Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2002-05-01
2004-03-16
Nguyen, Thinh (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S047000
Reexamination Certificate
active
06705699
ABSTRACT:
This application incorporates by reference Taiwan application Serial No. 090110667, filed May 3, 2001.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates in general to an image output device, and more particularly to an image output device for improving image resolution and tone expression.
2. Description of the Related Art
In recent years, the personal computer has become so popular that the peripheral computer products have developed very rapidly. Most users employ printers to create output images by printing the electrical documents, such as plain text, colorful graphics, or beautiful pictures, which might be downloaded from the Internet or photographed by a digital camera. By balancing the price and quality, the color ink-jet printer is an affordable option for most PC buyers and has thus become the most popular type of printer sold today.
In the ink-jet printer, a print head traverses over the surface of the paper and ejects ink onto the paper to form a printed image. The bubble jet and piezoelectric print head technologies are widely applied to ink-jet printers now to produce bubble jet printers and piezoelectric printers. The principal difference between bubble-jet printers and piezoelectric printers is that bubble-jet printers use special heating elements to prepare the ink, and the piezoelectric printers use piezoelectric crystals. In substance, the piezoelectric printer uses the expanding piezoelectric crystals to force ink drops out of the nozzle and onto the paper. Usually, the bubble jet printer includes a heating element, ink, and nozzle. The heating element heats the ink and forms a bubble until the pressure forces it to burst. A drop of ink is then forced out of the nozzle and onto the paper. During printing, it is required that the ink density and dropping location be controlled to form the desired printed image.
The printed image is a pattern consisting of a number of ink drops or pixels. The print quality relates to the resolution. Generally speaking, the higher the resolution, the more pixels per square inch an image has, and the better the overall print quality. For example, if the resolution of 600*600 dpi (dot per inch) increases to the resolution of 1200*600 dpi, the ink drop size decreases a half time accordingly. The U.S. Pat. No. 5,726,690 discloses a method for controlling the ink drop size by controlling the pulse width of the delivered firing pulse. However, the variation range of the ink drop size is only 16% by the method, which does not improve the resolution very much.
Another key factor of print quality for a color ink-jet printer is the tone expression. The traditional color ink-jet printer uses ink of four colors, M (Magenta), C (Cyan), Y (Yellow), and K (Black). In recent years, the color ink-jet printer uses ink of six colors including M, C, Y, K, light M, and light C, or even uses ink of seven colors by adding light Y. Therefore, the tone expression can enrich the color of the printed image. In a printer having six color inks, the printed image can have 2
5
=32 kinds of color combinations without the shortcoming of half tone simulation and the print quality will greatly improve. Therefore, the key factor of print quality for a color ink-jet printer is the number of the color combinations, that is to say, the tone expression.
The following statement is about the improvement on the variation range of the ink drop size (resolution) and the number of the color combination (tone expression) regarding the conventional image output device with ink of four/six colors.
Referring to
FIG. 1
, an arrangement for a nozzle of the conventional image output device with ink of four colors is shown. The conventional image output device with ink of four colors includes a color ink cartridge
110
and a black ink cartridge
140
. The color ink cartridge
110
has a yellow ink tank Y filled with yellow ink
112
, magenta ink tank M filled with magenta ink
114
, and cyan ink tank C filled with cyan ink
116
. The small circles near the ink tanks represent the nozzle of the printhead for ejecting ink. The yellow ink nozzle
122
is capable of ejecting yellow ink
112
, the magenta ink nozzle
124
is capable of ejecting magenta ink
114
, and the cyan ink nozzle
126
is capable of ejecting cyan ink
116
. The black ink cartridge
140
only has a black ink tank K filled with the black ink
142
, and the black ink nozzle
152
is capable ejecting black ink
142
.
Referring to
FIG. 2
, another arrangement for nozzle of the conventional image output device with ink of four colors is shown. The U.S. Pat. No. 6,149,260 discloses an ink jet recording apparatus capable of printing different dot sizes by using a large size nozzle and a small size nozzle to increase the variation range of the ink drop size. As shown in
FIG. 2
, the conventional image output device with ink of four colors includes a color ink cartridge
210
and a black ink cartridge
240
. The color ink cartridge
210
has a yellow ink tank Y filled with yellow ink
212
, magenta ink tank M filled with magenta ink
214
, and cyan ink tank C filled with cyan ink
216
. The yellow ink nozzles
222
,
232
are capable of ejecting yellow ink
212
, the magenta ink nozzles
224
,
234
are capable of ejecting magenta ink
214
, and the cyan ink nozzles
226
,
236
are capable of ejecting cyan ink
216
. The black ink cartridge
240
only has a black ink tank K filled with the black ink
242
, and the black ink nozzle
252
is capable ejecting black ink
242
.
In
FIG. 2
, the color cartridge
210
has nozzles with a large diameter and a small diameter. The nozzle with small diameter will be driven to eject the small ink drop or light ink drop. The nozzle with large diameter will be driven to eject the large ink drop or dark ink drop. The ejected ink has a proper size and color since the variation range of the ink drop size is increased. However, it requires a larger wafer for forming nozzles with different diameters on one printhead. Besides, the cost of manufacturing the printhead increases and the controlling method becomes more complicated. Although the ink jet recording apparatus is capable of printing in different dot sizes by using two nozzles with different sizes increases the variation range of the ink drop size, it increases the cost of manufacturing the printhead and the complexity of controlling the printhead.
Referring to
FIG. 3
, an arrangement for nozzles of the conventional image output device with ink of six colors is shown. The conventional image output device with ink of six colors includes color ink cartridges
310
and
340
. The color ink cartridge
310
has a yellow ink tank Y filled with yellow ink
312
, magenta ink tank M filled with magenta ink
314
, and cyan ink tank C filled with cyan ink
316
. The yellow ink nozzle
322
is capable of ejecting yellow ink
312
, the magenta ink nozzle
324
is capable of ejecting magenta ink
314
, and the cyan ink nozzle
326
is capable of ejecting cyan ink
316
. The color ink cartridge
340
has a black ink tank K filled with the black ink
342
, light cyan ink tank c filled with cyan ink
344
, and light magenta ink tank m filled with light magenta ink
346
. The black ink nozzle
352
is capable of ejecting black ink
342
, the cyan ink nozzle
354
is capable of ejecting cyan ink
344
, and light magenta ink nozzle
356
is capable of ejecting magenta ink
346
.
Comparing
FIG. 3
with
FIG. 1
, the light cyan ink and the light magenta ink are included in the color ink cartridge
340
. This increases the tone expression and therefore enriches the color of the printed image. However, the variation range of the ink drop sizes is limited due to the uniform size of the nozzles. It is still of no help to improve image resolution.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide an image output device for improving image resolution and tone expression by the arrangement for nozzles of the color ink cartridge of the image output device.
The invention achieves the above-identif
Du Ben-Chuan
Li Yung-Yi
Benq Corporation
Nguyen Thinh
Rabin & Berdo PC
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