recording head 1b having a different liquid color is sent to the recording head "lb" at a timing shifted by the distance between the liquid ejection ports of the recording heads 1a and 1b. If7, two-color printing is performed alternately at intervals, or in particular, when one recording head is red and the other is black, an underline is drawn in red below the black characters. or,
Although this embodiment shows the case where there are two print heads, printing in other colors is also possible by increasing the number of print heads to three or four.

When the recording head la reaches the right end, the carriage 2 stops traveling, and then the platen roller 10 is rotated by the motor 15.
rotates, and the recording paper 11 moves by one line in the sub-scanning direction.

Subsequently, the motor 6 rotates in the opposite direction, the carriage 2 moves to the left, and the recording heads la and lb perform recording to the left end. Of course, since the recording head lb is in the lead this time, the recording head 1a performs the recording operation at a timing that is a predetermined time later than the recording head lb.

When recording hands lb and 1a reach the left end, carriage 2
(stops)-L, and then the motor 15 rotates to move the recording paper 11 by one line in the sub-scanning direction. By repeating the above operations, a predetermined text or image is recorded on the front surface of the recording paper 11.

2 and 3 are perspective views showing the detailed structure of the head of the recording apparatus of the present invention.

Reference numeral 16 in each figure is a liquid discharge member having a plurality of liquid discharge ports 16a, which is made of nickel using an electroforming method or by etching glass.

A groove 16b is formed on the back surface of the liquid discharge member 16, and a liquid discharge port 16a and a partition wall 16c are provided in the groove 16b. The partition wall 16c is provided to prevent liquid from being ejected from other liquid ejection ports when liquid is ejected from a specific liquid ejection port 16a.On the other hand, since the groove portion 16b surrounds the liquid ejection port 16a, the liquid is not ejected during the ejection operation. Discharge port 16a
This has the effect that the ink ejection pressure within the ink droplet also escapes, thereby increasing the ejection distance of the droplet.

Reference numeral 17 denotes a substrate made of a glassy material that is much cheaper than silicon or siliconium.
7c is provided. When a predetermined current is passed through the electrode 17b, the resistor 17a generates heat. The size of this resistor 17a is approximately 50 pLm×501Lm.

The substrate 17 may be an inexpensive ceramic plate provided with a vitreous layer having an appropriate heat storage effect necessary for rapid temperature rise at least in the vicinity of the resistive element.

18 is a substrate holding member having a groove 18a for attaching the substrate 17, a liquid supply hole 18b, and a plurality of connecting holes 18c. Further, reference numeral 19 indicates a liquid bag to be accommodated, and a flange 19a
have.

The opening of the liquid bag 19 has an elliptical shape with a width and a height M such that L<M. It is effective to make the opening portion elliptical in order to make the head width N as small as possible and, on the other hand, to increase the liquid storage capacity of the front cover 19. In addition to the above-mentioned parts, the recording head housing 1 has a rear catch part 15. Multiple coupling pins
g. It has a straddle storage part lh. Moreover, the notch 11 provided at the lower end is made by breaking off the protruding piece 1j. The protruding piece 1j is attached to the lower end of the recording hand outer body 1a, lb.
A cut-out part IT corresponding to the primary color is made by cutting off the position corresponding to the primary color in the front 19 provided with a cylinder.

Next, based on FIG. 4, the assembled state of the recording head, the mounting state of the recording heads la, lb and the carriage 2, and the recording operation of the recording heads la, lb will be explained. FIG. 4 is a sectional view taken along the center direction of the recording spatula l"la in FIG. 1. FIG.

The liquid discharge member 16 and the substrate 17 are bonded together with an adhesive. Furthermore, the substrate 17 and the holding member 18 are also bonded together with an adhesive.

A groove 18e is provided on the outer periphery of the flange 18d provided on the holding member 18, and the liquid 2 is inserted into the groove 18e with the inside of the flange 19a of the liquid bag 19 biting into the groove 18e.
The liquid bag 19 containing 0 is connected to the holding member.

In the above state, the coupling pin 1g of the housing 1 passes through the coupling hole 18c of the holding member 18 in FIG.
The holding member 18 and the housing 1 are joined by crushing the tip of the holding member 18 and the housing 1. When the holding member 18 and the casing 1 are connected using an automatic fence machine, the liquid bag 19 is firmly connected to the holding member 18 with the liquid bag 19 biting into the groove 18e as described above, so when attaching the casing 1, Next, a state in which the recording heads la and lb are attached to the carriage 2 will be described, which improves the ease of assembly without worrying that the liquid bag 19 will come off the holding member 18.

The rear catch part 15 of the recording spatula FLa, lb is used for carrying.
The recording heads 1 a and 1 b are fixed to the carriage 2 by coupling the hole 2 C of the cartridge 2 with the front hook IC and the hook 2 a, respectively.

Since the hook parts IC and 15 are provided in the casing 1, the force when the recording head 1 is fixed to the carriage 2 is applied to the casing 1, but the rigidity of the hook 1 is high, so that the force is absorbed by the casing 1. The substrate 17 having the resistive element 17a is hardly affected by the distortion caused by the force. Therefore, the resistor element will not be destroyed by carrying the recording head several times.

On the other hand, since the catch part is provided on one side (i) and the rear of the recording head, when the recording heads la and lb are installed side by side, it is possible to mount multiple recording heads closely on the carriage 2 without creating a space between adjacent recording heads. It becomes possible.

When the recording heads are arranged in parallel in an electrically connected state, the distance between the liquid ejection ports between the recording heads can be reduced, and therefore the scanning stroke of the carriage 2 with respect to the paper 1 is also reduced, making the recording apparatus more compact. I can do it.

The protruding member 2d provided on the upper surface of the carriage 2 engages with the cutout portions 11 of the recording heads la and lb, and when multiple heads are attached, a plurality of protruding portions are provided corresponding to the positions. For example, heads with black liquid can only be mounted in fixed positions.

The liquid 20 in the advance 19 is supplied to the liquid supply hole 18 of the holding member 18.
a and the liquid discharge member 1 through the liquid supply hole 17c of the substrate 17.
6 is supplied to the groove portion 16b.

When putting the liquid 20 into the advance 19, the advance 19 is crushed and the liquid is put in, so the restoring force of the advance 19 always acts on the liquid in the liquid discharge port 16a to return to the advance. Liquid does not leak from the liquid ejection ports 16a due to fluctuations in atmospheric pressure or vibrations applied to the recording heads la and lb.

Next, the recording operation will be explained.

A recording pulse current generated by a head control section indicated by the reference numeral 21 in FIG. 4 is sent from an electrode section 3a provided at the tip of the flexible cable 3 through an electrode 17b of the substrate 17 to the resistor 17a.

The resistor 17a to which the printing pulse is applied instantly changes to 300°.
Since heat is generated up to about C, the liquid 20 on the resistor 17a is instantaneously vaporized and bubbles are generated. Therefore, the liquid 2o in the liquid discharge port 16a is ejected from the liquid discharge port 16a due to the bubbles and hits the recording paper 11, thereby performing recording. When the front body is discharged from the liquid discharge port 16a, the groove 16b becomes a negative pressure, so the liquid 2o of the front body 19 flows into the groove 16. The above recording operation is repeated while the carriage 2 is moving, and characters and images are formed on the surface of the recording paper 11.

Next, the liquid 20 will be explained. Since this liquid is usually called ink, it will be referred to as ink in the following description. The main ingredients of this ink are water, polyethylene glycol, diethylene glycol, and a dye agent, and the mixing ratio by weight is 50% water and 50% other components. If the above recipe is made to have 60% water and 40% other components, the viscosity of the ink will be greatly reduced, increasing the fluidity of the ink inside the liquid ejection port, ensuring reliable ejection at the start of printing, and increasing the ejection frequency. Enables high-speed printing.

However, if the tip of the liquid ejection port is left open to the atmosphere, water will evaporate from the tip of the liquid ejection port over time, and the proportion of increase in ink viscosity within the liquid ejection port will be 6% compared to 50%.
0% is larger.

Therefore, in ink containing 60% water, the main ingredients other than water quickly settle and stick inside the liquid ejection port.

Once the ink main agent is stuck inside the liquid ejection port, it cannot be recovered by any means. In order to prevent such ink from sticking, the ink inside the liquid ejection port may be sealed by sealing the liquid ejection port opening with a cap, humidifying the inside of the cap, or performing dry ejection unrelated to printing at regular intervals. Conventionally, methods such as keeping the ink fresh are used, but in the recording device of the present invention, the tip of the liquid ejection port is always open to the atmosphere, so in order to avoid ink adhesion, the water content is 50% or more. Use 55% ink.

After a printing operation is completed and the next printing operation begins, the tip of the liquid discharge port is always open to the atmosphere as described above.
Particularly in dry seasons, moisture is frequently released from the tip of the liquid ejection port, increasing the viscosity of the ink near the liquid ejection port, which may result in ink ejection failure when printing starts next time. As a result of experiments, it has been found that in order to lower the viscosity of the ink which has become highly viscous, it is effective to rapidly heat the vicinity of the liquid ejection port to about 60°C to 80°C.

In Figure 5, the curve marked A is the temperature-viscosity characteristic of an ink consisting of 50% water, 47% dichelene glycol, and 3% dye, while the curve marked CB) indicates that most of the moisture in the ink L has been released. This shows the temperature-viscosity characteristics of the ink in which 10% water content of diethylene glycol remains as water.

The viscosity of the ink inside the liquid ejection port changes from the characteristics of (A) to (B) due to water emitted from the tip of the liquid ejection port over time.
) changes in the direction of the characteristic.

From the characteristics of (A), the ink viscosity at 25°C is 7 cp
However, at 60° C., the viscosity is 3.8 cp, which is about 1/2 the viscosity. Also, from the characteristics of (B), the ink viscosity at 25% is 64 cp, or at 60°C, it is 20 cp and 1/3
The viscosity is reduced below. According to experiments, the viscosity of ink that can be ejected is approximately 20 cp or less, so it is clear that by heating the vicinity of the liquid ejection port to 60° C. to 80° C., ink ejection can be performed reliably even after a long period of time has elapsed.

Incidentally, as a method for reducing the viscosity and solving the non-ejection problem, for example, as described in JP-A-58-424H, two electrothermal transducers are provided at a predetermined interval along the liquid flow path, and the recording At times, a drive signal is applied to one electrothermal transducer having an energy level capable of forming a flying droplet, and during recording standby, a drive signal is applied to the other electrothermal transducer having an energy level that does not allow the formation of a flying droplet. There is a method to give this and reduce the viscosity of the liquid. However, if such a method is adopted, a 21% electrothermal converter is required, which makes it complicated, and it is difficult to control the energy level.
Not practical.

Since the recording head of the recording apparatus according to the present invention uses the electric resistor 17a as an ink ejection drive element, the resistor 17a
By energizing a under the condition that no ink is ejected, the static temperature of the ink near the liquid ejection port can be increased without providing any special heating element.

Moreover, in the recording head of the recording apparatus of the present invention, the electric resistor 1
The distance between 7a and the liquid ejection port 16a is as thin as about 100 μm, so the ink layer between them is thin and the speed at which heat is transferred to the ink is fast.Furthermore, the electric resistor 17a is provided on a glass material that has an appropriate heat storage effect. Therefore, the rate at which the temperature of the resistor 17a itself rises due to the heat generated by the resistor 17a is fast, and in addition to the effect of the thinness of the ink layer, the time for the ink in the liquid ejection port to reach 60° C. is short, for example, several m5 ec, and the temperature rises thereafter. It is desirable that the heating be short-term, since there is little need to wait for the printing operation, and heating for several minutes will evaporate the water in the ink and greatly reduce the viscosity of the ink.

Further, since the liquid ejection port 16a is provided directly above the resistor 17a, most of the ink whose viscosity has been reduced due to the heat generated by the resistor 17a is easily ejected from the liquid ejection port, and the subsequent printing ejection operation is reliable. It is carried out in

Next, the means for not performing discharge will be explained based on FIG. FIG. 6 (A), (B), and (C) show the resistor 17a.
The waveform shown by the two-dot chain line is for normal printing.

As one of the means for not performing the above-mentioned ejection, there is a method of lowering the voltage than the voltage applied in the case of normal printing, as shown in Fig. 6 (
In A), the voltage level a is set to b.

One similar method is to set the pulse width C to d in FIG. 6(B) by making the pulse width shorter than the pulse width applied in normal printing.

As one of the similar means, there is a method of applying a combination of the means shown in (A) and (B).

Furthermore, in order to shorten the time required to raise the temperature of the ink after applying the above method, there is a method of lowering the applied voltage and increasing the repetition frequency, which corresponds to the waveform e in Fig. 6 (C). .

Note that Japanese Patent Laid-Open No. 55-132 discloses a method of increasing the droplet ejection speed and ejection frequency by changing the waveform of the drive pulse.
Although there is a method as described in No. 2Ela, this method does not attempt to realize an ink non-discharge state like the present invention.

Control of such means is carried out by controlling with micro-prosensors singly or in combination. Since the microprocessor is used in all recording apparatuses, there is no need to provide a special one, and a simple modification of the software is sufficient, so the present invention requires almost no expense for using the means.

The ink viscosity-lowering heating operation by the resistor 17a is performed immediately after the recording apparatus is turned on, immediately after the first printing command is received, and immediately after the recording signal does not come for a predetermined period of time (for example, 3 minutes) and then comes again. It will be done.

On the other hand, when recording 10 or so dots immediately after heating the ink to lower its viscosity, there is a drawback that the dot diameter is small and the dots are not aligned with other donts due to the low water content of the ink. It is sufficient to perform printing ejection after performing idle ejection unrelated to recording for the 10-odd dots described above. The dry discharge is 1/10 to 1/100 of the conventional dry discharge.
, the amount of ink wasted is greatly reduced.

The present invention is most effective when applied to a liquid jet recording device having the structure explained with reference to the above drawings, but it is also described in, for example, German Publication No. 284308.4 and German Publication No. 2944005. The present invention can also be effectively applied to other types of liquid jet recording devices.

[Effects] As is clear from the above description, according to the present invention, since the recording head is configured to be freely replaceable,
It is possible to obtain a liquid jet recording apparatus that can perform multicolor recording using a plurality of recording heads with different previous colors and that does not require a droplet non-ejection recovery mechanism.

A perspective view of the main parts of the device, Fig. 2 is an exploded perspective view of the recording head, Fig. 3 is a perspective view of the liquid ejection port, Fig. 4 is a vertical cross-sectional side view of the main parts, and Fig. 5 is the relationship between temperature and viscosity. Diagram showing , Figure 6 (
A) to (C) are diagrams illustrating different driving pulse controls.

1... Housing 1a, 11)... Recording head 1c...
-Hatch portion 1d...Handle 1f...Rear hook portion 1g...Connection pin 1h...Advance storage section 11...
Notch portion 1j... Projection piece 2... Carriage 2a... Hook portion 10... Platen 11... Recording paper 16... Liquid ejection member 16
A river liquid discharge hole 16b... Groove portion 16c... Partition wall 17... Substrate 17a... Electric resistor 18... Substrate holding member 19... Advance 20... Liquid

Claims (1)

[Claims] In a liquid jet recording apparatus having a recording head that performs dot recording by ejecting droplets, hooks are provided at the front and back of the lower part of the recording head, and one hook is engaged with the carriage on the side of the carriage on which the recording head is mounted. What is claimed is: 1. A liquid jet recording device characterized in that a hook portion is provided.