Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2001-05-15
2003-10-14
Meler, Stephen D. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
C347S009000
Reexamination Certificate
active
06631970
ABSTRACT:
This application is based on Patent Application No. 2000-143852 filed May 16, 2000 in Japan, the content of which is incorporated hereinto by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink jet recording apparatus which ejects ink from a print head onto a recording sheet to record an image or the like, and more specifically to an ink jet recording apparatus and an ink jet print head which have a status detection function to detect a state of the print head or, in more specific terms, a state of the ink in the print head.
2. Description of the Related Art
Recording apparatus with functions of printer, copying machine and facsimile, combination type recording apparatus including computers and word processors, and recording apparatus used as output devices for work stations are all designed to record an image on a recording sheet, such as paper and plastic thin plate (for OHP, for example), according to image data. Such recording apparatus can be classed into an ink jet type, wire dot type, thermal recording type, thermal imprint type, and laser beam type according to the recording method of the printing means used.
Of these recording methods, the ink jet type recording apparatus (ink jet recording apparatus) ejects ink from the ink jet print head (also referred to simply as a print head) as a printing means onto a recording medium such as a recording sheet to form an image and has the advantage of being able to easily reduce the size of the printing means and print a very fine image at high speed. Other advantages include a low running cost because it can print on plain paper with no special treatment, low noise during printing operation because the ink jet recording apparatus employs a non-impact printing method, and ease with which multicolor inks can be used in forming a color image.
FIG. 24
is a block diagram schematically showing a system configuration in a conventional ink jet recording apparatus.
In the figure, a main controller
11
has a CPU and constitutes a main controller of the ink jet recording apparatus. The main controller
11
converts image data sent from a host computer
10
into pixel data and stores them in a frame memory
12
. The main controller
11
also supplies each pixel data stored in the frame memory
12
to a driver controller
17
at a predetermined timing. The driver controller
17
converts the pixel data received into drive data for driving print elements
101
(data for turning on or off the print elements
101
in an ink jet print head board
100
). The converted drive data is stored in a drive data RAM
18
. According to a control signal output from the main controller
11
, the driver controller
17
reads the drive data from the drive data RAM
18
and feed it to a head driver
102
to control the drive timing of the print elements
101
.
In the following configuration, the main controller
11
controls the ejection of a conductive ink
50
from the print elements
101
installed in the ink jet print head board
100
, the rotation of a carriage feed motor
15
and the rotation of a paper feed motor
16
. This control is performed by the main controller
11
controlling the driver controller
17
and motor drivers
13
and
14
, thus recording characters and images corresponding to the image data.
The ink jet recording method described above has some ink ejection variations. One such variation is a bubble jet recording method. In this method a heater is installed in each nozzle to impart a thermal energy to the ink in the nozzle to generate a bubble in the ink. The bubble generating energy is used to eject ink from the nozzle. The heater as a print element to generate an energy for ejecting ink may be manufactured by using the semiconductor fabrication process. Hence, the ink jet print head using the bubble jet recording method has the print elements formed on a print head board, which is made from a silicon substrate and bonded with a top plate. The top plate, which is made of resin, such as polysulfone, and glass, is formed with grooves serving as ink passages.
Taking advantage of the fact that the print head board is made from a silicon substrate, not only the print elements but also other functional components are formed on the print head board. The functional components include, for example, a driver for driving the print elements, a temperature sensor used to control the print elements according to the temperature of the print head, and a drive controller for the temperature sensor.
Japanese Patent Application Laying-open No 7-256883 discloses an example of the ink jet print head board described above. The construction of the conventional ink jet print head board disclosed in the above official gazette is shown in FIG.
25
.
In
FIG. 25
, on the ink jet print head board
100
(simply referred to as a board) are arranged heaters
101
as print elements that apply an ink ejection thermal energy to the ink. Power transistors (driver elements)
102
are connected to the parallelly arranged heaters (print elements)
101
to drive the heaters
101
.
Also formed on the board
100
are a shift register
104
, a latch circuit
103
, and a plurality of AND gates
115
. The shift register
104
receives image data from outside through a terminal
106
in synchronism with a serial clock received from a terminal
105
, and holds image data representing one line.
The latch circuit
103
latches the image data for one line parallelly output from the shift register
104
in synchronism with a latch clock (latch signal) received through a terminal
107
, and transfers the image data parallelly to the power transistors
102
. The AND gates
115
are provided in one-to-one relationship with the power transistors
102
and apply output signals of the latch circuit
103
to the power transistors
102
in response to an external enable signal.
Denoted
108
is a drive pulse width input (heat pulse) terminal which receives from outside the print head a signal for controlling an ON time of the power transistors
102
as drive elements, i.e., the time during which to apply current to the heaters
101
. Designated
109
is a terminal for inputting a drive power (5V) for logic circuits such as the latch circuit
103
and shift register
104
. The board
100
also has a ground terminal
110
and terminals
112
for driving a sensor
114
and for a monitor. The terminals
105
-
112
formed on the board
100
are input terminals to receive the image data and various signals from outside.
Also formed on the print head board
100
is a sensor
114
such as a temperature sensor for measuring the temperature of the print head board
100
and a resistance sensor for measuring a resistance of each heater
101
. The head having the driver, temperature sensor and their driving controller all formed on the print head board has already been put to practical use, contributing to improving the reliability of the print head and to reducing the size of the recording apparatus.
In this construction, the image data entered as a serial signal is converted into a parallel signal by the shift register
104
, and the converted image data is held in the latch circuit
103
in synchronism with the latch clock. In this state, when a drive pulse signal for the heaters
101
(enable signal for the AND gates
115
) is entered through the input terminal
108
, the power transistors
102
are turned on according to the image data. Electric current flows to those heaters
101
that correspond to the turned-on power transistors
102
, causing these heaters
101
to generate a thermal energy.
The print head board
100
is bonded with the top plate to form liquid passages (or nozzles) for ejecting ink and a common liquid chamber communicating with the liquid passages. In this construction, the ink accommodated in the ink tank (or ink container) is supplied through the common liquid chamber to the nozzles. The thermal energy generated by the heaters as they are driven, as described above, heats the ink in the liquid passages (nozzles) and
Ikeda Tetsuhito
Sato Tomonori
Takagi Shinji
Yano Kentaro
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Meler Stephen D.
Nguyen Lam
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