Time division drive recording apparatus and method

A recording apparatus records an image by driving plural recording elements in blocks, into which the plural recording elements are divided. The plural blocks are divided into plural groups, each group having more than one block. A driving circuit drives each of the blocks independently. The driving circuit effects recording with high resolution or low resolution by respectively driving plural groups at a different timing in a first mode and driving the plural groups at a same timing in a second mode.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a time division drive recording apparatus and 
method. More specifically, this invention is suitable for the time 
division drive recording apparatus and method using an ink jet recording 
system that can record with high accuracy and at high speed. 
2. Description of the Related Art 
As copying apparatuses, information processing apparatuses such as word 
processors and computers, and communication apparatuses have become more 
and more widely used, image forming apparatuses which perform digital 
image recording using an ink jet system are rapidly becoming widely used. 
In such a recording apparatus, it is common to use a recording head 
(multi-head) in which plural recording elements are integrally arranged to 
improve recording speed. Ink discharge openings and liquid paths are 
integrally arranged to correspond to recording elements in the case of an 
ink jet system. 
Printing a monochromatic high resolution image or a color image requires 
good coloring, tonality, uniformity and so on. 
In a recording apparatus of the bubble jet system which discharges ink 
using thermal energy, among many kinds of ink jet recording apparatuses, a 
heat element is controlled by applying plural electric pulses to the heat 
element. By applying plural electric pulses or, in some cases, changing 
the width thereof, an ink discharge condition can be kept constant so 
printing quality can be maintained constant regardless of outside 
environmental conditions (e.g., temperature). 
However, recently in an ink jet system not only high printing quality but 
also high recording speed are expected. 
To control the heat element by applying plural pulses to improve printing 
quality requires much time for control because one dot must be formed by 
applying plural pulses, so it is a disadvantage in achieving high 
recording speeds. 
A driver structure of conventional printing heads 50A to 50D is shown in 
FIG. 4. In FIG. 4, the driver structure for black recording head 50A is 
shown in detail, but the driver structures for cyan head 50B, magenta head 
50C, and yellow head 50D are similar. Black printing data BKSi (CSi, MSi, 
YSi for the other heads) is transferred to a shift register 51 and it is 
once stored in a latch 52. By performing AND (logical product) of the data 
stored in the latch 52, common signals BEi1*, BEi2*, BEi3* and BEi4* 
commonly supplied to all heads and heat signal BkENB* (CENB*, MENB* and 
YENB* for the other heads), only designated heaters 54 can be driven by a 
transistor array 53. The symbol "*" designates low active. 
Drive timing in a conventional recording apparatus is shown in FIGS. 5A-5H. 
FIGS. 5A-5H show that common signals (BEi1*, BEi2*, BEi3*, BEi4*) and heat 
signals (BkENB*, CENB*, MENB*, YENB*) are driven in a time division manner 
and a number of the heaters heated at the same time is limited in order to 
reduce consumption of electric power in an actual drive. As mentioned 
above, the heat signal comprises plural pulses to maintain printing 
quality. 
In FIGS. 5E-5H, the manner of controlling by two pulses is shown. Each heat 
signal comprises a preheat pulse and a main heat pulse between which an 
interval period exists. The main heat pulse warms a heater for discharging 
ink by forming a bubble. The preheat pulse, however, is of insufficient 
duration to discharge the ink, but rather preheats the ink to control a 
bubble forming area. 
However, this method takes a relatively large length of time because of the 
duration of the preheat period and the interval period, in comparison with 
a head drive method in which temperature control is not performed. As a 
result, in this method the drive time as a whole becomes too long as to 
diminish the high-speed drive of a printer. Moreover, it is desirable to 
select high resolution recording or standard resolution recording as 
needed. 
SUMMARY OF THE INVENTION 
One object of the invention is to provide a time division drive recording 
apparatus and method which can shorten a drive time of a recording head 
and can record at high resolution. 
It is another object of the invention to provide a time division drive 
recording apparatus and method which can select high resolution recording 
or standard resolution recording. 
According to one aspect of the present invention there is provided a 
recording head with a driving circuit and comprising plural recording 
elements divided into plural blocks and the plural blocks being divided 
into plural groups, each group having more than one block. The driving 
circuit can drive each of the blocks independently. The driving circuit 
drives the plural groups at a different timing in a first mode and drives 
the plural groups at the same timing in a second mode. 
According to a further aspect of the present invention there is provided a 
recording head cartridge including a recording head and a container. The 
recording head is operable in first and second modes and includes plural 
recording elements divided into plural blocks and the plural blocks are 
divided into plural groups. Each group has more than one block. The 
driving circuit drives each of the plural blocks independently. The 
driving circuit drives the plural groups at a different timing in the 
first mode and drives the plural groups at a same timing in the second 
mode. Recording is effected by discharging a recording liquid from a 
liquid path by using thermal energy. The container holds the recording 
liquid to be supplied to the liquid path. 
According to another aspect of the present invention there is provided a 
recording apparatus for recording an image using a recording head having 
plural recording elements divided into plural blocks and the plural blocks 
being divided into plural groups, each group having more than one block. A 
driver can drive each of the plural blocks independently. A drive 
controller controls the driver to drive the plural groups at a different 
timing in a first mode and to drive the groups at the same timing in a 
second mode. 
According to yet another aspect of the present invention there is provided 
a method for recording an image using a recording head having plural 
recording elements divided into plural blocks and the plural blocks being 
divided into plural groups, each group having more than one block. A 
providing step provides a driver for driving each of the plural blocks 
independently. A first controlling step controls the driver to drive the 
plural groups at a different timing in a first mode. A second controlling 
step controls the driver to drive the plural groups at the same timing in 
a second mode. 
The individual components shown in outline or designated by blocks in the 
drawings are all well-known in the image recording arts and their specific 
construction and operation are not critical to the operation or best mode 
for carrying out the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The preferred embodiment of the present invention will now be described 
with reference to the drawings. 
FIG. 1 is a block diagram showing structure of an ink jet recording 
apparatus adaptable to the present invention. 
In FIG. 1, a recording medium 1 such as paper or a plastic sheet is 
supported by two pairs of conveyance rollers 2, 3, with one pair 
positioned above and the other pair positioned below a recording area. The 
recording medium 1 is conveyed by the pair of conveyance rollers 2 driven 
by a sheet feeding motor 4 in the direction of arrow A. In front of the 
pairs of conveyance rollers 2, 3, guide shafts 5 are provided parallel 
therewith. Along the guide shafts 5, a carriage 6 is scanned in the 
forward and reverse directions of arrow B by a wire 8 driven by a carriage 
motor 7. 
On the carriage 6, an ink jet recording head 90 is mounted. The recording 
head 90 comprises four heads for color image recording arranged along a 
carriage scanning direction. The four heads comprise a black head 9A, a 
cyan head 9B, a magenta head 9C and a yellow head 9D respectively 
corresponding to ink colors of black (Bk), cyan (C), magenta (M), and 
yellow (Y). On the front surface of each recording head 9, in other words 
on a surface facing a recording surface of the recording medium 1, at 
predetermined intervals (for example 0.8 mm), ink discharge sections, in 
which plural ink discharge openings (for example, numbering 48 or 64) are 
arranged in a row in a direction different from the carriage scanning 
direction, are provided. 
FIG. 2 is a schematic illustration showing a vertical sectional view of a 
part of an ink discharge section of one of the recording heads 90, with 
each of the recording heads 9A to 9D being of a similar construction. 
In FIG. 2, plural ink discharge openings 10 are formed at a predetermined 
pitch on the surface facing the recording medium 1. Electro-thermal 
converters (heat resistors or the like) 11 provided correspondingly to 
each ink discharge opening 10 are driven (heated) based on recording 
information, to effect a film boiling phenomenon in ink and form a bubble 
11A. Pressure from the bubble generation causes the ink to discharge in 
the form of a flying ink droplet 12 which lands on the recording medium 1, 
so as to effect recording as a constituent of a dotted pattern. 
A heat driver 13 that switches on and off a current application to the 
electro-thermal converter is provided for each recording head 90. A 
circuit board of a drive circuit (driver) 29 to drive as mentioned above 
is provided on the carriage 6. Reference numeral 10A is a liquid path and 
10B is a common liquid chamber. The ink is supplied to the liquid path 10A 
through the common liquid chamber 10B from an ink tank (not shown) filled 
with the ink. 
A control section including an engine control circuit (CPU) of the 
recording apparatus, ROM and RAM provided therewith receives a command 
signal and data signal (recording information) from a controller of a host 
computer 17 and drives a drive source such as a motor based on the 
signals, and drives an electro-thermal converter 10A of each of recording 
heads 9A to 9D through the heat driver 13. 
Both a key setting section including online/offline select key 16A, line 
feed key 16B, form feed key 16C, recording mode select key 16D and so on, 
and an indicator section including plural warning lamps 16E and power 
supply lamp 16F are provided on an operation panel 160 which is attached 
to the exterior of a housing (not illustrated) of the recording apparatus. 
FIG. 3 is a block diagram showing a control system of the color ink jet 
recording apparatus shown in FIG. 1. 
In FIG. 3, the CPU 21 is connected to the host computer 14 through an 
interface 22, and controls a recording operation based on both the command 
signal (command) and recording information signal read in a data memory 23 
from a controller of the host computer 14, and the program printing 
command data stored in a program memory 24, working memory 25 and so on. 
CPU 21 controls the carriage motor 7 and the sheet feeding motor 4 through 
an output port 26 and a motor driver 27, and controls the recording head 9 
through the control circuit 29 based on the recording information stored 
in the data memory 23 to record. 
An output from each of operation keys 16A to 16D (FIG. 1) on the operation 
panel 160 mentioned above is transmitted to the CPU 21 through an input 
port 32. Moreover, a control signal is supplied through an output port 36 
from the CPU 21 to the warning lamps such as the alarm lamps 16E and the 
power supply lamp 16F. 
Reference numeral 33 represents a timer provided on a control board and is 
connected to an interrupt port of the CPU 21 through an input port 34. 
From a power supply circuit 28, logic drive voltage VCC (for example, 5V) 
to drive a control logic circuit, motor drive voltage VM (for example, 
30V), reset voltage RESET, heat voltage VH (for example, 25V) to heat the 
electro-thermal converter 11 of the recording head 90 and backup voltage 
VDDH to protect the recording head 9 are output. 
The heat voltage VH is applied to the recording head 9 and backup voltage 
VDDH is applies to the head control circuit 29 and the recording head 90. 
As mentioned above, the conventional method described with reference to 
FIGS. 4 and 5 takes much time because of the preheat period and the 
interval period accompanying therewith in comparison with the head drive 
method in which temperature control (preheat control) is not performed, so 
the conventional method as a whole becomes long and it is disadvantageous 
in achieving high-speed drive of a printer. The manner for solving this 
problem, which is a premise of this embodiment, will be explained 
referring to FIG. 6. 
FIG. 6 shows structure of a driver housed in the recording head. This 
structure enables the apparatus to print at a high speed while it drives 
to control the temperature of the recording head using two or more pulses. 
In FIG. 6, plural (here, 2) decoders 61, 62 are respectively connected to 
the corresponding heaters 63 (here, odd numbered heaters and even numbered 
heaters). Each of the heaters (odd numbered heaters) according to common 
signals COM11, COM12 and heat signal P1 and the heaters (even number 
heaters) according to common signals COM21, COM22 and heat signal P2 can 
be driven independently. The line to supply the record data (recording 
information) is omitted to simplify the explanation. 
According to the structure, each of the odd numbered heaters and the even 
numbered heaters can be driven independently, so the head can be driven at 
a timing as shown in FIG. 7. FIG. 7 is a timing chart showing the 
independent drive of the heat signals P1, P2 to print in a forward 
direction (PT direction in FIG. 1) and reverse direction (CR direction in 
FIG. 1). 
Two or more pulses to perform temperature control can be generated by using 
each of signals P1, P2 in spite of its simple iteration. By controlling 
each of signals P1, P2 independently, the preheat pulse and the main heat 
pulse can be driven during the interval period between another preheat 
pulse and another main heat pulse. The above mentioned structure can 
minimize the minimum drive time needed to drive in spite of control by 
plural pulses and can easily drive at a high speed. As shown in FIG. 7, 
the heaters can be easily driven in reverse order in the reverse direction 
driven by reversely applying the common signals in the forward driving 
order. 
Although the example that a drive block is divided into two to be driven 
has been explained, the drive block may be divided into more than two. 
The above mentioned structure enables plural blocks to be driven 
independently and to drive with plural pulses efficiently, so it is 
possible to print at a high speed. 
Next, another embodiment of the invention will be explained. 
In this embodiment, plural drivers are provided on a head unit and they are 
driven simultaneously, so it is possible to print at a double resolution. 
In the recording apparatus of the structure mentioned above, a carriage is 
moved to the right and left, and a recording head is driven by triggering 
at any position to print. In the apparatus of this embodiment, the landed 
position of a dot (ink) ejected in a subsequent timing will be shifted 
from the landed position of a dot (ink) ejected in a previous timing in 
order to drive the printing head in the time division manner while the 
carriage is moving. The head is inclined beforehand in this embodiment to 
line up the landed positions of printed dots. The control to line up the 
landed positions of the printed dots in the embodiment will be shown in 
FIGS. 8(A) and 8(B). FIG. 8(A) shows landed spots of printing dots on the 
recording medium without correction of the recording head. In FIGS. 8(A) 
and 8(B), vertical lines represent ideal landed positions. In FIGS. 8(A) 
and 8(B), heating 32 nozzles, which are double the number of nozzles shown 
in FIG. 6, will be explained. 
In FIGS. 8(A) and 8(B), the printing head comprises 64 total nozzles 
instead of 32 nozzles. The 1st and 2nd nozzles and the 33rd and 34th 
nozzles are heated at the same time to discharge ink. An inside driver 
circuit of the head is structured to enable the 1st, 2nd, 33rd and 34th 
nozzles (heaters) to be driven in common as shown in FIG. 9. The drive 
timing will be shown in FIGS. 10A-10R. 
A driver circuit shown in FIG. 9 independently drives two systems by 
signals P1, P2 and signals COM11, COM12, COM21, COM22 which are input in 
the decoders 71, 72 as in FIG. 6. An UPPER ENABLE signal enables the 1st 
to 16th and 33rd to 48th heaters 73 to be driven, and a LOWER ENABLE 
signal enables the 17th to 32nd and 49th to 64th heaters 73 to be driven. 
Those two signals can be driven independently. Drive timing in the first 
mode which is recording at standard resolution is shown in FIGS. 10A-10R. 
In FIGS. 10B, 10C, 10K and 10L, by applying pulses 1 to 8 as in FIGS. 7A, 
7B, 7G and 7H and at that time enabling the UPPER ENABLE signal, the 1st 
to 16th heaters 73 as well as the 33rd to 48th heaters 73 can be driven. 
Afterward, by enabling the LOWER ENABLE signal, the 17th to 34th heaters 
73 and the 49th to 64th heaters 73 can be driven. A period is provided 
between each data latch signal in FIG. 10A to compensate for motor 
fluctuation or jitter. 
As shown in FIG. 8(A), that result produces an image in which landed 
positions of ink discharged from nozzles 1 to 32 are shifted according to 
printing timing. Then, if the printing head is inclined beforehand 
according to a difference of printing timings, it is possible to print at 
accurate positions 20 as shown in FIG. 8(B). 
In drive timing in the second mode which is recording at high resolution is 
shown in FIGS. 12A-12R. In FIGS. 12A-12R, during pulses 1 to 8 and during 
pulses 9 to 16 by enabling the UPPER ENABLE signal and the LOWER ENABLE 
signal, it is possible to print at double resolution. 
While nozzles 1 to 16 are driven during pulses 1 to 8 in the first mode, in 
addition, nozzles 17 to 32 can be driven in the second mode. Afterward, 
nozzles 1 to 16 as well as nozzles 17 to 32 are driven during pulses 9 to 
16. As a result, nozzles 1 to 16, 17 to 32, 33 to 48, and 49 to 64 are 
driven in a same period. 
Printing landed spots can be in two rows in the second mode as shown in 
FIG. 11(A), although they are in one row in the first mode. In other 
words, it is possible to record in the second mode at twice the resolution 
as in the first mode. Since the head is inclined in fact, recording can be 
effected as shown in FIG. 11(B). 
By having plural driver circuits in the printing head and driving plural 
driver circuits simultaneously, it is possible to triple or quadruple 
resolution. 
According to the embodiment as mentioned above, the drive circuit can drive 
plural blocks independently, so it is possible to drive the preheat pulse 
and the main heat pulse efficiently and to shorten the drive time. 
In addition, by simultaneously driving the blocks which can be driven 
independently, it is possible to achieve high resolution. 
Further, the ink jet recording apparatus using heating elements as 
recording elements is an example of a recording apparatus, but the present 
invention is not limited to that. The present invention can be applied to 
other recording apparatuses such as a thermal recording apparatus using 
heating elements, an LED recording apparatus using LED elements, and an 
impact recording apparatus using wire elements as recording elements. 
Typical structures and operational principles of such devices to which the 
present invention can be applied, can preferably be such as those 
disclosed in U.S. Pat. Nos. 4,723,129 and 4,740,796. Those principles and 
structures are applicable to a so-called on-demand type recording system 
and to a continuous type recording system, but are particularly suitable 
for the on-demand type. Such an approach adopts the principle that at 
least one driving signal is applied to an electrothermal transducer 
disposed on a liquid (ink) retaining sheet or in a liquid passage, the 
driving signal being sufficient to provide a quick temperature rise beyond 
a departure-from-nucleation boiling point. The thermal energy provided by 
the electrothermal transducer produces film boiling on the heating portion 
of the recording head, whereby a bubble can be formed in the liquid (ink), 
in response to each driving signal. The production, development and 
contraction of the bubble cause ejection of the liquid (ink) through an 
ejection outlet to produce at least one droplet. The driving signal is 
preferably in the form of a pulse, because this enables the development 
and contraction of the bubble to be effected instantaneously, and 
therefore, the liquid (ink) is ejected with quick response to the driving 
signal. The pulse-shaped driving signal is preferably formed as disclosed 
in U.S. Pat. Nos. 4,463,359 and 4,345,262. In addition, the temperature 
increasing rate of the heating surface is preferably such as disclosed in 
U.S. Pat. No. 4,313,124. 
The structure of the recording head may be as shown in U.S. Pat. Nos. 
4,558,333 and 4,459,600, wherein the heating portion is disposed at a bent 
portion, as well as the structure of the combination of the ejection 
outlet, liquid passage and the electrothermal transducer as disclosed in 
the above-mentioned patents. In addition, the present invention is 
applicable to the structure disclosed in Japanese Laid-Open Patent 
Application No. 59-123670, wherein a common slit is used as the ejection 
outlet for plural electrothermal transducers, and to the structure 
disclosed in Japanese Laid-Open Patent Application No. 59-138461, wherein 
an opening for absorbing pressure waves of the thermal energy is formed 
corresponding to the ejecting portion. This is because the present 
invention is effective to perform recording with certainty and at high 
efficiency regardless of the type of recording head. 
In addition, the present invention is applicable to a serial type recording 
head wherein the recording head is fixed on the main assembly, to a 
replaceable chip type recording head which is connected electrically with 
the main apparatus and which can be supplied with the ink when it is 
mounted in the main assembly, or to a cartridge type recording head having 
an integral ink container. 
Provision of recovery means and/or auxiliary means for preliminary 
operation is preferable, because those features can further stabilize the 
effects of the present invention. Examples of such means include a capping 
means for the recording head, cleaning means therefor, pressurizing or 
suction means for keeping the ink ejection outlets or orifices clean, and 
preliminary heating means (which may be an electrothermal transducer, an 
additional heating element or a combination thereof). Also, means for 
effecting preliminary ejection (to precede the actual recording operation) 
can stabilize the recording operation. 
The recording head may be a single head which records using a single color 
ink, or may be plural heads corresponding to plural ink materials having 
different recording colors or densities. The present invention is 
effectively applied to an apparatus having at least one of a monochromatic 
mode (using black ink, most commonly), a multi-color mode using different 
color ink materials, and/or a full-color mode using a mixture of colors, 
which may be an integrally-formed recording unit or a combination of 
plural recording heads. 
Furthermore, in the foregoing embodiments, the ink has been described as 
being liquid. It also may be an ink material which is solid below room 
temperature but liquid at room temperature. Since the ink is kept within a 
temperature range between 30.degree. C. and 70.degree. C., in order to 
stabilize the viscosity of the ink to provide stabilized ejection in the 
usual recording apparatus of this type, the ink may be such that it is 
liquid within that temperature range, whatever its phase outside that 
range. With one type of ink, temperature rise due to the thermal energy is 
positively prevented by consuming that energy for the state change of the 
ink from the solid state to the liquid state. Another ink material 
solidifies when it is left undisturbed for a certain time, thus preventing 
evaporation of the ink. In either of these cases, in response to 
application of the recording signal producing thermal energy, the ink 
liquefies, and the liquefied ink can be ejected. Another usable ink 
material may be one that starts to solidify upon reaching the recording 
material. 
The present invention is also applicable to ink materials that are 
liquefied by application of thermal energy. Such an ink material may be 
retained as a liquid or solid material in through-holes or recesses formed 
in a porous sheet, as disclosed in Japanese Laid-Open Patent Application 
No. 54-56847 and Japanese Laid-Open Patent Application No. 60-71260. The 
sheet is arranged facing the electrothermal transducers. The most 
effective one of the techniques described above is the film boiling 
system. 
The ink jet recording apparatus may be used as an output terminal of an 
information processing apparatus such as a computer or the like, as a 
copying apparatus when combined with an image reader or the like, or as a 
facsimile machine having information sending and receiving functions. 
The entire disclosures of U.S. Pat. Nos. 4,740,796; 4,723,129; 4,558,333; 
4,463,359; 4,459,600 and 4,345,262, and those of Japanese Laid-Open Patent 
Application Nos. 54-56847, 59-123670, 59-138461 and 60-71260, are 
incorporated herein by reference. 
While the invention has been described with reference to the preferred 
structures disclosed herein, it is not confined to the details set forth 
above; to the contrary, many modifications and variations thereof will be 
readily apparent to those skilled in the art, and this application is 
intended to cover all such modifications or changes as may come within the 
purposes of the disclosed improvements disclosed above, within the scope 
of the following claims.