JP2002055785A - Picture forming device and packet selecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printing system capable of improving efficiency as whole printing processing by using a packet size which seems optimal at the time of performing data transfer, and automatically performing optima data transmission and reception. SOLUTION: A transferring speed in a unit time is calculated by monitoring the quantity and transferring time of data to be transferred with a print information supplying device, and the transferring speed is stored so as to be made correspond to a data packet size used at the time of monitoring the transferring time (S505), and at the time of adjusting the packet size to be used for the data transfer with the print information supplying device, the optimal packet size is selected so that the transferring speed can be made the highest by referring to the stored data packet size and the transferring speed corresponding to the packet size (S503, S506).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus connectable to an information supply device via a communication medium and an information transmission method.

[0002]

2. Description of the Related Art In a conventional printing apparatus which can be connected to a higher-level apparatus (information supply apparatus) via a communication medium, when performing packet-type data transfer, the printing apparatus simply uses a packet of a predetermined size. Only transfer could be performed.

[0003]

However, the packet size is determined by the internal processing specifications of the printing apparatus and resources such as the memory of the printing apparatus and cannot be changed dynamically. Since the once determined packet size is not changed in this way, even when the packet size is low in transfer efficiency for the host device, the packet transfer with low data transfer efficiency has to be performed.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has, for example, the following arrangement as one means for solving the above-mentioned problems.

That is, an image forming apparatus which is connected to an information supply apparatus via a communication medium and performs data transfer with the information supply apparatus by a packet communication method, wherein the image formation apparatus is connected to the information supply apparatus via the communication medium. Storage means for monitoring the amount of data transferred and the transfer time communicated therebetween, calculating the transfer rate per unit time, and storing the transfer rate in correspondence with the data packet size used at the time of monitoring And packet size selection means for selecting / changing several types of packet sizes in accordance with a specific procedure when arbitrating a packet size used for data transfer with the information supply device. The means refers to the data packet size stored by the storage means and the transfer rate corresponding to the packet size so that the transfer rate is maximized. And selects the optimal packet size.

[0006] For example, the packet size selecting means executes a packet size selection in response to an instruction from an operation unit mounted on the image forming apparatus. Alternatively, the packet size selecting means executes the number of times of changing the packet size by the number of times specified by an operation unit mounted on the image forming apparatus, and executes an optimal packet size selection.

Also, for example, the packet size selecting means executes a packet size selection in response to an instruction by a specific command from the information supply device. Alternatively, the packet size selecting means executes the number of times of changing the packet size by the number of times specified by the specific command from the information supply device, and executes an optimum packet size selection.

Further, for example, the packet size selecting means adopts a procedure instructed from an operation unit mounted on the image forming apparatus as a procedure for selecting a packet size. Alternatively, the packet size selection means adopts a procedure instructed by a specific command from the information supply device as an execution procedure of the packet size selection.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[First Embodiment] An embodiment of the present invention according to the present invention will be described below in detail with reference to FIG. FIG. 1 is a side sectional view showing the structure of a laser beam printer (hereinafter referred to as “LBP”) which is an image forming apparatus according to an embodiment of the present invention.

The printer to which the present embodiment is applied is not limited to the LBP, and it goes without saying that a printer (printing apparatus) of another printing method may be used.

FIG. 1 shows an LB applied to this embodiment.
This LBP is a cross-sectional view showing the internal structure of P. In this LBP, registration of a character pattern and registration of a fixed format (form data) can be performed from an information supply device (upper device) which is a data source described later.

In FIG. 1, reference numeral 1000 denotes an LBP main body, which inputs and stores character information (character code), form information, macro instructions, and the like supplied from an externally connected higher-level device (such as a host computer). At the same time, a corresponding character pattern, form pattern, or the like is created according to the information, and an image is formed on a recording paper as a recording medium.

A printer control unit 1001 controls the entire LBP 1000 and analyzes character information and the like supplied from the host computer. The printer control unit 1001 mainly converts character information into a video signal of a corresponding character pattern and outputs the video signal to a laser driver 1002. The laser driver 1002 is a semiconductor laser 100
3 for driving the laser light 1004 emitted from the semiconductor laser 1003 in accordance with an input video signal.

A laser 1004 is swung right and left by a rotary polygon mirror 1005 to scan on an electrostatic drum 1006. As a result, an electrostatic latent image of a character pattern is formed on the electrostatic drum 1006. After the latent image is developed by the developing unit 1007 around the electrostatic drum 1006, it is transferred to recording paper as an image forming medium.

A cut sheet is used as the recording paper. The cut sheet recording paper is stored in a paper cassette 1008 mounted on the LBP 1000, is taken into the apparatus by a paper feed roller 1009 and transport rollers 1010 and 1011 and is charged in the apparatus. It is supplied to the drum 1006. Also, 1012
Is an operation unit in which switches for operation, an LED display, and the like are arranged.

FIG. 2 is a block diagram illustrating the configuration of the printing apparatus and the host apparatus according to the present embodiment. In the following description, the laser beam printer shown in FIG. 1 will be described as an example of the image forming apparatus. Note that if the functions of the present embodiment are executed, the processing is performed via a network such as a LAN, regardless of whether the printing apparatus is a single device or a system including a plurality of devices. It goes without saying that the present invention can be applied to a system.

In FIG. 2, reference numeral 3000 denotes a host computer which performs document processing in which graphics, images, characters, tables (including spreadsheets, etc.) are mixed based on a document processing program or the like stored for a program in the ROM 3. C to execute
The CPU 1 has a PU 1 and the CPU 1 comprehensively controls each device connected to the system bus 4. 2 is a RAM, a CPU
1 functions as a main memory, a work area, and the like.

The program ROM of the ROM 3
Stores a control program of the CPU 1 and the like.
The font ROM stores font data and the like used in the document processing, and the data ROM of the ROM 3 stores various data used in the document processing and the like.

5 is a keyboard controller (KBC)
Controls the key input from the keyboard 9 or a pointing device (not shown). 6 is a CRT controller (C
RTC) controls the display on a CRT display (CRT) 10. Reference numeral 7 denotes a memory controller (MC), which accesses an external memory 11 such as a hard disk (HD) for storing a boot program, various applications, font data, user files, and editing files, and a floppy (registered trademark) disk (FD). Control.

Reference numeral 8 denotes a printer controller (PRTC)
A predetermined bidirectional interface (interface)
The communication device 21 is connected to the printer 1000 via the printer 21 and executes communication control processing with the printer 1000.

The CPU 1 executes a process of rasterizing an outline font into the display information RAM set on the RAM 2, for example.
YSIWYG is possible. Further, the CPU 1
Various registered windows are opened based on a command specified by a mouse cursor or the like (not shown) on the RT 10,
Perform various data processing.

In the printer 1000, reference numeral 12 denotes a printer CPU, which controls various devices connected to the system bus 15 based on a control program or the like stored in a program ROM of a ROM 13 or a control program or the like stored in an external memory 14. Control access to
An image signal as output information is output to a printing unit (engine) 17 connected via the printing unit interface 16. A time management unit such as a timer is also provided inside the CPU 12 (or outside not shown).

The program ROM of the ROM 13
May store a control program of the CPU 12 as shown in the above-described flowchart of the embodiment. The font ROM of the ROM 13 stores font data and the like used when generating the output information,
An M13 font ROM stores font data and the like used when generating the output information, and a ROM 13 data ROM stores an external memory 14 such as a hard disk.
In the case of a printer having no printer, information used on the host computer is stored.

The CPU 12 is capable of communicating with the host computer via the input unit 18 and is configured to be able to notify the host computer 3000 of information in the printer and the like. Reference numeral 19 denotes a RAM that functions as a main memory, a work area, and the like of the CPU 12, and is configured so that the memory capacity can be expanded by an optional RAM connected to an additional port (not shown).

The RAM 19 has an output information development area,
Used for environmental data storage area, NVRAM, etc. The access to the external memory 14 such as a hard disk (HD) and an IC card is controlled by a memory controller (MC) 20. The external memory 14 is connected as an option and stores font data, an emulation program, form data, and the like.

Reference numeral 18 denotes the above-described operation panel on which switches for operation, an LED display, and the like are arranged. Further, the number of the external memories described above is not limited to one, and at least one
It may be configured such that a plurality of external memories in which an optional font card and a program for interpreting a printer control language of a different language system are stored in addition to the built-in fonts can be connected. Further, an NVRAM (not shown) may be provided to store the printer mode setting information from the operation panel 1012.

FIG. 3 is a block diagram of the inside of the printing apparatus viewed from the flow of print data in the embodiment.

In FIG. 3, print data transferred from the host device 3000 is stored in the reception buffer 1300 via the input unit 18. Then the reception buffer 13
From 00, it is passed to the analysis unit 1301, and after analysis, is transferred to the development unit 1302. When the developing unit 1302 finishes developing the print data in the developing memory 1303, the transfer unit 1
304 transfers data to the printing unit via the printing unit I / F, and records the data on a recording medium.

The expansion memory 1303 is provided in the RAM 19
May be a part of.

Interface 2 in the present embodiment
1 (FIG. 2) are a parallel interface (Centronics interface) (IEEE1284) and an IEEE12
Since it is assumed that it is composed of 84.4,
An overview of each technology is also described here. << Schematic Description of Parallel Interface >> A parallel interface, also called a Centronics interface, is one of main interfaces for transferring data from a host computer (hereinafter, sometimes referred to as a “host”) to a printer. This is a standard developed by the US company Centronics for sending data from a computer to a printer, and is an interface specification that allows inexpensive and high-speed data transmission. Although widely used as a means for transmitting data from a personal computer (PC) to a printer, it has not been officially standardized.

Although there are many variations that vary from host to printer, they are basically similar. Basic control consists of three signal lines (DATA STROBE, AC
K, BUSY). This transfer method is called a compatibility mode with respect to a nibble mode, a byte mode, an ECP mode, and the like, which will be described later.

Hereinafter, the compatibility mode will be described in more detail with reference to the drawings. Since there are many variations as described above, it is not possible to explain all of them here, so the Canon printer "LBP-
730 "will be described below as an example.

First, the pin arrangement of the interface connector used in the parallel interface will be described with reference to FIG. The connector used in the parallel interface has a total of 36 pins arranged in the arrangement shown in FIG. The number is the number of each pin.

Each pin corresponds to one signal line, and the following signal lines are assigned. For example, the pin No. 1 is a signal line called DATA STROBE. Pin number Signal line name Function 1 DATA STROBE The steady state is HIGH, and when it becomes LOW, the printer operates DATA1 to DAT.
The state of A8 is read. 2-9 DATA1-8 Indicates the information of the 0th to 7th bits of the data sent from the host. HIGH
Indicates that the data is 1, and LOW indicates that the data is 0. The steady state is undefined, and is valid only when DATASTROBE is LOW. 10 ACK The steady state is HIGH, and a LOW pulse is issued in the next state. -When one byte has been received and the next one byte can be received.-When the reception buffer has free space, the status has shifted from offline to online onion. 11 BUSY Printer receives data from host computer Indicates whether it can. LOW indicates a receivable state, and HIGH indicates a non-receivable state. It becomes HIGH in the next state. -Offline status-When an error has occurred-When one byte has been received but the next one cannot be received yet-When there is no space in the receiving buffer 12 An error has occurred in the PE printer HI when doing
GH; otherwise, it is LOW. 13 SELECT High when the printer is online, LOW otherwise. 14 AUTO FD Not used 15 AUX OUT 1 Always HIGH 160 V Printer ground level 17 Frame GND Printer frame ground 18 +5 V Always HIGH 19-30 GND Ground (ground level) 31 INIT Normal HIGH, but LOW By doing this, the input prime process is performed. 32 FAULT This becomes HIGH when the printer is online. In other states, it is LOW 33 AUX OUT 2 Always LOW 34 AUX OUT 3 Always LOW 35 AUX OUT 4 Always HIGH In the compatibility mode, mainly used are pins 1 to 11, that is, DATA STR.
OBE, DATA1, DATA2, DATA3, DAT
A4, DATA5, DATA6, DATA7, DATA
8, ACK and BUSY signal lines. FIG. 5 shows a handshake in the compatibility mode. FIG. 5 is a data transfer timing chart in the parallel interface. The example shown in FIG. 5 shows a case where 1-byte data is transferred. << Schematic Description of IEEE 1284 >> The compatibility mode in this parallel interface has a drawback that data can be transferred only from the host to the printer in one direction and not from the printer to the host. Then, in order to improve the point that the data cannot be transferred from the printer to the host, a centro bidirectional communication handshake has been standardized by IEEE as an upper compatibility of the compatibility mode (IEEE1284-1994).

The IEEE 1284-1994 includes, in addition to the compatibility mode (conventional handshake for transferring data from the host to the printer) described above, a new nibble mode, byte mode,
A plurality of communication modes such as an ECP mode are additionally defined. In these newly added modes, connectors and cables having the same shape as in the compatibility mode can be used.

The nibble mode is a mode for transferring data from the printer to the host. By using the nibble mode alternately with the compatibility mode, bidirectional communication between the host and the printer can be realized. That is, bidirectional communication can be performed by performing transmission from the host to the printer in the compatibility mode and transmitting from the printer to the host in the nibble mode.

In the nibble mode, ACK and AUTO F
D is used for control, and data is BUSY, PE, S
Set to four signal lines of ELECT and FAULT.
One byte of data is divided into 4 bits,
Bit and then the upper 4 bits, 8 bits (1
Byte) transfer. The FAULT is also used by the printer at a specific timing to indicate whether data to be sent to the host is ready. In the compatibility mode, handshaking is performed without using the signal lines DATA1, DATA2,..., DATA8 controlled only by the host. These DATA1, D
ATA2,..., DATA8 are called data bust.
In the nibble mode, since the data bus is not used, there is no need to deal with hardware on the host side. Therefore, mounting can be performed relatively easily.

The byte mode is a mode for performing communication from the printer to the host similarly to the nibble mode, and is used alternately with the compatibility mode.
Bidirectional communication between the host and the printer can be realized. That is, bidirectional communication can be performed by transmitting data from the host to the printer in the compatibility mode and transmitting data from the printer to the host in the byte mode.

In the byte mode, STROBE, AC
Control is performed by K, BUSY, PE, AUTO FD, and FAULT, and data is transmitted on the data bus (DATA1, DA1).
TA2,..., DATA8). Compared with the nibble mode, 1-byte (8-bit) data is transmitted at the same time, which is efficient. However, since the data bus is controlled by the printer, hardware on the host side is required.

The ECP mode is a mode for performing both communication from the host to the printer and communication from the printer to the host. Internally, bidirectional data transfer is possible within the same ECP mode by switching between forward phase transfer from the host to the printer (Forward Phase) and from printer to the host. And

In the ECP mode, STROBE, AC
K, BUSY, AUTO FD, INIT, FAUL
Control is performed using T and PE, and data is set on the data bus. Since the printer controls the data bus,
It is necessary to respond to hardware on the host side.

Since bidirectional data transfer is possible in one mode, the overhead for switching between modes is small, and the handshake of normal phase transfer of ECP is smaller than the handshake of compatibility mode. The advantage is that the transfer speed is considered so as to be able to be increased. << Overview of IEEE1284.4 >> Using the data transfer (or other interface) using IEEE1284 described above, the concept of credit is used between two devices (for example, a higher-level device and a printing device). The control for mainly providing two of the flow control and the multiplexing (multi-channelization) for exchanging a plurality of information (for example, data and control information) at the same time is an IEEE1212 standard.
84.4. In the internal processing of the host device and the printing device, the control of IEEE1284.4 is located in the process of printing using transfer data (commonly called application) and the intermediate portion of IEEE1284 which is the actual data transfer portion. is there. FIG. 6 is a conceptual diagram showing the relationship. FIG. 6 is a diagram illustrating processing in the host device and the printing device, which are used in the description of the present embodiment, such as application, IEEE1284.4, and IEEE12.
It is a figure which expressed the relationship of 84 simply.

Next, the structure of data handled by IEEE1284.4 shown in FIG. 6 will be described in more detail. IEEE
Data handled by 1284.4 always has a block of several bytes as one unit, and it is read as a packet. The structure of the packet is defined as shown in FIG.

That is, the data handled by IEEE1284.4 is composed of a 6-byte header shown in FIG. 7 and data following the header. Looking further at the header part, the first byte is the primary socket ID (Primary Socket ID).
ID) (hereinafter referred to as “PSID” and an IEEE described later)
A socket ID (Socket ID), which will be described later in detail, of a device that has started the initialization of 1284.4 control.

The second byte is a secondary socket ID (Second
ary Socket ID), which represents the socket ID of the other device with respect to the device that has initiated the initialization. The third and fourth bytes indicate the size of the entire packet including the two bytes. For example, in the case of a packet including 10-byte data, 16 (header 6 bytes +
(Data 10 bytes).

When the data is a packet of 0 bytes, a value (6) representing 6 bytes of only the header portion is entered. However, since the actual contents are expressed in hexadecimal, the above 16 and 6
Are represented as 0x0010 and 0x0006, respectively (1
In the case of a hexadecimal number, it usually starts with “0x” and one byte is represented by two digits.)

The fifth byte indicates a credit, which will be described in detail later. The 6th byte name is Control (Cont
rol). One bit (one byte is eight bits) in this one byte indicates whether or not the packet is a normal packet (expressed as 0 for a normal packet). It has become. The remaining 7 bits are reserved areas and are not used at present (represented by 0). Therefore, this byte is usually 0x00.

The data portion is transfer data (print data and control data) created by the respective applications of the host device and the printing device, or IEEE 1284.4 described later.
Will be entered.

As a comparative example, FIG. 8 is a diagram showing both packetized data and non-packetized data.

Next, the socket ID will be described.

One interface (for example, IEEE1
284), a plurality of processes (mainly processing of an application part) in two devices connected to each other identify their own counterparts (processes in the other device) and exchange data independently. In order to execute multi-channeling, an individual number assigned to each process in the device is a socket (Socket) ID.

Next, the concept of the socket ID will be described.
For example, there are two processes (process A and process B) in the application of the host device, and two processes (process a for process A and process b for process B) for each of them. A, processing PSID A =
0x10, process B = 0x20, SSID, process a = 0
x10, process b = 0x20.

Then, the processing A is the data ("A", "I")
Is sent, the packet P is controlled under the control of IEEE1284.4.
SID and SSID are set to 0x10 and 0x10 in the same manner as when process B sends data ("?"
By setting the IDs to 0x20 and 0x20, it is possible to recognize from which process the transmitted packet was transferred to which process, and the data is reliably transferred to the target process, and logically using a plurality of channels. (Multi-channel).

FIGS. 9 to 13 show a case where data is transferred from a plurality of (two in the figure) applications on the higher-level device side to a plurality of target applications on the printing device side (again, two ) Are sequentially shown.

Hereinafter, a specific procedure in which print information, which is image forming information, is packetized and transferred from the higher-level device to the printing device from the host device will be described with reference to FIGS.

FIG. 9 shows the application on the host device side as 2
There are three processes (processes A and B), each of which has data to be transferred (process A = “a”, “i”, process B = “ka”, “ki”).

FIG. 10 shows the IEEE1284.
4 shows a state in which a packet is created by the processing of No. 4 and the socket ID is attached to each packet. Also,
The procedure in which the packet is transferred will be described later.

FIG. 11 shows a state in which packetized data is transferred from a higher-level device to a printing device via an interface process (IEEE 1284 process). As shown in FIG. 11, the order in which the packets are transferred is not specified.

In FIG. 11, four packets are processed A (a packet having "A" data) and process B
(Packet with "ka" data), second in process A (packet with "i" data), and second in process B with packet "ki" data Have been.

FIG. 12 shows a state in which the packet transferred to the printing apparatus is received by the IEEE1284.4 on the printing apparatus side, and data extracted from the packet is passed to each application according to the socket ID.

As a result, as shown in FIG. 13, data is transferred to the processing (processing a, b) of the target application in the printing apparatus.

It goes without saying that the same applies to the transfer in the reverse direction (from the processing of the printing apparatus to the processing of the host apparatus).

The socket ID 0x00 (PSI
IEEE128 if D and SSID are both 0x00)
Commands required to execute 4.4 processing (Comman
It is used only to transfer d) and a reply packet (Reply Packet) described later.

Next, a basic control procedure in IEEE1284.4 will be described with reference to flowcharts of FIGS. 14 to 16 show IEEE1284.
4 is a flowchart for explaining a basic control procedure in FIG.

First, in step S1701 shown in FIG. 14, a device that wants to start IEEE 1284.4 control sends an initialization command packet (In) to another device.
it Command Packet). Normally, a higher-level device issues an initialization command packet (Init Command Packet) to a printing device.
The other is called a printing device). The initialization command packet (InitCommand Packet) has a data structure shown in FIG.
Except for the part of t), it is practically fixed data.

An initialization command packet (Init Command P)
The printing apparatus that has received the (acket)
In, it is determined whether or not the control of IEEE1284.4 can be started. A response packet indicating that the control of IEEE1284.4 cannot be started is created, and step S
Proceed to 1705.

On the other hand, in step S1702, the
If the control of 84.4 can be started, step S170
In step S1706, a response packet indicating that the control of IEEE1284.4 can be started is created. In this case, since control of IEEE1284.4 can be started, initialization for start is also executed.

In step S1705, a response packet (Init Reply Packet) for initializing the higher-level device created in steps S1703 and 1704 is returned to the upper-level device. FIG. 18 shows the configuration of a response packet to the host device. The 8th byte (Result data) of the response packet to the initialization is normally IEEE1
The information includes whether the process of 284.4 can be started or cannot be started for some reason.

For this reason, the host device determines in step S1706
Receives the response packet for the initialization from the printing apparatus, analyzes the information of the eighth byte of the response packet for the initialization, and determines whether or not to continue the processing of IEEE1284.4. If the processing cannot be started and the IEEE 1284.4 processing cannot be continued, corresponding error processing is performed.

For example, if the printing device is IEEE1284.4
Cannot be started, the initialization command packet is transmitted again from step S1701 or the IE
Processing such as giving up performing the processing of EE1284.4 will be performed.

On the other hand, if the processing can be continued normally in step S1706, the host device proceeds to step S1707 to open a channel open command packet (Open Channel Com
mandPacket). Figure 1 shows the structure of a channel open command packet (Open Channel Command Packet).
It is shown in FIG.

This channel open command packet (Op
When the printing device receives the “En Channel Command Packet”, the printing device first determines in step S1708 a secondary socket ID (Second) which is one of the parameters in the packet.
ary socket ID) (hereinafter sometimes referred to as "SSID") is checked by checking whether it is the SSID owned by the user. Establish channel (open) if you have your own (= openable) SSID
Will do.

The socket ID (PSID,
The combination of the SSIDs makes it possible to identify the opened channel. In the above description of the socket ID, the channel connecting the process A of the application of the host device and the process a of the application of the printing device is a combination of the socket ID PSID = 0x10, SSID
= 0x10 (similarly, the channel connecting application process B of the host device and application process b of the printing device is PSID = 0x2
0, SSID = 0x20).

Subsequently, in step S1709, the printing apparatus sets a parameter (Primary To Secondary Packet Size) indicating the maximum value of the packet size required for transfer from the higher-level apparatus to the printing apparatus. A parameter (Secondar) that indicates the maximum packet size required by the device when transferring from the printing device to the host device.
y To Primary Packet Size) to determine if each is a packet size that you can prepare.

As a result of the determination, if the requested size is possible, a channel open response packet (Open Channel Rep
ly Packet), and set a parameter indicating the size of each packet that can be prepared by two parameters (Primary To Secondary Packe
t Size) and (Secondary To Primary Packet Size).

Subsequently, in step S1710, the printing apparatus is a parameter representing information on credit (Credit) requested by the higher-level apparatus (Credit Requested).
And (Maximum Outstanding Credit) are analyzed. Then, a response to the request represented by the combination of the two parameters is sent to a channel open response packet (Open Channel Reply Packet) in the same manner as the packet size described above.
And transfer it to the host device.

A channel open command (Open Channel
When the analysis of each parameter of (Command) is completed, the printing apparatus compiles replies to the higher-level apparatus based on the analysis result and creates a channel open response packet (Open Channel Reply Packet) as shown in step S1711. Then, in a succeeding step S1712, the data is transferred to the higher-level device. FIG. 20 shows the structure of a channel open response packet (Open Channel Reply Packet) transferred to the higher-level device.

The host device fetches the channel open response packet (Open Channel Reply Packet), and in step S1713, the host device analyzes the parameters of the channel open response packet and checks whether the channel has been opened. If the channel cannot be opened, the printing apparatus cannot start the processing of IEEE1284.4. For example, the process returns to step S1707 to open another channel, or
Processing such as giving up performing the processing of 4.4 is performed.

On the other hand, if the channel is opened in step S1713, the control of the higher-level device is stopped in step S1713.
Proceeding to step 14, the state is such that the data packet can be transferred to the opened channel. Then, the transfer of the data packet to the opened channel is started.

The structure of the data packet to be transferred here is the packet having the structure shown in FIG. The transfer packet size is determined as follows.

That is, in this case, the packet size requested by itself (the host device that issued the channel open command packet) is compared with the packet size requested by the printing device returned by the channel open response packet. Whichever is smaller is adopted. Of course, the transfer of the data packet is in the opposite direction (from printing device to host device)
Is also possible, and credits (Credi
The transfer of the command packet (Command Packet) relating to t) is also effective at this point.

Any number of channels can be opened as long as the processing in the apparatus permits (and the combination of socket IDs does not overlap). In this case, returning to step S1707 to open the next channel is repeated.

In the example of the description of the socket ID, two channels, ie, a channel connecting process A of the host device and process a of the printing device, and a channel connecting process B and process b are open.

In the above description, the flow up to the opening of the channel connecting the processes of the host device and the application inside the printing device has been described.
Various commands and response packets (In
It is not necessary to follow the above procedure because a channel (hereinafter, sometimes referred to as a “command channel”) to which an it or an Open Channel is transferred is implicitly opened.
As already described, the socket ID for identifying the channel is 0x00.

When the upper-level device performs the packet transfer process of step S1714 and obtains a channel for which data exchange has been completed (to be completed), the process proceeds to step S1715, and the channel close command packet (Close) is transmitted.
An open channel can be terminated (closed) using a Channel Command Packet).

When the host device attempts to close the channel, as shown in step S1715, a channel close command packet (Close Channel Command Packe
Issue t) and transfer it to the printing device. FIG. 21 shows the structure of a channel close command packet (Close Channel Command Packet). A combination of a socket ID indicating a channel to be closed is described in a first socket ID (Primary Socket ID) and a secondary socket ID (Secondary Socket ID) which are parameters of a channel close command packet (Close Channel Command Packet). .

The printing apparatus sends a channel close command packet (Close Channel Command Packe) from the host apparatus.
t) is received, and its parameters are analyzed in step S1716. Then, in step S1717, it is checked whether the channel specified to be closed can be closed (is open).

If it is determined that the channel designated to be closed can be closed, the flow advances to step S1718 to
A channel close response packet (Close Channel Reply Packet) storing information indicating that the channel designated to be closed can be closed is prepared, and preparations are made for replying to the host device.

Similarly, if it is determined that it cannot be closed,
A channel close response packet (Close Channel Reply Packet) storing information indicating that the channel designated to be closed cannot be closed is prepared, and preparations are made for replying to the host device.

The channel close response packet (Close Ch)
Step S17 when creating an annel reply packet)
Proceeding to 20, the data is transferred to the host device. This channel close response packet (Close Channel Reply Packe)
FIG. 22 shows the structure of t).

In step S1721, the higher-level device transmits the channel close response packet (CloseChannel Reply Packe).
By receiving t) and analyzing the status information (Result) of the eighth byte, which is a parameter, it is possible to recognize whether the channel has been closed. After the channel is closed, if necessary, step S1707 is performed again.
Returning to step S1714, the channel can be opened by the channel open command packet, and if there is another channel that is open, the process may return to step S1714.

On the other hand, the control of IEEE1284.4 can be terminated as it is at the confirmation of step S1721. If the control of IEEE1284.4 is to be ended as it is, the process proceeds to step S1722, and the host device transfers a connection release command packet (Exit Command Packet) to the printing device. Exit Command Packet
Packet) is shown in FIG.

A connection release command packet (Exit Command
Packet) is received by the printing apparatus, in step S172.
In step 3, the process using IEEE1284.4 (exchanging data on an open channel) is terminated.
Then, in step S1724, the connection release response packet (Ex
it Reply Packet) and transfer it to the host device. Figure 2 shows the structure of a connection release reply packet (Exit Reply Packet).
It is shown in FIG.

As a result, the control of IEEE1284.4 is completed, and the packet (the packet of IEEE1284.4) is completed.
Also terminates the data transfer. Again, IEEE1284.
If it is desired to start the control of step S1701, In of step S1701
It must be executed from the transfer processing of the it Command Packet. Of course, other command packets (Command Pack
Exit Command Packet (Exit Command)
Packet) may be issued at any time when the control of IEEE1284.4 is being executed.

By the way, if the processing is executed up to step S1714 and the channel is opened, the transfer of the data packet can be started. However, in the present embodiment, when the data packet is sent, the transfer destination is set. Is controlled so that it cannot be transferred unless the credit (Credit) has been obtained from the processing. In this way I
The flow control in EEE1284.4 is performed.

In the description of the socket ID, when the process A on the host device transfers a packet to the process a on the printing device, the process A transfers the packet unless a credit is received from the process a. Can not.

For example, a resource owned by the user (generally called a buffer or the like which is a readable and writable storage means. In the example of this embodiment, a printing device is assumed to be referred to as a “reception buffer” hereinafter). In other words, if the data to be transferred from the other party is to be stored even temporarily, it is necessary to control the data so that it does not exceed the capacity of the reception buffer and not receive the data. Will be gone. In order to prevent such a situation, the flow control adjusts the stop and restart of the data transfer.

Next, IEEE1 used in the present embodiment will be described.
The concept of credit used for flow control of packet transfer in 284.4 will be described.

Credits are issued from the recipient of the packet to the sender, and the credit indicates how much the recipient is ready to receive the packet. The receiving side of the packet guarantees that the packet issued as a credit can always be received.

For credit exchange, a credit command packet (Credit Command Packet) or a credit request command packet (Credit Request Com
mandPacket) and its response packet are mainly used, but credit can also be issued by a data packet (Data Packet) or a channel open response packet (Open Channel Reply Packet).

However, only the command channel is special, and already has two credits at initialization. This is in order to be able to execute IEEE 1284.4 Init and error handling in any case.

The above-described credit state transition will be described with reference to FIG.

First, in an initialization state where the power is turned on to the apparatus (upper apparatus, printing apparatus), the credit of the command channel (Credit) is internally set to “2”. Credit (Cred) for the channel (not yet open) for transferring data (packets)
it) is "0". In this description, only one channel for data transfer is described, but if a plurality of channels are opened, credit management is also performed for each channel.

Next, the host device uses the IEEE1284.
In order to start the control of No. 4, the credit of the command channel on the higher-level device side is decremented (-1) by issuing an initialization command packet (Init Command Packet).
It becomes "1". At the same time, when the printing apparatus receives an initialization command packet (Init Command Packet), the credit of the command channel becomes (3).
This is because it is promised that the credit parameter (the fifth byte of the header) of the packet transferred through the command channel always contains "1".

This is because the fact that the credit becomes “0” in the command channel and the packet cannot be transferred means that the subsequent processing cannot be continued. A promise has been set.

An initialization command packet (Init Command P)
acket), the printing device returns an initial command response packet (Init Reply Packet), and conversely, the credit of the command channel of the printing device is decremented (-1).
It becomes "2", and the credit of the command channel of the host device returns to "2" (+1 is added).

Next, the higher-level device attempts to open a channel for data with a channel open command packet (Open Channel Command Packet), and the printer responds to the request by opening a channel open response packet (Open Channel Command Packet).
If the reply is normally returned, a credit such as “2” is issued to the higher-level device using the credit parameter (15th and 16th bytes) of the channel open response packet (Open Channel Reply). The channel credit for transferring the data on the device side is "2" (+2).

Next, the higher-level device has opened a channel for transferring data, and has received a credit for the same channel from the printer, so that the data packet can be transferred. As a result, two data packets can be successively transferred. The second data packet includes one credit for a channel for transferring data to the printing apparatus, and the credit parameter of the data packet (fourth parameter). Bytes).

At that time, the credit of the channel for transferring the data of the printing apparatus is incremented by 1 to “1”. Also, the credit of the command channel remains "2" because the command packet has not been transferred (and has not been transferred by itself). Only here can the printing device transfer the data packet to the host device.

Next, since the higher-level device has transmitted two data packets in succession, it has run out of the credit of the channel for transferring its own data, and To send a credit request command packet (Credit Request Command Pac
Use ket) to make a credit request to the printing device. Credit Request Command Packet (Credit Request
Command Packet) is shown in FIG. Credit Request Command Packe
The printing device requested for credit by t) analyzes the contents of the request (by looking at the parameters) and attempts to return a response packet along with the request. For example, in the case of the example shown in FIG. 25, it is assumed that only one credit can be issued to the host device. The issued credit is transferred to a higher-level device in a credit parameter (the eleventh and twelfth bytes) of a credit request reply packet (Credit Request Reply Packet). Credit request response packet (Credit R
FIG. 27 shows the structure of the request reply packet.

By receiving the response packet, the higher-level device increases the credit of the channel for transferring the data of the higher-level device by +1 to "1", and the data packet can be transferred again.

Also, since the printing apparatus has issued a credit for the channel for transferring data from the host apparatus, only one data packet can be transferred.
Therefore, as shown in FIG.
If you transfer one, the credit you had is decremented by 1 and "0"
Becomes It is, of course, possible to issue a credit to a higher-level device using the credit parameter in the data packet, and the higher-level device increases its own credit by the issued credit. In the figure, the credit of the channel for data transfer is incremented by one, for a total of "2". <Description of Characteristic Configuration of the Present Embodiment> Referring to the drawings, one embodiment of the present invention will be described with reference to FIGS.
This will be described in more detail with reference to FIG. First, a rough operation of the printing process will be described with reference to FIGS.

When the power of the printing apparatus is turned on, the processing shifts to the processing of FIG. 28, the apparatus is initialized in step S300, and when the initialization is completed, the normal print (control) data is transferred from the upper apparatus in step S301. It is in a state of waiting for it to come.

In the present embodiment, the printing (control) data of the printing apparatus is received by the hardware (not shown) by executing the processing shown in the flowchart of FIG. 29 and receiving the multi-byte printing (control data). This can be known by an interrupt (or flag monitoring).

That is, the printing (control) data receiving process of the printing apparatus is performed as follows. When one byte of print (control) data is transferred, the memory (R
AM 19) are sequentially written to the set locations (step S400). The setting to which location in the memory (RAM 19) is written is initialized (step S300).
Set in advance. Similarly, initialization (step S300)
It is checked whether print (control) data has been received up to the number of bytes set in step S401 or the like (step S401). If the number of bytes has reached the set number, it indicates that some interrupt processing is to be performed or that the set number of bytes has been received. A flag is set (step S402). If the number of bytes has not been reached, the process waits for the next data to be transferred.

When packet data is received, if the packet size is set to the set number of bytes, an interrupt is generated every time one packet is received, and it is possible to know the end of packet reception. That is, waiting for reception of print (control) data (step S301) means waiting for the interrupt processing (or setting of a flag) generated in step S402.

Returning to the description of FIG. 28, when print (control) data is received by the set number of bytes, the received data is analyzed in step S302. As a result of the analysis, if it is found that the data is the control data, the process according to the data in step S303, for example, if there are a plurality of places where the printed paper is to be discharged, the process proceeds to step S308 to determine the discharge destination. Or the contents of the printer mode setting information set from the operation panel 1012 stored in the NVRAM (not shown), and changes the settings inside the printing apparatus.

On the other hand, if it is determined in step S309 that the received data is print data, the flow advances to step S304 to check whether the received data is a print execution (activation) instruction. If the data is not print execution data, the process advances to step S305, and since the data is print data itself, it is further analyzed / developed to have print execution.

On the other hand, if it is determined in step S304 that the command is a print execution (activation) command, the flow advances to step S306 to check whether the printing unit 17 is usable. If the print section is not available, wait until it is possible. If the printing unit 17 is usable, the process proceeds from step S306 to step S307.
To print the print data that has been analyzed / developed until then.

Normally, print data (control data) is received under the above-described control, and print processing is executed in accordance with the received data.

As described above, in the present embodiment, the interface 21 with the host device is connected to the IEEE 128
4-1994, which is assumed to be a parallel interface (commonly referred to as a Centronics interface). Therefore, by using an existing signal line, the printing apparatus can execute the above-described nibble mode, byte mode, ECP mode, and the like. Data transfer to a higher-level device (hereinafter, reverse transfer) can be performed.

Next, a method of determining the size of a packet transmitted / received to / from a higher-level device specific to the present embodiment will be described with reference to FIG.
This will be described with reference to FIGS.

In IEEE1284.4, the packet size used for data transfer is determined by exchanging a channel open command packet (Open Channel Command Packet) and a channel open response packet (Open Channel Reply Packet). Open Channel CommandPa
The following processing is performed when a channel open response packet is received, and a channel open response packet (Open Channel Reply Packe) is received.
Packet size returned in (t) (Primary To Secondary Pack)
et Size and Secondary To Primary Packet Size).

First, a storage area as shown in FIG. 35 (hereinafter referred to as a “packet information storage area”) is provided on an NVRAM or a hard disk (HD) (not shown) of the printing apparatus, and a packet size to be exchanged with a higher-level apparatus is determined. The transfer speed and the like for the size are stored so that they can be stored even after the power is turned off. In the following description, the description will be made from the state where the storage area is initialized.

When the printing apparatus receives the channel open command packet (Open Channel Command Packet), the printing apparatus shifts to the processing of FIG. 30. In step S500, the printing apparatus sets the “Primar” to the host specified size (E area) of the packet information storage area.
y To Secondary Packet Size ”is stored. Further, the transfer speeds (areas of A-3, B-3, C-3, and D-3) are checked to confirm whether any data (transfer speed) is stored therein.

If no data is stored, the flow advances to step S501 to derive an optimum and maximum packet size for the printing apparatus from the size of the RAM 19 of the printing apparatus in accordance with a specific procedure (calculation method, etc.), The packet is stored in the packet size (size A) portion of the storage area.

Subsequently, in step S502, the packet size (size B, size C, size D) is similarly stored. Then, the process proceeds to step S504. In the present embodiment, it is assumed that the size of the packet size is derived so that size A> size B> size C> size D. However, the specific procedure may be any. Detailed description is omitted. Further, instead of deriving the packet size according to a specific procedure, a predetermined value may be stored in the ROM 13, and the value may be stored as the packet size.

Next, the details of the procedure for determining the packet size to be returned to the host device in the channel open response packet (Open Channel Reply Packet) using this packet information storage area in step S503 will be described with reference to FIG. FIG. 31 shows a channel open response packet (Op
FIG. 9 is a flowchart for explaining details of a procedure for determining a packet size to be returned to a higher-level device in an en Channel Reply Packet).

In the process of determining the packet size, first, in step S5010, the stage (the horizontal row of the region) in which valid data is not stored in the transfer speed region in the packet information storage region is determined. From the largest stage (in the case of the present embodiment, in the order of the stages of size A to D)
Search and select the packet size of that stage. In this case, since no valid data is stored in the transfer speed area, the size A is selected.

Next, in step S5011, the selected packet size is compared with the size stored in the host designated size (E) area in the packet information storage area. If the value selected in step S5010 is smaller than the value of the host designated size (E) as a result of the comparison, the value is set to the channel open response packet (Open Channel Reply Pac).
ket) to determine the packet size data to be returned to the host device.

On the other hand, if the value selected in step S5010 is larger, the flow advances to step S5012, and based on the size stored in the host designated size (E) area in the packet information storage area, steps S501 and S502 are performed. Is performed again, and in the packet information storage area, the value of the packet size area of all the stages where valid data is not stored in the transfer speed area is changed.

If the processing of this step is performed in the case of the present embodiment, all of the sizes A to D are changed. After changing the packet size area, the process returns to step S5010 to continue the processing again. When the processing in step S503 is completed in this way, a channel open response packet (Open C
Since the packet size to be returned to the higher-level device is determined by the “hannel Reply Packet”, a channel open response packet (Open Channel Reply P) is used together with other parameters using the packet size determined in step S504.
acket) and transfer it to the host device.

On the other hand, as a result of the determination in step S500, the transfer speed (A-3, B-
If it is found that any data (speed data) is stored in any one of the areas of C3, C-3, and D-3, the process proceeds to step S505, and then the data is stored in all the transfer speed areas. Is checked (whether there is no area where no data is stored).

As a result, if there is at least one free area (an area in which no data is stored), step S50 is performed.
Proceed to 3 and open channel response packet (Open Chann
el Reply Packet).

On the other hand, if there is no free space in the transfer speed area in step S505 (if transfer speeds corresponding to all packet sizes are stored), the flow advances to step S506, where the stored transfer speeds are And selects the packet size corresponding to it (for example, if the speed of C-3 is the fastest, size C). The selected packet size is used in step S504.

When the processing in FIG. 30 is completed in this way, data packets can be exchanged.
When receiving a data packet, the printing apparatus according to the present embodiment performs the following processing to check the transfer speed according to the packet size.

In this embodiment, when the data packet is started to be received, the operation of the hardware (not shown) for receiving the data described above is performed as shown in FIGS.
The settings are changed so as to follow the flowchart shown in FIG. FIG. 29 and FIG. 32 are diagrams for explaining data reception control according to the present embodiment.

First, a flag is set to indicate that the processing for checking the transfer rate of the data to be used in the determination in step S4011 in FIG. 32 has been started. The process of setting this flag may be performed at any timing before data is received, and is not particularly illustrated in the flowchart. In this state, when the first data of the packet is received by one byte, the data is sequentially written to the set location of the memory (RAM 19) as shown in step S4010.

Then, as shown in step S4011, a flag indicating whether or not the processing for checking the data transfer rate has been started is checked. If the flag is set, step S40 is performed.
Proceed to 12 to notify the reception of the first byte of the packet by an interrupt or the like.

Thereafter, the flag is cleared in step S4013, and the flow returns to step S401 in FIG. 29, where normal reception is continued until the specified number of bytes is reached.

On the other hand, if the above flag is not set in the check in step S4011, step S401 in FIG.
Continue to normal reception.

If an interrupt or the like occurs in the processing of step S4012 described above, the flow shifts to the processing of FIG. 33 to execute the processing of step S5020. FIG. 33 is a flowchart for explaining the interrupt processing at the time of data reception according to the present embodiment.

In this case, the value of the timer (current time) inside the CPU 12 (or outside the not shown) is read, and the value is read, for example, in the start time area (A-1 to D-D) of the packet information storage area in FIG. 1 area). Needless to say, it is stored in a location corresponding to the packet size used in the packet reception.

Next, with reference to FIG. 34, a description will be given of the packet reception end processing of the present embodiment. FIG. 34 is a flowchart for explaining the packet reception end processing in the present embodiment.

When reception of one packet is completed, FIG.
Since an interrupt occurs in the processing of step S402 of
Upon receiving the interrupt, the flow shifts to the processing in FIG. First, in the process of step S5021, the CP
The timer value (current time) inside U12 (or outside not shown) is read out, and the packet size of the end time area (area A-2 to D-2) of the packet information storage area shown in FIG. Store it in the corresponding location.

Next, in step S5022, the data transfer amount (transfer speed) per unit time is calculated and obtained from the packet size corresponding to the stored start / end time. Next, the calculated result is written in the transfer speed area (A-3 to D-3 area). If the data (transfer rate) has already been stored in that location, that is, after the data transfer rate has been checked, If the second and subsequent packets are received, the newly calculated result is added to the value already stored in step S5023, the average value is recalculated, and the average value is stored again in step S5024.

As described above, according to the present embodiment, the data transfer rate is obtained each time a packet is received, the value is stored, and the packet size is automatically automatically adjusted each time the channel open processing is performed. After the data transfer rate of a plurality of packet sizes is measured, the packet size having the highest speed can be automatically used.

Further, it goes without saying that these processes can be similarly executed even in the case of data transmission from the printing apparatus to the host apparatus.

Further, NVRAM and a hard disk (H
D) A process for initializing the packet data storage area stored in the storage device is provided. When the host device is changed or the data transfer process in the host device is changed, the initialization is performed. Again, the optimal packet size can be used automatically.

[Second Embodiment] In the first embodiment described above, the packet size used in data transfer is unconditionally changed when the channel open command is executed, and the optimum transfer speed is set. However, the present invention is not limited to the above example, and whether or not to change the packet size is performed when instructed by an operation switch or the like mounted on the printing apparatus. The same effect can be obtained.

[Third Embodiment] In the above-described first embodiment, the packet size used for data transfer is unconditionally changed when the channel open command is executed, and the optimum transfer speed is set. However, the present invention is not limited to the above example, and whether or not to change the packet size is performed in response to an instruction by a specific command from a higher-level device. In this case, a similar effect can be obtained.

[Fourth Embodiment] In the above-described first embodiment, the type (number) of changing the packet size to check the data transfer rate is only a predetermined number. The same effect can be obtained by changing the number according to the type (number of times) specified by an operation switch or the like mounted on the printing apparatus.

[Fifth Embodiment] In the above-described first embodiment, the type (number of times) of changing the packet size in order to check the data transfer speed is only a predetermined number. A similar effect can be obtained even if the change is made in accordance with an instruction by a specific command from the host device.

[Sixth Embodiment] In the above-described first embodiment, the packet size used to check the data transfer rate is determined according to a predetermined specific procedure. A similar effect can be obtained even if a plurality of procedures are prepared and the packet size is determined by an operation switch or the like mounted on the printing apparatus according to a procedure instructed from them.

[Seventh Embodiment] In the above-described first embodiment, the packet size used to check the data transfer rate is determined according to a predetermined specific procedure. A similar effect can be obtained even if a plurality of procedures are prepared and the packet size is determined according to an instruction from a higher-level device according to a specific command according to the instruction specified from among them.

[Eighth Embodiment] In the above-described first embodiment, the packet size used to check the data transfer rate is determined according to a predetermined specific procedure. A similar effect can be obtained even if the packet size is determined according to a procedure specified by a specific command from a higher-level device.

[0158]

As described above, according to the present invention, it is possible to use a packet size which seems to be optimal when performing data transfer, automatically perform optimal data transmission / reception, and improve the efficiency of the entire printing process. Can be raised.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing the structure of a laser beam printer according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a certificate stamp of the printing apparatus and the host apparatus according to the embodiment.

FIG. 3 is a block diagram illustrating an internal configuration of the printing apparatus viewed from a flow of print data according to the embodiment.

FIG. 4 is a diagram illustrating a pin arrangement of an interface connector used in a parallel interface.

FIG. 5 is a data transfer timing chart in a parallel interface.

FIG. 6 illustrates an application, an IE, which is a process in a host device and a printing device used in the description of the embodiment.
It is the figure which expressed the relationship of EE1284.4 and IEEE1284 simply.

FIG. 7 shows IEEE128 used in the present embodiment.
FIG. 4 is a diagram illustrating a basic configuration of a 4.4 packet.

FIG. 8 shows IEEE128 used in the present embodiment.
FIG. 7 is a diagram showing a comparison between data using a packet of 4.4 and data not using the packet.

FIG. 9 shows IEEE used in the description of the embodiment.
It is the figure showing operation | movement of 1284.4 multi-channel.

FIG. 10 shows an IEEE used in the description of the embodiment.
It is a figure showing the operation | movement of the multichannel of E1284.4.

FIG. 11 illustrates an IEEE used in the description of the present embodiment.
It is a figure showing the operation | movement of the multichannel of E1284.4.

FIG. 12 shows an IEEE used in the description of the embodiment.
It is a figure showing the operation | movement of the multichannel of E1284.4.

FIG. 13 illustrates an IEEE used in the description of the embodiment.
It is a figure showing the operation | movement of the multichannel of E1284.4.

FIG. 14 shows IEEE used in the description of the embodiment.
It is a flowchart for demonstrating the basic control procedure of 1284.4.

FIG. 15 shows IEEE used in the description of the embodiment.
It is a flowchart for demonstrating the basic control procedure of 1284.4.

FIG. 16 shows IEEE used in the description of the embodiment.
It is a flowchart for demonstrating the basic control procedure of 1284.4.

FIG. 17 illustrates an IEEE used in the description of the present embodiment.
E1284.4 initialization command packet (Init Comma
FIG. 3 is a diagram illustrating a data structure of an (nd Packet).

FIG. 18 illustrates an IEEE used in the description of the present embodiment.
It is a figure showing the structure of the first response packet (Init Reply Packet) with respect to the host device of E1284.4.

FIG. 19 is an IEEE diagram used in the description of the embodiment.
It is a figure showing the structure of the channel open command packet (Open Channel Command Packet) of E1284.4.

FIG. 20 illustrates an IEEE used in the description of the present embodiment.
E1284.4 channel open response packet (Open
FIG. 3 is a diagram illustrating a structure of a Channel Reply Packet).

FIG. 21 illustrates an IEEE used in the description of the present embodiment.
It is a figure showing the structure of the channel close command packet (Close Channel Command Packet) of E1284.4.

FIG. 22 illustrates an IEEE used in the description of the present embodiment.
E1284.4 channel close response packet (Clos
3 is a diagram illustrating a structure of an e-channel reply packet (e.g.

FIG. 23 is an IEEE diagram used in the description of the embodiment.
E1284.4 connection release command packet (Exit Com
FIG. 3 is a diagram showing the structure of a mand packet.

FIG. 24 is an IEEE diagram used in the description of the embodiment.
E1284.4 connection release response packet (Exit Reply P
FIG. 2 is a diagram showing the structure of an acket.

FIG. 25 is an IEEE diagram used in the description of the embodiment.
Credits used in flow control of E1284.4 (Cr
FIG. 9 is a diagram for explaining a transition state of (edit).

FIG. 26 is an IEEE diagram used in the description of the embodiment.
E1284.4 credit request command packet (Cr
3 is a diagram illustrating a structure of an edit request command packet).

FIG. 27 is an IEEE diagram used in the description of the embodiment.
E1284.4 credit request response packet (Credit
FIG. 2 is a diagram illustrating a structure of a Request Reply Packet).

FIG. 28 is a flowchart showing a schematic control procedure of the present embodiment.

FIG. 29 is a flowchart illustrating a print data reception control procedure of the printing apparatus according to the present embodiment.

FIG. 30 is a flowchart illustrating a method of determining a packet size to be transmitted / received to / from a higher-level device according to the present embodiment.

FIG. 31 is a flowchart illustrating details of a procedure for determining a packet size using a packet information storage area in the present embodiment.

FIG. 32 is a diagram for describing data reception control according to the present embodiment.

FIG. 33 is a flowchart illustrating an interrupt process at the start of data reception according to the present embodiment.

FIG. 34 is a flowchart illustrating a packet reception end process according to the present embodiment.

FIG. 35 is a diagram for explaining a packet information storage area in the memory according to the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 CPU 2 RAM 3 ROM 4 System bus 5 KBC 6 CRTC 7 MC 8 PRTC 9 KB 10 CRT 11 External memory 12 CPU 13 ROM 14 External memory 15 System bus 16 Printing section interface 17 Printing section 18 Input section 19 RAM 20 MC 1020 Operation Unit 1000 printing device 1002 laser driver 1003 semiconductor laser 1004 laser beam 1005 rotating polygon mirror 1006 electrostatic drum 1007 developing unit 1008 paper cassette 1009 paper feed roller 1010 transport roller 1011 transport roller 1012 operation panel 1300 reception buffer 1301 analysis unit 1302 development unit 1303 Expansion memory 1304 Transfer unit 2000 Host computer

Claims (16)

[Claims] 1. An image forming apparatus connected to an information supply device via a communication medium and performing data transfer with the information supply device by a packet communication method, wherein the information supply device is connected to the information supply device via the communication medium. Storage means for monitoring the amount of data transferred and the transfer time communicated therebetween, calculating the transfer rate per unit time, and storing the transfer rate in correspondence with the data packet size used at the time of monitoring And packet size selection means for selecting / changing a packet size when arbitrating a packet size used for data transfer with the information supply device, wherein the packet size selection means is stored by the storage means. An image forming apparatus for selecting a packet size by referring to the data packet size and a transfer rate corresponding to the packet size. 2. The image forming apparatus according to claim 1, wherein said packet size selecting means executes a packet size selection in response to an instruction from an operation unit mounted on the image forming apparatus. 3. The apparatus according to claim 1, wherein said packet size selecting means executes the packet size selection the number of times specified by an operation unit mounted on the image forming apparatus.
Alternatively, the image forming apparatus according to claim 2. 4. The image forming apparatus according to claim 1, wherein said packet size selecting means executes a packet size selection in accordance with an instruction by a specific command from said information supply device. 5. The image forming apparatus according to claim 1, wherein the packet size selection unit executes the packet size selection the number of times specified by a specific command. 6. The packet size selection unit according to claim 1, wherein the packet size selection unit executes a packet size selection in accordance with a procedure instructed from an operation unit mounted on the image forming apparatus. The image forming apparatus as described in the above. 7. The apparatus according to claim 1, wherein said packet size selection means executes a packet size selection in accordance with a procedure specified by a specific command from said information supply device. Image forming device. 8. A method for selecting a packet size in a case where data is transferred by a packet communication method between the information supply apparatus and the information supply apparatus via a communication medium, wherein the information is transmitted via the communication medium. The amount of data to be transferred to and from the supply device and the transfer time are monitored to calculate the transfer speed per unit time, and the calculation result is transferred according to the data packet size used at the time of the monitoring. A speed is stored, and a packet size used for data transfer can be selected / changed when arbitrating with the information supply device. The packet size is selected based on the stored data packet size and the stored data packet size. A packet size selecting method, wherein a packet size is selected with reference to a transfer speed corresponding to the packet size. 9. The packet selection method according to claim 8, wherein the selection of the packet size is performed in accordance with an instruction from an operation unit mounted on the image forming apparatus. 10. The apparatus according to claim 8, wherein the selection of the packet size is performed by the number of times specified by an operation unit mounted on the image forming apparatus.
Alternatively, the packet selection method according to claim 9. 11. The packet selection method according to claim 8, wherein the selection of the packet size is performed in accordance with an instruction by a specific command from the information supply device. 12. The packet selection method according to claim 8, wherein the selection of the packet size is performed by the number of times specified by a specific command. 13. The apparatus according to claim 8, wherein the selection of the packet size is performed according to a procedure instructed from an operation unit mounted on the image forming apparatus. Information transmission method described. 14. The apparatus according to claim 8, wherein the selection of the packet size is performed in accordance with a procedure specified by a specific command from the information supply device. Packet selection method. 15. A computer program sequence for realizing the function according to any one of claims 1 to 14. 16. A computer-readable recording medium storing a computer program for realizing the functions according to claim 1. Description: