Ink cartridge

This application claims the benefit of Korean Patent Application No. 2002-51604, filed Aug. 29, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

1. Field of the Invention

The present invention relates to an ink cartridge, and more particularly, to an ink cartridge preventing air from flowing into a printing head chip before ink contained in the ink cartridge is used up.

2. Description of the Related Art

Generally, an ink cartridge for an inkjet printer includes a main body filled with ink. The ink in the main body is sprayed onto a paper by a predetermined amount at a time through an ink head chip provided to the main body.

FIG. 1 is a view showing the conventional ink cartridge disclosed in U.S. Pat. No. 4,771,295. Referring to FIG. 1, the conventional cartridge includes a main body 1 divided into three ink tanks. Each ink tank is provided with foam 2 made of a polyurethane material. The main body 1 is provided at a lower part thereof with an ink head chip 3 having ink spray nozzles 3 a . Each ink tank inside the main body 1 is further provided at a bottom thereof with an ink pipe 4 having an ink chamber of a predetermined height in an upright position. Each ink pipe 4 is provided at an upper end thereof with a filter 5 filtering the ink to be supplied to the ink head chip 3 . The ink pipe 4 and the filter 5 compress a lower portion of the foam 2 in an upward direction. Therefore, in a contact portion of the foam 2 with the ink pipe 4 and filter 5 , capillary actions are increased. The foam 2 is compressed to increase density of a structure, thereby further preventing the air from moving toward the ink pipe 4 .

However, the conventional ink cartridge with the above construction has to compress the lower portion of the foam 2 toward an upper end of the ink pipe 4 , whereby a height of the ink pipe is increased. Thus, a distance between the foam 2 and the head chip 3 becomes longer. Therefore, a head loss (pressure loss) expressed by −ρ gh, wherein ρ g is a specific weight, and h is the height of the ink pipe 4 , occurs corresponding to the height of the ink pipe 4 , and thus a negative pressure in the head chip 3 is decreased. Thus, ink sprays through the head chip 3 are not performed normally, causing a print quality degradation.

An aspect of the invention is to solve the above and/or other problems and to provide an improved ink cartridge of simple construction capable of blocking air from flowing into a head chip.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Accordingly, an aspect of the present invention is to solve the foregoing and/or other problems by providing an ink cartridge including a main body having an ink absorbent body filled with ink, an ink head chip disposed at a lower portion of the main body to spray the ink onto a printing paper, an ink feeding pipe disposed at a lower portion inside the main body to feed the ink in the main body to the ink head chip, and a pressure rib protruding from a bottom of the main body to be higher than the ink feeding pipe to press the ink absorbent body which contacts the pressure rib before the ink feeding pipe comes in contact the ink absorbent body.

According to another aspect of the invention, the ink feeding pipe is disposed in a vertically upright position and is provided at an upper end with an ink filter.

Moreover, the main body includes a partition dividing an inside thereof into a foam chamber and an ink chamber and having a passage. The foam chamber includes the ink head chip disposed at a lower portion thereof and further includes the ink absorbent body, and the ink chamber communicates with the foam chamber through the passage and is filled with the ink.

These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic cross-sectional view showing a conventional ink cartridge; and

FIG. 2 is a schematic cross-sectional view showing an ink cartridge in accordance with an embodiment of the invention.

Reference will now be made in detail to the present preferred embodiment of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiment is described in order to explain the present invention by referring to the figures.

An ink cartridge according to an embodiment of the invention will be hereinafter described in detail with reference to the accompanying drawings.

Referring to FIG. 2, the ink cartridge includes a main body 20 of which inside divided into an ink chamber 21 and a foam chamber 23 by a partition 24 , a head chip 30 disposed at a lower portion of the foam chamber 23 , an ink feeding pipe 40 feeding ink in the foam chamber 23 to the head chip 30 , and a filter 50 disposed at an upper end of the feeding pipe 40 and a pressure rib 60 .

The ink chamber 21 and the foam chamber 23 are filled with ink. The foam chamber 23 receives an ink absorbent body 25 , such as a sponge, that is, a foam material. The foam chamber 23 is provided at an upper portion with an air vent 23 a through which air flows into the foam chamber 23 .

The partition 24 is disposed inside the main body 20 of the ink cartridge in a vertically upright position. The main body 20 is provided with a partition 22 having a passage 22 between a bottom 20 a of the main body 20 and the partition 24 . Through the passage 22 , ink and air may flow between the ink and foam chambers 21 and 23 .

The head chip 30 is disposed outside the lower portion of the foam chamber 23 , and the ink feeding pipe 40 is disposed at a bottom inside the foam chamber 23 .

The head chip 30 sprays the ink fed through the ink feeding pipe 40 onto a printing paper based on a predetermined input data for printing. To this end, the head chip 30 includes a spray nozzle and a printing circuit controlling a drive of the spray nozzle so that printing is performed by spraying on the printing paper a predetermined amount of the ink at a time according to the input data for printing.

The ink feeding pipe 40 is disposed at the bottom inside the foam chamber 23 in the vertically upright position with a predetermined height. The ink filter 50 is disposed at the upper end of the ink feeding pipe 40 . The ink filter 50 blocks impurities and air by filtering the ink to be fed to the head chip 30 through the ink feeding pipe 40 .

The pressure rib 60 protrudes from the bottom inside the foam chamber 23 higher than the ink feeding pipe 40 . The pressure rib 60 comes in contact with the ink absorbent body 25 before the ink feeding pipe 40 does. The pressure rib 60 naturally protrudes higher than the ink filter 50 . Therefore, a contact portion in a lower portion of the ink absorbent body 25 with an upper end of the pressure rib 60 is compressed so that capillary actions therein are increased.

With the above construction of the ink cartridge according to the embodiment of the invention, a height of the ink feeding pipe 40 can be shortened to decrease the distance between the ink absorbent body 25 and the head chip 30 , thereby increasing a negative pressure.

That is, an ink feeding pipe is used to press a lower portion of a foam in the related art, thus, a height of the ink feeding pipe has to be high. However, according to the present invention, the pressure rib 60 is configured to be higher than the feeding pipe 40 to press the ink absorbent body 25 , thereby obtaining the same capillary actions as in the related art. Consequently, the height of the ink feeding pipe can be lower than the related art. By lowering the height of the ink feeding pipe 40 , a head loss, that is, a negative pressure loss of −ρ gh′ (ρ g is a specific gravity, and h′ is the height of the ink feeding pipe) can be reduced. The lower portion of the ink absorbent body 25 is compressed by the pressure rib 60 and thus a density thereof is increased, whereby air is blocked from passing easily to the ink feeding pipe 40 and thus ink can be used stably.

As described above, with the ink cartridge according to the invention, the pressure rib 60 is configured to be higher around the ink filter and ink feeding pipe to press the lower portion of the ink absorbent body, whereby capillary actions occur in the ink absorbent body while the height of the ink feeding pipe is lowered to reduce the negative pressure loss due to the height of the ink feeding pipe.

Therefore, the negative pressure can be maintained to be high to feed ink stably through the ink feeding pipe and head chip, and a good quality of printed images can be obtained.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.

The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present invention. The present teaching can be readily applied to other types of apparatuses. The description of the present invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art.