Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2002-09-12
2004-03-30
Adams, Russell (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
C347S012000, C347S190000
Reexamination Certificate
active
06712438
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Korean Application No. 2002-7007, filed Feb. 7, 2002, in the Korean Industrial Property Office, the disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink-jet printer, and more particularly, to an ink-jet printer capable of preventing a malfunction of a head driving unit, which occurs when ink is simultaneously discharged from a plurality of nozzles.
2. Description of the Related Art
Usually, a printer using one of a wire dot method, a heat transfer method, and an ink jet method of forming an image on a recording medium, such as printing paper or an OHP (over head project) film, uses a recording head.
The recording head of an ink-jet printer using one of the above methods has a plurality of nozzles being formed with minute discharging holes to eject ink. The ink in the nozzles is heated and expanded by heating elements disposed in corresponding ones of the nozzles and is ejected outside of the nozzles and stuck on the recording medium.
Accordingly, the ink-jet printer forms the image on the recording medium by ejecting the ink through the nozzles by selectively heating the nozzles in the recording head corresponding to the image to be recorded.
As shown in
FIG. 1
, a general ink-jet printer
200
includes an interface
210
receiving printing data and a control command from a host
100
, an input unit
230
allowing a user to input a selection command, a storage unit
250
storing a program for driving and controlling each part of the ink jet printer
200
and the printing data, a printing unit
270
performing a printing operation, and a controller
290
controlling the entire system of the ink-jet printer
200
in accordance with the program.
A nozzle selection data signal is transmitted to a head driving device
271
of the printing unit
270
in order to drive selected ones of a plurality of nozzles of the recording head
273
in response to the printing data.
As shown in
FIG. 2
, the head driving device
271
includes a first data unit
21
and a second data unit
23
receiving the nozzle selection data signal having an ADDR (address) data signal ADDR and a P (primitive) data signal P_Data, a signal supply
27
having AND gates, and a nozzle driving unit
29
driving the selected nozzle among the plurality of nozzles to discharge the ink.
For example, in a case of the recording head having an n×m number of nozzles, the ADDR data signal ADDR is a data signal to select one of n number of fire groups A
1
-An each having an m number of nozzles, and the P data signal P_Data is a data signal to select a predetermined number of nozzles among the m number of nozzles in a corresponding one of the fire groups A
1
-An.
In other words, when the ADDR data signal ADDR and the P_data signal P_Data have 10 bits, then one fire group is selected among the 10 fire groups A
1
-A
10
in response to corresponding one of the 10-bits of the ADDR data signal ADDR, and the number of the nozzles capable of simultaneously discharging the ink in response to the P data signal P-Data in the fire groups A
1
-A
10
is 10. In other words, the entire number of nozzles of the recording head is 10×10=100.
Hereinbelow, a general operation of the head driving device
271
according to the input data signals will be described by referring to
FIGS. 3A-3F
.
The ADDR data signal Addr_
1
and the P_data signal Data_a of the nozzle selection data signal are synchronized with a clock signal CLOCK, shifted to each bit shift register, and stored in each latch.
Then, when a load signal LOAD is input, the ADDR data signal Addr_
1
and the P_data signal Data_a stored in each of the bit shift register are latched.
After that, when a fire strobe signal STRB_
1
to discharge the ink in the nozzles by heating the heating element is input from the controller
290
to the signal supply
27
, next ADDR data signal Addr_
2
and next P data signal Data_b are stored in respective one of the n-bit shift register and the m-bit shift resistor.
Therefore, the latched data signals Addr_
1
and Data_a and the strobe signal STRB_
1
are input into the signal supply
27
having the n×m number of AND gates to drive the nozzle driving unit
29
.
In other words, a transistor (or FET) of the nozzle driving unit
29
is turned on in response to an output signal of the AND gate corresponding to the selected nozzle among the n×m number of AND gates of the signal supply
27
.
Therefore, an electric current flows as a driving voltage is supplied to each heating element connected with the turned on transistor (or FET) among the n×m number of transistors (or FET) to eject the ink through the selected nozzle.
As described above, to discharge the ink from the plurality of nozzles, a large amount of electric current is required.
Recently, the number of nozzles simultaneously discharging the ink in order to perform a high density and printing speed has been increased. Accordingly, a high electric current flows to a power supply terminal Vp of the recording head
273
of the printing unit
270
.
As shown in
FIGS. 4A-4G
, the high electric current flowing to the power supply terminal Vp in order to drive the plurality of the nozzles causes a noise signal to be input to an input signal line (P_data, ADDR). Because the high electric current flows to the recording head
273
within a relatively short period of time, the power supply terminal Vp becomes unstable, and as a result, the noise signal is produced.
Therefore, there is a problem of a malfunction in controlling the nozzles as the noise signal is input into the head driving device together with the data signals.
SUMMARY OF THE INVENTION
The present invention has been made to overcome the above and other problems of the related art. Accordingly, it is the object of the present invention to provide an ink-jet printer capable of preventing a malfunction of a head driving device, which is generated when the ink is simultaneously discharged from a plurality of nozzles.
Additional objects 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.
An ink-jet printer is provided in order to achieve the above and other objects and includes a nozzle driving unit driving a plurality of nozzles to discharge ink, a signal supply supplying a driving signal to the nozzle driving unit, a shift register storing the nozzle selection signal to select a nozzle in response to a recording image after the nozzle selection signal is synchronized with a clock signal, a counter counting an input number of the clock signal and deciding whether to operate the shift register, and a controller inputting a discharge signal to discharge the ink into the signal supply when the shift register is disabled.
The counter compares a set-up value set up in accordance with a predetermined bit number of the nozzle selection data signal and the input number of the clock signal. When the input number is over the set-up value, the shift register is disabled.
On the other hand, a method of driving a head of an ink-jet printer according to an aspect of the present invention includes inputting a nozzle selection data signal to select a nozzle among a plurality of nozzles into a shift register when the nozzle selection data signal is synchronized with a clock signal, disabling the shift register when an input number is above a predetermined value after counting the input number of the clock signal, latching the nozzle selection data signal stored in the shift register, and inputting a discharge signal to discharge ink from the selected nozzle based on the latched nozzle selection data signal.
The latching of the nozzle selection data signal includes resetting a counter counting the input number of clock signals . Therefore, noise generated in the data signal by the discharge signal is eliminated as the disch
Adams Russell
Dudding Alfred E.
Staas & Halsey , LLP
LandOfFree
Ink-jet printer and method of driving head thereof does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ink-jet printer and method of driving head thereof, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink-jet printer and method of driving head thereof will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3193684