JPS591265A - Ink feeder - Google Patents

Abstract

PURPOSE:To prevent ink surface from waving, by a construction wherein stepping structures are formed at the coupling part between ink inlets and a tank, and protruded partitions are formed at the marginal parts thereof in the moving direction of the carriage, in an ink jetting printer. CONSTITUTION:An ink tank 16 is divided into 4 colors by partitions 26a-26c. For example, in the color chamber (a), an antivaporator 17 is provided at the upper part and an ink cartridge 15a is inserted therein. The ink fed into the first and second ink inlets 19, 20 provided at the lower part thereof comes up through an ink passage 11b by means of capillarity and flows into a pressure chamber 11e. Steps are formed at the second ink inlet 20, and protruded partitions 23a, 23b in the normal direction with respect to the moving direction of a carriage 12 are provided at both sides thereof facing each other and an ink level sensing electrode rod 24 is disposed therebetween. With this construction, the ink surface is kept comparatively stable and the ink level senser is not misguided even when big mechanical shaking is rendered and the amount of ink is comparatively large when the carriage moves.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ink supply device that supplies ink to a nozzle t in an inkjet printer that prints by ejecting ink from a nozzle.

In conventional ink supply devices, an ink tank is installed outside the carriage, the ink tank is connected to a nozzle installed in the print head through a conveying pipe, and ink is supplied to the nozzle through the pipe by driving a pump. was. However, such a device has a complicated structure, and there is a limit to miniaturization. Therefore, in order to make this device simple and compact, it is possible to create a device in which the ink tank is installed directly on the carriage without using a pipe, but the ink liquid level fluctuates greatly due to mechanical vibrations during printing. . Fig. 1 is a diagram for explaining the fluctuation state of the ink liquid level, but when the ink 2 in the ink tank l decreases to a certain extent, the ink liquid level fluctuates as shown by the two-dot chain line in the figure. Then, the ink 2 may not come into contact with the ink level sense electrode rod 3. Ink level sensing is performed by applying an alternating current signal between the head and an ink level sensing electrode rod 3 provided at a position in contact with the ink 2. In other words, when the electrode rod 3 is in contact with the ink 2, electricity flows between the electrode rod 3 and the head due to the conductivity of the ink 2, whereas when the ink decreases and the ink 2 does not contact the electrode rod 3, the electrode rod 3 and the head are not energized and an ink out signal is generated. Therefore, when there is no ink shortage, the ink 2 is applied to the electrode rod 8 due to the fluctuation of the ink liquid level.
There is a drawback that when the ink stops coming into contact with each other, an erroneous ink out signal is issued.

This invention was made in view of the above circumstances, and is an ink supply device in which an ink tank is attached to a carriage.
To provide an ink supply device that does not perform ink level sensing by mistake.

To summarize, the present invention provides an ink supply device in which an ink tank is attached to a carriage, in which a stepped portion is formed at the bottom of the ink tank and the opening facing the tip of the ink level sense electrode rod, and a stepped portion is formed at the bottom of the ink tank. ,
The present invention is characterized in that projecting walls are provided on both sides of the opening and perpendicular to the moving direction of the carriage.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a perspective view of a carriage section of an on-demand inkjet printer according to an embodiment of the present invention.

In the figure, a print head 11 is attached to a position facing a platen 14 of a carriage I2. Slide pars 14a and 14b are provided at the bottom of the carriage I2 in parallel to the axial direction of the platen 13, and the carriage 12 slides on these slide pars 14a and 14b in conjunction with a moving mechanism (not shown) such as a motor. It has a moving structure. An ink tank 16 is formed above the carriage 12 and is loaded with four ink cartridges 15a, 15b, 15c, and 15d containing inks of magenta, yellow, cyan, and black colors. Note that an ink evaporation prevention device 17 is attached to this ink tank 16.

3 is a cross-sectional view taken along line AA in FIG. 2, FIG. 4 is a cross-sectional view taken along line B-B in FIG. 2, and FIG. 5 is a schematic cross-sectional view taken along line C-C in FIG.

In FIG. 3, the print head 11 includes a base 11a, an ink introduction path 11b communicating with the ink tank 16 via an ink supply pipe 18, a nozzle slit portion +1c communicating with the ink introduction path 11b, and a nozzle slit portion +1c communicating with the ink introduction path 11b. Part 1
Orifice lid communicating with 1c and orifice lid
a pressure chamber lie communicating with the slit portion +1c;
A piezoelectric element 11f, which is a vibrating element, is formed on the back surface of the pressure chamber 11e. Ink supply tube 1
8 is a first opening formed in the ink tank 16;
The ink supply port 19 and the second ink supply port 20 are connected to the ink tank 16 . A hole 21 is formed in the ink tank clay wall above the first ink supply port 19 to prevent negative pressure inside the tank, and an evaporation hole 21 is formed to prevent ink from evaporating from this hole 21 during non-printing. A prevention device 17 is provided. The evaporation prevention device 17 includes an evaporation prevention rod 17b having a return spring 17a attached to the bottom thereof, a magnet 17c attached to the top of the evaporation prevention rod 17b, and a magnet 17c attached to the top of the evaporation prevention rod 17b. A magnet 17c' placed at the main body position opposite to 17c, a magnet mounting plate +7d to which this magnet 17c' is attached, and the evaporation prevention rod 17b are located approximately in the center thereof. On the other hand, a stepped portion 22 is formed around the joint between the second ink supply port 20 and the ink tank 16, and a protruding wall 28a is provided at the outer edge of the stepped portion 22 perpendicularly to the bottom surface of the tank 16 and in the traveling direction of the carriage 12. slide par 1
It is provided in a direction perpendicular to 4a and 14b. Also,
As shown in FIG. 4, a protruding wall 23b is provided in parallel to the protruding wall 28a at a position facing the protruding wall 28a with the stepped portion 22 in between. An ink level sense electrode rod 24 for detecting ink deficiency is attached to the upper wall of the ink tank 16 above the ink supply port 20.

Note that the pillars 25a and 25b are only for guiding the ink cartridge 15a. Further, the two-dot chain line in the figure indicates the ink liquid level.

The ink tank 16 is divided by three partition walls 26a, 26b, and 26c as shown in FIGS. 4 and 5.
The ink tank 16 is divided into four tank chambers by the partition walls 26a, 26b, and 26c. Each of the four tank chambers has ink cartridges 15a, 15b, 1
5c and 15d are respectively loaded, and each tank chamber is formed with two protruding walls. The configuration of each tank chamber is similar to that shown in FIG. 2.

In such a configuration, ink passes through the ink supply pipe 18 from the first ink supply port 19 or the second ink supply port 20, rises through the ink introduction path 11b by capillary action, and flows into the pressure chamber 11e. . During printing, a predetermined signal is input to the piezoelectric element 11f, and ink particles are ejected from the nozzle slit portion 11c in response to vibrations of the piezoelectric element Iff.

On the other hand, when printing the valve, the two magnets of the evaporation prevention device 17)
17c and 17c' are bonded in opposing positions. The evaporation prevention rod +7a moves upward, and the O-ring 17f and sealing plate 17e seal the hole 21 accordingly. In this way, evaporation of ink during non-printing is prevented. Ink level sensing is performed by applying an alternating current voltage between the metal head 11 and the electrode rod 24, which are provided at a position in contact with the ink, using the conductivity of the ink. If the ink runs out, no electricity is applied, so this state is detected and an ink out signal is output. Note that the bottom of the ink tank is slanted, but by doing this, even if the ink runs out in the middle of printing a - line, the ink remaining on the first supply port 19 side can complete the printing of one line. This is to make it possible. In this case, -
After printing a line, it issues an ink out signal.

In the carriage mechanism as described above, the carriage 12
The ink receives a rocking force due to the mechanical vibration caused by the movement of the ink, but when there is a relatively large amount of ink, a pair of protruding walls 23a are formed inside the ink tank 16.

23b, the contact area between the ink and the ink tank 16 near the ink supply port 20 is large.

That is, in this vicinity, the ink and the protruding wall 23a.

A large viscous friction occurs between the ink and the ink 23b, and the fluctuation width of the ink liquid level becomes minute. Therefore, even if the mechanical vibration of the carriage 12 increases, the ink oscillation wavefront remains stable.
No more mistakes in ink level sense. On the other hand, when the liquid level decreases to near the tip of the ink level sense electrode rod 24, the contact area of the ink with the protruding walls 2:lla, 28b becomes small;
Since ink accumulates in the step part 2, the liquid level becomes difficult to fluctuate due to viscous friction with the peripheral wall of the stepped part. That is, the peripheral wall of the stepped portion 22 functions in the same way as the protruding walls 23a and 23b, thereby stabilizing the reduced ink level.

Due to the above-described actions of the protruding walls 28a, 28b and the stepped portion 22, the liquid level height is always maintained constant without being affected by the degree of ink reduction. In particular, even when the ink level is low and the ink level is located near the tip of the ink level sense electrode rod 22 and a sharp ink level sense is required, the action of the stepped portion 22 prevents the ink level sense from malfunctioning. Ink-out notification can be performed with high accuracy without any occurrence.

As described above, according to the present invention, a stepped portion is formed at the joint between the ink supply port and the ink tank, and the carriage is provided at the outer edge of the stepped portion at positions facing each other through the supply port. An ink supply device that has a protruding wall perpendicular to the direction of movement, so it is almost unaffected by the amount of remaining ink, whether it is large or small, and the ink level height hardly fluctuates. can be provided.

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining the swing state of the ink liquid level of a conventional ink supply device, Fig. 2 is a perspective view of the carriage section of an on-demand inkjet printer which is an embodiment of the present invention, and Fig. 3 is a sectional view taken along line A-A in Fig. 2, and Fig. 4 is “
FIG. 5 is a schematic sectional view taken along the line CC. 12... Carriage, 16... Ink tank,
18... Ink supply pipe, 20... Second ink supply port (opening), 22... Step portion, 28 a,
2 B b...Protruding wall, 24... Ink level sense electrode rod. Applicant Sharp Corporation Agent Patent Attorney Hisao Komori Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] (1) An ink supply device for an inkjet printer in which an opening is formed in the bottom of an ink tank provided in a carriage, the tip of an ink level sense electrode rod is exposed to this opening, and an ink supply pipe communicating with a nozzle is connected. forming a step in the opening;
An ink supply device characterized in that a protruding wall is provided on the bottom of the ink tank on both sides of the opening and perpendicular to the moving direction of the carriage.