Image recording apparatus

A recording head having a plurality of recording elements arranged thereon is moved in a different direction than a direction of arrangement to make record scan and a recording sheet is fed by a distance corresponding to a recording width of the recording head for each scan. The record scan (main scan) and the sheet feed (sub-scan) are repeated to record received image data on the recording sheet. The feed amount of the recording sheet is counted, and the data is sent to a recording unit until the count reaches a predetermined count, that is, the data a predetermined amount before a trailing edge of the recording sheet is sent, without synchronization with the operation of the recording unit. Thereafter, when the recording of the sent-out data is completed, the remaining data is sent for each record scan in synchronism with the operation of the recording unit During the period other than the recording operation period, the detection of the trailing edge of the recording sheet is monitored by a sensor provided before a recording position. When the trailing edge of the recording sheet is detected, whether the remaining data is recordable or not is determined bases on the count, and if it is recordable, the process is continued and if it is not recordable the renewal of page is made.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an image recording apparatus for recording 
an image in accordance with image data. 
2. Related Background Art 
In a prior art facsimile apparatus, when a printer unit is used in a 
recording unit, one page of recordable area of the facsimile is determined 
by the printer unit. That is, the printer unit itself detects a trailing 
edge of a record sheet, and when it detects the trailing edge, renewal of 
page is immediately executed without regard to a status of the image data 
being recorded. 
When a printer unit such as a line printer which has no concept of page is 
used in the prior art apparatus, the renewal of page may be made while a 
large blank is left in a trailing edge of the record sheet or the renewal 
of page is made while it is not desired. Thus, control is not well 
attained. 
In a printer unit which has no interface to transmit an operation status of 
the printer to the external, it is not known from the external whether the 
recording has been surely done or not. Accordingly, it cannot be used for 
a facsimile apparatus which needs to surely record a received image. For 
those reasons, a recording unit which is exclusively designed for the 
facsimile apparatus and which is expensive in cost has been used for the 
facsimile apparatus. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an improved image 
recording apparatus in the light of the above. 
It is another object of the present invention to provide an image 
processing apparatus which can properly record an image on a recording 
medium without failure. 
It is still another object of the present invention to provide an image 
processing apparatus which can surely record an image up to a 
predetermined position in a trailing edge area of the recording medium. 
It is still another object of the present invention to provide an image 
processing apparatus which can execute the renewal of page at a proper 
position. 
It is still another object of the present invention to provide an image 
processing apparatus which records an image at a proper position on a 
recording medium by controlling a recording unit by detecting the position 
of the recording medium by a communication control unit. 
The above and other objects of the present invention will be apparent from 
the accompanying drawings and the following description.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The preferred embodiments of the present invention are now explained with 
reference to the accompanying drawings. 
EMBODIMENT 1 
FIG. 1 shows a block diagram of a configuration of a facsimile apparatus in 
accordance with the present embodiment. In FIG. 1, numeral 1 denotes a 
control unit which controls an entire facsimile apparatus. The control 
unit 1 comprises a CPU 1a, a ROM 1b and a RAM 1c. The CPU 1a executes 
control programs stored in the ROM 1b to control the facsimile apparatus. 
Various control programs such as those shown in flow charts to be 
explained later are stored in the ROM 1b. The RAM 1c has a memory area for 
temporarily storing data for the CPU 1a to execute the processing. 
Numeral 2 denotes a reader unit which reads an image of a document sheet to 
generate image data and transfers it to the control unit 1. Numeral 3 
denotes a communication unit which includes a modem circuit and a network 
control circuit and is connected to a line to transmit and receive data to 
and from an external facsimile apparatus. Numeral 5 denotes an image 
memory which stores received image data. Numeral 6 denotes an image buffer 
which temporarily stores image data produced by converting image data read 
from the image memory in accordance with a resolution of the recording 
unit 4. The image buffer 6 has a capacity corresponding to an area which 
the recording unit 11 can draw in one main scan movement. Numeral 7 
denotes a feed amount counter unit which counts the feed amount of a 
record sheet and issues an interruption signal to the CPU 1a when a 
predetermined feed amount is attained. 
A detail of the recording unit 4 is now explained with reference to FIGS. 2 
and 3. FIG. 2 shows a configuration of a recording unit of the present 
embodiment. 
Numeral 11 denotes a recording head which has ink droplet discharging 
nozzles of a 64-dot line at a density of 360 dpi along a sub-scan 
direction (arrow A). In the present embodiment, the ink droplet is 
discharged from the nozzle by causing a status change in the ink by using 
a thermal energy generated by an electro-thermal conversion device 
provided for each nozzle. The recording head 11 records data on a 
recording sheet at a recording density of 360 dpi while it is moved in a 
main scan direction (normal to the plane of the drawing, an arrow B in 
FIG. 3). In this manner, the image is recorded at a recording density of 
360 dpi.times.360 dpi. Numeral 12 denotes a record sheet feed unit which 
feeds and ejects a record sheet and transport the record sheet at a 
precision of 360 dpi to position it along the sub-scan direction when 
recording is made by the recording unit 11. Numeral 13 denotes a recording 
sheet sensor which is in an ON state when a recording sheet 16 is present, 
and in an OFF state when the recording sheet 16 is not present to detect 
the presence or absence of the recording sheet and a leading edge and a 
trailing edge of the recording sheet. Numeral 14 denotes a reflection type 
photosensor which detects an image density on a recording plane of the 
recording sheet 16. Numeral 15 denotes a record control unit which 
controls the recording unit 11, the recording sheet feed unit 12 and the 
recording sheet sensor 13 in accordance with a command of control data 
sent form the CPU 1a. Numeral 16 denotes a recording sheet on which an 
image is recorded. Numeral 18 denotes an image buffer of the recording 
unit which stores image data for each scan and a line feed command. 
FIG. 3 shows a positional relation between the recording sheet sensor 13 
and the photo-sensor 14 and numeral 17 shows a footer mark and a record 
position thereof to be explained later. The sensors 13 and 14 and the mark 
17 are arranged to be aligned along the transport direction (direction A) 
of the recording sheet. They are located at a leftmost end of a recordable 
area of the recording unit 11 to the recording sheet 11. 
FIG. 4 shows a block diagram of a configuration of the recording sheet feed 
amount counter unit 7. The recording sheet feed amount counter unit 7 is a 
circuit for counting pulses of a PF motor which is a motor of the 
recording sheet feed unit. Pulses sent to a driver of the PF motor from 
the record control unit 15 are applied to a counter unit 7a which latches 
a preset initial value by a first pulse and is subsequently decremented by 
one for each input pulse. When the counter reached zero, the output port 
is rendered high. This output port is connected to an interruption 
terminal of the CPU 1a. 
A recording operation-of the facsimile apparatus of the embodiment 1 
configured as described above is now explained. 
A general operation of the recording operation of the facsimile apparatus 
is first explained with reference to FIGS. 5 and 6. FIG. 5 shows a flow 
chart of the recording operation of the facsimile apparatus of the 
embodiment 1. FIG. 6 shows the recording operation of the facsimile 
apparatus of the embodiment 1. 
In FIG. 5, when the communication unit 3 receives image data in a step S1, 
the received data is stored in the image memory 5 in a step S2. When the 
image data is stored in the image memory 5, the recording operation is 
started in a step S3. In a step S4, queuing of the recording sheet 16 is 
effected to set the recording sheet at a predetermined position. In a step 
S5, count data is set in the counter unit 7a so that interruption is 
issued to the CPU 1a of the control unit 1 when the recording head reaches 
the last scan line position. In a step S6, image data of a number of lines 
which can be recorded in one page is developed into image data and it is 
sent to the recording unit 4 as data having scan data and a feed command. 
Referring to FIG. 6, the number of lines which can be recorded on the 
recording sheet is 4052. Since 1 scan=64 lines, it is necessary to conduct 
3988 line feeding in order to position the recording head at the last scan 
position. Accordingly, 3987 is set in the counter unit 7a. The value set 
in the counter unit 7a is equal to 3988-1 because one pulse is used to set 
the data in the counter unit 7a. 
In a step S7, the completion of the recording of the image data sent by the 
recording unit 4 in the step S6 is monitored. The completion of the 
recording can be detected by the issuance of an interruption signal from 
the counter unit 7a. When the interruption signal is issued, the recording 
head 11 is at the last scan line position and it prints out the footer 
mark in a step S8. In a step S9, the sheet ejection process is conducted 
to eject the printed recording sheet 16. In a step S10, whether data to be 
recorded is left or not is determined, and if it is left, the process 
returns to the step S4. If it is not left, the process is terminated. 
In the recording process of the steps S3-S10, recording sheet edge 
detection process (steps S11-S14) is conducted. In a step S12, the 
recording sheet sensor 13 is monitored to detect the trailing edge of the 
recording sheet 16. When the trailing edge of the recording sheet is 
detected in a step S12, the process proceeds to a step S13. In the step 
S13, whether the image data sent in the step S6 can be recorded in the 
recording sheet or not is determined. 
By a structure of the recording unit 4, two more scans of recording can be 
made after the detection of the trailing edge of the recording sheet by 
the recording sheet sensor 13. Accordingly, if the content of the counter 
unit 7a is no larger than 64 when the trailing edge of the recording sheet 
is detected, all of the sent-out data can be recorded. If the decision in 
the step S13 indicates that the data is recordable, the process is 
terminated. If the data is not recordable, the process proceeds to a step 
S14. In the step S14, a page end signal is sent to the recording unit 4 to 
conduct the renewal of page by the recording unit 4. Unrecorded data which 
has been sent to the recording unit 4 is recorded on a new page. 
A more detailed control procedure for attaining the above operation is 
explained below. 
FIG. 7 shows a flow chart of a storing process for storing one page of 
image data stored in the image memory 5 in the present embodiment. It is 
executed by the CPU 1a. 
In a step S702, queuing of the recording sheet is conducted and a PE 
handler initialization process is conducted to initialize flags and a 
counter. The PE handler controls the PE signal to the recording unit while 
it monitors the recording sheet edge sensor. The processing by the PE 
handler (FIG. 13) and the initialization process (FIG. 12) of the PE 
handler will be described later. 
In a step S703, 64 is set in an image buffer line counter IMAGE.sub.-- 
BUF.sub.-- LINE. In a step S704, if a flag PIX.sub.-- END.sub.-- FLAG 
which indicates the end of one page of image data is ON, the process is 
terminated. If not, the process proceeds to a step S705 to read out one 
page of image data from the image memory 5. In the present embodiment, 
data is stored in the image memory 5 in an MR code and it is decoded and 
developed into raw image data. Since the decoding process is not directly 
related to the present invention, the explanation thereof is omitted. When 
the end (RTC) of one page of image is detected in a step S706, the process 
proceeds to a step S714. In the step S714, the PIX.sub.-- END.sub.-- FLAG 
is set to ON and the process proceeds to a step S715. 
On the other hand, if the end of image is not detected, the process 
proceeds to a step S707 to store the developed image data in the image 
buffer 6. In the present embodiment, the raw line data having the 
resolution of 8 pels/mm read in the step S705 is converted to data having 
a resolution of 360 dpi and it is developed into the image buffer 6 having 
the memory capacity of 360 dots.times.64 lines data. A technique for 
converting the resolution is known and it is not directly related to the 
present invention. Accordingly, the explanation thereof is omitted. 
In a step S708, if a PRE.sub.-- PE.sub.-- FLAG is OFF and a PAGE.sub.-- 
LINE.sub.-- CNT is no larger than 64, the PRE.sub.-- PE.sub.-- FLAG is set 
to ON in a step S713 and the process proceeds to a step S715. The 
PRE.sub.-- PE.sub.-- FLAG is set to ON when the content of the counter 
unit 7a is zero. Namely, it is set to ON when the number of remaining 
recordable lines is 64. In the step B708, if the PRE.sub.-- PE.sub.-- FLAG 
is ON or the PAGE.sub.-- LINE.sub.-- CNT which indicates the number of 
remaining recordable lines (to be described later) is no smaller than 64, 
the process proceeds to a step S709 to decrement an IMAGE.sub.-- 
BUF.sub.-- LINE which indicates the number of data lines stored in the 
image buffer 6 and the PAGE.sub.-- LINE.sub.-- CNT by one, respectively. 
In a step S710, if 64 lines of data has been stored in the image buffer 6 
(the IMAGE.sub.-- BUF.sub.-- LINE is zero), the process proceeds to a step 
S711. On the other hand, if it is not yet full, the process returns to the 
step S705. 
In the step S711, if the PRE.sub.-- PE.sub.-- FLAG is ON, a PE.sub.-- FLAG 
is set to ON in a step S712 and the process proceeds to a step S715. The 
PE.sub.-- FLAG indicates that 64 lines of data have been prepared after 
the PRE.sub.-- PE.sub.-- FLAG was set to ON, that is, the number of 
remaining recordable lines is zero. On the other hand, if the PRE.sub.-- 
PE.sub.-- FLAG is OFF in the step S711, the process proceeds to a step 
S715. In the step S715, the content of the image buffer 6 is sent to the 
recording unit and the process returns to the step S703. The recording 
process for one scan of data is explained below. 
FIGS. 8 and 9 show flow charts of detail of the process of the step S715. 
In a step S802, if the PIX.sub.-- END.sub.-- FLAG is ON, that is, if the 
image has been completed, the number of remaining lines of the recording 
sheet under recording is set in a step S803. It is used for the 
positioning of the trailing edge of the recording sheet in the page ending 
process in a step S820. The PAGE.sub.-- LINE.sub.-- CNT indicates the 
number of remaining recordable lines. In order to feed the recording sheet 
by the number of recorded lines collectively at the time of the 
positioning of the recording sheet trailing edge, the feed amount of the 
recorded lines is set to zero (step S806) and it is added to the 
PAGE.sub.-- LINE.sub.-- CNT. In a step S804, the remaining area of the 
image buffer is filled with white. If the RTC is detected in the step S706 
in the course of the process of the steps S705 to S708, the image data of 
the image buffer 6 is partially set. Accordingly, it is necessary to clear 
the remaining area of the image buffer 6 in the manner described above. In 
the step S805, the flag PE.sub.-- FLAG which shows the end of record is 
set to ON, in a step S806, the number FLC of lines of feed is set to zero, 
and the process proceeds to a step S817. 
On the other hand, if the PIX.sub.-- END.sub.-- FLAG is OFF in the step 
S802, the process proceeds to a step S807. In the step S807, if the 
PRE.sub.-- PE.sub.-- FLAG is ON, the process proceeds to a step S809. In 
the step S809, if the PE.sub.-- FLAG is OFF, the process proceeds to a 
step S810 to set the number of prepared lines to the number of feed lines 
FLC (step S810) and fill the remaining area of the image buffer 6 with 
white (step S811), and the process proceeds to a step S812. When the 
PRE.sub.-- PE.sub.-- FLAG is ON and the PE.sub.-- FLAG is OFF, it means 
that the number of remaining recordable lines is 64. If a FOOTER.sub.-- 
FLAG is ON, that is, a footer print mode (step S812) and a FOOTER.sub.-- 
IN.sub.-- PIX is ON, that is, a mode to print the footer outside of the 
image (step S813), the PE.sub.-- FLAG is set to ON in a step S814 and the 
process proceeds to a step S817. In the facsimile apparatus of the present 
embodiment, the footer is recorded in a reception mode and not recorded in 
a copy mode. Accordingly, the FOOTER.sub.-- FLAG is ON in the reception 
mode. The FOOTER.sub.-- IN.sub.-- PIX indicates one of a mode to record 
the footer in the received image and a mode to record the footer outside 
of the received image. If the mode to record in the received image is 
selected, both the footer and the image are recorded in an area on the 
recording sheet in which the last scan line is to be recorded. When the 
mode to record outside of the received image is recorded, only the footer 
is recorded in the area in which the last scan line is to be recorded. The 
selection of the mode is done by a key entry of a console unit. 
In the step S809, if the PE.sub.-- FLAG is ON, the number of remaining 
recordable lines is zero and the recording sheet is to be ejected. Thus, 
the number of feed lines FLC is set to zero (step S815) and the process 
proceeds to a step S817. 
If the PRE.sub.-- PE.sub.-- FLAG is OFF in the step S807, it means normal 
printing before the trailing edge of the recording sheet. Thus, the number 
of feed lines FLC is set to 64 (step S816) and the process proceeds to a 
step S817. 
In the step S817, the image data of 360.times.64 dots formed in the image 
buffer 6 is sent to the recording unit. 
In a step S818, a command to feed the recording sheet by the number of 
lines designated by the FLC is sent to the recording unit to set the 
recording sheet to the next recording position. Detail of this feed 
process will be explained later (FIG. 11). 
In a step S819, if the PE.sub.-- FLAG is ON, the page ending process to 
print the footer and eject the recording sheet is conducted in a step S820 
and the process is terminated. If the PE.sub.-- FLAG is OFF, the process 
is directly terminated. The page ending process will be explained later. 
FIG. 10 shows a flow chart of the page ending process in a step S820 of 
FIG. 8. 
In a step S902, if the PIX.sub.-- END.sub.-- FLAG is ON, the recording 
sheet is fed to the trailing edge in a step S903 and the process proceeds 
to a step S904. In the step S902, if the PIX.sub.-- END.sub.-- FLAG is 
OFF, the process directly proceeds to the step S904. In the step S904, an 
interruption signal from the counter unit 7a is monitored to monitor the 
completion of the image data sent to the recording unit 4. Since one page 
of lines have been set in the counter unit 7a during the initialization 
process of the PE handler (which will be explained later in connection 
with FIG. 12) at the start of recording, the completion of the record can 
be detected by the zero count interruption of the counter unit 7a. 
In a step S905, a SYNC.sub.-- FLAG which indicates a synchronization mode 
with the recording unit is set to ON, and if the FOOTER.sub.-- FLAG is ON 
in a step S906, the process proceeds to a step S907, and if it is OFF, the 
process proceeds to a step S908. The footer process of the step S907 will 
be explained later with reference to FIGS. 7A, 7B and 8. The sheet 
ejection process of the step S908 will be explained later with reference 
to FIG. 17. 
In a step S909, if the PIX.sub.-- ENF.sub.-- FLAG is ON, that is, there is 
no longer line to be recorded in the image under recording, the process is 
directly terminated. In the step S909, if the PIX.sub.-- END.sub.-- FLAG 
is off, that is, if there is a line to be recorded, the PE handler 
initialization process is conducted in a step S910 to queue the next 
recording sheet and initialize variables, and the process is terminated. 
The PE handler controls the PE signal to the recording unit 4 while it 
monitors the edge of the recording sheet by the recording sheet sensor 13. 
The processing of the PE handler (FIG. 13) and the initialization process 
of the PE handler (FIG. 12) will be explained later. 
FIG. 11 shows a flow chart of the feed process in the step S818 of FIG. 8. 
In a step S1102, if the SYNC.sub.-- FLAG which indicates whether it is in 
the synchronization mode with the recording unit is ON, the process 
proceeds to a step S1003. In the step S1003, a value equal to the number 
of feed lines (FLC) minus 1 is set to the counter unit 7a (step S1004). 
Because one pulse is used to set the cont in the counter unit, 1 is 
minused from the FLC. After the constant has been set in the counter unit 
7a, a command of FLC/360 inches feed is sent to the recording unit 4 (step 
S1005) and zero count interruption of the counter unit is monitored to 
monitor the completion of the feed of the recording unit (step S1005). In 
this manner, the synchronization with the recording unit is maintained. On 
the other hand, if the SYNC.sub.-- FLAG is OFF in the step S1002, the 
FLC/360 feed command is sent to the recording unit 4 in a step S1006 and 
the process is terminated. 
FIG. 12 shows a flow chart of the initialization process of the PE handler 
in the step S702 of FIG. 7A and the step S910 of FIG. 10. 
In a step S1102, flags are initialized. The PE.sub.-- FLAG which indicates 
that the number of remaining recordable lines is zero and the PRE.sub.-- 
PE.sub.-- FLAG which indicates that the number of remaining recordable 
lines is 64 (that is, one more scan of lines are recordable) are set to 
OFF. A buffer FEED.sub.-- OUT.sub.-- STEP which stores the feed amount 
from the end of the image to the trailing edge of the recording sheet is 
set to zero, and a flag PAGE.sub.-- START.sub.-- FLAG which indicates the 
start of queuing of the recording sheet and the flag SYNC.sub.-- FLAG 
which indicates the synchronization mode with the recording unit are set 
to ON. 
In a step S1103, a switch of the size of the recording sheet which is set 
by a user is checked, and if a size A4 recording sheet has been set, the 
process proceeds to a step S1104, and if a size LTR recording sheet has 
been set, the process proceeds to a step S1005. In the present embodiment, 
the number of recordable lines at the recording density of 360 dpi is 4052 
lines for the size A4 recording sheet (step S1104), and 3798 lines for the 
size LTR recording sheet (step S1105). Those numbers of recordable lines 
are set in the PAGE.sub.-- LINE.sub.-- CNT. 
Then, the queue command for the recording sheet is sent to the recording 
unit 4 (step S1106). In the present embodiment, a space command and a 
backspace command are sequentially sent to set the recording position at 
the left top corner of the recording sheet. In a step S1107, the 
completion of the queuing by the queue command is monitored. When the 
queuing is completed, an asynchronous mode with the recording unit 4 is 
initiated (step S1108) and a value equal to the number of lines of one 
page minus 65 is set in the counter unit 7a (step S1109) and the process 
is terminated. In the step S1109, 64 is minused because it is necessary to 
leave the last one scan of recordable lines in order to record the footer 
mark in the position of the last one scan, and 1 is further minused 
because the first pulse is used for the latch of the count register. 
The ending process of the queuing in the step S1107 is conducted by the 
zero count interruption of the counter unit 7a. When the PE sensor detects 
the head of the recording sheet during the process by the PE handler to be 
explained in FIG. 13, the number of pulses from the PE sensor to the 
record start position is set to the counter unit 7a so that the end of 
queuing can be detected by the zero count interruption of the counter unit 
7a. 
FIGS. 13 and 14 show flow charts of process of the PE handler. 
The PE handler is an interruption handler which is activated at a period of 
5 milliseconds. When it is activated, it compares a status of the current 
PE sensor (that is, the recording sheet sensor 13) and a flag PES.sub.-- 
STATUS which indicates a status of the previous PE sensor (step S1202), 
and if they are equal, the process is terminated. If they are not equal, 
the status of the current PE sensor is stored in the PES.sub.-- STATUS 
(step S1203). The PE sensor is OFF when the recording sheet is on the 
sensor, and ON when the recording sheet is not on the sensor. 
When the change of the status of the PE sensor to ON, that is, the trailing 
edge of the recording sheet is detected, the process proceeds to a step 
S1210. When the change of the status of the PE sensor to OFF, that is, the 
leading edge of the recording sheet is detected, the process proceeds to a 
step S1205. 
In the step S1205, if the PAGE.sub.-- START.sub.-- FLAG is ON, the 
PAGE.sub.-- START.sub.-- FLAG is set to OFF (step S1206) and a PE.sub.-- 
CONTROL.sub.-- FLAG is set to ON (step S1207). The PE.sub.-- 
CONTROL.sub.-- FLAG indicates whether the status of the PE sensor 13 is to 
be directly informed to the recording unit 4 or the timing thereof is to 
be adjusted by the control unit. When the PE.sub.-- CONTROL.sub.-- FLAG is 
OFF, the status of the PE sensor 13 is directly sent to the recording unit 
4 by the PE handler. In a step S1208, 452 is set in the counter unit 7a. 
It is the number of steps from the reception of the paper start signal by 
the recording unit 4 to the stop of the feed of the recording sheet at the 
first recording position. When the count of the counter unit 7a is zero, 
it means the completion of the queuing of the recording sheet. 
In the step S1205, if the PAGE.sub.-- START.sub.-- FLAG is OFF, the process 
proceeds to a step S1209, which is a process in a printer mode not shown. 
The recording unit 4 of the present embodiment has an external interface, 
not shown. In the printer mode, the recording unit 4 is separated from the 
control unit 1 and operates by an external command. In this case, since 
the PE sensor 13 which should have been connected to the record control 
unit 15 which controls the recording unit 4 is connected to the control 
unit 1, it is necessary to inform the status of the PE sensor to the 
control unit 1 as much in detail as possible. To this end, in the present 
embodiment, the PAGE.sub.-- START.sub.-- FLAG and the PE.sub.-- 
CONTROL.sub.-- FLAG are used to switch between the mode in which status of 
the PE sensor is directly sent to the recording unit 4 and the mode in 
which the control unit 1 controls the information of the PE sensor. In a 
step S1209, the paper start signal is sent to the recording unit 4 and the 
process is terminated. 
When pty trailing edge is detected, if the PE.sub.-- CONTROL.sub.-- FLAG is 
OFF in a step S1210, the paper end signal is immediately sent to the 
recording unit 4 (step S1214) and the process is terminated. If the 
PE.sub.-- CONTROL.sub.-- FLAG is ON, the process proceeds to a step S1211 
to set the PE.sub.-- CONTROL.sub.-- FLAG to OFF. In a step S1212, if the 
SYNC.sub.-- FLAG is ON, that is, if it is in the synchronization mode, the 
process is terminated. In a step S1213, if the count of the counter unit 
7a is smaller than the number of recordable lines 64 after the detection 
of the trailing edge of the recording sheet, the process is terminated. In 
the present embodiment, since the distance from the recording sheet 
retainer to the PE sensor is approximately 9.4 mm, that is, two scans, 128 
line are recordable. In the step S1213, if a count larger than 128 remains 
in the PAGE.sub.-- LINE.sub.-- CNT, it means that data of larger number of 
lines than the number of recordable lines have been sent to the recording 
unit 4. Accordingly, the paper end signal is immediately sent to the 
recording unit 4 (step S1214) and the renewal of page is made in the 
recording unit 4, and the process is terminated. 
The footer process in the step S907 of FIG. 10 is now explained. 
FIG. 15 and 16 show flow charts of the footer mark detection method. 
FIG. 16 shows a process of an interruption handler which is activated at 
every 1 millisecond to monitor the footer mark sensor and FIG. 15 shows a 
process of the control unit 1 for controlling it. 
In a step S402 of FIG. 15, a status of the footer mark sensor 14 is saved 
in a FIRST.sub.-- BLACK and PERV.sub.-- FOOTER.sub.-- STATUS, a 
WHITE.sub.-- CNT which indicates the number of times of change from white 
to black and a BLACK CNT which indicates the number of times of change 
from white to black are initialized, and a footer sensor monitor 
interruption is enabled. Then, in a step S403, the image (solid black) of 
the footer mark is sent to the recording unit 4 to cause the recording 
unit 4 to record the footer mark. In a step S404, a sheet ejection command 
is sent to the recording unit 4. The sheet ejection process of the step 
S404 will be explained in detail later (FIG. 17). 
In a step S406, the zero count interruption of the counter unit 7a which is 
a pulse counter for the PF motor is monitored. When the zero count 
interruption occurs, the process proceeds to a step S407 and the footer 
monitor interruption is disabled. 
In a step S408, if a FIRST.sub.-- BLACK is ON, that is, if the initial 
state of the photo-sensor 14 is black, the process proceeds to a step 
S409, and if it is white, the process proceeds to a step S411. In the step 
S409, if the WHITE.sub.-- CNT is 0, the process proceeds to a step S410. 
This means that the footer sensor continuously detected only black could 
not detect white at all until the end of the sheet ejection. The following 
four causes therefor are considered. 
a: A colored sheet is used as the recording sheet. 
b: A black material (for example, a trailing end of a recording sheet 
contaminated by ink) is deposited to the footer sensor so that it can 
detect only black. 
c: The recording sheet has jammed while black image information is at the 
position of the footer sensor. 
d: A trailing end of the recording sheet is contaminated by ink. In the 
present embodiment, this error is called a colored sheet error and a 
message is generated to a user to request the use of a white sheet. 
In the step S411, if the WHITE.sub.-- CNT is 0, the process proceeds to a 
step S412. This means that the footer sensor continuously detected only 
white and did not detect black at all until the end of the sheet ejection, 
or the status change of only white to black was included and the white in 
the image information on the footer, the white of the footer, the white in 
the trailing end margin and the black after the trailing edge of the 
recording sheet were detected. That is, non-footer status was detected. 
Thus, in a step S412, a flag NON-FOOTER which indicates the detection of 
the non-footer is set to ON and the process is terminated. When the 
NON-FOOTER flag is set to ON, an error process is executed. 
FIG. 16 shows a flow chart of the footer monitor interruption process in 
which the WHITE.sub.-- CNT and the BLACK.sub.-- CNT used in the flow chart 
of FIG. 15 are set. In the step S402, if the footer monitor interruption 
is enabled, the interruption occurs at an interval of 1 millisecond so 
that the process of the steps S502 et seq are executed. In the step S502, 
the status of the current sensor 14 is read and it is saved in a temporary 
buffer CURRENT.sub.-- FOOTER. In a step S503, if the status of the current 
footer is equal to the previous status, the process proceeds to a step 
S508 and the process is terminated. If they are not equal, the status of 
the current footer is saved in a buffer PREV.sub.-- FOOTER.sub.-- STATUS 
in a step S504. In a step S505, if the status of the current footer is 
black, it means that the status of the footer sensor 14 has changed from 
white to black, and in a step S506, the BLACK.sub.-- CNT is incremented by 
one. On the other hand, if the status of the current footer is white in 
the step S505, it means that the status of the footer sensor has changed 
from black to white and the WHITE.sub.-- CNT is incremented by one in a 
step S507. 
FIG. 17 shows a flow chart of the sheet ejection process in the step S908 
of FIG. 10 and the step S404 of FIG. 15. 
The recording unit 4 used in the present embodiment returns the recording 
head 11 to a home position only when five seconds have elapsed without 
receiving command or when the paper end signal is received. When the 
recording sheet 16 is ejected while the recording head 11 is on the 
recording sheet 16, the trailing edge of the recording sheet 16 abuts 
against the head 11 when the recording sheet escapes from the sheet 
retainer and it may be contaminated by ink. When the recording unit 4 
receives the paper end signal after it has received the sheer ejection 
command and before the start of the sheet ejection operation, it feeds a 
new recording sheet 16 and ejects it. In order to prevent such 
inconvenience from occurring, the following sheet ejection process is 
conduced in the present embodiment. 
First, 1 is set in the counter unit 7a (step S1302) and the sheet ejection 
command is sent to the recording unit (step S1303). The start of the sheet 
ejection is monitored by the zero count interruption (step S1304) and the 
paper end signal is sent to the recording unit (step S1305). The purpose 
of first setting 1 in the counter unit 7a is for checking whether the 
sheet ejection operation has been started after the sheet ejection command 
was sent. Finally, the number of steps for the recording sheet to be 
ejected from the sheet ejection port is set in the counter unit 7a (step 
S1306) and the process is terminated. 
An operation of the flow chart shown above is now explained. 
(1) A mode to record the footer mark outside of the image (the 
FOOTER.sub.-- FLAG is ON, the FOOTER.sub.-- PIX.sub.-- IN is OFF) 
First, the CPU 1a of the control unit 1 conducts the initialization process 
(FIG. 12) of the PE handler and sends the queuing command for the 
recording paper to the record control unit 15 so that the queuing of the 
recording sheet is started. After the PE sensor 13 has detected the 
leading edge of the recording sheet, the counter unit 7a counts a 
predetermined count (452) so that the recording sheet is fed by a 
predetermined amount and set to the recording position. After the 
predetermined count (PAGE.sub.-- LINE.sub.-- CNT- 65) has been set in the 
counter unit 7a, the image data is read from the image memory 5 line by 
line and they are developed and stored in the image buffer 6. When 64 
lines of image data is stored in the image buffer 6, the content of the 
image buffer 6 is sent to the recording unit 4 and the data is stored in 
the image buffer 18. Further, a command to feed the sheet by 64 lines for 
the sub-scan is sent to the record control unit 15. This operation is 
repeated until the number of remaining recordable lines on the record 
sheet reaches 64 lines. During this period, the data is sent without 
synchronization with the recording operation of the recording unit 
(asynchronous mode). The record control unit 15 sequentially reads the 
data from the image buffer 18, scans them and feeds the recording sheet by 
64 lines each time one record scan is completed. 
During this period, the control unit 1 monitors the detection of the 
trailing edge of the recording sheet by the PE sensor 13, and if the 
trailing edge of the recording sheet is detected when the number of 
remaining recordable lines on the recording sheet is no smaller than 128 
(counter unit 7a&gt;64), the control unit 1 sends the paper end signal to the 
record control unit 15 to cause the record control unit 15 to conduct the 
renewal of page. 
When the number of remaining recordable lines (PAGE.sub.-- LINE.sub.-- CNT) 
on the recording sheet reaches 64, the data in the image buffer 6 (if the 
number of lines of data currently stored in the image buffer 6 does not 
reach 64, the data derived by filling the remainder of the image buffer 6 
with white data) is sent to the recording unit 4. Further, a command to 
feed the sheet by the number of lines of data stored in the image buffer 6 
when the number of remaining recordable lines reaches 64 is sent to the 
record control unit 15. The recording unit 4 makes the record scan in 
accordance with the data and sets the recording head to the final scan 
position. 
Then, the control unit 1 sends the image of the footer mark to the 
recording unit 4. The recording unit 4 records the footer mark at the last 
scan position on the recording sheet and then ejects the recording sheet. 
During the sheet ejection, the footer mark is detected and if it is 
normal, whether it is the end of one page of image or not is determined. 
If it is not the end, the renewal of page is made and the next recording 
sheet is fed to record the remaining image and the same operation is 
repeated. 
If the footer mark is not normally recorded, a predetermined error process 
is conducted and the data of the current page stored in the image memory 5 
is saved. 
When the control unit 1 detects the end (CRT) of one page of image before 
the number of remaining recordable lines on the recording sheet reaches 
64, it sends the data currently stored in the image buffer 6 (if the 
number of lines of data currently stored in the image buffer 6 does not 
reach 64, the data derived by filling the remainder of the image buffer 6 
with white data) is sent to the recording unit 4. Further, a command to 
feed the recording sheet until the recording head reaches the final scan 
position is sent to the record control unit 15. Thereafter the recording 
and the detection of the footer mark as those described above are 
conducted. 
(2) A mode to record the footer mark in the image (the FOOTER.sub.-- FLAG 
is ON, the FOOTER.sub.-- PIX.sub.-- IN is ON) 
The same operation as that of (1) is conducted until the number of 
remaining recordable lines on the recording sheet reaches 64. When it 
reaches 64, the data in the image buffer 6 (if the number of lines of the 
data currently stored in the image buffer 6 does not reach 64, the data 
derived by filling the remainder of the image buffer 6 with white data) is 
sent to the recording unit 4. Further, a command to feed the sheet by the 
number of lines of the data stored in the buffer 6 when the number of 
remaining recordable lines reaches 64 is sent to the recording unit 4. The 
recording unit 4 conducts the record scan in accordance with the data and 
sets the recording head to the final scan position. The image data is read 
from the image memory 5 line by line for the final scan and they are 
developed and stored in the image buffer 6. When 64 lines of data is 
stored in the image buffer 6, it is sent to the recording unit 4. In this 
case, sheet feed is not conducted (FLC=0). Under this condition, the 
footer mark is recorded in the same manner as that of the case (1) and the 
record status is detected to determine whether the received data has been 
properly recorded or not. 
When the end of one page of image is detected before the number of 
remaining recordable lines on the recording sheet reaches 64, the data 
currently stored in the image buffer 6 (if the number of lines of the data 
currently stored in the image buffer 6 does not reach 64, the data derived 
by filling the remainder of the image buffer 6 with white data) is sent to 
the recording unit as it is in the case (1). Further, a command to feed 
the sheet to set the recording head to the final scan position is sent to 
the recording unit 4. The recording of the footer mark and the detection 
of the record status are conducted as they are in the case (1) to 
determine whether the received data has been properly recorded or not. 
(3) A mode not to record the footer mark (the FOOTER.sub.-- FLAG is OFF, 
the FOOTER.sub.-- PIX.sub.-- IN is OFF) 
In this case, the operation is same as that of the case (2) until the data 
of the final scan is sent to the recording unit 4. Thereafter, the sheet 
is ejected without printing the footer mark and the printed sheet is 
ejected out of the apparatus. 
As explained above, by setting the number of recordable lines in the 
counter unit 7a at the start of the recording and monitoring the zero 
count interruption of the counter unit 7a, the image data can be sent to 
the recording unit 4 while neglecting the operation of the recording unit 
4. Accordingly, the idling time can be effectively used for other 
processes. Further, in accordance with the present method, the image 
buffer 18 in the recording unit 4 can be effectively used and the record 
control unit 15 conducts the recording process while it refers to the 
previous image data. As a result, the recording speed is improved. 
EMBODIMENT 2 
In the method of the embodiment 1, the constant number of lines are printed 
on the preset recording sheet. Thus, where the recording sheet feed 
precision of the recording unit 4 is low, the trailing edge margin of the 
recording sheet 16 increases or decreases. Further, when a recording sheet 
of a different size than that which the user has set, the trailing edge 
margin increases if it is larger than the preset size and the renewal of 
page is made by the recording unit if it is smaller than the preset size. 
The facsimile apparatus of the embodiment 2 monitors the completion of the 
recording each time one scan of data is sent, and the send-out of the data 
is synchronized with the operation of the recording unit 4. In this 
manner, whenever the trailing edge of the recording sheet is detected, the 
facsimile apparatus can cope therewith. When the trailing edge of the 
recording sheet is detected, a predetermined amount of recording is 
conducted after the detection of the trailing edge and then the renewal of 
page is made so that the trailing edge margin of the recording sheet is 
uniform and the footer mark is surely recorded. The configuration of the 
facsimile apparatus of the embodiment 2 is similar to that of the 
embodiment 1 and the explanation thereof is omitted. 
In a step S1108 of FIG. 12, the SYNC.sub.-- FLAG which is OFF is set to ON 
and the content of the page recording process shown in FIGS. 7A and 7B are 
changed to those shown in FIGS. 18 and 19. The steps S904 and S905. of the 
page ending process of FIG. 10 are deleted. By those modifications, the 
completion of the feed of the recording sheet is monitored in the feed 
process of FIG. 11. A step S1215 shown in FIG. 20 is added as a PE handler 
process. Accordingly, the operation is synchronized with the operation of 
the recording unit 4 for each scan of recording and whenever the PE 
handler detects the trailing edge of the recording sheet, it can cope 
therewith. 
FIGS. 18 and 19 show flow charts of the page recording process in the 
embodiment 2. Steps S1401 to S1407 and steps S1409 to S1416 correspond to 
the steps S701 to S707 and the steps S709 to S716 of FIGS. 7A and 7B, 
respectively, and the explanation thereof is omitted. The process of the 
step S708 of FIG. 7A is modified to steps S1420 to S1423. 
In a step S1420, if the PES.sub.-- STATUS is ON, it means that the 
recording sheet has not been detected by the recording sheet sensor (PE 
sensor) 13 and the process proceeds to a step S1421. If it is OFF, it 
means that the recording sheet has been detected and the process proceeds 
to a step S1409. In the step S1421, if the PRE.sub.-- PE.sub.-- FLAG is 
ON, the process proceeds to a step S1409, and if it is OFF, the process 
proceeds to a step S1422. The PES.sub.-- STATUS is a flag which is set by 
the PE handler (see FIG. 13) to represent the status of the PE sensor 
(recording sheet sensor) 13. The PRE.sub.-- PE.sub.-- FLAG indicates that 
the number of remaining recordable lines is one-scan lines. Namely, the 
process proceeds to the step S1422 during the period between the passage 
of the trailing edge of the recording sheet past the PE sensor and the 
reach of the number of remaining recordable lines to one-scan lines. 
In the step S1422, an AFTER.sub.-- PES.sub.-- CNT which represent the 
number of remaining recordable lines before the number of remaining 
recordable lines reaches one-scan lines is decremented, and if the 
AFTER.sub.-- PES.sub.-- CNT reaches 0 (step S1423), the PRE.sub.-- 
PE.sub.-- FLAG is set to ON (step S1413). If it is not 0, the process 
proceeds to a step S1409. 
The AFTER.sub.-- PES.sub.-- CNT has been set in the step S1215 of FIG. 14. 
The meaning represented by the AFTER.sub.-- PES.sub.-- CNT is explained 
with reference to FIG. 22. The trailing edge of the recording sheet is 
detected during the execution of the feed process (FIG. 11) while the 
counter unit 7a is set to 63. Accordingly, when the AFTER.sub.-- 
PES.sub.-- CNT is set to (64--the content of the counter unit 7a) in the 
step S1215, it means that the recording of up to 64 lines (one-scan lines) 
is conducted from the detection position of the trailing edge of the 
recording sheet in the page recording process. The PRE.sub.-- PE.sub.-- 
FLAG is always set at the position of 64 lines from the detection position 
of the trailing edge of the recording sheet. 
In this manner, the number of record lines after the detection of the 
trailing edge of the recording sheet by the PE sensor is kept uniform. In 
the embodiment 2, after the detection of the trailing edge of the 
recording sheet, two-scan lines (128 lines) including the scan for 
processing the footer are recorded. In this manner, the image is always 
recorded up to the predetermined position from the trailing edge of the 
recording sheet and the footer is recorded, without regard to the error in 
the feed of the recording sheet and the size of the recording sheet. 
EMBODIMENT 3 
In the method of the embodiment 2, the footer mark can be recorded at the 
predetermined position from the trailing edge of the recording sheet 
whatever it is but only one-scan lines of image buffer 18 of the recording 
unit 4 can be used. Further, since the record control unit 15 cannot 
monitor the previous image data, the recording speed is lower than that of 
the embodiment 1. 
In the embodiment 3, facsimile apparatus in which the recording is made in 
the method of the embodiment 1 in a range a little bit smaller than the 
size of the recording sheet which is probably actually used, and 
thereafter the recording is made in the method of the embodiment 2. The 
facsimile apparatus of the embodiment 3 also has a similar configuration 
to that of the embodiment 1 and the explanation thereof is omitted. 
FIGS. 23 and 24 show flow charts of the page recording process in the 
embodiment 3. Steps S1501 to S1507 and steps S1509 to S1516 correspond to 
the steps S701 to S707 and the steps S709 to S716 of FIGS. 7A and 7B, 
respectively, and the explanation thereof is omitted. The process of the 
step S708 of FIG. 7A is modified to that of steps S1519 to S1525. 
In a step S1519, if the SYNC.sub.-- FLAG is ON, the process proceeds to a 
step S1520. In the step S1520, if the PES.sub.-- STATUS is ON (the 
recording sheet has not been detected by the recording sheet sensor 13), 
the process proceeds to a step S1521. If it is OFF (the recording sheet 
has been detected by the recordings sheet sensor 13), the process proceeds 
to a step S1509. In a step S1521, if the PRE.sub.-- PE.sub.-- FLAG is ON, 
the process proceeds to a step S1509, and if it is OFF, the process 
proceeds to a step S1522. The PES.sub.-- STATUS is a flag which is set by 
the PE handler (see FIG. 13) and it represents the status of the PE sensor 
13. The PRE.sub.-- PE.sub.-- FLAG indicates that the number of remaining 
recordable lines is one-scan lines. Namely, during the period between the 
passage of the trailing edge of the recording sheet past the PE sensor 13 
to the reach of the number of remaining recordable lines to one-scan 
lines, the process proceeds to a step S1524. In the step S1522, the 
AFTER.sub.-- PES.sub.-- CNT which indicates the number of remaining 
recordable lines before the number of remaining recordable lines reaches 
one-scan lines is decremented, and if the AFTER.sub.-- PES.sub.-- CNT 
reaches 0 (step S1523), the PRE.sub.-- PE.sub.-- FLAG is set to ON (step 
S1513). If the AFTER.sub.-- PES.sub.-- CNT is not 0, the process proceeds 
to a step S1509. 
In the step S1519, if the SYNC.sub.-- FLAG is OFF, the process proceeds to 
a step S1524. In the step S1524, if the PRE.sub.-- PE.sub.-- FLAG is ON, 
or in a step S1525, if the PAGE.sub.-- LINE.sub.-- CNT is larger than 64, 
the process proceeds to a step S1509. If the PRE.sub.-- PE.sub.-- FLAG is 
OFF in the step S1524 and the PAGE.sub.-- LINE.sub.-- CNT is no larger 
than 64 in the step S1525, the PRE.sub.-- PE.sub.-- FLAG is set to ON in a 
step S1513 and the process proceeds to a step S1515. 
FIG. 25 shows a flow chart of the page ending process in the embodiment 3. 
In a step S1602, if the PIX.sub.-- END.sub.-- FLAG is ON, the recording 
sheet is fed to the trailing edge in a step S1603 and the process proceeds 
to a step S1604. In the step S1602, if the PIX.sub.-- END.sub.-- FLAG is 
OFF, the process proceeds to the step S1604. 
In the step S1604, if the SYNC.sub.-- FLAG is OFF, an interruption signal 
from the counter unit 7a is monitored in a step S1604 to monitor the 
completion of the recording of the image sent by the recording unit 4. 
When the recording of the image is completed, the SYNC.sub.-- FLAG is set 
to ON (step S1606) and the process proceeds to a step S1607. Namely, when 
the SYNC.sub.-- FLAG is OFF, the number of lines of one page has been set 
in the counter unit 7a during the initialization process of the PE handler 
(which will be described later with reference to FIG. 24) done at the 
start of the recording. Accordingly, the end of the recording can be 
detected by the zero count interruption of the counter unit 7a. In the 
step S1604, if the SYNC.sub.-- FLAG is ON, it means the synchronization 
mode. Since the image data sent to the recording unit 4 has already been 
recorded, the process proceeds to a step S1607. 
In the step S1607, if the PES.sub.-- STATUS is ON, that is, if the trailing 
edge of the recording sheet has already passed the PE sensor 13, the 
process proceeds to a step S1608 to conduct the page ending process. In 
the step S1608, if the FOOTER.sub.-- FLAG is ON, the process proceeds to a 
step S1609 to conduct the footer process. If it is OFF, the process 
proceeds to a step S1610 to conduct the sheet ejection process. The footer 
process of the step S1609 is same as that shown in FIGS. 15 and 16. The 
detail of the sheet ejection process is same as that shown in FIG. 17. In 
a step S1611, if the PIX.sub.-- END.sub.-- FLAG is ON, that is, if there 
is no longer line to be recorded in the image under recording, the process 
is terminated. In the step S1611, if the PIX.sub.-- END.sub.-- FLAG is 
OFF, that is, if there is a line to be recorded, the next recording sheet 
is queued in a step S1612 and the PE handler initialization process is 
conducted to initialize variables. 
In a step S1607, if the PES.sub.-- STATUS is ON, that is, if the trailing 
edge of the recording sheet has not yet passed the PE sensor, the process 
proceeds to a step S1613 to continue the recording in the synchronization 
mode. In the step S1613, if the PE.sub.-- FLAG is ON, it means that the 
sheet ejection is to be conducted but the sheet has not yet been fed, and 
the sheet is fed by one-scan lines and the process proceeds to a step 
S1615. In the step S1613, if the PE.sub.-- FLAG is OFF, the process 
proceeds to the step S1615. The PE.sub.-- FLAG and the PRE.sub.-- 
PE.sub.-- FLAG are set to OFF (steps S1615 and S1616) to continue the 
recording in the synchronous mode and the process is terminated. 
FIG. 26 shows a flow chart of the initialization process of the PE handler 
in the embodiment 3. 
Steps S1701 to S1702 and steps S1706 to S1710 correspond to the steps S1101 
to S1102 and the steps S1106 to S1110 of FIG. 9, respectively, and the 
explanation thereof is omitted since it is identical to that of the 
embodiment 1. 
The shortest recording sheet of the recording sheets which may possibly 
used in the present embodiment is a letter LTR sheet. It has a length of 
279 mm of which 268 mm is a recordable range. An error between the 
designated feed amount from the leading edge to the trailing edge in the 
recording process and the actual feed amount is determined based on the 
precision of the parts and the mounting presicion and the recordable range 
is set to 260 mm. Accordingly, in a step S1704, 3685 lines are set to be 
recorded in a fixed size mode. 
In accordance with the facsimile apparatus of the above embodiments, the 
operation status can be grasped even in a printer unit such as a line 
printer which has no concept of page or a printer unit which has no 
interface to transmit an operation status of the printer to external. 
Further, a recordable range of one page is flexible. Accordingly, an 
inexpensive printer can be used as a recording unit of the facsimile 
apparatus. 
The present invention may be applied to either a system comprising a 
plurality of equipments or a system comprising a single equipment. The 
present invention is also applicable to a combination of the system and a 
program. 
The present invention is also applicable to a facsimile apparatus which 
uses an ink jet recording system such as a so-called piezo type ink jet 
recorder using a piezo-electric element as an energy source to discharge 
ink as a recording unit. High density recording and fine recording are 
attained particularly when the present invention is applied to a recording 
head and recording apparatus in which status change in ink is caused by 
thermal energy and the ink is discharged from a discharge port by the 
status change. 
A typical configuration thereof and a principle are disclosed in U.S. Pat. 
No. 4,723,129 and U.S. Pat. No. 4,740,796. The present system is 
applicable to either an on-demand type or a continuous type. In the 
on-demand type, at least one drive signal which causes a rapid temperature 
rise over a nuclear boiling point in accordance with recording information 
is applied to electro-thermal converters arranged on sheets by which 
liquid (ink) is held in order to generate the thermal energy in the 
electro-thermal converters to cause film boiling on a thermal acting plane 
of a recording head. As a result, bubbles of ink which directly correspond 
to the drive signal are formed. To form the bubbles, the liquid (ink) is 
discharged by contraction through the discharging port to form at least 
one droplet. When the drive signal is a pulse signal, the formation and 
the contraction of the bubble can be attained instantly and properly and 
highly responsible discharge of liquid (ink) is attained. The drive by the 
pulse signal is disclosed in U.S. Pat. No. 4,463,359 and U.S. Pat. No. 
4,345,262. When a condition disclosed in U.S. Pat. No. 4,313,124 relating 
to a temperature rise factor on the thermal acting plane is adopted, 
better recording can be attained. 
The recording head may be a combination of discharge ports, a liquid path 
and electro-thermal converters (linear liquid flow path or orthogonal 
liquid flow path) disclosed in the above patents, or a construction shown 
in U.S. Pat. No. 4,558,333 or U.S. Pat. No. 4,459,600 which discloses to 
arrange the thermal acting portion in a curved area. Further, it may be a 
construction as disclosed in Japanese Laid-Open Patent Application No. 
59-123670 in which a common slit to a plurality of electro-thermal 
converters is used as a discharge portion of the electro-thermal 
converters or Japanese Laid-Open Patent Application No. 59-138461 in which 
an aperture for absorbing a pressure wave of thermal energy is formed for 
the discharge potion. Whatever the construction of the recording head is, 
the recording can be attained in the efficient manner. 
The present invention is also applicable to a full line type recording head 
having a length equal to a maximum width of a recording medium on which 
the recording apparatus can print. Such a recording head may meet the 
length requirement by a combination of a plurality of recording heads or a 
single integral recording head. In a serial type recording head, the 
present invention is also applicable if an exchangeable chip type 
recording head which permits electrical connection with a main unit and 
supply of ink from the main unit when it is mounted on the main unit, or a 
cartridge type recording head is used. 
It is preferable to add auxiliary means to the recording head used in the 
recording unit of the present invention to further stabilize the effects 
of the present invention. For example, preliminary heating means by an 
electro-thermal converter or other heating element or a combination 
thereof may be provided to attain stable recording. 
The type and the number of the recording heads mounded may be one for 
monochromatic ink or plural for a plurality of inks of different colors or 
densities.