JP3024135B2 - Data communication method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a multiplexer for connecting a plurality of data processing devices (computers, word processors, etc.) to one device such as a printer.

(Prior Art) When a single printer or the like is shared by a plurality of data processing devices, it is necessary to connect them using a multiplexer.

In the conventional multiplexer, switching of the data processing device was manually performed using a switch. In recent years,
A so-called auto-scan type multiplexer, which detects a data input from a data processing device and automatically switches the data, has also been commercialized.

(Problems to be Solved by the Invention) A device such as a printer usually only receives data and performs processing, but transmits a response to a command from the data processing device, or Many devices that transmit trouble information on the device side are also known.

However, when a device such as a printer capable of transmitting and receiving such data is shared by a plurality of data processing devices, a conventional multiplexer only connects a specific data processing device and a device such as a printer in both transmission and reception. That is, data output from a device such as a printer is output only to a specific data processing device that outputs data to the device such as a printer.

However, data output from a device such as a printer has a high degree of urgency and needs to be applied to a plurality of data processing devices at the same time, and data that is not necessarily synchronized with reception from the data processing devices, that is, Since some data processing apparatuses are different from the data processing apparatus currently receiving data, a conventional multiplexer cannot be used.

Therefore, the object of the present invention is to solve the above problems,
A multiplexer that connects a plurality of data processing apparatuses and a responsive printer transmits a message from a printer having a high degree of urgency, such as failure information, to a plurality (or all) of the data processing apparatuses. An object of the present invention is to provide a multiplexer capable of transmitting a response that is not synchronized with transmission / reception to / from a device to a data processing device to which the response is directed.

(Means for Solving the Problems) In order to achieve the above object, in the data communication method according to the present invention, a plurality of data processing devices and a printer that forms an image based on data sent from each data processing device are provided. , Two-way communication of data output from each data processing device and printer. Data output from the printer is transmitted to a data processing device corresponding to information included in the data.

Preferably, when transmitting data from a plurality of data processing devices to a printer, one of the plurality of data processing devices is selected, data from the selected data processing device is received, and the received data is transmitted to the printer. When data is transmitted from the printer to a plurality of data processing devices, the data is received from the printer, the data processing device to be transmitted is specified in accordance with information included in the received data, and the data is received by the specified data processing device. And send the data.

(Operation) In a system in which a plurality of data processing apparatuses share one printer, the multiplexer according to the present invention automatically selects data from the data processing apparatus, transmits the data to the printer, and transmits the data to the printer. Data
The data is transmitted to an arbitrary data processing device according to the contents.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

i. Printer Network System FIG. 1 shows an application example of a printer network system according to an embodiment of the present invention.

The data from the plurality of data processing devices 1A, 1B, 1C is transmitted by the communication lines B1a, B1b, B1c to a file multiplex having functions as a multiplexer and a buffer.
After being collected in buffer 2 (hereinafter referred to as FMB2), it is output to printer system 10 via communication line B2. Information such as status from the printer system 10 is
Output to the required data processing device by FMB2.

In this embodiment, the printer system 10 includes a bitmap type data processing device 3, a print engine 4 using an electrophotographic process and a laser, and auxiliary devices such as an external paper feed unit 5 and a sorter 6.

ii. Printer System FIG. 2 shows an external view of the printer system 10. The print engine 4 incorporates the bitmap type data processing device 3 and can connect an external paper feed unit 5 and a sorter 6 as accessories. An operation panel 44 on which a display indicating the status of the system and keys for performing simple operations are arranged on the upper front surface of the print engine 4.
Is installed.

FIG. 3 shows details of the operation panel 44. Here, 901 to 903 are input keys, and 910 to 918 are display elements. A key 901 is used to temporarily stop printing operation.
AUSE key. The key 903 is a shift key, and the key 902
When pressed at the same time, it becomes the CANCEL key to interrupt printing. The reason why the keys 902 and 903 are simultaneously pressed to make the interruption function is to prevent interruption due to careless operation.

FIG. 4 is a central sectional view showing a paper passing path of the printing system, and includes three detachable paper feed cassettes (51, 52, 53).
Paper is fed selectively. After the toner is removed by the cleaner 406 in the print engine 4, the photosensitive drum 401 is uniformly charged by the charging charger 404 and the eraser lamp 405, and receives image exposure from the optical system 409. Then, a toner image is formed on the photosensitive drum 401 by the developing device 402, and the transfer charger 403
The image is transferred onto the paper fed by the printer, conveyed to the paper fixing device 408 by the conveyor belt 407, and stored in the sorter 6 after the fixing process by the fixing device 408.

FIG. 5 is a schematic block diagram of the printer system 10.

The bitmap type data processing device 3 includes a bitmap control unit (BMC) 30 (see FIG. 6), a bitmap RAM (BM-RAM) 32 for bitmap, and a bitmap writing for performing drawing on the BM-RAM 32. Section (BMW) 31 and font section 33
Consisting of The font section 33 includes a ROM section in which a predetermined font is stored in advance, and a RAM section in which a font downloaded from the outside can be stored. The connection to the print engine 4 is made by a bus B3 for control data (number of sheets, accessory control, etc.) and a bus B4 for image data.
Performed by

The print engine 4 mainly includes three control devices. First, the interface controller (IFC) 40 processes control data from the bitmap controller 30, controls the operation panel, and controls the timing of the entire printer through the internal bus B5. The electrophotographic control unit 41 is connected to the internal bus B5.
The control of the electrophotographic process unit 45 is performed according to the data sent from the interface control unit 40 through the.

The print head control unit 42 writes the image data sent from the bitmap writing unit 31 through the internal bus B4 onto the photoconductor 1, and prints the print head according to the information sent from the interface control unit 40 through the internal bus B5. The section 43 controls the light emission of the semiconductor laser and the rotation of a polygon motor (not shown).

The external paper feed unit 5 and the sorter 6 are also connected to the internal bus B5.
Through the interface control unit 40.

The printer system 10 described above is a bitmap laser printer in this embodiment. The print data (mostly represented by codes) sent from the data processing devices 1A, 1B, 1C is developed as an actual print image on the BM-RAM 32 of the bitmap processing device 3 and output to the print engine 4. Is done. The print engine 4 modulates the laser beam according to the data from the bitmap type data processing device 3, records the modulated laser beam on the photoconductor, and transfers the modulated laser beam to recording paper.

The data sent from the data processing devices 1A, 1B, and 1C includes codes for controlling the format and setting the engine mode in addition to the print data.

The bitmap type data processing device 3 also analyzes these protocols in addition to the print data, and issues format information and, if necessary, instructions such as paper passing to the print engine 4 and optional mode change. The print engine 4 performs, in addition to the above-described recording control, control of an electrophotographic system accompanying the recording control, timing control of recording paper, and processing synchronized with paper passing to another option. The control of the print engine 4 is the same as that of the electrophotographic copying machine except for the scanning system.

FIG. 6 is a block diagram of the bitmap control unit 30. The bitmap control unit 30 is composed of several blocks connected by an internal bus B30. BM-CPU301,
It is a control unit at the center of the bitmap type data processing device 3, and any one of the data processing devices 1A, 1B, 1C or a file
It communicates with the multiplex buffer 2, converts print data, controls the bitmap writing unit 31 through the bitmap writing unit interface 306, and controls the print engine 4 through the print engine interface 307. The SYS-ROM 302 stores a program of the BM-CPU 301. The SYS-RAM 303 is a working storage area of the BM-CPU 301, and is used for storing stacks and basic flags.

The R-buffer 304 is connected to an external (data processing device 1A, 1B, 1C
And a file multiplexing buffer 2). The purpose of the present invention is to enable processing between the processing program of the BM-CPU 301 and the data processing device 1 to be processed asynchronously.

Packet buffer (hereinafter abbreviated as P-buffer) 305
Stores the data from the data processing devices 1A, 1B, and 1C as an intermediate code (hereinafter, referred to as a packet) converted from the font attribute and easily drawn on the BM-RAM 32.

The actual drawing of the font is performed by the bitmap writing unit 31. As information to the bitmap writing unit 31, it is necessary to calculate parameters such as a font pattern built-in address and a drawing address in the BM-RAM 32. There is. This takes a certain amount of time. Therefore, by pre-processing the data of the next page while printing the data in the BM-RAM 32, the processing speed is increased. Therefore, P
-The movement of the data in the buffer 305 is FIFO (first in first out).

The print engine interface 307 is an interface with the print engine 4, and exchanges a job control command such as a print command with the interface of the print engine 4 via the bus B3.

iii. File Multiplex Buffer FIG. 7 is a diagram showing a schematic configuration of the FMB 2 having a multiplexer function and a buffer function of the present invention.

The FMB2 is configured with a microprocessing unit (hereinafter, referred to as an MPU) 211 capable of processing two-channel communication lines (B25, B26) as a main controller.

Communication lines B1a, from a plurality of data processing devices 1A, 1B, 1C
B1b, B1c are the corresponding level conversion circuits 215, 216, 2 respectively.
After being converted to the internal logic level by 17, the specific data processing device
It is connected to MPU 211 via 25. Selector 214 is MPU211
Is switched through the internal bus B21. Meanwhile, MPU
Communication between the printer 211 and the printer system 10 is performed on one line (B
This is performed via a 26-level conversion circuit 218B2).

The ROM 213 stores a control program for the MPU 211, and the RAM 212 is used as a work area for the control program and a data buffer for communication lines.

The setting switch 219 is a switch for setting the operating conditions of the FMB2.

iii-1. MPU FIG. 8 shows a schematic configuration of the MPU 211.

The MPU 211 includes a plurality of circuits controlled by a central control unit (hereinafter referred to as a CPU) 2111.

The timer 2112 performs timing control in a program executed by the MPU 211, and issues an interrupt to the CPU 2111 through the internal bus B211.

Two communication control units (hereinafter referred to as CCU ₁ and CCU ₂ ) 2
Reference numerals 113 and 2114 denote circuits for communicating with the data processing device and the printer system, respectively.

For the external bus interface 2115, the CPU 2111
For executing an external control program and accessing the RAM 212.

iii-2. Selector FIG. 9 shows the configuration of the selector 214.

The communication lines B22, B23, B24 with the data processing devices 1A, 1B, 1C via the level conversion circuits 215, 216, 217 respectively comprise four signal lines RD, RE, TD, TE. R
Da, RDb, RDc receive data from the data processing devices 1A, 1B, 1C, TDa, TDb, TDc receive data transmitted to the data processing devices 1A, 1B, 1C, and REa, REb, REc receive FMB2. State signals to the data processing devices 1A, 1B, 1C indicating that
b, TEc is a data processing device 1A indicating that reception is possible,
The status signals from 1B and 1C to FMB2 are shown, respectively.

Each received data RDa, RDb, from the data processing devices 1A, 1B, 1C,
RDc is input to the AND gates G4, G5, G6, respectively, and the switching signal RDSE from the MPU 211 via the bus interface 2141.
By L, only the data received from the specific data processing device is connected to the communication input terminal of the MPU 211 of B25 as RDm via the OR gate G7.

TDm output from communication output terminal of B25 of MPU211 is AND
The gates G1, G2, and G3 are input to the gates G1, G2, and G3, respectively.
Data can be output to a specific data processing device.

TE is the same as RD, and the data processing devices 1A, 1B,
Each status signal TEa, TEb, TEc from 1C is AND gate G8, G9, G10
Respectively, and only the status signal from the specific data processing device is transmitted to the TEm via the OR gate G11 by the switching signal RDSEL from the MPU 211 via the bus interface 2141.
To the communication input terminal of the MPU 211 of the B25.

For RE, REm that switches according to the state of the buffer in FMB2 is input to AND gates G12, G13, and G14, respectively, and REm is set to REm by RDSEL and the MRE used for switching.
The data is output to a specific data processing device as one of a, REb, and REc.

An example of the operation of the selector 214 is shown in FIGS.
It is shown in accordance with the timing charts of data reception from the data processing devices 1A, 1B, and 1C and data transmission to the printer system 10.

The operation of this selector will be briefly described. Here, mainly, data reception on the FMB side from the data processing device and F
The transmission will be described separately from the transmission of data from the MB to the data processing transmission.

Data processing device → FMB First, in receiving data from the data processing device on the FMB side, it is necessary to select only one data processing device from a plurality of data processing devices and receive data therefrom. Therefore, the CPU 2111 in the MPU 211
Via a signal RDSEL to select one data processing device
Turn on only one of a, RDSELb, and RDSELc. As an example, consider the case where the data processing device 1A is selected.
SELa is turned on. If the received data RD buffer is in a receivable state (for example, there is an empty area), the CPU 2111 determines the state and turns on REm. Further, even if the RD buffer can be received, the signal MRE provided so as to enable / disable the reception by software is also turned on. Only after all three of these signals are turned on, the gate G12 opens and the data receivable signal REa is output to the target data processing device 1A. Upon receiving this output, data processing device 1A transmits data RDa to FMB2. In the selector 214, RDSELa has already been turned on, and therefore, RDA is output as it is from the AND gate G4, and the CCU ₁ passes through the bus B25 as RDm via the OR gate G7.
The data is received by the external bus interface 2115 and further stored in the RD buffer in the RAM 212 via the external bus interface 2115 and the bus B21, thereby completing the data reception.

FMB → Data Processing Device Next, in data transmission from the FMB to the data processing device, it is necessary to select to which of the plurality of data processing devices the data in the RD buffer is to be transmitted. Therefore, the CPU 2111 in the MPU 211 transmits, via the bus B21, a signal TD for selecting which data processing device to transmit.
Turn on one or all of SELa, TDSELb, and TDSELc. As an example, if transmission is performed to all of the data processing devices 1A, 1B, and 1C, TDSELa, TDSELb, and TDSELc are turned on, and transmission data is transferred from the TD buffer in the RAM 212 to the bus B21, the external bus interface 2115, and the CCU _1. Via 2113, it is input to the selector 214 as TDm. Selector 214 already has TDSE
La, TDSELb, TDSELc are turned on, TDm remains as it is,
The gates G1, G2, G3 output the data to the data processing devices 1A, 1B, 1C as TDa, TDb, TDc, and the data transmission is completed.

Note that the data reception permission signals TEa, TE
b and TEc, together with RDSELa, RDSELb and RDSELc,
Input to ND gates G8, G9, G10, OR gate G11, bus B25
Is output to the CCU ₁ 2113 of the MPU 211 as TEm.
Therefore, normally, when the TEm signal is on, the data processing device selected by RDSEL can receive data, and thus the CCU ₁ 2113 controls the FMB2 to transmit data. Also, when transmitting to a plurality of data processing devices, regardless of whether the TEm is on or off, ignore this, turn on all the target TDSELs, and the CCU ₁ 2113 transmits the TDm to the selector 214. Then, it is transmitted to all the target data processing devices.

In Figure 8, the communication control unit CCU ₂ 2114 is for performing communication with the printer system 10 via a level conversion circuit P218, the communication line B26, like B25, R
It consists of D, RE, TD and TE. RDp indicates reception data from the printer system, REp indicates a reception permission signal from the printer system, TDp indicates transmission data from the data processing device, and TEp indicates a transmission permission signal from the data processing device.

iii-3. Buffer in FMB FIG. 10 shows the configuration of the RAM 212 in FMB2.

The RAM 212 has four parts: a parameter area, an RD buffer, a TD buffer, and an RP buffer.

The parameter area is an area for storing variables such as flags used in the control program stored in the ROM 213 executed by the MPU 211, and the RD buffer stores data to be received from the data processing device and output to the printer. The TD buffer is a buffer for storing data to be output to the data processing device, and the RP buffer is a buffer for storing data received from the printer.

iv. Timing chart of received data from data processing device FIG. 12 shows an example of timing on a communication line when selecting received data from a plurality of data processing devices, which will be described below. .

As a selection method, first, the MRE signal is turned on to turn on the reception enable signal REa to the data processing device 1A which permits reception, and the corresponding gate G4 is turned on by RDSELa.
Is turned on (FIG. 12).

Thereafter, when no data is sent from the data processing device 1A for a predetermined time T _SCAN , the MRE signal is turned off to turn off the REa (FIG. 12).

Further, if no data is received during the predetermined time T _IDLE , RDSELa is turned off, and at the same time, RDSELb is turned on, and MR is turned on.
By turning on the E signal, the signal REb is turned on for the next data processing device 1B (FIG. 12).

If data is sent from the data processing device 1B before the elapse of T _SCAN (FIG. 12), the ON of the RE signal is continued.

The reception of data from the data processing device 1B is interrupted (the
After elapse of a predetermined time T _KEEP (FIG. 12), the MRE signal is turned off, and after elapse of T _IDLE (FIG. 12), RDSELb is turned off and RDSELc is turned on. Then, the REc signal is turned on (FIG. 12). Here also, the data reception from the data processing device 1C is T _SCAN and T
If it is not during _IDLE (FIGS. 12 to), RDSELc is turned off, the MRE signal is turned on for the next (first in this embodiment) data processing device 1A, RDSELa is turned on,
Turn on REa from the processing unit.

By the way, T _IDLE is set to a time sufficiently longer than the time to transmit data for one character, and after T _SCAN elapses, the MRE
The REa signal is turned off by turning off the signal, but if data is received during T _IDLE (Fig. 12), the REa signal is turned on again by continuing with RDSELa on and turning on the MRE signal. (FIG. 12) to continue receiving. In this case, if no data is received during T _KEEP , the MRE signal is turned off to turn off the REa signal (the 12th
Figure).

If there is no received data even after T _IDLE elapses, RDS
While ELa is turned off, REb and RDSELb for the next data processing device 1B are turned on (FIG. 12).

The received data is temporarily stored in a buffer in the RAM 212 in the FMB2, and then output to the printer 10.When the data processing device is switched, a code corresponding to the new data processing device is indicated to indicate a data break. (DPU code) is also stored in the buffer.

The above is the case where the buffer in the FMB2 has room and the reception is always possible. However, when the buffer in the FMB2 (in the RAM 212) has no room and the reception is not possible, the reception enable signal RE is output.
Only off (see Figure 17 # 60), regardless of T _KEEP
The reception line is set to be the same, and the timing is restarted from the time when the buffer becomes available. Also, when status information from the printer and data from the data processing device remain unprocessed and remain in the FMB2, the processing related to the data processing device is continuing and the RE signal is kept on.

v. Buffer free area and data reception Figure 13 shows FM receiving data from data processing device
Buffer free area size in B2 and receivable signal
This shows the relationship between REs.

When the free area is equal to or higher than the predetermined value LEVEL1, data from the data processing device is continuously received (FIG. 13 to FIG. 13).
).

When the free area falls below LEVEL1, the RE is turned off and transmission to the data processing device is prohibited (FIG. 13). However, even if the empty area is below LEVEL1, the value LE is smaller than LEVEL1
If it is equal to or more than VEL2, the RE is turned on once after a lapse of a predetermined time T _STEP (FIG. 13, FIG. 13), and after retrieving a minimum (one character) of data, it is prohibited again (FIG. 13, FIG. 13).

This is performed not to completely prohibit data reception but to continue data reception while reducing the reception speed.

However, if the free area is less than LEVEL2,
No reception is performed.

According to this, for example, the data interval at the time of continuous reception from the data processing device is 120 μs, LEVEL1 is 512 bits, LEVE
If L2 is 128 bits and T _STEP is 5 seconds, the empty area is LE
38.4ms when receiving continuously from VEL1 to LEVEL2
, Reception is not performed at all, but if reception is performed every T _STEP , reception is performed at a predetermined interval of 5 seconds for a maximum of 32 minutes. Naturally, until the free area becomes LEVEL1, 10
Data is received every 0 μs.

If a trouble occurs in the printer, this process is not performed and the reception stops.

vi. Data transmission timing FIG. 14 shows data transmission timing from the FMB 2 to each of the data processing devices 1A, 1B, and 1C. The transmission from the FMB2 is enabled when the signals TEa, TEb, and TEc indicating that the data processing device can receive data are turned on. However, if there is no data to be transmitted to FMB2, it is not transmitted.

Normally, each receivable signal from data processing devices 1A, 1B, 1C
TEa, TEb, and TEc are turned on when the power of each data processing device is turned on and after the initialization is completed (FIG. 14, FIG.
). At this time, if there is data to be transmitted to FMB2, the gate G1 is opened by turning on TDSLa for the corresponding data processing device, and the data TDm is
Output as Da (Fig. 14).

If the data processing device 1A temporarily cannot receive data during data transmission from the FMB2, the TEa is turned off. In this case, the TEm is also turned off on the FMB2 side (FIG. 14), and the CCU _{1 of the} MPU 211 is turned off. Transmission from 2113 stops. this is
When TEa is turned on (Fig. 14), transmission is resumed (Fig. 1).
4).

Transmission to another data processing device 1B is performed by turning on TDSELb (FIG. 14).

At the same time, when outputting data to a plurality of data processing devices 1A and 1C, the TDSELa, T
After turning on DSELc (FIG. 14, FIG. 14), data TDm is output.

The data sent from the printer to the data processing device
As shown in Format 1 in FIG. 11, it is composed of an ID code for specifying the data processing device, information to be sent, and an end code. Returning after sending data to a plurality of data processing devices is performed after sending this end code (FIG. 14, FIG.
). When synchronizing between the data processing device and the printer,
There is a case where the ID code is not attached as in the format 2 in FIG.

In the present embodiment, data transmitted to each data processing device is determined as follows.

The data sent from the printer to the data processing device mainly includes a response to a command output from the data processing device to the printer. Therefore, normally, the switching signal TDSEL to the transmission data is the switching signal R of the reception data.
Matches DSEL.

However, if a code specifying a specific data processing device is added to the data from the printer, the TD is temporarily sent to send the data to the corresponding data processing device.
Switch to SEL. At this time, if the specific code indicates all data processing devices, all TDSELs are turned on. In the case of normal transmission, when the receivable signal TE of the data processing device is off, the transmission waits, but when sending data to all the data processing devices, the TE is off except for the last designated data processing device. In this case, since the data processing device itself may not be used, it is ignored (FIG. 14) and the transmission is performed.

vii. Control Flow of MPU FIGS. 15 to 22 are flowcharts of control programs stored in the ROM 213 executed by the MPU 211.

FIG. 15 shows a processing flow of the main routine.

The main routine is divided into an initialization section (# 1 to # 10) and a loop section (# 11, # 12).

When the power is turned on (# 1), the MPU 211 is initialized (# 2), and TDSEL and RDSEL are reset (# 3).
Various parameters are cleared (# 4). The functions of the parameters used in the control program will be described below.

CRDPU: Code indicating the data processing device currently connected to the reception line CTDPU: Code indicating the data processing device currently connected to the transmission line SCSTAT: Code indicating the status of reception control from the data processing device, 0 : No control 1: Wait for the first data during scanning 2: Indicates that the data processing device is being switched LKDPU: At least 1 from the current data processing device
DRDPU: Flag set each time data is received from the data processing device DRTMR: Timer for controlling reception from the data processing device DTTMR: Transmission control to the data processing device Timer RITMR: Timer for controlling the data reception interval from the data processing device CCUTB1: Flag indicating that data is being transmitted from CCU ₁ to the data processing device CCUTB2: Flag indicating that data is being transmitted from CCU ₂ to the printer ENBID: Data for the printer ID for each processing unit
TMPREG: Temporary storage register ERROR: Flag indicating that an error has occurred in the printer Return to the description of the main routine again.

After the parameter clear (# 4), the leading code n of the data processing device to be scanned is set (# 5), the operation mode is read from the setting switch 218 (# 6), and the transmitted code of the data processing device is read. After setting the ENBID to specify whether or not to send to the printer (# 7), set the timer to start the timer interrupt routine (see FIG. 22) at a predetermined cycle (# 8), Authorization is performed (# 9), and a signal REp indicating that data can be received from the printer is turned on (# 10).

Next, it moves to a loop part. The loop unit performs DPU scan control for performing a scan process on a data processing device (hereinafter, referred to as a DPU) according to a data reception state (# 11, see FIG. 16).
And printer status processing for selecting a DPU according to data from the printer (# 12, FIGS. 20 (a), (b)
Reference).

Actual data input / output control is performed by an interrupt routine started by an interrupt signal generated in CCU ₁ or CCU ₂ in accordance with data input / output (see FIGS. 17, 19, 21, and 22).
It is performed by

Hereinafter, FIGS. 16 to 22 will be described with reference to FIGS. 12, 13, and 14 showing timing charts.

FIG. 16 is a flowchart of a control process for scanning the DPU shown in FIG. This will be described below.

First, since the data is not controlled at first (YE at # 21)
S), sets the T _SCAN to the timer DRTMR (# 22), it resets the LKDPU and DRDPU (# 23), corresponding to CRDPU RDSE
After turning on L and MRE (# 24, see Fig. 12, refer to)
It enters a data waiting state. At this time, if the DPU to be transmitted is not specified (NO in # 25), only the TDSEL corresponding to the DPU is turned on to specify the same DPU (# 26). Then, SCSTAT is set to 1 to wait for data during scanning (# 27), and the routine returns (# 2).
8).

The data reception is performed by an interrupt process (FIG. 17) described later, but if no data is received during T _SCAN , that is, if no reception interrupt occurs, the timer DRTMR ends. Also, R
If there is enough room in the D buffer, the timer DRTMR is reset to T _KEEP every time a reception interrupt occurs.

If the scan is started and the head data is waiting (YES in # 29), the timer DRTMR has expired (YE in # 30).
S) If all the buffers are empty (YES in # 31), the MRE and the RE of the DPU are turned off (# 32, see FIG. 12, see FIG. 12) and T _IDLE is newly set in the timer DRTMR (# 33). ), Next DPU
Reset DRDPU to prepare for switching to SCSTA
T is set to 2 (# 34), and the routine returns (# 28).
If the timer DRTMR has not expired (NO in # 30) or if all buffers are not empty (NO in # 31), the process returns (# 28).

During preparation for DPU switching, data reception has not been performed yet, that is, DRDPU is 0 (YES in # 35),
If the timer DRTMR has not expired (NO in # 36), the routine directly returns (# 28). If the timer DRTMR has expired (YES in # 36, see FIG. 12), in order to switch the DPU, the CRDPU is updated and the current RDSEL is updated.
Is turned off (# 37, see FIG. 12) to return to the data non-control state (# 38).

However, if data reception is performed even during preparation for switching to the DPU (NO in # 35, see FIG. 12,), SCSTAT is set to 1 to stop preparation for switching to the DPU.
(# 39), and turn on the MRE signal to turn on the RE again (# 40). Thereafter, the process returns (# 28), and the processes after # 29 are performed.

FIG. 17 is a flowchart of an interrupt process started when the CCU ₁ receives data from the DPU.

When data is received, the printer
If the ENBID that specifies the ID for receiving data from the DPU is 1 (YES in # 51) and no data is received from the current DPU (YES in # 52), the current reception line is sent to the RD buffer. A CRDPU indicating the DPU to which is connected is output as an ID code (# 53). ENBID is 0 (# 5
If it is 1 (NO at 1), even if ENBID is 1, if it has already been received (NO at # 52), it is not stored in the RD buffer.

Next, to indicate that the data has been received, DRDPU, LK
Set both DPUs to 1 (# 54).

The data input to the CCU ₁ (# 55) is written into the RD buffer (# 56), and as long as the RD buffer has a free space equal to or higher than the predetermined value LEVEL1 (YES in # 57, see FIG. 13). Each time
The timer DRTMR is updated to T _KEEP (# 58, see Fig. 12), and since there is no need to control the reception interval, the timer
RITMR is cleared (# 59) and returns (# 6)
3).

However, the received data was written to the RD buffer (#
56) Later, if the free space in the RD buffer falls below LEVEL1 (NO in # 57, see FIG. 13), REm is turned off (# 60) to inhibit reception from the DPU, and DRTMR is also cleared. (# 61), the timer RITMR is set to T _STEP (# 62),
The data reception interval is set.

FIG. 18 is a flow chart of a CCU ₂ transmission process called by an interruption process (FIG. 19) started when data transmission from the CCU ₂ to the printer is completed.

If there is no data in the RD buffer (NO in # 81), it is not transmitted. If there is data (YES in # 81), the printer checks whether TEp indicating that data can be received is on or off (# 82). If it is on (YES), data is taken out from the RD buffer (# 82). 83) and output to CCU ₂ (# 8
Four). Then, CCUTB2 for notifying the DPU that the CCU ₂ is transmitting data is set to 1 (# 85). It continues to transmit from RD buffer data to the printer, if the free space of RD buffer LEVEL1 more (YES at # 87, see FIG. 13), since it is possible to receive data from DPU, CCU ₁
Is turned on (# 88), T _KEEP is set in the timer DRTMR (# 89), and the routine returns (# 90). However, when the DPU scan process is being switched (SCSTAT = 2), REm is not operated (# 86). If the free area of the RD buffer is equal to or less than LEVEL1 (NO in # 87), the process returns without changing REm (# 90).

FIG. 19 is a flow of a transmission interrupt of the CCU ₂ .

First, after resetting CCUTB ₂ (# 101), C in FIG.
Call the CU ₂ transmission process (# 102) and return (#
103).

FIGS. 20 (a) and 20 (b) are flowcharts (# 12 in FIG. 15) for processing the printer status from the printer stored in the RP buffer.

TMREG is a register for temporarily storing printer status information. If there is no data in this register (# 121)
YES), check for the presence or absence of data in the RP buffer (# 124), if not (NO), return (# 137), return (YES), and extract data from the RP buffer (# 12)
5) Because of this, the RP buffer becomes available, so if the REp of CCU ₂ is off (YES in # 126), it is turned on (# 127).

If the data extracted at # 125 is an ID code specifying a DPU (YES at # 128) and a specific DPU is specified (YES at # 129), the CTDPU is updated (# 130) and Do
Only TDSEL is turned on (# 131). When the DPU is not specified (NO in # 129), all TDSELs are turned on (# 132).

If the data extracted in # 125 is an end code (# 1
33), checks whether CTDPU has been set or not (#
134) If already set (YES), only TDSEL of CTDPU is turned on (# 135). If not set (NO), CRDPU
Only TDSEL is turned on (# 136). This is currently sending data, especially when the DPU is not set
This is because the response often corresponds to the DPU.

Further, if the data extracted in # 125 is the printer status, the data is stored in TMREG (# 1).
38) If the printer status is already stored in TMREG (NO in # 121), it is checked whether or not CTDPU has been set (# 139).
S), TE of CTDPU is turned on (YES in # 140),
Also, if CTDPU has not been set (NO in # 139), CRDP
If the U TE is on (YES in # 142), TMREG
Is output to the CCU ₁ (# 141), and TMPREG is cleared (# 143). If NO in both # 140 and # 142, the process returns as it is (# 137). If the content of TMREG output to CCU ₁ is a trouble code (YES in # 144), a printer error occurs. Is set to 1 (# 145), and if the content of TMREG is a trouble clearing code (YES in # 146), ERROR is set to 0 (# 147) and the process returns (# 137). If it is not any of these codes, return as it is (# 13
7).

Figure 21 shows a flow of a reception interrupt CCU _2.

The data (# 151) input from the printer to CCU ₂ is R
The data is written into the P buffer (# 152), but when the RP buffer is full (YES in # 153), the REp is turned off to stop the reception of the CCU ₂ (# 154). As long as there is a space in the RP buffer (NO in # 153), the REp is not turned off.

FIG. 22 shows a flow of an interrupt that the timer 2112 periodically gives to the CPU 2111.

This flow is based on the counts of the timers DRTMR and DTTMR (# 171
~ # 174), CCU ₂ for data from RD buffer to printer
(# 175, # 176) and control of data reception interval when RD buffer space becomes small (# 177)
~ # 183).

First, when a timer interrupt occurs, the timer DRTMR, DTTM
If R is in operation (YES in # 171, # 173), each is updated (# 172, # 174), and if not (NO), nothing is done. If CCUTB2 is 0 (YE at # 175)
S), the CCU ₂ transmission processing shown in FIG. 18 is performed (# 176). Further, no error has occurred on the printer side and the printer is normal (YES in # 177), and the data reception interval control timer RITMR.
Is running (YES in # 178), update RITMR (# 1
79) Also, if the RITMR is terminated (# 180) and the RD buffer is more than LEVEL2 (YES in # 181), the CCU ₁
Turn on REm to allow reception (# 182), and set timer DRTMR to T
Set to _STEP (# 183) and return (# 184).

After # 182, when data is received (CCU ₁ reception interrupt processing, FIG. 17), if the empty area is LEVEL2 or more and LEVE
Since it is smaller than L1 (NO in # 57, FIG. 17), REm is turned off to stop receiving again (# 60).

Thus, the space in the RD buffer is smaller than LEVEL1 and LE
In the case of VEL2 or higher, data reception can be performed if it is not continuous.

Also, the printer is in an error state (N in # 177)
O) If RITMR is not operating (NO in # 178) or if the RD buffer is less than LEVEL2 (NO in # 181), no data is received.

In the above embodiment, a plurality of data processing apparatuses are described as sharing a responsive electrophotographic printer. However, the present invention is not limited to this. For example, plotters, digitizers, and the like can be used. The above-described device can be applied.

It goes without saying that the present invention can be applied to a device having no response function.

(Effect of the Invention) By using the multiplexer of the present invention, a device such as a printer which can respond can be shared by a plurality of data processing devices, and a message or other data from a device such as a printer can be used as an arbitrary data processing device. Since it is possible to transmit the message with a high degree of urgency to all data processing devices, even if the transmission and reception are not synchronized, the data can be transmitted to the target data processing device, Usability is improved, and the range of use of the multiplexer is expanded.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a printer network system according to an embodiment of the present invention. FIG. 2 is a perspective view of the printer system. FIG. 3 is a plan view of an operation panel of the printer. FIG. 4 is a central sectional view of the printer system. FIG. 5 is a block diagram of a bitmap type data processing device of a printer system and a print system. FIG. 6 shows a bitmap control unit of the printer. FIG. 7 is a schematic configuration diagram of a file multiplex buffer according to the present invention. FIG. 8 is a schematic configuration diagram of an MPU of a file multiplex buffer according to the present invention. FIG. 9 is a schematic configuration diagram of a selector of a file multiplex buffer according to the present invention. FIG. 10 is a diagram showing an area configuration of a RAM of a file multiplex buffer according to the present invention. FIG. 11 is a diagram showing a format of data transmitted from the printer to the data processing device. FIG. 12 is a timing chart of a selector for selecting data received from a plurality of data processing devices. Figure 13 shows the RAM of the file multiplex buffer
Receivable signal RE according to the free area size of the buffer in the
FIG. FIG. 14 is a timing chart of data transmission from the file multiplex buffer to the data processing device according to the present invention. FIG. 15 is a main flowchart of the MPU. FIG. 16 is a flowchart of scan control of the data processing device by the MPU. FIG. 17 is a flowchart of a CCU ₁ reception interrupt by the MPU. FIG. 18 is a flowchart of CCU ₂ transmission by the MPU. FIG. 19 is a flowchart of a CCU ₁ interrupt by the MPU. FIGS. 20A and 20B are flowcharts of printer status processing by the MPU. FIG. 21 is a flowchart of a CCU ₂ reception interrupt by the MPU. FIG. 22 is a flowchart of a timer interrupt by the MPU. 2 File multiplex buffer 211 MPU 212 RAM 213 ROM 214 Selector 215 to 218 Level conversion circuit 219 Setting switch 2111 CPU 2112 Timer 2113 CCU ₁ 2114 …… CCU ₂

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G06F 3/12

Claims (2)

(57) [Claims] 1. A method for bidirectionally communicating data output from each data processing device and a printer between a plurality of data processing devices and a printer that forms an image based on data sent from each data processing device. A data communication method for transmitting data output from a printer to a data processing device according to information included in the data. 2. When transmitting data from a plurality of data processing devices to a printer, selecting one of the plurality of data processing devices, receiving data from the selected data processing device,
When transmitting the received data to the printer, and transmitting the data from the printer to a plurality of data processing devices, receiving the data from the printer, specifying a data processing device to be transmitted according to information included in the received data, The data communication method according to claim 1, wherein the received data is transmitted to the specified data processing device.