Image information transmission system

An image information transmission system comprises a plurality of image information processing units for processing image information, an image information transmission line and a control information transmission line independent from the image information transmission line for transmitting control information related to the processing of the image information processing units. The control information can be transmitted even during the transmission of the image information.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an image information transmission system 
for transmitting image information among a plurality of image information 
processing units. 
2. Description of the Prior Art 
Typical prior art image information transmission systems include a loop 
network system in which a plurality of terminals each having image 
information forming and recording functions are connected in a loop by a 
transmission line such as an optical fiber and the image information is 
transmitted from one of the terminals to other one or more of the 
terminals and a star network system in which a master station which can 
distribute an input signal to a plurality of terminals is provided and the 
output signal from the master station is transmitted to the plurality of 
terminals. These systems need the transmission of control information 
called a protocol including a destination terminal address, the number of 
images to be transmitted and the size of image, from a source terminal of 
the image information. The transmission of information on the status of 
the terminal such as a ready for reception signal and an end of reception 
signal, from the destination terminal to the source terminal is also 
required. 
Such information other than the image information is usually transmitted 
through the same transmission line as that for the image information, 
before or after the transmission of the image information. 
Control information for indicating an abnormal condition of the unit such 
as a signal to indicate a jam of a record paper may be generated during 
the transmission of the image information. 
However, if the transmission line is being used to transmit the image 
information, the control information cannot be transmitted to the source 
terminal of the image information. As a nature of the image information 
transmission, a large quantity of information is continuously transmitted 
through the transmission line. As a result, a long time is required from 
the occurrence of the abnormal condition during the transmission of the 
image information to a time point permitted to inform the abnormal 
condition to the source terminal. 
It may be possible to switch the transmission line to the transmission of 
the control information upon the occurrence of the abnormal condition 
during the transmission of the image information, but the transmission of 
the image information to normal terminals is interrupted by the 
transmission of the control information. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an image information 
transmission system which provides a smooth flow of image information. 
It is another object of the present invention to provide an image 
information transmission system which permits transmission of control 
information during transmission of image information. 
It is another object of the present invention to provide an image 
information transmission system which stores an abnormal condition of the 
system as status information when such an abnormal condition occurs during 
the transmission of image information. 
It is another object of the present invention to provide an image 
information transmission system which permits the transmission of control 
information indicating an abnormal condition of the system when such an 
abnormal condition occurs during the transmission of image information. 
It is another object of the present invention to provide an image 
information transmission system which displays an abnormal condition of 
the system when such an abnormal condition occurs. 
It is another object of the present invention to provide an image 
information transmission system which permits succession of an operation 
of an abnormal terminal to a normal terminal when an abnormal condition 
occurs during the transmission of image information. 
It is another object of the present invention to provide an image 
information transmission system which can operate a terminal having an 
image information forming unit and a recording unit as an apparatus 
independent from the image information transmission system (local use). 
It is another object of the present invention to provide an image 
information transmission system which can operate terminals as apparatus 
independent from the image information transmission system when image 
information is not transmitted. 
It is another object of the present invention to provide an image 
information transmission system which permits the transmission of control 
information among terminals irrespctive of the presence or absence of the 
transmission of image information even if one or more terminals are 
operating as independent apparatus. 
It is another object of the present invention to provide an image 
information transmission system which permits the transmission of image 
information among terminals even if one or more terminals are operating as 
independent apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIGS. 1A and 1B show a configuration of the image information transmission 
system of the present invention. FIG. 1B is a detailed diagram of FIG. 1A. 
Symbols A, B, C and D denote terminals each having a reader (image 
information forming unit) for reading an original bearing information to 
be read, a printer (recording unit) for recording image information and a 
control unit. For the purpose of simplification, a system having four such 
terminals is shown, although the number of terminals is not limited 
thereto. 
Terminals A, B, C and D are connected to control information transmission 
lines, clock lines and image information transmission lines. L1-1 denotes 
a control information transmission line between the terminals C and D, 
CL1-1 denotes a clock line for synchronizing the transmission of the 
control information between the terminals C and D, L1-2 denotes a control 
information transmission line between the terminals B and C, CL1-2 denotes 
a clock line for synchronizing the transmission of the control information 
between the terminals B and C, L1-3 denotes a control information 
transmission line between the terminals A and B, CL1-3 denotes a clock 
line for synchronizing the transmission of the control information between 
the terminals A and B, L1-4 denotes a control information transmission 
line between the terminals A and D and CL1-4 denotes a clock line for 
synchronizing the transmission of the control information between the 
terminals A and D. 
L2 denotes an image information transmission line and CL2 denotes a clock 
line for synchronizing the terminals A-D which are connected in parallel 
to the lines L2 and CL2. 
A-1, B-1, C-1 and D-1 denote pulse generators for generating clock pulses 
for synchronizing the terminals A-D when the control information is 
transmitted. A-2, B-2, C-2 and D-2 denote pulse generators for generating 
clock pulses for synchronizing the terminals A-D when the image 
information is transmitted. The transmission lines may be optical fiber 
cables. In that case, opto-electrical converters and electro-optical 
converters to be described later are contained in the terminals. 
E denotes an image information recording unit (for example, disc memory) 
which is connected to the image information transmission line L2, the 
control information transmission line L1 and the clock lines CL1 and CL2. 
During the transmission of the image information, the image information is 
sent out to the image information transmission line L2, and the image 
information on the image transmission line L2 is sequentially recorded in 
the image information recording unit E. The image information in the image 
information recording unit E is read out by a command in the control 
information and sent out to the image information transmission line L2. 
SW-A, SW-B, SW-C and SW-D denote a start of transmission switch and key 
switches to be actuated by an operator to specify a destination terminal, 
the number of times of transmission, the size of an original, the content 
of processing, a local use and a secret document. In the local use mode, a 
specified terminal is used as an apparatus having image information 
forming and recording functions independent from the system. 
AS, BS, CS and DS denote displays for displaying status information such as 
an abnormal condition of the terminal to the operator. 
FIG. 2 shows one embodiment of the image information forming unit. An 
original 11 bearing information to be read thereon is illuminated by a 
light source 12 such as a fluorescent lamp. A light reflected by the 
original 11 is focused by a lens 13 onto a line image sensor 14 such as a 
CCD. The present unit reads one line of image on the original in a 
direction of main scan at a rate of 16 picture cells/mm while sub-scanning 
laterally for a size A4 original and longitudinally for a size B4 
original. A line density is 16 lines/mm so that a total number of lines is 
6702 for the size A3 original and 3360 for the size A4 original. The 
number of picture cells in the direction of main scan is 4752 bits, which 
are read by two image sensors. The image information read by the image 
sensors 14 is shaped by amplifiers 15, outputs of which are then applied 
to an adder 16, which combines the two-channel input image information to 
one line of one-channel image information, which is then taken out of an 
output terminal OUT. 
The imge information supplied from the image information forming unit is 
shown in FIG. 3. The pulse generators A-2, B-2, C-2 and D-2 of FIG. 1B 
each generates a clock signal (b) which rises at a rising edge of the 
image information (a) and falls at a stable point in a middle of the image 
information (a). 
When the image sensors 14 of FIG. 2 are driven by the clock pulses of 7 
MHZ, the size A4 original can be read in 1.14 seconds and the size A3 
original can be read in 2.28 seconds. 
The control unit is now explained. FIG. 4 shows the control information (c) 
and the transmission clock signal (d). The control information is produced 
as packet information of 32-bit per packet. Like the clock signal for the 
image information, the clock signal (d) rises at a rising edge of the 
control information (c) and falls at a stable point in a middle of the 
control information (c). The clock signals generated in synchronism with 
the image information and the control information are transmitted through 
the clock lines CL2, CL1-1, CL1-2, CL1-3 and CL1-4 of FIG. 1 to 
synchronize the information of the source terminal and the destination 
terminal. 
When the transmission lines are of the same material, two pulse generators 
as shown in FIG. 1B are not necessary but only one terminal may be used in 
each terminal. 
FIG. 5 shows a content of one packet of control information. First to 
sixteenth bits represent a destination address and a source address, each 
by eight bits so that up to 256 terminals can be connected twenty-first to 
thirty-second bits are used for the transmission of the control 
information for the image information transmission. Table 1 shows types 
and contents of the control information. Dither processing means half tone 
(gray level) processing for the image information. 
TABLE 1 
______________________________________ 
Bit No Type Content 
______________________________________ 
1-8 Destination Set address by 8-bit signal 
address 
9-16 Source Set address by 8-bit signal 
address 
17-20 Number of Set number of times of trans- 
times of mission by 4-bit signal 
transmission 
21 Size of "1" for size A4 and "0" for 
original size A3 
22 Content of "1" for dither processing and "0" 
processing for no processing 
23 Start of "1" to command start of 
transmission 
transmission 
command 
24 Secret "1" to designate secret document 
document and "0" for non-designation 
command 
25, 26 -- -- 
27 Local mode "1" for local mode 
28, 29 Status of "00" for normal, "01" jam, 
receiver "10" for no paper and "11" for 
no toner 
30 End of "1" to indicate end of 
transmission 
transmission 
31 Transmis- "1" for transmission/reception 
sion/recep- OK 
tion OK 
32 Line busy "1" for control information 
transmission line busy 
______________________________________ 
FIG. 6 shows a configuration of an embodiment of the image information 
recording unit. The image information supplied through the image 
information transmission line is applied to a laser driver 21 from an 
input terminal IN. The laser driver 21 modulates a laser generator (for 
example, semiconductor laser) 22 with the input signal. The light 
generated by the laser generator 22 is directed to a polygon mirror 23 
rotating at a constant speed and deflected by the mirror 23 to primarily 
scan a photosensitive member 24. 
An image written on the photosensitive member 24 by the laser beam is 
developed by developing means, not shown, and the image is transferred to 
a recording medium such as a paper. 
FIG. 7 shows a block diagram of an overall configuration of the terminal of 
the image information transmission system of the present invention. L2 
denotes the image information transmission line. L1 denotes the control 
information transmission line such as L1-1, L1-2, L1-3 or L1-4 shown in 
FIG. 1B. The transmission lines are optical fibers in the present 
embodiment. 
Numeral 2 denotes an opto-electric converter for converting a light signal 
supplied from the control information transmission line L1 to an 
electrical signal, numeral 3 denotes an input register for storing one 
packet of or 32 bits of control information converted to the electrical 
signal and supplied from the opto-electric converter 2, numeral 4 denotes 
an output register for storing one packet of control information to be 
outputted, numeral 5 denotes an electro-optical converter which converts 
the electrical signal of the control information supplied from the output 
register 4 to a light signal and supplies it to the control information 
transmission line L1, numeral 6 denotes a controller which controls the 
operation of the terminal and analyzes the control information stored in 
the input register 3 and supplies the control information to the output 
register 4, numeral 7 denotes an image reading and recording unit which 
includes the image information forming unit and the recording unit shown 
in FIG. 2 and FIG. 6, numeral 2' denotes an opto-electric converter for 
converting a light signal on the information transmission line L2 to an 
electrical signal, numeral 5' denotes an electrooptical converter which 
converts the output image information to a light signal and supplies it to 
the image information transmission line L2 and numeral 10 denotes a 
bilateral buffer which controls input/output operation of the image 
information in accordance with a command from the controller 6. The 
operation of those units will be described later. 
FIG. 8 shows a detail of FIG. 7. The controller 6 of FIG. 7 includes an 
address discriminator 30, a command decoder 31, key switches SW, a status 
information memory 35, an output control information memory 36 and a 
display 49. In FIG. 8, the controller 6 is encircled by a chain line 
block. The key switch SW correspond to the switches SW-A, SW-B, SW-C and 
SW-D shown in FIG. 1B. Numerals 38 and 38' denote control information 
signal lines for controlling the recording unit 32 and the image 
information forming unit 33 through drivers 34. Numeral 39 denotes a 
control information signal line for controlling the bilateral buffer 10. A 
switch SW1 is selectively connected to a contact 44 or 45 to supply the 
image information to the image information transmission line L2 or to 
cause the terminal to operate as an apparatus having image information 
forming and recording functions independent from the system (local mode), 
and a switch SW2, when connected to a contact 46, supplies the image 
information on the image information transmission line to the recording 
unit. A control information signal line 41 connects the address 
discriminator 30 and an OR gate 40. A control information signal line 42 
connects the command decoder 31 and a control information memory 36. A 
control information signal line 43 connects the control information memory 
36 and the OR gate 40. 
The status information memory 35 stores a status of the terminal in an 
abnormal condition through the control information signal line 48. The 
display 49 displays the status information AS, BS, CS and DS shown in FIG. 
1B. Numeral 37 denotes sensors for detecting abnormal conditions. The 
control information memory 36 selects one of the memories of the control 
information corresponding to the detected abnormal condition. For example, 
when the paper is exhausted, the memory M1 is selected. The control 
information memory 36 sends out the corresponding control information to 
the control information signal line 43, which information is then supplied 
to the control information transmission line L1 through the OR gate 40, 
the output register 4 and the opto-electric converter 5. The abnormal 
conditions may include paper exhaust, toner exhaust and jam. When such 
abnormal condition is detected, it is displayed on the display 49. 
The operation of the present embodiment is now explained in detail with 
reference to FIGS. 5, 7 and 8 and Table 1. 
The control information on the control information transmission line L1 is 
read into the address discriminator 30 of the controller 6 through the 
opto-electric converter 2 and the input register 3 to discriminate the 
address. The address of the bits 1-16 of the control information shown in 
FIG. 5 and Table 1 is discriminated. When the address is not related to 
the terminal under consideration, it is sent out to the control 
information signal line 41. The control information is then supplied to 
the control information transmission line L1 as the light signal, through 
the OR gate 40, the output register 4 and the electro-optical converter 5. 
If the address specifies the terminal under consideration, the control 
information is read into the command decoder 31 through the control 
information signal line 47 to discriminate the content of the control 
information. The command decoder 31 supplies signals to the control 
information signal lines 42, 38, 38', 39 and 48. 
The control information transmitted through the control information signal 
line 42 is supplied to the output control information memory 36, which 
supplies the corresponding control information from the corresponding 
memory to the control information signal line 43. It is then supplied to 
the control information transmission line L1 as the light signal through 
the OR gate 40, the output register 4 and the electro-optical converter 5. 
When one of the terminals is designated as a source terminal, that is, when 
an operator depresses the start of transmission switch of the key switches 
SW, the address of the terminal is applied to the bits 9-16 of the control 
information shown in FIG. 5 and Table 1, as a source terminal address. The 
control information is applied to the address discriminator 30 of the 
terminal so that it is determined that the terminal is the source 
terminal. 
When the source terminal address of the bits 9-16 of the control 
information of FIG. 5 and Table 1 designates the terminal under 
consideration and the terminal is ready to transmit by the bit 27 (local 
mode) and the bits 28 and 29 (status of receiver) of the control 
information of FIG. 5 and Table 1, necessary bits such as the bit 21 (size 
of original), the bit 22 (content of processing), the bit 23 (start of 
transmission command) and the bit 24 (secret document) of the control 
information of FIG. 5 and Table 1 are set in the control information 
memory 36 and they are sent out one packet at a time to the control 
information transmission line L1 from the output register 4. When the bit 
31 of the control information of FIG. 5 and Table 1 at the destination 
terminal becomes "1" and the source terminal receives the control 
information indicating the completion of the reception of the control 
information, the source terminal transmits the image information to the 
destination terminal. 
The source terminal simultaneously activates the image information forming 
unit 33 through the control information signal line 38 and the driver 34. 
It also activates the bilateral buffer 10 through the control information 
signal line 39. That is, the switch SW1 is connected to the contact 45. 
The image information to be transmitted is sent out to the image 
information transmission line L2 through the electro-optical converter 5'. 
When the transmission is to be terminated, the bit 30 of FIG. 5 and Table 1 
is set to "1" to indicate the end of transmission and the image 
information transmission is terminated. The control information is reset. 
When the address discriminator 30 and the command decoder 31 discriminate 
that the control information is a command to record the image information, 
that is, when the destination address of the bits 1-8 of the control 
information of FIG. 5 and Table 1 is the address to designate the terminal 
under consideration, the terminal receives the bits 17-20 (number of times 
of transmission), the bit 21 (size of original), the bit 22 (content of 
processing) and the bit 24 (secret document) of the control information of 
FIG. 5 and Table 1. It also transmits the bits 28 and 29 (status of 
receiver), and if the terminal is normal and the bit 30 of the control 
information indicating the end of transmission is sent from the source 
terminal and the reception is terminated, it transmits the bit 31 
(transmission/reception OK), and when the bit 23 of the control 
information (start of transmission command) is received, it prepares for 
reception. That is, it activates the bilateral buffer 10 through the 
control information signal line 39 and connects the switch SW2 to the 
contact 46. It also activates the recording unit 32 through the control 
information signal line 38' and the driver 34. As a result, the image 
information on the image information transmission line L2 is recorded in 
the recording unit through the opto-electric converter 2. 
In the local mode, the operator turns on the local mode selection in the 
key switches SW. The information is read into the command decoder 31 
through the control information signal line 50, hence it is supplied to 
the control information signal lines 38, 38', 39 and 42. The control 
information memory 36 selects the corresponding memory through the control 
information signal line 42 and reads out the content thereof to the 
control information signal line 43, hence it is supplied to the control 
information transmission line L1 through the OR gate 40, the output 
register 4 and the electro-optical converter 5. This control information 
is the bit 27 in FIG. 5 and Table 1 which indicates the local mode. By 
informing the local mode to other terminals, the terminal under 
consideration operates as an independent apparatus from the system. The 
terminal activates the bilateral buffer 10 through the control information 
signal line 39, connects the switch SW1 to the contact 44 and activates 
the image information forming unit 33 and the recording unit 32 through 
the control information signal lines 38 and 38' and the driver 34. Thus, 
the image information from the output terminal of the image information 
forming unit 33 is supplied to the input terminal of the recording unit 
32. 
The operation when the receiving terminal assumes an abnormal condition 
during the transmission of the image information is now explained. 
Let us assume that during the transmission of the image information by a 
request for the transmission of a plurality of images, the paper in the 
terminal is exhausted after one print operation. In this case, the 
receiving terminal sets the bits 28 and 29 of the control information of 
FIG. 5 and Table 1 to "10", which are transmitted to the source terminal 
through the control information transmission line. Since the control 
information transmission line is independent from the image information 
transmission line, it is possible to communicate the abnormal condition to 
the source terminal of the image information without interrupting the 
transmission of the image information to other normal terminals. 
When the source terminal recognizes that the abnormal condition has 
occurred in the destination terminal and it cannot receive the image 
information, the source terminal stores the status in the status 
information memory 35 of the controller 6. If at least one destination 
terminal in the system is normal, the source terminal continues to 
transmit the image information. 
On the other hand, when papers are supplemented in the abnormal terminal 
and the terminal is ready to operate normally, the terminal sets the bits 
28 and 29 of the control information of FIG. 5 and Table 1 to "00" to 
inform the ready status to the source terminal of the image information. 
When the source terminal recognizes this control information, it resumes 
the transmission of the image information to that terminal. 
Even if one or more of the terminals in the transmission system are 
operating as the independent apparatus, the image information can be 
transmitted among other terminals, and in this case it is possible to 
transmit the control information irrespective of the transmission or 
non-transmission of the image information. 
When the abnormal condition occurs during the transmission of the image 
information, the control information for informing it to the terminal 
located near the point of the occurrence of the abnormal condition is 
transmitted through the control information transmission line which is 
independent from the image information transmission line. Accordingly, the 
reception of the image information continuously transmitted from the 
source terminal can be succeeded by the normal terminals. 
As described hereinabove, according to the present invention, the control 
information can be transmitted during the transmission of the image 
information. Accordingly, even if the abnormal condition occurs in the 
terminal during the transmission of the image information, the abnormal 
condition can be informed to other terminals without interrupting the 
transmission of the image information. 
Consequently, the flow of information in the image information transmission 
system is smoothened and effective information transmission is attained.