GB2030824A - Transmission-reception apparatus - Google Patents

Abstract

A transmission-reception apparatus wherein signals are bidirectionally and mutually transmitted and received between a transmitter (S) and a receiver (R) using a single transmission line (21), characterized in that the transmitter (S) and the receiver (R) are respectively equipped with line drivers (23S) (23R), receiver circuits (22S) (22R), and with flip-flops (24S), (24R) that are set and reset by signals transmitted over the line to effect change over of the direction of transmission through the line. The apparatus is used for transmission of picture and control signals between a copying machine and a remote station. <IMAGE>

Description

SPECIFICATION Transmission-reception apparatus This invention relates to a transmission-reception apparatus and specifically to a transmission-reception apparatus for electric information signals in a recording apparatus for composite-information consisting of a copying machine which is furnished also with a recording function of external electric information signals.

It is an object of the present invention to provide a transmission-reception apparatus capable of high speed transmission and reception of electric information between a recorder (receiver) and a reader (transmitter) such as- of a composite recording apparatus, which -rec- ords electric information signals in addition to its copying function, by the use of a single transmission line and a relatively simple transmission-reception circuit In a tranmission-reception apparatus such as the above-mentioned recording apparatus for composite-information wherein transmission and reception of signals between the transmission side and the reception siide are carried out through a single transmission line and synchronizing signals are periodically fed from the reception side to the transmission side, another object of the present invention is to provide a transmission-reception apparatus which stops the feed of the synchronizing signals at the time of trouble of the reception side so that the trouble is detected on the transmission side.

Other objects and features of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings.

Fig. 1 is a schematic view showing the general construction of a recording apparatus for composite-information and useful for explaining an example of the application of the transmission-reception apparatus in accordance with the present invention; Figure 2 is a diagram showing the signal system of the transmission-reception apparatus in accordance with the present invention; Figure 3 is a circuit diagram showing the transmission-reception apparatus in accordance with the present invention; Figure 4 is a block diagram useful for explaining the trouble detection circuit of the transmission-reception apparatus in accordance with the present invention; and Figures 5(a) through 5(c) are time-charts useful for explaining the action of the circuit of Fig. 4, respectively.

As a recording apparatus for compositeinformation consisting of a copying machine which is additionally furnished with the recording function of external electric information signals, there has been known a recording apparatus such as shown in Fig. 1. Around the periphery of a photosensitive drum 1 are disposed a corona charging electrode 2, a developing device 3 such as a magnetic brush developing device, a transfer electrode 4, a separating electrode 5, a discharging elec trode 6 and a cleaning device 7 in the rotat ing direction of arrow A and in the order mentioned. A recording paper of a copying paper 9 (hereinafter referred to as a recording paper) supplied from a magazine 8 via feed rollers passes through between the photosen sitive drum 1 and the transfer electrode 4.

During this period of copying or recording operation, a toner image formed on the photd- sensitive drum is transferred onto the record ing paper which then passes through a con veyor device 10 and a heat fixing device 11 whereby the toner image on the recording paper is melted and fixed thereon as is well known in the art. The transferred paper on which the toner image is visualized is taken out through a paper receiving means.

On the upper portion of the housing is placed a copy board 1 2 which will be moved at a controlled speed towards the direction of arrow B in accordance with the copying opera tion. The copy board 1 2 is illuminated by a source of light 1 3 located just beneath there of. Between the copy board 1 2 and the photo sensitive drum 1 is provided an exposure optical system X consisting of a first mirror 14, a lens 15 and a second mirror 16. The image of the original placed on the copy board 1 2 is formed on the circumferential surface of the photosensitive drum 1 between the corona charging electrode 2 and the de veloping device 3 so that the picture of the original is successively formed on the photo sensitive drum 1 as an electrostatic latent image.

A reproducing device Z having an electric/ optical conversion means such as optical fiber tube (OFT) to direct a recording face is pro vided on the circumferential surface of the photosensitive drum 1 between the corona charging electrode 2 and the developing de vice 3. To the input terminals of the reproduc ing device Z are fed electric information sig nals or facsimile output signals stored in a memory such as electronic computer or the like, so that the picture possessed by the electric information is scanned and repro duced on the photosensitive drum 1 as an electrostatic latent image. While the reproduc ing device Z is in operation, the source of light 1 3 is cut off or the shutter 1 7 is closed to halt the operation of the optical system X.

Fig. 2 illustrates the transmission-reception signal system in the present invention wherein arrow S represents signals to be sent from the transmitter to the receiver while arrow R does signals to be sent from the receiver to the transmitter. An interrupt-demand signals S, is sent from the transmission side to the reception side. To this signal S, the receiver sends a preparation-ready signal S2 to the transmitter when preparation is completed for recording a piece of information from the outside.

When the interrupt-demand signal St is applied during copying of the original in the case of the aforementioned composite recording apparatus, copying is stopped when copying of one page of the original is completed and the apparatus then enters the recording mode of external signals. Upon receiving the preparation-ready signal S2 from the receiver, the transmitter transmits a transmission-start signal S2 to the receiver. Upon receiving this signal S3, the receiver in turn starts recording and feeds a main scan-synchronizing signal S4. According to this synchronizing signal S4, the transmitter scans the recorded signal and sends a picture signal S5 read in this manner to the receiver. Thereafer, the transmitter sends to the receiver the picture signals S7, Sg, S1, . ..that are read by the former in synchronism with the main scan-synchronizing signals S6, S8, S10. . from the receiver. In this way, the picture signals covering the information of one page of the original are sent from the transmitter to the receiver while the receiver records the electric signals covering one page of information.

Fig. 3 shows an embodiment of the transmission-reception circuit of the transmitter and the receiver in accordance with the abovementioned signal system. The transmitter S and the receiver R connected with each other by a single transmission line 21 each have a bidirectional line driver consisting of an input buffer 22S, 22R and an output buffer 23S, 23R so that signals from the transmission side are taken into the input buffer 22R on the reception side from the output buffer 23S through the transmission line 21 while signals from the reception side are taken into the input buffer 22S on the transmission side from the output buffer 23R through the transmission line 21, The action of the input- and output buffers 22R, 23R, 22S, 23S on both reception- and transmission sides is switched over by flip-flops 24R, 24S incooperation with buffer gates 25R, 26R, 25S, 26S.

The flip-flops 24R and 24S are reset at the initial state, enable the input buffer 22R on the reception side to receive signals and keep it under such state and also enable the output buffer 23S to transmit signals and keep it under such state. Under this condition the interrupt-demand signals (signal S, in Fig. 2) produced by a control section 27 of the transmitter S is sent to the receiver through an OR gate 28 and through the output buffer 25S and the receiver takes this signal S, through the input buffer 22R whereby the signal S, is applied through an AND gate 29 to a control section of the receiver such as to an interrupt input INT of a micro-computer 30, for example.At its rear end the signal S, sets the count value of a counter 32 to + 1 through a monostable multi-vibrator 31, closes the AND gate 29 and opens a subsequent AND gate 34.

The output of the monostable multi-vibrator 31 sets the flip-flop 24R through an OR gate 35 whereby input buffer 22R on the reception side is closed while the output buffer 23R is opened. In the similar manner, on the transmission side, the signal S, sets, at its rear end, the flip-flop 24S through an OR gate 36 whereby the output buffer 23S is closed and the input buffer 22S is kept open. When interruption becomes possible on the receiver R side in response to the interrupt-demand signal S1, a start-ready signal (signal S2 in Fig.

2) is produced from the control section 30 of the receiver and is sent to the transmitter through an OR gate 37 and the output buffer 23R and to the control section 27 of the transmitter through its input buffer 22S.

Hence, the control section 27 starts readcontrol of the recorded information.

The flip-flop 24S is reset at the rear end of the signal S2 whereby the input buffer 22S is closed and the output buffer 23S is opened.

When reading of the recorded information is started, the control section 27 first sends a start signal S3 to the receiver, which takes out the signal S3 from the AND gate 34 whereby the control section 30 starts information record-control such as rotation of the photosensitive drum, feed of the recording paper and so forth in Fig. 2, for example. On the side of the receiver which is now in the record-control mode, it feeds sequentially the synchronizing signals SYNC (signals S4 S6, S,...in Fig. 2).

Whenever the control section 27 receives the synchronizing signals on the transmission side, it opens an AND gate 38 and feeds sequentially picture signals (signals S,, S7, 59... in Fig. 2). Since the synchronizing signals SYNC and the picture signals are alternately produced as output, they set and reset alternately both flip-flops 24R and 24S, thereby changing over the input- and output buffers 22S, 22R, 23S, 23R.

Reference numerals 39 and 31 represent monostable multi-vibrators having the same time limit with each other and this time limit corresponds to the period of one frame of the picture signals. The picture signals on the reception side are suitably separated into each frame by means of the output of a decoder 33 or applied as continuous signals to the recorder.

Incidentally, the picture signals may be analog signals besides the pulse train signals. In such a case, the transmission-reception route of the picture signals is an analog switch circuit in place of the logical operation circuit.

As described above, the tranmission-reception apparatus in accordance with the present invention consists of the transmitter and the receiver each equipped with the bidirectional line driver and with the flip-flop for changing over the line driver so that transmission and reception are bidirectionally made between them through the single transmission line and their switching is made by means of setting and resetting of the flip-flops. Accordingly, the apparatus of the present invention enables the line change at a higher speed than by the sequence control using a microcomputer or the like. Moreover, the receiver in the present apparatus discriminates the reception signals by the use of the counter which counts the number of the reception signals and of the decoder which decodes the output of the counter. Hence, high speed processing of the reception signals is feasible.

Fig. 4 is a circuit diagram showing an example of the trouble detection circuit in the transmission-reception apparatus in accordance with the present invention. Simultaneously with transmission of the transmission start signal S3 from the transmission side to the reception side, the start signal S3 is applied as a set input to a flip-flop FF, whereby an AND gate G, is opened and the synchron izing signals S4, S6. . . that are being fed from the reception side are applied as input to a retrigger type monostable multi-vibrator MM,.

The time constant of this re-trigger type monostable multi-vibrator is set to a value greater than the period of the synchronizing signals S4, S6.... The output of a monostable multivibrator MM2 (differential circuit), which is triggered by the rear end output of the monostable multi-vibrator MM1, is applied to gates G2 and G3. To the other terminals of these gates G3, G2 are applied a signal Tw which is changed over by the last signal of the synchronizing signals S4, .... . and its inversion signal Tw The output of the gate G2 is used as a clock input to a flip-flop FF3 and also as a clock input through an OR gate G4 to a flip-flop FF2 as the trouble detection output.

The output of the gate G3 is applied as input to the abovementioned OR gate G4 through an AND gate G6 which is opened only while the flip-flop FF3 is set. The output of the AND gate G, is applied as clock input to a flip-flop FF4 through an AND gate G6 which uses, as its gate input, those signals which are generated from the record start till the generation, as output, of the first synchronizing signal. The output of the AND gate G, resets compulsively the flip-flop FF3 and further the monostable multi-vibrators MM,, MM2 till the flip-flop FF4 is set.

Provision of such trouble detection circuit on the transmission side enables to detect trouble on the reception side. Figs. 5 are time charts useful for explaining the action of each portion. Fig. 5(a) shows the case where no trouble occurs while Figs. 5(b) and 5(c) show the cases where troubles take place, respectively. In Fig. 5(a), when the synchronizing signals SYNC (S4, S6 . . . ) are applied as input subsequent to the transmission start signal S3, the output of the monostable multi-vibrator MM, is in the mode of logic "1" output till the synchronizing signals continue, that is to say, till the time Tw. The monostable multivibrator MM2, which detects the rear end of this output, generates one pulse as its output after the passage of the time Tw.Though the output of the monostable multi-vibrator MM2 reaches the gate G5 through the gate G3, no input is applied to the flip-flop FF3- and the gate G5 is closed so that the output of the multi-vibrator MM2 is prevented and no change occurs in the state of the flip-flop FF2.

Next, Fig. 5(b) shows the state where a trouble occurs at the time Tt during reception and the trouble is removed at the time TR.

Since the synchronizing signals SYNC terminate at the time Tt, the output of the monostable multi-vibrator MM, changes to the logic "O" at the time T, and produces one pulse at the time TR. The output of the monostable multi-vibrator MM2 produces as output two pulses till time Tw and these signals pass through the gate G2 and flow into the flip-flop FF3 as the set input and at the same time, set and reset the flip-flop FF2. Consequently, the set period of the flip-flop FF2 is generated as output representing the trouble-occurring period.

Fig. 5(c) shows the case where the release of the trouble is made after the passage of the time Tw. When the trouble is released at the time TR after Tw, the pulse of the monostable multi-vibrator MM2 at the time TR flows through the gate G3 and through the gate G6 to reset the flip-flop FF2 since the flip-flop FF3 is set. In this case, too, the output of the flipflop FF2 is set during the trouble period from the time Tt to TR and is able to detect the trouble.

As described in the foregoing paragraph, in the trouble detection system in accordance with the present invention, the trouble detection on the reception side is carried out by stopping the transmission of the synchronizing signals while the stop of the synchronizing signals is detected by the re-trigger type monostable multi-vibrator on the reception side.

Accordingly, the trouble detection system can be adapted to the transmission-reception apparatus of the bidirectional signal transmission-reception system using the single transmission line, can detect troubles in a reliable manner using a relatively simple circuit and enables to detect the trouble period of the reception side on the transmission side.

Claims (4)

1. In a transmission-reception apparatus wherein signals are bidirectionally and mutually transmitted and received between a transmitter and a receiver using a single transmission line, the improvement characterized in that the input and output portions of the transmitter and the receiver are respectively equipped with bidirectional line drivers and with flip-flops that are set by signals received through the line drivers are reset by signals transmitted through the line drivers and change over the line drivers to signal transmission and reception.

2. The transmission-reception apparatus as defined in claim 1 wherein the receiver is eqipped with a counter for counting the number of signal reception, a decoder for decoding the output of the counter and means for discriminating the reception signals by means of the output of the decoder.

3. The transmission-reception apparatus as defined in claim 1 wherein the transmitter uses synchronizing signals as the input to a re-trigger type monostable multi-vibrator having a time constant larger than the period of the synchronizing signals and detects the absence and presence of the trouble of the receiver by detecting whether or not the output of the re-trigger type monostable multivibrator is interrupted, the synchronizing signals being sent periodically from the receiver to the transmitter and stopped at the time of trouble of the receiver.

4. Transmission-reception apparatus, substantially as hereinbefore described with reference to the accompanying drawings.