JPH0782283B2 - Serial communication control method - Google Patents

Description

The present invention relates to a communication method between an apparatus main body and an additional apparatus in an image recording apparatus capable of recording or copying an image such as a copying machine.

"Prior Art" A copying machine is a typical image recording apparatus. The functions of copying machines have recently become complicated, and various functions such as a sorter can be attached to the main body of the copying machine to realize the functions suitable for the user.
Therefore, in recent copying machines, a main CPU (central processing unit) is arranged in the main body of the device, and a CPU as a slave is arranged in each of the main part of the main body of the device and the additional device. is there.

In such a device, by connecting these CPUs by a serial line, the configuration of the device can be flexibly changed, and a huge amount of wires connecting the devices can be drastically reduced.

FIG. 9 shows an example of a serial communication control method in a conventionally used image recording apparatus. The image recording device main body 11 is connected to the plurality of additional devices 14-1, 14-2, 14-3, ... By both the serial line 12 for supplying the additional device and the serial line 13 for supplying the main body. Has become.

As shown in FIG. 10A, the image recording apparatus main body 11 to the additional apparatus
For 14-1, 14-2, 14-3, ..., the time T is 1
The data D11 to D17 are transmitted in time division as a frame. Identification of each of the data D11 to D17 for the additional devices 14-1, 14-2, 14-3, ... Is based on address information incorporated in the data sent from the image recording device main body 11. Is done.
Transmission (return) of the data D21 to D27 from each of the additional devices 14-1, 14-2, 14-3, ... To the image recording device main body 11 is performed in the same manner as shown in FIG. 10b. Be seen.

In addition, in the same figure a, each additional device 14-1, 14-2,
Each unit of data (block data) D11 to D17 sent to 14-3, ... Is continuous without a gap.
Since these are data that are sent out uniformly from the apparatus main body 11 side, it is not necessary to provide a time margin from the end of transmission of one unit of block data to the start of transmission of the next unit of block data. On the other hand, in FIG. 9B, the additional device designated on the image recording device main body 11 side returns the block data at the following timing. Therefore, a predetermined time margin t _L is set before the return time.

"Problems to be Solved by the Invention" According to the serial communication control method used in this image recording apparatus, it is possible to connect a plurality of additional apparatuses to the same line without increasing the cost of the main body apparatus. There are advantages. However, at the same time, there are the following problems.

(I) When an IC card reader is connected as an additional device, a relatively large amount of data may be transmitted to the main device. Even in such a case, it is necessary to set a long frame period T in order to end the data transmission at one time. However, if the frame period T is set to be long, the data transmission interval between each additional device and the main body device also becomes long during normal transmission. As a result, for example, when the sheet is detected by the sheet conveying system and then the corresponding action is taken, the time required for it becomes long, and there is a problem that an erroneous operation occurs in the control of the additional device.

(Ii) Further, if the data length is increased only for a specific device, the timing of data transmission will be delayed in other devices that transmit data after that device, and similarly malfunctions are likely to occur.

Therefore, an object of the present invention is to provide a serial communication control method that enables large-capacity data transmission / reception without changing the normal data communication method.

"Means for Solving Problems" In the present invention, the main body of the image recording device and a plurality of additional devices connected to the main body are connected by a common serial line, and normally, the main body side and a plurality of additional devices are connected. In a communication system in which each frame is time-divided with an additional device for data transmission, let the main unit determine whether or not data transmission by these time-divisions is necessary. The frame is exclusively used by the additional device and the main body side within a predetermined period, and a large amount of data can be transmitted during this period.

By the way, when the frame is exclusively occupied by a specific additional device and the main body side, the remaining additional devices cannot communicate with the main body side until the end of the period. To prevent this from being mistakenly detected as a line error, when a specific additional device is transmitting data to or from the main unit, other additional devices should not detect that an error has occurred on the line. Is effective.

According to the present invention, data is normally transmitted in a configuration in which a plurality of data is transmitted in one frame, while a specific additional device is made to monopolize the frame in a predetermined case. For this reason, it becomes possible to transmit a large amount of data in a relatively short time without hindering the operation of the image recording apparatus itself.

[Examples] The present invention will be described in detail below with reference to Examples.

FIG. 2 shows a schematic circuit configuration of a copying machine to which the serial communication control method of the present invention is applied. This copying machine is provided with two supply trays (not shown) in the copying machine main body 21 and the copying machine main body 21 itself can make a copy. Further, the function can be improved by selectively adding the following additional device to the copying machine main body 21. Data transmission to and from these additional devices can be performed by the serial communication control method using the two types of transmission lines 22 and 23.

(I) Automatic document feeder 24; The automatic document feeder 24 is a device which automatically feeds a document onto a platen glass (not shown) of the copying machine main body 21 and discharges it after the copying is completed. There are two types of automatic document feeder 24, one for single-sided copying and one for double-sided copying, and either of these can be mounted on the upper part of the apparatus main body 21 at the user's request. Among these, in the device for single-sided copying, the originals are sequentially fed onto the platen glass, one side of them is copied, and the originals are discharged. On the other hand, in the automatic document feeder for double-sided copying, it is possible to send an original once on the platen glass to make a copy, then turn the original over and send it again on the same platen glass to make a copy. Has become.

These automatic document feeders 24 are independently equipped with CPUs for controlling them, and block data in 5-byte units are sent from the copying machine main body 21 to the automatic document feeders 24.
Conversely, block data in units of 4 bytes is sent.

(Ii) Sorter 25; The sorter 25 is a device for sorting paper after copying is completed. The copier body 21 of this embodiment has 10 pins
Any one of the 20-pin sorters can be installed. The sorter 25 also has an independent CPU, and the copier body 2
From 1 to the sorter 25, 4-byte unit block data is transmitted, and vice versa, 3-byte unit block data is transmitted.

(Iii) Character display device 26; The character display device 26 is arranged on the console panel of the copying machine main body 21, and displays various character information including kanji and displays these figures when the figures are edited. I do. An independent CPU is also used for the character display device 26. In this embodiment, block data in 9-byte units is sent from the copying machine main body 21 to the character display device 26.

(Iv) Partial image erasing device 27; The partial image erasing device 27 is a partial image erasing device using a so-called inter-image lamp. The inter-image lamp is a device that irradiates a part of the photoconductor with light, and partially erases the charges on the photoconductor prior to development to partially erase the image.

This inter image lamp has been conventionally used for the purpose of preventing a toner image from being formed in a region other than a region corresponding to a copy sheet. In the copying machine of this embodiment,
Further, a white “frame” is set around the image, a “white” binding margin of a predetermined width is provided at one end of the image, or the image is extracted into a graphic specified by the character display device 26 or its area. It can be used for the purpose of erasing the image of. In this embodiment, the image partial erasing device 27 is removed from the copying machine main body 21.
The block data is sent in units of 11 bytes, and vice versa.

(V) Copy paper automatic double-sided device 28; The copy paper automatic double-sided device 28 is a device that performs control for automatically making double-sided copies on copy paper. This apparatus temporarily stores the copy-finished paper for one side, reverses the side of the copy paper, and sends it out again to make a copy on the side that has not been copied.
The copy paper automatic duplexer 28 is provided with a motor for transporting copy paper, a plurality of solenoids for controlling storage of copy paper, and the like, and a CPU is independently used for these controls. Copying machine 21 to copy paper automatic duplexer 28
The block data is sent in units of 5 bytes, and vice versa.

In this copying machine, three supply trays can be added, and two of them can be replaced with a large capacity tray instead of the normal supply tray. The large capacity tray also uses a single CPU for its control.

(Vi) IC card device 29; The IC card device 29 is a device for reading and writing the IC card 31, but in the device 29 of this embodiment, it is also possible to connect an editor pad 32 as a coordinate input device. . I c
The card 31 is used, for example, when supplying data necessary for complicated area designation. The editor pad 32 is a device for inputting coordinates by operator's operation. When the character display device 26 is not attached to the copying machine main body 21, a figure can be input also by operating a ten key (not shown) on the console panel.

In this embodiment, block data in units of 5 bytes is sent from the main body 21 of the copying machine to the IC card device 29, and vice versa.

FIG. 3 shows the copying machine main body 21 and each additional device 24 shown in FIG.
3 shows a circuit configuration of a data passing portion in the above. Data is transferred between these devices by electric-optical-electrical signal conversion. That is, the line driver 33 is arranged in the copying machine main body 21, and the line driver 34 is arranged in the additional device 24 and the like. Then, they are transmitted through the transmission lines 22 and 23, respectively, to the light emitting element 3 of the device on the other side.
Connected to 7,38. As a result, on the side of the additional device 24 or the like, the light emission of the light emitting element 37 is converted into an electric signal by the light receiving element 41 and supplied to the CPU side thereof. Further, on the side of the copying machine main body 21, the light emission of the light emitting element 38 is converted into an electric signal by the light receiving element 42 and supplied to the main CPU.

FIG. 4 is for explaining a normal serial communication control method in such a copying machine.

From the copying machine main body 21 side shown in FIG.
Set to 100 mS (millisecond) and the data will be sent to the additional device side. The addresses (slave addresses) of the additional devices 24-29 (see FIG. 2) are as shown in Table 1 below.

That is, as shown in FIG.
From the 21 side, (i) sorter 25, (ii) automatic document feeder 24,
(Iii) Copy paper automatic duplexer 28, (iv) Image partial erasing device 27, (v) IC card device 29, (vi) Character display device
The transfer of the 6 block data to 26 is performed in these order. In this figure, the numerical value shown by "" represents the number of bytes of each block data. In the normal serial communication control method, the maximum length of these block data is limited to 15 bytes.
Since one frame period T is 100 mS, the maximum number of data that can be accommodated in a frame is 43 bytes.

FIG. 5 shows the structure of each block data. One block data is composed of control address data, interface data, and BCC. Here, the control address data is composed of a slave address indicating the type of the additional device and information indicating the data length of the block data. Also, BCC
Is a kind of check code for checking whether the transmitted data has an error.

Each block data is added from the main body 21 of the copying machine.
When it reaches 24 to 29, as shown in FIG. 4B, the corresponding additional device returns the block data within 2 mS after the transmission of the corresponding block data is completed.

Now, a case will be described in which, for example, a large-capacity data of 88 bytes as shown in the following Table 2 is transmitted from the IC card 31 to the copying machine main body 21.

Here, this IC card 31 has various copying modes (copy magnification, copy density, data for setting the copy paper size, etc.) and X coordinates of 16 points necessary for editing the area and The Y coordinate can be stored. As is clear from Table 2, the X coordinate and the Y coordinate are each represented by 20-byte data. This is because the size of the editor pad 32 is 297 mm × 432 in this embodiment.
This is because the coordinates are specified with a precision of 1 mm for each mm. When editing an image, these data can be supplied to the character display device 26 and the image partial erasing device 27 via the copying machine main body 21.

In the case of the IC card of this example, since it takes about 200 mS to transfer 88 bytes of data, the data cannot be transferred within the cycle T of 100 mS. Therefore, in this case, serial communication control exclusively for the entire frame, which is a feature of the present invention, is performed.

FIG. 6 shows a transmission format that can be adopted in such a case. This serial communication control method will be described with reference to FIG. As shown in FIG. 6B, in the IC card device 29, when the IC card is inserted, the inquiry signal 51 is transmitted to the copying machine main body 21 side at a timing at which the own station (IC card device 29) can transmit. The main body of the copying machine monitors whether or not a large amount of data needs to be transferred (step in FIG. 1), and when the request is met, whether or not the line may be opened for this purpose. Determine (step). In this embodiment, the line is allowed to be opened when the line can be opened by 300 mS or more, for example. Therefore, when data is frequently transmitted and received between the copying machine main body 21 and one or more slaves, such as during the copying operation, the line release is not permitted.

When the line is permitted to be released, the copying machine main body 21 transmits the large capacity transfer permission signal 52 as shown in a of FIG. 6 at the transmission timing of the block data to be transmitted to the IC card device 29 (step). . Further, the wait signal 53 during loading is sent to the remaining slaves 24 to 28. When the wait signal 53 during loading is received, these slaves 24 to 28 are made to wait for the transmission of their own station until the transfer of a large amount of data is completed (step). Also, during this period, no line error check is performed. Each slave 24-28 has a timer in order to detect when the end of the transfer of the large amount of data.

When the large-capacity transfer permission signal 52 is transmitted from the copying machine main body 21, the IC card device 29 receiving this signal starts transmitting 54 bytes of data 54. Then, the transmission work is completed within the frame expanded to 300 mS. In addition,
The 88-byte data can be expanded to 500 bytes, for example, and a larger amount of data can be transmitted.

FIG. 7 shows a case of writing data to an IC card as an example of transmitting a large amount of data from the copying machine body side to the slave side. As shown in FIG. 7B, an IC card is inserted into the IC card device 29, and this card insertion information 61 is sent in a normal frame of 100 mS and notified to the copying machine main body 21 side. On the copier body 21 side
When the writing of data to the IC card is instructed, the mode for transferring a large amount of data is set, and the frame cycle becomes 300 mS as shown in FIG. In this state, the copying machine main body 21 first sends a write command 62 to the IC card device 29 in a normal transmission format. Also with this,
It also outputs the in-store wait signal 63 for waiting the work of other slaves while the writing to the IC card is being performed.

When this write command 62 is sent, the IC card device 29 returns a writable signal 64 if writing to the IC card is possible. As a result, the copying machine main body 21 starts transmitting the large capacity data 65 as the write data to the IC card device 29. When the IC card device 29 finishes receiving the large amount of data 65 without any trouble, it sends out a response signal 66 to that effect. After that, the copying machine main body 21 and each of the slaves 24 to 29 can return to normal work.

FIG. 8 shows a basic circuit configuration of the copying machine main body 21 which employs the serial communication control method as described above.

That is, these devices are provided with a CPU (central processing unit) 71 as a control center. The CPU 71 is connected to a read only memory (ROM) 72 storing a control program, a random access memory (RAM) 73 for operation, an error monitoring circuit 74, a BCC generation circuit 75 for generating a check code, etc. There is. The buffer excision circuit 76 is for each slave 24
A first buffer 77 storing addresses 29 to 29, and second and third buffers 78 used when transmitting a large amount of data,
Equipped with 79. Here, the first buffer 77 generates the slave addresses "00" to "05" shown in Table 1. The second buffer 78 generates a large capacity address "06", and the third buffer 79 generates an address "07" as another large capacity address. These are selectively selected by the operation of the reply identification circuit 82 operated by the reception control unit 81 for exchanging data with the CPU 71, and the address is controlled by the buffer switching circuit 76 and the transmission register 83 for transmission control. It will be sent to the section 84 and will be sent to each slave 24-29.

In the embodiments described above, the copying machine is used as the image recording apparatus, but it goes without saying that the present invention can be applied to a printer and other apparatuses.

[Advantages of the Invention] As described above, according to the present invention, in a communication system in which a main body of an image recording apparatus and an additional apparatus (slave) are connected by a serial line, a large capacity transmission and a normal transmission are performed. We decided to change the form of data transmission.
Therefore, for these two types of communication, the device can be manufactured at low cost without the need to provide independent lines. Further, an additional device can be added or changed on the same line, and the device can be easily expanded or changed.

[Brief description of drawings]

1 to 8 are for explaining one embodiment of the present invention, in which FIG. 1 is a flow chart showing a state of serial communication control, and FIG. 2 is a schematic circuit configuration of a copying machine. FIG. 3 is a block diagram, FIG. 3 is a circuit diagram showing a data transfer part in the copying machine main body and each additional device, FIG. 4 is a timing diagram showing a serial communication control method in a normal case, and FIG. 5 is a block data structure. 6 is a timing chart showing a serial communication control method when transmitting a large amount of data to the main body of the copying machine, and FIG. 7 is a serial communication when transmitting a large amount of data to the IC card device side. FIG. 8 is a timing diagram showing a control method, FIG. 8 is a block diagram showing the basics of a circuit portion for realizing the serial communication control method of this embodiment, and FIG. 9 is a configuration of an image recording apparatus using the conventional serial communication control method. To block diagrams, FIG. 10 is a timing chart for explaining the conventional communication method. 21 …… Copier body, 22, 23 …… (serial) line, 24-29 …… Additional device, 71 …… CPU, 72 …… ROM, 73 …… RAM.

Claims (2)

[Claims] 1. A main body of an image recording device and a plurality of additional devices connected to the main body are connected by a common serial line, and usually each frame is provided between the main body side and the plurality of additional devices. A serial communication control method, wherein data is transmitted in a time division manner, and the frame is exclusively used by a specific additional device and the main body during a predetermined period determined by the main body. 2. When the frame is exclusively used by a specific additional device and the main body side, the remaining additional devices do not indicate that there is an error in that data transmission is not performed with the main body. The serial communication control method according to claim 1.