Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2000-06-02
2002-10-22
Eickholt, Eugene (Department: 2854)
Incremental printing of symbolic information
Ink jet
Controller
C347S037000, C347S182000, C347S192000
Reexamination Certificate
active
06467863
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink jet recording head for discharging ink to form a desired image on a material to be recorded, and an ink jet recording device.
2. Related Background Art
There has heretofore been known an ink jet recording method comprising: applying heat and other energy to ink; causing a state change with a steep volume change (bubble generation) in the ink; discharging the ink from a discharge port by the action force based on the state change; and attaching the ink to a material to be recorded to form an image, which is a so-called bubble jet recording method. A recording device using the bubble jet recording method is, as disclosed in U.S. Pat. No. 4,723,129, generally provided with a discharge port for discharging ink, an ink channel communicating with the discharge port, and an electrothermal converter as energy generating means disposed in the ink channel to discharge the ink.
According to the recording method, a high-grade image can be recorded at a high speed and with a low noise, and a head for performing this recording method can be provided with highly densely arranged discharge ports for discharging the ink, so that a recorded image with a high resolution by a small device, an easily obtainable color image, and many other superior respects are realized. Therefore, in recent years, the bubble jet recording method has been utilized in a printer, copying machine, facsimile machine and many other office apparatuses, and further utilized in industrial systems such as textile printing equipment.
Additionally, a recording element for generating an energy to discharge the ink can be formed using a semiconductor manufacture process. Therefore, the head utilizing the bubble jet technique is constituted by forming the recording element on an element substrate formed of a silicon substrate, and bonding onto the element a top plate provided with a groove for forming the ink channel and formed of polysulfone, another resin, glass or the like.
Moreover, since the element substrate is formed of the silicon substrate, not only the recording element, but also a driver for driving the recording element, a temperature sensor used for controlling the recording element in accordance with a head temperature, a drive controller, and the like are constituted on the element substrate.
One example of the head substrate is shown, for example, in FIG.
25
. Additionally,
FIG. 25
shows the constitution as the related art of Japanese Patent Application Laid-Open No. 7-256883.
In
FIG. 25
, an element substrate
900
is provided with: a plurality of heaters (recording elements)
901
, arranged in parallel, for applying a discharging heat energy to the ink; power transistors
902
for driving the respective heaters
901
; a shift register
904
to which image data serially inputted from the outside and a serial clock synchronous with the data are inputted, and which latches the image data for each line; a latch circuit
903
for latching the image data for one line outputted from the shift register
903
in synchronization with a latching clock, and transferring the data in parallel to the power transistor
902
; a plurality of AND gates
915
, disposed for the respective power transistors
902
, for applying the output signal of the latch circuit
903
to the power transistor
902
in response to an enabling signal from the outside; and input terminals
905
to
912
for inputting the image data, various signals, and the like from the outside.
Moreover, the element substrate
900
is provided with a temperature sensor for measuring the temperature of the element substrate
900
, a resistance sensor for measuring the resistivity of the respective heaters
901
, or another sensor
914
.
The head constituted by forming the driver, temperature sensor, drive controller, and the like on the element substrate is practically used, and contributes to the enhancement of a recording head reliability and the reduction in size of the device.
In this constitution, the image data inputted as a serial signal is converted to a parallel signal by the shift register
904
, and outputted/held by the latch circuit
903
in synchronization with the latching clock. When a drive pulse signal (enabling signal for the AND gate
915
) of the heater
901
is inputted via the input terminal in this state, the power transistor
902
turns on in accordance with the image data, an electric current flows in the corresponding heater
901
, and the ink of a liquid channel is heated and discharged as a liquid drop from a nozzle tip end.
Here, in the constitution shown in
FIG. 25
, a main body device in the ink jet recording device monitors the output of the sensor
914
to detect the resistivity of the heater
901
, and changes a power voltage and drive pulse width in accordance with the value, so that a substantially constant energy is applied to the heater
901
.
In the ink jet recording device described in the Japanese Patent Application Laid-Open No. 7-256883, for a purpose of reducing the load of the main body device of the ink jet recording device, it is proposed to drive the sensor
914
, form on the element substrate
900
the drive controller for controlling the drive pulse width of the heater
901
in accordance with the output from the sensor
914
, monitor the resistivity of the respective heaters
901
and temperature sensor in the element substrate
900
and detect head property and state and to change the drive pulse width of the heater
901
in accordance with the property and state.
In recent years, for the ink jet recording device, there has been an increasing demand for a higher grade image output in various products and fields. Moreover, a demand for enhancing a recording speed has also increased, and the increase of the number of nozzles for discharging the ink and the shortening of a recording period have been achieved. As a result, the number of the recording elements to be simultaneously driven increases, cost increases because of a necessity of increasing a power capacity, and additionally in respect of fluid the simultaneous discharge of much ink is disadvantageous in performing a stable discharge.
To cope with the problem, it is effective to reduce the number of simultaneously driven recording elements by shortening the width of the drive pulse signal applied to the recording element.
Here, in the conventional example, a head discharge frequency is about 10 KHz (period of 100 &mgr;S), and about 6 &mgr;S per time division in case of a time division number of 16. In this case, one heat signal pulse width can be handled at about 4 to 5 &mgr;S. Here, when the time resolution necessary for generating and controlling a heat signal pulse in the head is of the order of 1/20 to 1/40 of the heat signal pulse, the feedback to the pulse width by the sensor output can be performed, and the clock frequency as a reference for obtaining the resolution is in a range of 5 to 10 MHz (period of 0.2 &mgr;S to 0.1 &mgr;S).
Moreover, when the width of the heat pulse signal is shortened to cope with the increase of a momentary current by the increase of the nozzle number, and the high printing speed, for example, at the drive frequency of 30 KHz and the time division number also of 16, one time division time is only about 2 &mgr;S, and the time for one time division is much shorter than the conventional time of about 6 &mgr;S. Therefore, in this case, one heat signal pulse width is requested to be set to 2 &mgr;S or less (about 0.5 to 1.5 &mgr;S). The resolution required for the heat signal in consideration of the pulse width control is in a range of 0.01 &mgr;S to 0.07 &mgr;S, and the reference clock signal for satisfying this level of the resolution requires a frequency of 15 MHz to 100 MHz (period of 0.07 &mgr;S to 0.01 &mgr;S).
When the transfer clock frequency of the image data is increased (the period is shortened), the resolution can be enhanced, but the clock signal is usually supplied to the head from the main body device of the recording
Imanaka Yoshiyuki
Kubota Masahiko
Yamanaka Akihiro
Canon Kabushiki Kaisha
Eickholt Eugene
Fitzpatrick ,Cella, Harper & Scinto
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