JPH11282645A - Image forming system, printing controller and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain simultaneous data transfer even when the transfer speeds of respective transferred destinations are different in the case of simultaneously transferring a large amount of image data to plural destinations in IEEE1394 isochronous transfer mode. SOLUTION: An image data controller 102 receives data in page description language(PDL) from a network 100, converts the received data into bit map data, and in the case of tandem printing, selects plural printers 104, 105, and transmits the bit map data to the printers 104, 105. When the corresponding data transfer speeds of the printers 104, 105 are respectively different, the lower transfer speed is used or the bit map data are transmitted to both the printers 104, 105 through respectively different channels.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming system including a systemized digital copying machine such as a printer and a scanner, a printer, and the like, and a print control apparatus and method.

[0002]

2. Description of the Related Art Recently, copiers have been multi-functionalized by digitization and systemization. In addition to the integration of the FAX function, the printer function is added to the network and the printer function is added. FIG. 2 shows an office network environment including a digital copying machine. The network 200 is a network such as an Ethernet to which network devices such as a personal computer, a printer, and a digital copier in an office are connected. Personal computer 20
Reference numeral 1 denotes a server personal computer (hereinafter, PC) to which the scanner of the digital copying machine 202 is connected.
The digital copying machine 202 is connected to a network via a controller 203. The color copying machine 204 is connected to a network via a controller 205.
The network 200 includes another network printer 2
06, 207 and PC clients 208, 209, 2
10, 211, 212, and 213 are connected.

Under such a network environment,
When printing out from the PC client side, the digital copying machine 202 via the network printers 206 and 207 or the controller 203 or the color copying machine 204 via the controller 205
From the client and send the printout data. When a large number of copies are made by the digital copying machine 203, it is necessary to output to the network printers 206 and 207 via the network 200 when the processing speed of the digital copying machine is insufficient.

[0004]

Here, a large amount of data is flowing on the network 200 in addition to printout data. When large image data is sent for printout, the throughput of the entire network is significantly reduced. In particular, when transferring the same print data to a plurality of printers in order to obtain a large amount of print output, the amount of data flowing on the network is large, and the network throughput is greatly reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above conventional example, and provides an image forming system, a print control apparatus, and a method capable of transferring a large amount of data for printout without reducing network throughput. The purpose is to do.

[0006] It is an object of the present invention to provide an image forming system, a print control apparatus, and a method capable of simultaneously printing even when the data transfer speeds of a plurality of printers used do not match.

[0007]

To achieve the above object, the present invention has the following arrangement. That is, a first network that connects at least one printer that receives and prints image data, and a second network that connects at least one device that generates print data in a predetermined format.
And a gateway for connecting the first network and the second network, receiving the print data in the predetermined format from the second network, converting the print data into image data, and transmitting the image data to the first network. An image forming system comprising: an image forming apparatus;

[0008] Alternatively, a printing control device connected to a plurality of printers for receiving and printing image data, wherein when printing a plurality of copies, a selection means for selecting a plurality of printers; And transmitting means for transmitting image data to each of the plurality of printers selected at the lowest data transfer speed among the corresponding data transfer speeds.

Alternatively, a plurality of printers for receiving and printing image data and a print control device connected via a network capable of using a plurality of channels, and when printing a plurality of copies, selecting a plurality of printers. Selecting means;
For each corresponding data rate of the selected printer,
Transmission means for transmitting image data to each of the plurality of printers selected by different channels.

[0010] Alternatively, there is provided a control method in a print control device connected to a plurality of printers for receiving and printing image data, wherein, when printing a plurality of copies, a selecting step of selecting a plurality of printers; Transmitting the image data to each of the plurality of printers selected at the lowest data transfer speed among the data transfer speeds corresponding to the selected printers.

Alternatively, there is provided a printing control method connected to a plurality of printers for receiving and printing image data and a network capable of using a plurality of channels, and when printing a plurality of copies, selecting a plurality of printers. And transmitting the image data to each of the plurality of printers selected on different channels for each data transfer speed corresponding to the selected printer.

Alternatively, the present invention is a computer-readable storage medium for storing a program to be executed by a computer connected to a plurality of printers for receiving and printing image data, wherein the program is for printing a plurality of copies. The method includes a selecting step of selecting a plurality of printers and a transmitting step of transmitting image data to each of the plurality of printers selected at the lowest data transfer rate among the corresponding data transfer rates of the selected printers.

Alternatively, there is provided a computer-readable storage medium storing a plurality of printers for receiving and printing image data and a program executed by a computer connected via a network capable of using a plurality of channels, wherein the program comprises: A step of selecting a plurality of printers when printing a plurality of copies; and a step of transmitting image data to each of the plurality of printers selected on different channels for each of the corresponding data transfer speeds of the selected printer. And

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] In this embodiment, a digital I / F for connecting each device is set to IEEE1.
Since a 394 serial bus is used, an IEEE 1394 serial bus will be described in advance.

<< Overview of IEEE 1394 Technology >> With the advent of home digital VTRs and DVDs, it is necessary to support real-time and high-information-volume data transfer of video data and audio data. In order to transfer such video and audio data in real time, and to transfer it to a personal computer (PC) or other digital devices, an interface capable of high-speed data transfer with the necessary transfer functions is required. The interface developed from such a viewpoint is IEEE 1394-1995 (High Pe
rformance Serial Bus) (hereinafter 1394 serial bus)
It is.

FIG. 16 shows an example of a network system configured using a 1394 serial bus. This system is provided with devices A, B, C, D, E, F, G, and H. A-B, A-C, B-D, D-E, C-F
, CG, and CH are connected by a twisted pair cable of a 1394 serial bus.
The devices A to H are, for example, PC, digital VTR, DV
D, digital camera, hard disk, monitor, etc.

The connection method between the devices is such that the daisy chain method and the node branch method can be mixed.
A highly flexible connection is possible.

Each device has its own unique ID and recognizes each other to form one network in a range connected by a 1394 serial bus. One 1394 connection between each digital device
Just by sequentially connecting with a serial bus cable, each device plays a role of relay, and constitutes one network as a whole. In addition, it has a function of automatically recognizing the device and recognizing the connection status when the cable is connected to the device by the Plug & Play function, which is a feature of the 1394 serial bus.

In the system shown in FIG. 16, when a device is deleted from the network or newly added, the bus is automatically reset, and the network configuration up to that point is reset. Then, rebuild a new network. With this function, the configuration of the network at that time can be constantly set and recognized.

The data transfer rate is 100/200 /
It has a transmission rate of 400 Mbps, and a device having a higher transfer rate supports a lower transfer rate and is compatible.

The data transfer mode includes asynchronous data such as control signals (hereinafter referred to as A).
Asynchronous transfer mode for transferring sync data)
There is an isochronous transfer mode for transferring synchronous data (Isochronous data: hereinafter, iso data) such as real-time video data and audio data. This Asyn
In each cycle (usually 125 μS per cycle), the c data and the Iso data follow the transfer of a cycle start packet (CSP) indicating the start of the cycle, followed by the Is data.
o Data is transferred together in a cycle while giving priority to data transfer.

Next, FIG. 17 shows the components of the 1394 serial bus.

The 1394 serial bus has a layer (hierarchical) structure as a whole. As shown in FIG.
The most hardware type is a 1394 serial bus cable, which has a connector port to which a connector of the cable is connected.
There are layers and link layers.

The hardware part is a substantial part of an interface chip. The physical layer performs coding and control related to connectors, and the link layer performs packet transfer and cycle time control.

The transaction layer of the firmware section manages data to be transferred (transacted), and issues commands such as Read and Write.
The serial bus management is a part that manages the connection status and ID of each connected device and manages the configuration of the network.

The hardware and firmware are the actual configuration of the 1394 serial bus.

The software application
The layer differs depending on the software used, and is a part that defines how data is placed on the interface.
It is specified by a protocol such as the V protocol.

The above is the configuration of the 1394 serial bus.

Next, FIG. 18 shows a diagram of the address space in the 1394 serial bus.

Each device (node) connected to the 1394 serial bus always has a 64-bit address unique to each node. By storing this address in the ROM, it is possible to always recognize the node address of oneself and the other party, and perform communication specifying the other party.

The addressing of the 1394 serial bus is based on the IEEE1212 standard, and the first 10 bits are used for specifying the bus number.
The next 6 bits are used for specifying the node ID number. The remaining 48 bits become the address width given to the device,
Each can be used as a unique address space. The last 28 bits store information such as identification of each device and designation of use conditions as an area of unique data.

The above is the outline of the technology of the 1394 serial bus.

Next, the technical portion which can be said to be a feature of the 1394 serial bus will be described in more detail.

<< Electrical Specifications of 1394 Serial Bus >> FIG. 19 is a sectional view of a 1394 serial bus cable.

In the 1394 serial bus, a power supply line is provided in a connection cable in addition to two twisted pair signal lines. As a result, power can be supplied to a device having no power supply, a device whose voltage has dropped due to a failure, and the like.

The voltage of the power supply flowing in the power supply line is 8 to 40.
V and the current are specified as the maximum current DC 1.5A.

<< DS-Link Coding >> A data transfer format D which is adopted in the 1394 serial bus.
FIG. 20 is a diagram illustrating the S-Link coding scheme.

In the 1394 serial bus, DS-Lin
The k (Data / strobe Link) coding method is adopted. This DS-Link coding scheme is suitable for high-speed serial data communication, and its configuration requires two signal lines. The main data is sent to one of the twisted pairs, and the strobe signal is sent to the other twisted pair.

On the receiving side, the clock can be reproduced by taking the exclusive OR of this communicated data and the strobe.

Advantages of using the DS-Link coding method include higher transfer efficiency as compared with other serial data transfer methods, and the circuit scale of the controller LSI can be reduced because a PLL circuit is not required.
Since there is no need to send information indicating the idle state when there is no data to be transferred, the power consumption can be reduced by setting the transceiver circuit of each device to the sleep state.

<< Sequence of Bus Reset >> In the 1394 serial bus, each connected device (node) is given a node ID, and is recognized as a network configuration.

When there is a change in the network configuration, for example, a change occurs due to an increase or decrease in the number of nodes due to insertion / removal of a node or turning on / off of a power supply, etc. Each detected node sends a bus reset signal on the bus,
Enter the mode to recognize the new network configuration. The method of detecting the change at this time is performed by detecting a change in the bias voltage on the 1394 port board.

When a bus reset signal is transmitted from a certain node, the physical layer of each node transmits the bus reset signal to the link layer at the same time as receiving the bus reset signal, and transmits the bus reset signal to another node. . After all the nodes finally detect the bus reset signal, the bus reset is activated.

The bus reset is also activated by the above-mentioned activation by hardware insertion / removal due to a cable disconnection or network abnormality or the like, and also by directly issuing an instruction to the physical layer by host control from a protocol.

Further, when the bus reset is activated, the data transfer is suspended, the data transfer during this period is waited, and after the end, the data transfer is resumed under a new network configuration.

The bus reset sequence has been described above.

<< Node ID Determination Sequence >> After the bus reset, each node starts an operation of giving an ID to each node in order to construct a new network configuration. The general sequence from the bus reset to the determination of the node ID at this time will be described with reference to the flowcharts of FIGS. 21, 22, and 23.

The flowchart of FIG. 21 shows a series of bus operations from the occurrence of a bus reset until the node ID is determined and data transfer can be performed.

First, as step S101, the occurrence of a bus reset in the network is constantly monitored, and if a bus reset occurs due to power ON / OFF of a node, the process proceeds to step S102.

In step S102, a parent-child relationship is declared between the directly connected nodes in order to know the connection status of the new network after the network has been reset. As step S103,
When the parent-child relationship is determined between all nodes, step S
One route is determined as 104. Until the parent-child relationship is determined between all nodes, the parent-child relationship is declared in step S102, and the route is not determined.

After the route is determined in step S104, the operation of setting a node ID for giving an ID to each node is performed in step S105. Node IDs are set in a predetermined node order, and I
The setting operation is repeatedly performed until D is given. When the IDs are finally set in all the nodes in step S106, the new network configuration is recognized in all the nodes. And data transfer is started.

When the state of step S107 is reached, a mode for monitoring the occurrence of a bus reset again is entered.
When the bus reset occurs, the setting operation from step S101 to step S106 is repeatedly performed.

The flow chart of FIG. 21 has been described above. The flow chart of FIG. 21 shows the part from the bus reset to the route determination and the procedure from the route determination to the end of the ID setting in a more detailed flow chart. Are shown in FIGS. 22 and 23, respectively.

First, the flowchart of FIG. 22 will be described.

When a bus reset occurs in step S201, the network configuration is reset once. The occurrence of a bus reset is constantly monitored in step S201.

Next, in step S202, as a first step in re-recognizing the reset network connection status, a flag indicating a leaf (node) is set for each device. Further, in step S203, each device checks how many ports it has are connected to other nodes.

According to the result of the number of ports in step S204, the number of undefined (undetermined parent-child) ports is checked in order to start the declaration of the parent-child relationship.
Immediately after the bus reset, the number of ports = the number of undefined ports. However, as the parent-child relationship is determined, the number of undefined ports detected in step S204 changes.

First, immediately after the bus reset, only the leaves can declare the parent-child relationship first. A leaf can be known by checking the number of ports in step S203. In step S205, the leaf declares "I am a child and the other is a parent" to the node connected thereto, and ends the operation.

A node which has a plurality of ports in step S203 and is recognized as a branch has the number of undefined ports> 1 in step S204 immediately after the bus reset.
Moving to step S206, a flag of branch is first set, and in step S207, the process waits for reception of "parent" in the parent-child relationship declaration from the leaf.

The leaf declares the parent-child relationship, and the branch that has received the declaration in step S207 appropriately returns to step S20.
Confirm the number of undefined ports of 4 and find that the number of undefined ports is 1
If it becomes, it becomes possible to declare “I am a child” in step S205 for the node connected to the remaining port. After the second time, step S204
Even if the number of undefined ports is checked in step S207, for a branch having two or more ports, the process waits again in step S207 to accept a "parent" from a leaf or another branch.

Finally, if any one of the branches or exceptionally leaves (because it did not operate quickly enough to allow child declaration) becomes zero as a result of the number of undefined ports in step S204, In this case, the declaration of the parent-child relationship of the entire network has been completed, and the only node for which the number of undefined ports has become zero (all are determined as parent ports) is flagged as a root in step S208, and the root is set in step S209 Is recognized.

In this manner, the steps from the bus reset shown in FIG. 22 to the declaration of the parent-child relationship between all the nodes in the network are completed.

Next, the flowchart of FIG. 23 will be described.

First, in the sequence up to FIG.
Since the information of the flag of each node such as branch and route is set, classification is performed in step S301 based on this.

As a task of assigning an ID to each node, an ID can be first set from the leaf. The IDs are set in ascending order of leaf → branch → route (node number = 0).

In step S302, the number N (N is a natural number) of leaves existing in the network is set. Thereafter, in step S303, each leaf requests the root to give an ID. If there are a plurality of such requests, the route performs arbitration (operation of arbitration into one) in step S304, and performs step S3.
As 05, an ID number is given to one winning node, and a failure result is notified to the losing node. In step S306, the leaf whose ID acquisition has failed fails issues an ID request again, and repeats the same operation. In step S307, the ID information of the node is transferred to all the nodes by broadcasting from the leaf whose ID has been acquired. One node I
When the broadcasting of the D information is completed, step S30
As 8, the number of remaining leaves is reduced by one. here,
In step S309, when the number of the remaining leaves is one or more, the operation from the ID request in step S303 is repeatedly performed, and finally, when all the leaves broadcast the ID information, N = 0 in step S309, and the next Moves to the branch ID setting.

The setting of the branch ID is performed in the same manner as in the case of the leaf.

First, as step S310, the number M of branches existing in the network (M is a natural number) is set. Thereafter, in step S311, each branch requests the root to give an ID. On the other hand, for the route, arbitration is performed in step S312, and the branch is given in order from the winning branch to the next youngest number given to the leaf. In step S313, the root notifies the branch that issued the request of ID information or a failure result, and in step S314, the branch whose ID acquisition has failed fails issues an ID request again and repeats the same operation. In step S315, the ID information of the node is broadcast and transferred to all the nodes from the branch where the ID has been obtained. When the broadcast of the one node ID information ends, the number of remaining branches is reduced by one in step S316. Here, step S3
When the number of the remaining branches is 1 or more, the operation from the ID request in step S311 is repeated until all branches finally broadcast ID information. When all the branches have acquired the node IDs, M = 0 in step S317, and the branch ID acquisition mode ends.

At this point, since only the root node has not acquired the ID information at the end, step S
318 is set as the own ID number among the unassigned numbers, and the root I
Broadcast D information.

Thus, as shown in FIG. 23, the procedure from the determination of the parent-child relationship to the setting of the IDs of all the nodes is completed.

Next, the operation in the actual network shown in FIG. 24 as an example will be described with reference to FIG.

Referring to FIG. 24, the (root) node B
Are directly connected to node A and node C,
Further, a node D is directly connected below the node C, and a node E and a node F are directly connected below the node D in a hierarchical structure. The procedure for determining the hierarchical structure, the root node, and the node ID will be described below.

After the bus reset, a parent-child relationship is declared between the directly connected ports of each node in order to recognize the connection status of each node. The parent and child can be said to be such that the parent is higher in the hierarchical structure and the child is lower.

In FIG. 24, the node A first declares the parent-child relationship after the bus reset. Basically, a node (called a leaf) having a connection to only one port of the node can declare a parent-child relationship. Since the user can first know that only one port is connected, it recognizes that this is the edge of the network, and the parent-child relationship is determined from the node that operates earlier in the network. In this manner, the port on the side that has declared the parent-child relationship (node A between AB) is set as a child, and the port on the other side (node B) is set as a parent. Thus, between node AB, child-parent, node E-
The child-parent is determined between D and the child-parent is determined between the nodes FD.

Further up in the hierarchy, a node (called a branch) having a plurality of connection ports, in which a parent-child relationship has been declared from another node, is sequentially declared further higher in order from a node receiving a parent-child relationship. To go. In FIG. 24, first, after the parent-child relationship between the node D and DE and between DF is determined,
The parent-child relationship is declared for node C, and as a result, child-parent is determined between nodes D and C.

The node C receiving the parent-child relationship declaration from the node D becomes the node B connected to another port.
Declares a parent-child relationship. As a result, a child-parent is determined between the nodes C and B.

In this way, a hierarchical structure as shown in FIG. 24 is formed, and the node B that has become the parent in all finally connected ports is determined as the root node. There is only one route in one network configuration.

In FIG. 24, the node B is determined to be the root node. This is because the node B, which has received the parent-child relationship declaration from the node A, makes the parent-child relationship declaration to other nodes at an early timing. If so, the root node may have moved to another node. That is, any node may become a root node depending on the transmission timing, and the root node is not always constant even in the same network configuration.

When the root node is determined, the process enters a mode for determining each node ID. Here, all nodes notify their determined node IDs to all other nodes (broadcast function).

The self ID information includes its own node number, information on the connected position, the number of ports it has, the number of connected ports, information on the parent-child relationship of each port, and the like.

As a procedure for assigning node ID numbers, first, nodes can be started from a node (leaf) connected to only one port, and node numbers = 0, 1, 2, and so on are sequentially assigned from among these nodes. .

The node that has obtained the node ID transmits information including the node number to each node by broadcasting. As a result, it is recognized that the ID number is “assigned”.

When all the leaves have acquired their own node IDs, the next step is to move to a branch, and the node ID number following the leaf is assigned to each node. Similarly to the leaf, the node ID information is broadcast sequentially from the branch to which the node ID number is assigned, and finally, the root node broadcasts its own ID information. That is, the root always owns the maximum node ID number.

As described above, the assignment of the node IDs of the entire hierarchical structure is completed, the network configuration is reconstructed, and the bus initialization operation is completed.

<Arbitration> In the 1394 serial bus, arbitration (arbitration) of the right to use the bus is always performed prior to data transfer.

Since the 1394 serial bus is a logical bus network, each of the individually connected devices relays the transferred signal to transmit the same signal to all the devices in the network. Arbitration is necessary to prevent packet collisions. This allows only one node to transfer at a given time.

As a diagram for explaining arbitration, FIG. 25A shows a diagram of a bus use request, and FIG. 25B shows a diagram of a bus use permission, which will be described below.

When arbitration starts, one or more nodes issue a bus use request to the parent node. Nodes C and F in FIG. 25A are nodes that have issued a bus use right request. The parent node (node A in FIG. 25) that has received this further issues (relays) a request for the right to use the bus toward the parent node. This request is finally delivered to the arbitration route.

The root node receiving the bus use request determines which node uses the bus. This arbitration work can be performed only by the root node, and the node that has won the arbitration is given permission to use the bus. FIG.
In (b), use permission is given to the node C, and use of the node F is rejected. A DP (data prefix) packet is sent to the node that lost the arbitration to notify that the node has been rejected. The rejected node use request waits until the next arbitration.

As described above, the node that has won the arbitration and obtained the bus use permission can start transferring data thereafter.

Here, a series of arbitration flows will be described with reference to a flowchart shown in FIG.

In order for a node to be able to start data transfer,
The bus must be idle. In order to recognize that the data transfer that has been performed earlier is completed and that the bus is currently idle, a predetermined idle time gap length (eg, sub-action. Each node determines that its own transfer can be started by passing the gap.

In step S401, it is determined whether a predetermined gap length corresponding to each data to be transferred, such as Async data and Iso data, has been obtained. Unless the predetermined gap length is obtained, the request for the right to use the bus required to start the transfer cannot be made, so the process waits until the predetermined gap length is obtained.

If a predetermined gap length is obtained in step S401, it is determined in step S402 whether there is data to be transferred. If so, a request for a bus use right is issued in step S403 to secure a bus for transfer. Emit to the route. At this time, the transmission of the signal indicating the request for the right to use the bus is finally delivered to the route while relaying each device in the network, as shown in FIG. If there is no data to be transferred in step S402,
Wait as it is.

Next, when one or more bus use requests of step S403 are received by the route at step S404, the route checks the number of nodes that have issued use requests at step S405. If the selection value in step S405 is the number of nodes = 1 (the number of nodes that issued the use right request is one), the immediately subsequent bus use permission is given to that node. The selection value in step S405 is the number of nodes> 1
If (the number of nodes requesting the use is plural), the root performs an arbitration operation of deciding one node to which use permission is given in step S406. This arbitration work is fair, and the same node does not always obtain permission each time, and the right is equally given.

Step S407 is replaced with step S40
At step 6, the node arbitrates the route from among the plurality of nodes that have issued the use request and selects one node whose use has been granted and another node that has lost. Here, for one node that has been arbitrated and has obtained use permission, or a node that has obtained use permission without arbitration with the number of use request nodes = 1 from the selection value in step S405, the route is set to that node as step S408. A permission signal is sent to it. The node that has received the permission signal starts transferring data (packets) to be transferred immediately after receiving the permission signal. Further, the nodes that have been defeated in the arbitration in step S406 and have not been permitted to use the bus are given step S406.
At step 409, a DP (data prefix) packet indicating an arbitration failure is sent from the root, and the node that has received the packet returns to step S401 to issue a bus use request for performing transfer again, until the predetermined gap length is obtained. stand by.

The above is the description of the flowchart in FIG. 26 for explaining the flow of arbitration.

<< Asynchronous Transfer >> The asynchronous transfer is an asynchronous transfer. FIG. 27 shows a temporal transition state in the asynchronous transfer. The first sub-action gap in FIG. 27 indicates the idle state of the bus. When the idle time reaches a certain value, the node desiring transfer determines that the bus can be used and executes arbitration for acquiring the bus.

When the use of the bus is obtained by arbitration, data transfer is executed in packet format.
After the data transfer, the receiving node sets ack (reception confirmation return code) of the reception result for the transferred data to a.
After a short gap of ck gap, the transfer is completed by returning and responding or sending a response packet. The ack is composed of 4-bit information and a 4-bit checksum, and includes information such as success, busy status, and pending status, and is immediately returned to the source node.

Next, FIG. 28 shows an example of the packet format of the asynchronous transfer.

The packet has a header part in addition to the data part and the data CRC for error correction, and the header part has the destination node ID, the source node ID, the transfer data length and the like as shown in FIG. Various codes and the like are written and transferred.

Asynchronous transfer is one-to-one communication from a self-node to a partner node. The packet transferred from the transfer source node is distributed to each node in the network, but the address other than the address for itself is ignored, so that only one destination node reads the packet.

The above is the description of the asynchronous transfer.

<< Isochronous (Synchronous) Transfer >> Isochronous transfer is synchronous transfer. This isochronous transfer, which can be said to be the greatest feature of the 1394 serial bus,
In particular, this transfer mode is suitable for transferring data that requires real-time transfer, such as multimedia data such as VIDEO video data and audio data.

In addition, when the asynchronous transfer (asynchronous) is 1
Unlike the one-to-one transfer, the isochronous transfer is uniformly transferred from one transfer source node to all other nodes by the broadcast function.

FIG. 29 is a diagram showing a temporal transition state in isochronous transfer.

The isochronous transfer is executed on the bus at regular intervals. This time interval is called an isochronous cycle. The isochronous cycle time is 125 μS. A cycle start packet indicates the start time of each cycle, and plays a role of adjusting the time of each node. A node called a cycle master transmits a cycle start packet, and after a transfer in a previous cycle is completed, a predetermined idle period (subaction gap) is passed, and then the start of this cycle is announced. Send a cycle start packet. The time interval at which this cycle start packet is transmitted is 125 μS.

FIG. 29 shows channel A, channel B,
As indicated by the channel C, a plurality of types of packets can be separately transferred by being given channel IDs in one cycle. This allows real-time transfer between a plurality of nodes at the same time, and the receiving node fetches only the data of the channel ID desired by itself. The channel ID does not represent the address of the transmission destination, but merely gives a logical number for the data. Therefore, the transmission of a certain packet is 1
From one source node to all other nodes,
It will be transferred by broadcast.

Prior to the packet transmission in the isochronous transfer, arbitration is performed as in the asynchronous transfer. However, since the communication is not one-to-one communication as in the asynchronous transfer, there is no ack (reception confirmation reply code) in the isochronous transfer.

The iso gap (isochronous gap) shown in FIG. 29 indicates an idle period necessary for recognizing that the bus is empty before performing the isochronous transfer. After the predetermined idle period has elapsed, a node that wishes to perform isochronous transfer determines that the bus is free, and can perform arbitration before transfer.

Next, an example of the packet format of the isochronous transfer will be described with reference to FIG.

Each packet divided into each channel has a header portion in addition to a data portion and data CRC for error correction, and the header portion has a transfer data length and a channel length as shown in FIG. NO and other various codes and a header CRC for error correction are written and transferred.

The above is the description of the isochronous transfer.

<< Bus Cycle >> In actual transfer on the 1394 serial bus, isochronous transfer and asynchronous transfer can coexist. FIG. 31 shows a state of a temporal transition of the transfer state on the bus in which the isochronous transfer and the asynchronous transfer are mixed at that time.

The isochronous transfer is executed prior to the asynchronous transfer. The reason is that after the cycle start packet, the isochronous transfer can be started with a gap length (isochronous gap) shorter than the gap length (subaction gap) of the idle period required to start the asynchronous transfer. . Therefore, the isochronous transfer is executed with priority over the asynchronous transfer.

In the general bus cycle shown in FIG. 31, at the start of cycle #m, a cycle start packet is transferred from the cycle master to each node. As a result, each node adjusts the time, and after waiting for a predetermined idle period (isochronous gap), the node that should perform isochronous transfer performs arbitration and starts packet transfer. In FIG. 31, the channel e, the channel s, and the channel k are sequentially and isochronously transferred.

After the operations from the arbitration to the packet transfer are repeatedly performed for the given channel, when all the isochronous transfers in the cycle #m are completed, the asynchronous transfer can be performed.

When the idle time reaches the sub-action gap in which asynchronous transfer is possible, it is determined that the node wishing to perform asynchronous transfer can shift to execution of arbitration.

However, during the period in which the asynchronous transfer can be performed, a subaction gap for starting the asynchronous transfer is obtained from the end of the isochronous transfer to the time (cycle synch) at which the next cycle start packet should be transferred. Only if you have.

In cycle #m of FIG. 31, two packets (packet 1 and packet 2) of isochronous transfer for three channels and then asynchronous transfer (including ack) are transferred. After this asynchronous packet 2, the time to start cycle m + 1 (cycle syn.
ch), the transfer in cycle #m ends here.

However, the time (cyc) for transmitting the next cycle start packet during asynchronous or synchronous transfer operation
If le synch) is reached, the cycle start packet of the next cycle is transmitted after waiting for an idle period after the transfer is completed, without forcibly interrupting the transfer. That is, when one cycle continues for 125 μS or more, it is assumed that the next cycle is shortened by that much from the reference 125 μS. Thus, the isochronous cycle is 125 μS
Can be exceeded or shortened based on the standard.

However, the isochronous transfer is always executed if necessary every cycle to maintain the real-time transfer, and the asynchronous transfer may be transferred to the next and subsequent cycles due to the shortened cycle time.

The cycle time including such delay information is
Controlled by the master.

The above is the description of the IEEE 1394 serial bus.

<Structure of Print System> Next, the present print system will be described focusing on the digital copier controller. FIG. 1 shows the print system. The network 100 is a network to which a personal computer and a printer are connected,
A commonly used device such as Ethernet may be used. The image network 101 is a network provided for image transfer. In the present embodiment, an IEEE 1394 bus is used to configure the image work 101. The image data controller 102 controls input and output of image data via the network 100 and the image network 101. A color copier 103, printers 104 and 105, and a black and white digital copier 106 are connected to the image network 101. The network 100 includes personal computers 107, 108, 109, 11
0, 111 and 112 are connected. When printing out from a PC, the network 10
0, data is transmitted to a desired printer or copier via the image data controller 102 and the image network 101.

<Image Data Controller> Next, the image data controller 102 will be described. FIG. 3 shows a block diagram of the image data controller 102. CPU
Reference numeral 301 controls the entire image data controller, and controls data transfer to and from a PC or printer on a network. The bus 302 includes a card bus controller 304, a ROM 3
05, RAM 306, hard disk controller 30
7 are connected. The card bus controller 304
A card bus 303 for mounting a function board for adding a function to the image data controller 102 is controlled.
The ROM 305 is a program memory in which a control program for the image data controller is stored. A part of the program area is constituted by a flash ROM, and the program memory can be rewritten from a facsimile data modem 311 or an interface terminal (not shown) via a telephone line. RAM 306 is a DRA
It is composed of M or SRAM, and can be used as a work area for a normal program or as an image data memory. The hard disk controller 307 controls reading and writing of the hard disk 312. The hard disk 312 is for storing image data,
Used for storing program software. The hard disk controller 307 can compress data when storing image data, and can also expand data when reading image data.

Next, each functional board connected to the card bus 303 will be described. The network interface card 308 controls an interface with the network 100 to which the PC and the image data controller 102 in FIG. 1 are connected. If a card that supports a physical interface that constructs a network, such as Ethernet or token ring, is used, any interface can be used. The image network interface card 309 controls an interface for transferring image data between the color copier 103, the printers 104 and 105, the black and white digital copier 106, and the image data controller 102 in FIG. The image network needs to be configured with a high-speed bus capable of transferring a large amount of image data. Therefore, in the present embodiment, IEEE1394, which is a high-performance serial bus that has been receiving attention in recent years, is used. However, it is not necessarily limited to this.

The raster image development card 310 develops a printer description language into bitmap data. It is not used when the printer on the image network 101 individually supports the page description language. However, when the image data controller 102 develops the printer description language into bitmap data and transmits the bitmap data to the printer, a so-called dumb printer which simply prints bitmap data on the image network 101 is connected. Even if
The PC on the network 100 side is the image network 10
All of the printers on page 1 can be used as page description language compatible printers. Further, it is possible to cope with the support of many page description languages by replacing the card bus with a function board. Further, the program memory area of the raster image development card 310 is configured to be loadable like a flash ROM or a RAM, and a raster image development program for a plurality of page description languages is stored in the hard disk 312 in advance. Thus, even if the page description language desired by the user is loaded from the hard disk 312 into the program memory of the raster image development card 310, it is possible to support the desired page description language. FAX / data modem card 31
1 is connected to a telephone line to send and receive faxes,
Connection to a remote PC or workstation as a data modem is possible.

<Operation of Image Data Controller> Next, the operation of the image data controller 102 and the network 1
00, the flow of data on the image network 101 will be described. (1) When page description language (PDL) data is sent from a PC on a network and printout is performed, the printer 105 is selected from the PC 107 in FIG.
It is assumed that data transmission and printing (PDL printing) are designated. In that case, the PDL data is
The image data is input from the PC 107 to the image data controller 102 via the network 100. In the image data controller 102, the PDL data is input to the raster image development card 310 via the network interface card 308.

FIG. 7 is a block diagram of the network interface card 308. In FIG. 7, Ethernet is taken as an example. The interface card 308 includes a card bus interface 701, an Ethernet protocol controller 702, and a data transmission / reception buffer 70.
An Ethernet transceiver 704 including an interface portion with a medium to be connected to a network, such as 3, 10base2, or 10baseT, and a connector 705 corresponding to a network medium are included.

CPU 3 of image data controller 102
When the data 01 is determined to be PDL data via the network interface card 308, the data is transferred to the raster image development card.

FIG. 6 shows a raster image development card 310.
It is a block diagram of. Raster image expansion card 310
Are a card bus interface 601, a raster image processor 602 for developing PDL data to generate bitmap data, a ROM 603 as a program area for the raster image processor, a bitmap memory 604 for storing bitmap data, A bitmap memory controller 605 for controlling reading and writing of the memory is included. The PDL data input to the raster image development card is sent to the raster image processor 602 via the card bus interface 601. The bitmap data generated by the raster image processor 602 is stored in the bitmap memory 604 via the bitmap memory controller 605.

The bitmap data stored in the bitmap memory 604 is sent to the image network interface card 309.

FIG. 8 is a block diagram of the image network interface card 309. The image network interface card 309 includes a card bus interface 801, a fast-in fast-out memory (hereinafter, FIFO) 802 for transmitting image data, and an IEEE 13
94 link controller chip 803, IEEE139
4 includes a physical interface 804 and a connector 805 to which an image network interface cable is connected.
The connector 805 can connect up to three to one physical interface. The CPU 301 of the image data controller 102 transmits the bitmap data to the printer 105 specified by the PC 107.
Data transmission is performed through the following procedure via 09.・ Image data controller → Printer: Send data transmission request command ・ Printer → Image data controller: Send data reception confirmation command ・ Image data controller → Printer: Send print data start command ・ Image data controller → Printer: Send bitmap data ・Image data controller → Printer: Send print data end command ・ Printer → Image data controller: Send print data reception confirmation command In the data transfer mode of IEEE1394, data is transferred to the transfer destination, and the receiving side confirms data reception. There are an asynchronous transfer mode in which data is sent to the transfer source, and an isochronous transfer mode in which data is transferred to an unspecified transfer destination and no confirmation is sent from the receiving side. Here, the asynchronous transfer mode is selected for the command, and the isochronous transfer mode is selected for the bitmap data. 8, command data is transmitted to the link chip controller 8 via the card bus interface 801.
03 and transmitted as asynchronous data. On the other hand, the bitmap data is once written to the FIFO 802 via the card bus interface 801. The link chip controller 803 transmits an F signal to transfer bitmap data in the isochronous transfer mode.
The data is read from the IFO 802 and the data is transferred.

<Configuration of Printer> FIG.
It is a block diagram of 4,105. The CPU 901 performs all controls in the printer, such as mechatronic control of the printer and reception of bitmap data. ROM 902 is a CP
A memory in which a program of U901 is stored, a RAM 90
Reference numeral 3 denotes a memory used as a work area of the CPU 901 and the like. A bus 904 connects the CPU 901 and other devices. IEEE 1394 link controller 905
Performs an interface with the image network 101. The IEEE 1394 physical interface 906 is a physical level interface with the image network 101. The printer is connected to the image network 101 by a cable and a connector 907. The FIFO memory 908 temporarily stores the bitmap data transferred by the isochronous transfer.
The video data controller 909 outputs a bitmap data read video signal from the 908 FIFO in accordance with the operation timing of the printer engine. The laser driver 910 emits a laser beam according to a video signal from the video data controller 909. With this laser beam, a toner image is formed on a photosensitive drum provided in the printer engine 912 and transferred to a print medium to form an image. The printer engine 912 is controlled by an engine controller 911 that performs a mechatronic control such as a motor control and a paper feed control of the printer engine.

<Transfer Sequence between Image Data Controller and Printer> Next, the image data controller 102
The command and data transfer between the printer and the printer 105 will be described with reference to FIG. Although the color copier 103 and the printer 104 are interposed between the printer 105 and the image data controller 102 in the network configuration, they are not considered in the sequence because they simply pass signals. # 1001 The data transmission request command is transferred from the image data controller 102 to the desired printer (the printer 105 in this case) in the asynchronous transfer mode. # 1002 The printer receives the data in the asynchronous transfer mode, and confirms it (hereinafter, ACK) by IEEE.
Return to 1394 link controller 905. # 1003 In the printer, the CPU 901 receives a data transmission request command. # 1004 The CPU 901 confirms the current status of the printer and transmits a data transmission request permission command to the image data controller 102 when a printout operation is possible. This command is transmitted in the asynchronous transfer mode by the IEEE 1394 link controller 905. # 1005 The image data controller 102 receives an ACK for the data transmission request permission command data from the 804 IEEE 1394 link controller in FIG. # 1006 In the image data controller 102, the CPU 901 receives a data transmission request permission command. # 1007 Image data is transmitted from the image data controller 102 to the printer 105 in the isochronous transfer mode (this data transfer will be described later). # 1008 The image data controller 102 transmits a print data end command to the printer 105 after the image data transfer ends. # 1009 The printer 105 returns an ACK of the print data end command to the IEEE 1394 link controller 803. # 1010 The printer 105 receives the print data end command by the 901 CPU. # 1011 A print data reception confirmation command is sent from the printer 105 to the image data controller 102. # 1012 The image data controller returns an ACK of the print data reception confirmation command from the IEEE 1394 link controller 804. # 1013 In the image data controller, the CPU 301 receives a print data reception confirmation command.

As described above, commands are exchanged in the asynchronous transfer mode, and image data is transmitted from the image data controller 102 to the printer 105 in the isochronous transfer mode.

Next, how the image data transmission in the isochronous transfer mode is performed will be described.

<Transmission Procedure of Image Data> In data transfer in the isochronous transfer mode, packet transfer is performed every 125 μS. At this time, a time guarantee of data transfer is obtained by securing a channel in advance. Therefore, the image data controller 102 needs to confirm the printing speed of the printer to which the image data is to be transmitted in advance and secure a channel corresponding to the printing speed. The operation of the image data controller 102 will be described with reference to the flowchart of FIG. # 1101 The image data controller 102 checks the printer performance of the printer 105. Here, the time (1H time) of one scanning line cycle (1H) in the laser beam printer 105 and the number of pixels within 1H are confirmed. This period can be obtained from the period of a BD signal obtained by detecting a laser beam at a predetermined position on a scanning line in a laser beam printer. That is, the 1H time is a time for scanning one line, and the number of pixels in 1H is the number of pixels in one scanning line. # 1102 Next, the required channel width is calculated based on the confirmed printer performance. For example, 1H time = 375μ
S, 1H pixel count = 7200 pixels, 125 μS
7200 × (125/375) = 2 for each packet at intervals
It is necessary to temporally guarantee data transfer for 400 pixels. When the printer 105 is a binary printer, it can be seen that it is sufficient to secure a data transfer channel for 2400 bits per packet. # 1103 The image data controller 102 uses the IE
A necessary transfer channel is secured via the EE1394 link controller 803. # 1104 When a channel necessary for the printer is secured, the image data controller 102 converts the image data into
Transmission data generation is performed such that the start and end headers of the image data for one page are added and the start and end headers of the image data for 1H are added. Here, what kind of transmission data is generated is shown in FIG.
2 will be described.

A channel is formed in which one packet is formed every 125 usec, and a portion 121 in the packet is secured. The inside of the channel 121 is composed of header + image data. The header includes a code of page start, between pages, page end, 1H start, within 1H period, and 1H end. On the printer side receiving the transmitted image data, the image data in the channel is included in the entire image data. This is to make it possible to recognize the position. For example, 2 out of 7200 pixels having 1H pixels
When data of 400 pixels is transferred for each channel of one packet, three packets and three channels are equivalent to 1H7.
Data transmission of 200 pixels is performed. At this time, the generated image data is as shown in the figure.

When transmitting image data for n lines (n is a positive number), 3n channel data is transferred. In the header, the first packet is composed of page start (A0h), 1H start (A8h) + image data, the second packet is composed of page interval (A2h), 1H period (AAh) + image data, The three packets are composed of between pages (A2h), 1H end (ADh) + image data. Hereinafter, similarly, a header is added to the image data and the data is transmitted. The third packet is composed of the end of page (A5h), the end of 1H (ADh) + image data, and the transfer of image data for one page ends.

Now, return to the flowchart of FIG. # 1105 The transmission data generated by the image data controller 102 is transferred to the FIFO 802 in FIG. The size of the FIFO 802 must be at least as large as the data size to be transferred in one packet. # 1106 After the transmission data is stored in the FIFO 802, the data transmission is performed to the IEEE 1394 link controller 803. # 1107 As shown in FIG. 12, transmission data is created while performing a header attachment operation on image data, and data transmission is repeatedly performed. The transmission of print data is completed when the transmission of data for one page is completed. When sending multiple pages,
Repeat transmission for the number of pages to be transmitted.

<Print Output Procedure> Next, the timing at which print output is performed after the printer receives transmission data will be described with reference to the timing chart of FIG.

FIG. 13A shows a packet cycle. The hatched portion therein is the image data in the isochronous transfer mode.

FIG. 13B shows the timing of writing data to the FIFO 908. Each time one packet is received, transmission data is written from the IEEE 1394 link controller 905 to the FIFO 908. At this time, the header part is removed and the FI
The FO 908 has sufficient capacity to store one line of image data.

FIG. 13C shows the BD timing of the printer. In this example, the timing is such that a BD signal is generated once for every three packets.

FIG. 13D shows the read timing of the FIFO 908. Data for 3 packets is FI
After being written into the FO 908, the FIFO 908 is read out in synchronization with the next BD.

FIG. 13 (e) shows a state during the printing operation. The image data read from the FIFO 908 is converted into a video signal by the video data controller 909, and the laser driver 910 modulates the laser signal according to the r video signal. Oscillate to form and print an image.

At the above timing, the image data is transmitted from the image data controller 102 to the printer 105 in the image network 101.

<Printing Procedure by Plurality of Printers> Next, a page description language (hereinafter referred to as P
DL) data is sent and printout is performed from a plurality of printers.

When printing a plurality of copies in a short time,
The same print data can be transferred to a plurality of printers to print a plurality of copies (hereinafter referred to as tandem printing). This will be described with reference to the flowchart of FIG. FIG. 4 shows a tandem printing procedure performed by the entire system of FIG. In # 401, "tandem print" is selected from the output printer name in the PC application.
FIG. 5 is an example of a screen displayed to the operator to select a printer on the PC. When the operator selects tandem print from the printer name column 501, tandem print processing is started. The printer used for tandem printing may be specified by the operator, or may be appropriately specified by the PC or the image data controller 102. In # 402, the image data controller 102 checks whether a desired printer is connected to the image network 101. In # 403, the image data controller 102 informs a desired printer that tandem printing is to be performed. # 404 Transmit the PDL data created by the PC application program or the like to the raster image development card 301 of the image data controller 102 from the PC. # 405 The raster image development card 301 of the image data controller 102 develops PDL data into bitmap data. # 406 The image data controller 102 transfers the developed bitmap data to a desired printer. # 407 Each printer that has received the bitmap data prints out.

<Data Transmission Sequence During Tandem Printing> Next, a method of transferring commands and data between the image data controller 102 and a printer performing tandem printing will be described with reference to FIG. In this example, the printers 104 and 105 are used. # 1401 The tandem print request command is transferred from the image data controller 102 to the printer 104 on the image network 101 in the asynchronous transfer mode. With this command, the image data controller grasps the performance of the printer for performing tandem printing. # 1402 The ACK of the asynchronous transfer is returned to the image data controller. # 1403 The printer 104 transfers a tandem print permission command to return the printer performance required for performing tandem printing. # 1404 ACK of asynchronous transfer is returned to the image data controller 102. # 1405 The image data controller 102 also transmits a tandem print request command to the printer 105. # 1406 ACK of asynchronous transfer is returned to the image data controller. # 1407 A tandem print permission command is sent from the printer 105 to the image data controller 102. # 1408 An ACK for asynchronous transfer is returned from the image data controller 102 to the printer 105. # 1409 The image data controller 102 notifies the printer 104 of the channel number of the isochronous transfer data to be received. # 1410 ACK is returned to the image controller. # 1411 The image data controller 102 also transfers the isochronous channel number to the printer 105. # 1412 ACK is returned to the image controller. # 1413 The image data controller 102 transfers image data to the printers 104 and 105 using the isochronous transfer mode. In this case, since the broadcast transfer is performed, the printers 1 and 2 can receive the data in one transfer. The image data transfer is repeatedly performed in this manner. # 1414 The image data controller transmits the tandem print end to the printer 104. # 1415 ACK of asynchronous transfer is returned to the image data controller 102. # 1416 Similarly, a tandem print end command is transferred to the printer 105. # 1417 ACK of asynchronous transfer is returned to the image controller 102.

As described above, when a plurality of copies are to be printed, data can be simultaneously transferred to a plurality of printers by isochronous transfer broadcasting. In the network system of the present embodiment, since the network on which image data for printing is loaded is limited to the image network 102, no image data is loaded on the network 101 connecting the PCs, and network traffic for printing is reduced. It can be prevented from being raised.

Further, the image data controller is a gateway between the image network and a normal network,
In order to convert the PDL data into bitmap data in a lump, only the PDL data which is encoded data is present in the network 101 connecting the PCs even during printing. It will not be crowded.

Further, regardless of whether the printer used is a dumb printer or an intelligent printer capable of interpreting PDL, the PC as the user only needs to transmit the print data in PDL data, and the processing in the PC is simple. Become.

Also, when performing tandem printing, the printer used by the image data controller is managed and the image data is transmitted to the printer as appropriate. Therefore, it is necessary for the user PC to manage the printer individually. There is no need to send print data to each printer. Therefore, control on the PC side is simplified, and the amount of data loaded on the network can be reduced.

<Variation of Procedure for Ascertaining Node Attribute> In the above description, the performance of each printer is checked by the image controller 102 before the print data is transmitted. However, the configuration may be such that the performance of the printer is grasped in advance.

In IEEE 1394, after the power is turned on by the link controller, a topology map is created, and all nodes connected on the network are recognized. At this time, node numbers are assigned to all nodes according to the physical connection state and initial settings, and one root node (parent) is selected from the nodes.

When a topology map is created in the image data network, it is necessary to initialize the image data controller so that it is always selected as the root node. As a result, the subsequent image data network management can be smoothly performed. The image network initialization control of the image data controller will be described with reference to the flowchart of FIG. # 1501 All IEs connected on the image data network due to the occurrence of the IEEE 1394 bus reset
The EE1394 physical interface detects a bus reset and performs a reset release sequence. # 1502 Each node on the image network performs a predetermined control on a port connected after a predetermined wait time, and waits for node number allocation to create a topology map. # 1503, # 1504 If it is determined that the IEEE 1394 node of the image data controller 102 is not the root node, the wait time is increased by a predetermined value and reset, and the bus reset sequence is performed again in step # 1501. To recreate the topology map. Generally, a wait time that is sufficiently longer than the wait time at the time of bus reset of a printer, a color copier, a black-and-white digital copier, a scanner, or the like that is recognized in advance by the image controller 102 is given to the IEEE1394 link controller of the image data controller. Must be set. The determination as to whether or not the node is the root node in step # 1503 must be repeated by increasing the wait time to some extent until the image controller becomes the root for the subsequent image data network management. This is because the parent-child relationship between the nodes is determined by declaring the child nodes to other connected nodes in IEEE1394. Eventually, the node that is declared as a child from all connected nodes will be the root node, so if you set a long wait time before declaring it as a child, the node will become the root node become. # 1505 If the image data controller 102 is selected as the root node, the image network 101
Ask the above nodes for their attribute information. # 1506 Then, a node attribute table is created from the attribute information returned from each node. This table is
Whether the node can exchange image data from the image controller 102, and if data transmission is exchangeable, the performance of the device is registered. If the node is a printer, the presence of page memory, resolution,
The 1H time, the number of 1H pixels, the number of prints, and the like are registered. # 1507 Inquire attribute information of each node to all nodes.

Thus, the image data controller 1
02 when creating the topology map, the image network 1
By grasping the attributes of all the devices on 01, overhead for grasping the performance of each node at the time of data transfer is reduced.

<Tandem printing by printers with different transfer speeds> Next, the IEs in the items of the node attribute table
Regarding the transfer speed of EE1394, data transfer when the transfer speeds of a plurality of transfer destination printers are different during tandem printing will be described.

FIG. 32 is an example of the attribute table created in step # 1506 of the flowchart in FIG. The left column shows the item names, and the right column shows the contents. In FIG. 15, the node number is a number assigned to each node when the topology map is created. Transfer speed is IEEE1
400Mbps, 200Mbps, 100Mbps at transfer rates supported by 394 physical interfaces
There is s. The power supply capability of the node is IEEE 139
4 indicates whether power can be supplied via the cable. Also shown here is receiving power supply. The device name indicates how the node transmits / receives image data to / from the image controller or whether the node does not transmit / receive image data at all. If the device is a scanner, it is an image data transmission device, and it is black and white / color, or the number of bits per pixel (bits / pixel) and resolution (dp
Information such as i) is managed in a table. If the device is a printer, it is an image data receiving device,
Black / white / color, print output speed (ppm), bit /
There is information called pixel, dpi. Since the digital copier has both functions of a scanner and a printer, information is managed as an image data transmitting / receiving device.

FIG. 33 shows the image network 101 of FIG.
An attribute table of the upper color copying machine 103, printers 104 and 105, and monochrome digital copying machine 106 is shown. The transfer rates of the printer 104 and the printer 105 are 200 Mbps and 100 Mbps, respectively, which are different from each other.

Here, tandem printing is selected by the image data controller 102 and the printers 104 and 1 are selected.
The case where the image data is transmitted at 05 will be described with reference to the flowchart of FIG. # 3401 The image data controller 102 selects a plurality of printers (printers 104 and 105) on the image network when tandem printing is selected. # 3402 The image data controller checks the information of the attribute table of the selected printer 104 or 105. # 3403 From the attribute table information, the printer 104
Is 200 Mbps, and the transfer speed of the printer 105 is 100 Mbps.
Go to 04. # 3404 The image data controller 102 selects 100 Mbps, which is the transfer speed of the printer 105, and determines to perform image data transfer. # 3405 Next, the image data controller 102 notifies the two printers in the asynchronous transfer mode that image data transfer in the isochronous transfer mode is performed at a transfer speed of 100 Mbps. # 3406 Perform tandem print data transfer according to the data transfer flow of FIG.

If the transfer rates are the same in step # 3403, the flow advances to step # 3406.

As described above, the transfer speed is determined during tandem printing based on the attribute table created in advance by the image data controller.

As described above, the data transfer speed corresponding to the printer to be used is grasped, and the image data is transferred by using the minimum value, so that the tandem printing can be performed even if a printer having a different data transfer speed is used. It can be performed. [Second Embodiment] In the first embodiment, when performing tandem printing using a plurality of printers, when the transfer speed of the printer to be used is different, the configuration and procedure for performing printing in accordance with the slower one. In the present embodiment, a case will be described in which it is necessary to secure channels individually for a plurality of printers and transfer data.

FIG. 35 is a flowchart of a control procedure by the image data controller 102 in a case where channels are individually secured to a plurality of printers and data is transferred.・
# 3501 When tandem printing is selected, the image data controller 102 selects a plurality of printers on the image network. # 3502 The image data controller 102 selects the printers 104 and 105 for tandem printing,
Check the information in those attribute tables. # 3503 200 Mbps for printer 104 and 100 Mbps for printer 105 based on the transfer speed of attribute table information
bps, the process proceeds to step # 3504. # 3504 The image data controller 102 secures an isochronous transfer mode channel for each of the two printers 105 and 104. # 3505 Next, the image data controller transmits the channel numbers of the isochronous transfer data secured to the two printers in the asynchronous transfer mode. # 3506 Transfer image data to each printer in the isochronous transfer mode using a channel with a predetermined channel number.

If it is determined in step # 3503 that the transfer speed is tandem printing using the same printer, the flow advances to step # 3506.

As described above, tandem printing can be realized by securing an isochronous data channel for each printer having a different transfer speed by the image data controller. [Third Embodiment] In the first and second embodiments, the case where tandem printing is performed in printers having different transfer speeds has been described. The increase is inevitable. That is, in the first embodiment, in order to share the transfer speed between the two printers, the bandwidth that should be used by the printer corresponding to the high transfer speed is narrowed. In the embodiment, a different channel is used for each printer. Therefore, tandem printing by printers having different transfer speeds may be prohibited. That is, among printers connected on the image network managed by the image data controller, tandem printing is prohibited when there are no at least two printers having the same transfer speed.

In this case, since the data transfer speed corresponding to the printer is grasped by the image data controller 102, whether to prohibit the tandem printing is not determined by the PC requesting the printing, and the tandem printing is not determined. The image data controller that has received the request makes the determination, and if prohibited, responds to the requesting PC. For this purpose, in step # 3403 of FIG. 34 or step # 3503 of FIG. 35, if the determination result is "no", a response is sent to the PC that issued the print request indicating that tandem printing cannot be performed.

By doing so, the image network 101
Traffic can be prevented from increasing.

Further, instead of prohibiting tandem printing, tandem printing may be permitted according to the procedure of the first or second embodiment according to the priority of data transfer. For example, the priority of data transfer may be determined based on the print priority given by the print requesting PC, or may be assigned in advance according to the type of device such as a printer or a copying machine. The priority of the data transfer currently being performed between the image data controller 102 and each node is compared with the priority of the data transfer for tandem printing which is to be performed from now on. For example, tandem printing may be prohibited.

[0174]

[Other Embodiments] Even if the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus (for example, a copying machine) Machine, facsimile machine, etc.).

Further, an object of the present invention is to provide a storage medium storing a program code of software for realizing the functions of the above-described embodiments to a system or apparatus, and to provide a computer (or CPU) of the system or apparatus.
Or MPU) reads and executes the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) Performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instruction of the program code, The case where the CPU of the function expansion board or the function expansion unit performs part or all of the actual processing, and the function of the above-described embodiment is realized by the processing.

[0180]

As described above, according to the present invention,
When a large amount of image data is simultaneously transferred to a plurality of locations in the IEEE 1394 isochronous transfer mode, if a transfer speed of a transfer destination is different, a slow transfer speed is selected to enable simultaneous data transfer. If a sufficient channel can be secured, tandem printing can be realized by securing a channel for each transfer speed.

Further, since the network on which image data for printing is loaded can be locally limited, no image data is loaded on the entire network, and an increase in network traffic for printing can be prevented.

Further, a gateway is arranged between the first network and the normal second network, and in order to convert the PDL data into the image data there, a network other than the P image network includes:
Only PDL data that is sufficiently smaller than the image data flows, and an increase in traffic for the entire network can be prevented.

Further, regardless of whether the printer to be used is a dumb printer or a printer that can interpret PDL, the user only has to create print data using PDL data.

Also, when printing is performed using a plurality of printers, the gateway device transmits the image data to the printers as appropriate, so that the user does not need to manage the printers individually. No need to send to printer. Therefore, the printing procedure on the user side is simplified, and the amount of data loaded on the network can be reduced.

Further, when printing is performed using a plurality of printers, image data is broadcast to a printer to be used, so that printing using a plurality of printers can be performed without increasing network traffic. it can.

Further, when printing is performed using a plurality of printers, the corresponding data transfer speed of the printer to be used is ascertained, and the image data is transferred using the lowest value. Printers with different speeds can be used.

Further, when printing is performed using a plurality of printers, the data transfer speed corresponding to the printer to be used is ascertained. If the data transfer speeds are different, image data is transferred to each printer through a separate channel. By doing so, it is possible to use printers having different data transfer speeds.

[0188]

[Brief description of the drawings]

FIG. 1 is a diagram of a network system according to the present invention.

FIG. 2 is a diagram showing a conventional network.

FIG. 3 is a block diagram of an image data controller.

FIG. 4 is a first flowchart of tandem printing.

FIG. 5 is a diagram of a printer designation screen from a PC.

FIG. 6 is a block diagram of a raster image development card.

FIG. 7 is a block diagram of a network interface card.

FIG. 8 is a block diagram of an image network interface card.

FIG. 9 is a block diagram of a printer.

FIG. 10 is a data transfer flowchart of commands and image data between an image data controller and a printer.

FIG. 11 is a flowchart of the image data controller when transferring image data.

FIG. 12 is a diagram showing a configuration of transfer data.

FIG. 13 is an operation timing chart on the printer side.

FIG. 14 is a flowchart of command and image data transfer between the image data controller and the printer during tandem printing.

FIG. 15 shows an IEEE1394 image data controller.
It is a flowchart of a bus initialization.

FIG. 16 is a diagram illustrating an example of a network configuration connected using a 1394 serial bus.

FIG. 17 is a diagram illustrating components of a 1394 serial bus.

FIG. 18 is a diagram showing an address map of a 1394 serial bus.

FIG. 19 is a sectional view of a 1394 serial bus cable.

FIG. 20 is a diagram for describing a DS-Link coding scheme.

FIG. 21 is a flowchart showing a flow from a bus reset to a determination of a node ID.

FIG. 22 is a flowchart showing a flow of determining a parent-child relationship in a bus reset.

FIG. 23: after the parent-child relationship is determined in the bus reset,
It is a flowchart which shows the flow until a node ID is determined.

FIG. 24 is a diagram for explaining a topology setting for determining an ID of each node on a 1394 serial bus.

FIG. 25 is a diagram for explaining arbitration on a 1394 serial bus.

FIG. 26 is a flowchart for explaining arbitration.

FIG. 27 is a basic configuration diagram illustrating temporal state transition of asynchronous transfer.

FIG. 28 is a diagram illustrating an example of the format of an asynchronous transfer packet.

FIG. 29 is a basic configuration diagram showing a temporal state transition of isochronous transfer.

FIG. 30 is a diagram illustrating an example of a format of an isochronous transfer packet.

FIG. 31 is a diagram of an example of a bus cycle showing a state of a packet transferred on an actual bus in a 1394 serial bus.

FIG. 32 is a diagram of an attribute table created by the image data controller.

FIG. 33 is a diagram of an attribute table for each node on the image network.

FIG. 34 is a flowchart at the time of data transfer of the image data controller according to the first embodiment.

FIG. 35 is a flowchart at the time of data transfer of the image data controller according to the first embodiment.

Claims (12)

[Claims] 1. A first network connecting at least one printer for receiving and printing image data, and a second network connecting at least one device for generating print data in a predetermined format. A gateway device that connects the network to the first network and the second network, receives the print data in the predetermined format from the second network, converts the print data into image data, and transmits the image data to the first network An image forming system comprising: 2. When output of a plurality of copies is specified for the generated print data, the gateway device selects a plurality of printers from the first network, and sends an image to the selected printer. The image forming system according to claim 1, wherein the data is transmitted. 3. The apparatus according to claim 2, wherein the gateway device transmits the image data to each of the plurality of selected printers at the lowest data transfer speed when all of the corresponding data transfer speeds are not the same. Item 2. The image forming system according to Item 1. 4. The first network is a network that can use a plurality of channels, and the gateway device transmits to each of the plurality of selected printers if the corresponding data transfer rates are not all the same. 2. The image forming system according to claim 1, wherein image data is transmitted to each printer using a different channel. 5. The gateway device according to claim 1, wherein when the corresponding data transfer speeds of the plurality of selected printers are not all the same, output of one print data by a plurality of printers is prohibited. Claim 1
3. The image forming system according to 1. 6. The system according to claim 1, wherein the first network is an IEEE1
The image forming system according to any one of claims 1 to 5, wherein the image forming system is configured by a 394 serial bus. 7. A printing control device connected to a plurality of printers for receiving and printing image data, wherein when printing a plurality of copies, selecting means for selecting a plurality of printers, Of the corresponding data transfer rates of
A printing unit for sending image data to each of the plurality of printers selected at the lowest data transfer speed. 8. A plurality of printers for receiving and printing image data, and a print control device connected via a network capable of using a plurality of channels, wherein a plurality of printers are selected when printing a plurality of copies. And the corresponding data rate of the selected printer,
A print control device comprising: a transmission unit that transmits image data to each of a plurality of printers selected by different channels. 9. A control method in a print control apparatus connected to a plurality of printers for receiving and printing image data, wherein a selection step of selecting a plurality of printers when printing a plurality of copies, Of the corresponding data rates of the
A transmission step of transmitting image data to each of the plurality of printers selected at the lowest data transfer rate. 10. A print control method connected to a plurality of printers for receiving and printing image data through a network capable of using a plurality of channels, wherein a plurality of printers are selected when printing a plurality of copies. For each selected step and the corresponding data rate of the selected printer,
A transmission step of transmitting image data to each of a plurality of printers selected on different channels. 11. A computer-readable storage medium for storing a program to be executed by a computer connected to a plurality of printers for receiving and printing image data, the program comprising: A selection step of selecting a plurality of printers; and a data transfer rate corresponding to the selected printer.
Transmitting the image data to each of the plurality of printers selected at the lowest data transfer rate. 12. A computer-readable storage medium storing a plurality of printers for receiving and printing image data and a program to be executed by a computer connected via a network capable of using a plurality of channels, wherein the program comprises: In the case of printing a plurality of copies, a selection step of selecting a plurality of printers, and a corresponding data transfer speed of the selected printer,
A transmission step of transmitting image data to each of a plurality of printers selected by different channels.