Facsimile transmission apparatus

A facsimile transmission apparatus comprising a picture signal producing circuit for producing picture signals by scanning a region including the original sheet face of the original sheet of the maximum size in those sheets to be transmitted, circuitry for storing the picture signals produced by the picture signal producing circuit alternately in two memories under the control of clock signals having different frequencies corresponding to the size of the original document and giving a predetermined number of bits for each horizontal scanning line irrespective of the size of the original sheet, and a read-out circuit for reading out the picture signals stored in the two memories for transmission at the rate corresponding to the scanning rate in a receiver side.

The present invention relates to a facsimile transmission apparatus and, 
more particularly, to the one in which, when the width of the original 
sheet to be transmitted is wider than the effective recording width, it 
transmits such picture signals providing the picture reproduced at the 
receiving side in the form of a compression of the original sheet size. 
In the facsimile transmission apparatus by telephone lines, for example, 
the maximum scanning width is generally established in accordance with the 
size of the original sheet to be transmitted. Generally, ordinary 
documents are the original sheet commonly used in the fascimile 
transmission and the specified papers of A and B size by the Japanese 
Industrial Standards (JIS) are predominently used. For this, the maximum 
scanning width of the facsimile transmission apparatus also is established 
coinciding with those specified sizes. With recent prevalances of 
computers, the original sheet of the size other than specified one must 
frequently be transmitted. In the line printer of the computer, for 
example, of the sheet used the lateral length (width) is longer by about 
25 mm than that of B4 size specified by JIS. When the line printer sheet 
is used as the original sheet for transmission, one end of the sheet must 
be cut off 25 mm to 30 mm in the lateral direction, when it is used in the 
facsimile transmission apparatus for B4 size. In this case, accordingly, 
the visual information written or printed on the cut-off portion of the 
original sheet can not be reproduced at the receiver side. This problem 
can easily be solved if a set of newly developed facsimile transmission 
and receiving apparatuses are used. However, demand for such facsimile 
transmission apparatus is still little. More adversely, since specially 
treated paper such as electrostatic recording paper is used as the 
recording paper at the receiving side, this necessitates change of the 
electrostatic recording paper, being accompanied by change of the 
recording head. Accordingly, this method by the newly developed facsimile 
transmission apparatus is problematic and provides no answer to the 
above-mentioned problem. 
Accordingly, an object of the present invention is to provide a facsimile 
transmission apparatus permitting the picture transmission of the original 
sheet of which the size is the same as or larger than that of the 
recording paper at the facsimile receiving side, without any omission of 
the visual information on the original sheet, and without any change of 
the facsimile receiver. 
According to the present invention, there is provided a facsimile 
transmission apparatus comprising means for producing picture signals by 
scanning a region including the original sheet face of the original sheet 
of the maximum size in those sheet to be transmitted; means for storing 
the picture signals produced by the means under the control of clock 
signals having different frequencies corresponding to the size of the 
original documents and giving a predetermined number of bits for each 
horizontal scanning line irrespective of the size of the original sheet; 
and means for reading out the picture signals stored in the storing means 
for transmission at the rate in synchronism with the scanning rate in the 
receiver side.

Reference is now made to FIG. 1 illustrating one form of a facsimile 
transmission apparatus according to the present invention. In the figure, 
reference numeral 1 denotes the sheet face of an original sheet containing 
the visual information such as a picture, printing or writing. The visual 
information on the sheet face 1 is optically projected onto a solid-state 
scanning device 3 through a lens 2, to form an image thereon. The 
solid-state scanning device 3 in this embodiment is comprised of a 
plurality of photoelectric conversion elements such as photodiodes 
arranged in the horizontal direction of the original sheet. More 
particularly, it is constructed by five solid-state line scanners 
connected in series fashion, the line scanner being made by RETICON 
CORPORATION in U.S.A. and sold bearing the number of RL-512c. The RL-512c 
line scanner includes 512 photoelectric conversion elements and thus if 
five line scanners are connected in series, 512 .times. 5 = 2560, i.e. 
2560 photoelectric conversion elements are arranged in a line directed in 
the horizontal scanning direction of the original sheet. That is, the 
solid-state scanning device 3 is comprised of 2560 photoelectric 
conversion elements arranged in such a way. The solid-state scanning 
device 3 acts to successively switch 2560 photoelectric conversion 
elements thereby to electronically scan the original sheet face 1 in the 
horizontal direction. Through this scanning operation, the picture, for 
example, on the original sheet face 1 is successively transformed into 
electric signals which are in turn outputted as picture signals. The 
scanning in the longitudinal or vertical direction of the original sheet 
face 1 is carried out in a manner that the relative position of original 
sheet face 1 to the solid-state scanning device 3 is shifted every time 
one horizontal scanning is completed. The shifting operation is made by 
stepwisely shifting the original sheet through the drive of a pulse motor 
(not shown). 
The maximum horizontal scanning width A of the solid-state scanning device 
3 is set to 280 mm in this embodiment. This dimension of the width is 
larger than the lateral width 254 mm of B4 size of sheet (254 mm in width 
.times. 364 mm in length) by the Japanese Industrial Standards (JIS), but 
is substantially equal to the width of the line printer sheet. 
2560 Photoelectric elements in the solid-state scanning device 3 is 
successively scanned by applying to the scanning pulse input terminal of 
the apparatus 3 the pulse signals fs having 2560 pulses during the time T 
as shown in FIG. 3(c'). The signals fs are produced by frequency-dividing 
the output signal from a pulse generator 4 in a frequency divider 33. More 
precisely, 2560 photoelectric elements in the solid-state scanning device 
3 are successively switched from right to left as viewed in the drawing so 
that the sheet face 1 is scanned over its maximum scanning width A from 
left to right, resulting in outputting a series of 2560 bits of picture 
signals. When one scanning operation is completed in the solid-state 
scanning device 3, a 2560-bit counter 6 produces a carry signal which in 
turn is applied to the scanning starting terminal of the solid-state 
scanning device 3 to begin the scanning of the next scanning line. The 
carry signal from the counter 6 is also applied to the set terminal of the 
flip-flop 7 for controlling the writing operation into a memory and to the 
clock terminal of a flip-flop 8 for changing the input/output mode of the 
memory, thereby to set the flip-flop 7 and to change the flip-flop 8 to 
the opposite state. 
A series of the picture signals of 2560 bits obtained through one scanning 
operation of the solid-state scanning device 3 are fed to a sample-hold 
circuit 9 where those signals are converted into an analogue signal which 
is then delivered to a low-pass filter 10 where the analogue signal is 
smoothed in the wave shape. The cut-off frequency of the low-pass filter 
10 is selected to be, for example, the frequency of the pulse signal fs. 
The output signal from the low-pass filter 10 is applied to a sampling 
circuit 11 where it is again converted to digital picture signals. A 
sampling pulse to be applied to the sampling circuit 11 is fed from an OR 
circuit 22. Two input terminals of the OR circuit 12 are connected to the 
outputs of AND circuits 13 and 14, respectively. One of the input 
terminals of the AND circuit 13 receives the pulse signal f1 from the 
frequency divider 5, while the other input terminal of the AND circuit 13 
receives the output of a switch 15 for changing the original paper sheet 
width. The switch 15 is grounded at one terminal while at the other 
terminal connected to the input of the AND circuit 13 and also to a high 
voltage terminal 17 through a resistor 16. The switch 15 is also connected 
to one of input terminals of an AND circuit 14 through an inverter 18, and 
the other input terminal of the AND circuit 14 is connected to the output 
of a frequency divider 19. The frequency divider 19 divides the frequency 
of the output pulse signal of the pulse generator 4 to produce a pulse 
train with 2048 repetition frequency f2, as shown in FIG. 3(c). 
The analogue picture signal transferred to the input of the sampling 
circuit 11 is sampled by the sampling signal F (the pulse signal f1 or f2) 
from the OR circuit 12, thereby to be converted to picture signals of 2048 
bits. The digital picture signals converted are then transferred to one of 
the input terminals of each AND circuit 20 and 21. The Q output of the 
flip-flop 8 is coupled with the other input of the AND circuit 20. The Q 
output of the same flip-flop 8 is applied to the other input of the AND 
circuit 21. With this circuit connection, the picture signal from the 
sampling circuit 11 is loaded into a 2048 bit memory 22 through the AND 
circuit 20 when the Q output of the flipflop 8 is in the "1" condition, 
but, when the Q output of the flip-flop 8 is "1," the picture signal is 
loaded into a 2048 bit memory 23 through the AND circuit 21. 
The outputs of OR circuits 24 and 25 are connected to the memories 22 and 
23, respectively, for clock pulses supply. The OR circuit 24 is connected 
at its inputs to the outputs of AND circuits 26 and 27. The OR circuit 25 
is connected at the two inputs to the outputs of AND circuits 28 and 29. 
One of two inputs of each AND circuit 26 and 29 is connected to the Q 
output terminal of the flipflop 8. One of two inputs of each AND gate 27 
and 28 is connected to the Q output terminal of the flip-flop 8. The other 
input terminal of each AND circuit 26 and 28 is connected to the output of 
an AND circuit 30. One of inputs of the AND circuit 30 is connected to the 
Q output terminal of the flip-flop 7, while the other input is connected 
to the output of an OR circuit 12. The output of the AND circuit 30 also 
is connected to a 2048 bit counter 31 whose output is further connected to 
the reset input R of the flip-flop 7 for controlling the loading to the 
memory. The other inputs of the AND circuits 27 and 29 are coupled to the 
output of the frequency divider 5 for receipt of the pulse signal f1. 
The outputs of two 2048-bit memories 22 and 23 are connected to an OR 
circuit 32 connected further to a telephone line (not shown). The picture 
signal from the OR circuit 32 is transmitted to the specified facsimile 
receiver (not shown) through the telephone line. 
The description to follow referring to FIGS. 2 and 3 is the operation in 
detail of the facsimile transmitting apparatus mentioned above in 
construction referring to FIG. 1. The first case to be described is a case 
where an original sheet with the maximum width A is placed on the original 
sheet setting position. The photoelectric conversion elements of 2560 of 
the solid-state scanning device 3 are successively scanned by the pulse 
signal fs shown in FIG. 3(c') fed from the frequency divider 33. Through 
this scanning of the elements, the original sheet with the width A is 
scanned from one side to the other side in the horizontal direction, with 
the result that the picture signals of 2560 bits are successively fed to 
the sample-hold circuit 9. When one horizontal scanning operation is 
completed, the carry signal with the period T shown in FIG. 2(a) from the 
2560-bit counter 6 is delivered to the solid state scanning device 3 to 
begin the next line scanning and to set and change the flip-flops 7 and 8, 
respectively. The picture signal fed to the sample-hold circuit 9 is 
converted to an analogue signal which in turn is wave-shaped in the 
low-pass filter 10 and then is converted again to the original digital 
form of signal in the sampling circuit 11. For sampling pulses to the 
sampling circuit 11, the pulse signals f1 from the frequency divider 5 is 
used to reach the sampling circuit 11 after passing through the AND 
circuit 13 and the OR circuit 12. At this time, the AND circuit 13 is 
enabled by a high voltage fed through the resistor 16 from the terminal 17 
when the original sheet width changing switch 15 is opened. As shown in 
FIG. 2 and FIGS. 2(a) and (b), 2048 sampling pulses during the time T 
necessary for horizontal scanning one time across the original sheet with 
the maximum width A are fed to the sampling circuit 11. The picture signal 
from the sampling circuit 11 is applied to the input of the memory 22 
through the AND circuit 20 enabled by the Q output of the flip-flop 8. At 
this time, the AND circuit 26 is conditioned by the same Q output of the 
flip-flop 8. Further, the flip-flop 7 for exchanging the input and output 
modes of the memory is set and produces Q output which appears at one 
input of the AND gate 30. The AND gate 30 also has at the other input the 
pulse signals F from the OR gate 12 as mentioned above. Thus the AND gate 
30 is enabled to feed the output to the other input of the AND gate 26. 
Therefore, the AND gate 26 is enabled to feed its output CP1 (FIG. 3(i)) 
to the memory 22 through the OR circuit 24. Upon receipt of the clock 
pulses CP1, the memory 22 permits the output of the sampling circuit 11 to 
be loaded into the memory 22 per se. 
The AND circuit 21 remains disabled since the flip-flop 8 does not produce 
the Q output so that the output of the sampling circuit 11 is not applied 
to the memory 23. At this time, the AND circuit 29 permits pulse signals 
CP4 as shown in FIG. 3(g) from the frequency divider 5 to pass 
therethrough to the input/output control terminal of the memory 23 through 
the OR circuit 25. In response to the clock pulses CP3, the contents of 
the memory 23 is read out through the OR circuit 32. Incidentally, the 
frequency of the read-out clock pulses CP4 is set in synchronism with the 
scanning rate in the receiver side. The output pulses CP1 from the AND 
circuit 30 to reach in number 2048 and at this time the 2048 bit counter 
31 produces a carry signal (FIG. 2(d)) by which the flip-flop 7 is reset 
(FIG. 2(c)). As a result, the AND circuit 30 is disabled, and the writing 
and the reading operations of the memories 22 and 23 are completed. 
The 2560-bit counter 6 counts 2560 of the pulse signals fs to produce a 
carry signal (FIG. 2(a)) which in turn is applied to a pulse motor (not 
shown). The pulse motor is not shown here since this is not essential to 
the present invention and no description thereof does not provide any 
inconvenience in explaining the present invention. Upon receipt of the 
carry signal, the pulse motor is driven to shift the original sheet 1 in 
the vertical direction by one horizontal scanning line. Following the 
shift operation, the horizontal scanning to the solid-state scanning 
device 3 commences again. At this time, the carry signal from the counter 
6 sets the flip-flop 7 (FIG. 2(c)) and changes the flip-flop 8 to produce 
the output at the Q output (FIG. 2(b)). 
The original sheet on the original sheet setting position is scanned over 
the maximum width A thereof by the solid-state scanning device 3, with the 
result that the picture signals of 2048 bits are produced from the 
sampling circuit 11, as in the previous manner. In this scanning 
operation, since the output from the flip-flop 8 appears at the Q output, 
the AND circuits 20, 26 and 29 are disabled while the AND circuits 21, 27 
and 28 are enabled. Accordingly, the output from the sampling circuit 11 
is stored into the memory 23 in response to the clock pulses CP2 shown in 
FIG. 3(j), and the picture signals by the previous scanning stored in the 
memory 22 are read out through the OR circuit 32, in response to clock 
pulses CP3 (FIG. 3(g)). The counter 31 counts 2048 pulses of the pulse 
signals f1 to produce a carry signal (FIG. 2(d)) which then resets the 
flip-flop 7. In this manner, the horizontal scanning repeatably progresses 
from the top to the bottom of the original sheet. 
It will be understood, accordingly, that if the picture signals thus 
obtained is scanned at the receiver sides at a rate of time T per line, 
the picture on the original sheet of the line printer sheet is reproduced 
on the sheet of B4 size with a picture including 2048 bits a scanning 
line. 
Description will be given of the case where the original sheet is of the 
specified size, e.g. B4 size. In this case, the original sheet size 
changing switch 15 is closed. As a result, the connection point between 
the input of the AND gate 13 and the resistor 16, and the input of the 
inverter 18 as well are grounded and thus the inverter input is LOW and 
the AND gate 13 is disabled, but the AND circuit 14 is enabled. 
Accordingly, the OR circuit 12 permits the pulse signals f2 from the 
frequency divider 19 to pass therethrough to the AND circuit 30 and to the 
sampling circuit 11. The pulse signals f2 (FIG. 3(c)) have such a 
frequency that the number of pulses during time t necessary for scanning 
the B4 size original sheet with the width B by the pulse signals fs (FIG. 
3(c')), is 2048 pulses. 
The scanning of the original sheet face 1 by the pulse signals fs is made 
over the entire width A of the maximum, even if the original sheet to be 
scanned has the width of B. Therefore, the solid-state scanning device 3 
feeds the picture signals of 2560 bits to the sample-hold circuit 9. It is 
to be noted here that the picture information is included in the outputs 
of the photoelectric elements arranged corresponding to the range of B 
starting from the scanning starting point on the original sheet face, but 
it is not included in the outputs of the photoelectric elements arranged 
corresponding to the difference "A - B" on the face 1. The picture signal 
which is converted to the analogue signal in the sample-hold circuit 9 is 
wave-shaped in the low-pass filter 10 and then is applied to the sampling 
circuit 11. 
The pulse signals f2 are supplied to the sampling input terminal of the 
sampling circuit 11, and times the sampling of the output of the low-pass 
filter 10. At this time, the pulse signals f2 is outputted from the AND 
circuit 30 and thus two 2048-bit memories 22 and 23 are operated at the 
rate determined by the pulse f2. 
Assume now that the first carry signal of the counter 6 sets the flip-flop 
8 so as to produce the Q output "1." As in the previous case, the picture 
signals from the sampling circuit 11 is loaded into the memory 22 in 
response to the clock pulses CP1 (FIG. 3(e)). As the writing operations of 
the memory 22 are completed, the carry signal of the counter 31 (FIG. 
2(f)) resets the flipflop 7 (FIG. 2(e)), resulting in the case of the 
operation of the memory 22. At this time, the output of the sampling 
circuit 11 corresponds to the scanning completion point of the width B of 
the original paper and, hence, the picture signals produced by the 
scanning following that scanning completion point, i.e. those 
corresponding to the width difference "A - B," are cut away without 
storing it in the memory 22. 
In this way, the scanning of the maximum width A of the original sheet by 
the solid-state scanning device 3 is finished and, at this time, the 
counter 6 produces a carry which in turn causes to begin the next scanning 
of the solid-state scanning device 3 and to set the flip-flop 7, and the Q 
output of the flip-flop 8 becomes "1." Under this circuit condition, the 
picture signals from the sampling circuit 11 are loaded into the memory 23 
in response to clock signals CP2 (FIG. 3(f)), while, at the same time, the 
contents of the memory 22 are read out by the clock pulses f1 to be 
transmitted to the receiver side through the OR circuit 32, with the 
picture signals having 2048 bits per one scanning line. 
As described above, the pictue signals obtained by scanning a given region 
including the original sheet face are written into the memory, the picture 
signals including a predetermined number of bits irrespective of the size 
of the original sheet, by using the clock pulses having such a frequency 
corresponding to the size of the original sheet as to give a predetermined 
number of bits during the scanning period of time for the original sheet 
face, and, then the such picture signals stored in the memory are read out 
at a given frequency corresponding to the transmission rate, irrespective 
of the size of the original sheet. Therefore, the picture signals may be 
transmitted in an ordinary transmission mode for the original sheet of 
specified size, while the transmission is made in a contruction mode for 
the sheet larger than the specified size. The omission of the information 
which otherwise is needed is eliminated for the visual information 
transmission. With respect to the receiving side, the conventional 
receiving set may be used without any modification for it so that the use 
of recording papers for extra sizes as well as the use of modified 
receivers is unnecessary. 
In the case of the original sheet size larger than the specified one, the 
horizontal scanning length for the reproduced picture at the receiver side 
is relatively contracted in comparison with that of the original sheet. 
For thus, the resolution of the reproduced picture is slightly 
deteriorated. Such a degree of the resolution deterioration provides 
little problem in practice use, when the nature of characters need in the 
original sheet is taken into account. For example, the contents recorded 
on the line printer paper is readable even if it is physically contracted 
slightly in the lateral direction. 
In the heretofore described embodiment, description was given only about 
the picture transmission of the B4 size specified sheet and of the sheet 
larger than that. It will be understood, however, that clock signals with 
a plurality of frequencies each having the same number of bits, such as 
2048 bits, for the respective times t1, t2 and t3 required for scanning 
various sizes or original documents, for example, B4, A4 and B5 sizes, may 
be used for executing the writing, and reading of the picture signals for 
memories may be executed by using clock pulses having a specified 
frequency. In this case, a single transmission apparatus is available for 
a plurality of facsimile receiving apparatuses having various effective 
recording widths, for example, B4, A4 and B5. 
While, in the embodiment mentioned above, two one-line memories are used, a 
number of memories may be used with the sequential operation thereof. 
The memory for frequency-band compression frequently used in the facsimile 
transmission apparatus may be commonly used for the memories of the 
facsimile transmission apparatus of the present invention. 
As a matter of course, the memory having a memory capacity capable of 
storing more than two scanning lines may be used in place of the one 
scanning line storing memory. 
In the above-mentioned embodiment, 2048 bits was selected for one scanning 
line of the picture signal, with intentions to easily compress the digital 
band width and to store the picture signals at a possibly high density in 
the memory within the storage capacity thereof. 
Various other modifications of the disclosed embodiment will become 
apparent to the person skilled in the art without departing from the 
spirit and scope of the invention as defined by the appended claims.