JPH028931A - Printer - Google Patents

Abstract

PURPOSE:To improve the utilization efficiency of a receiving buffer by providing a means which controls the receiving buffer to write printing data, means which selectively reads out the printing data from the receiving buffer for printing of one page quantity, etc. CONSTITUTION:Ports P1-P5 are connected to a CPU 12, pre-buffer 15, receiving buffer 16, page buffer 17, and printer control section 18 through a changeover switch 10, an the internal bus 11 of a printer. The CPU 12 stores printing data from each port in the buffer 15 by successively changing over the switch 10 while the CPU 12 manages the storage capacity of the prepositional buffer 15. When the printing data storing quantity of the buffer 15 reaches a specific value, the CPU 12 stores the remaining printing data in the buffer 16 by adding port identifying codes. Upon receiving a page segmenting code, the CPU 12 successively reads out the printing data of the port number from the buffer 16 and writes the read-out data in the buffer 17. The control section 18 prints one page quantity of the printing data by controlling a printing section 19 based on the data written in the buffer 17. Thus the utilization efficiency of the buffer 16 can be improved and the cost can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention receives print data included in separate pages from multiple hosts through multiple ports in a time-sharing manner, The present invention relates to a printer that prints each page.

(Prior Art) In a system in which one printer is shared by a plurality of hosts, a so-called multi-port printer having a plurality of ports is used as the printer.

FIG. 2 shows a block diagram of a conventional multiport printer.

This printer 1 includes five ports PI to P5 to which five hosts H1 to H5 are connected, respectively, and receive buffers B to B8 in which print data received through each port is temporarily stored. It is being

FIG. 3 shows the operation of a conventional multiport printer.

As shown in this figure, the print data 2 transferred from the host is composed of a series of character codes 2a and, at the end, a page separator code (FF code) 2b indicating the end of one page of print data. There is. If you print this on printing paper 3, it will look like the figure.

Incidentally, such print data is not necessarily transmitted continuously from each host. Depending on the host, data transmission may be temporarily interrupted to edit data or prepare for transmission. During this time, it is preferable to receive print data from hosts connected to other ports, thereby increasing the throughput of the entire system.

Therefore, in conventional printers, reception buffers B1 to B,
each has a capacity that can store print data for one page, and while receiving print data from each host H1 to H5 in a time-division manner, the printer The print data was transferred to the control unit and printing was executed.

(Problem to be solved by the invention) Now, here, as an example, 8CP is printed on 84 size paper.
If the maximum number of characters that can be printed is the number of characters when printing Kanji characters on the entire surface at a density of I (characters per inch) and 8 LPI (lines per inch), the amount of data is calculated as follows.

Number of characters: 7 lines:= (257/25.4) X 8=80
．． 80 out of 9 (rounded down) Row/Bage = (384/25.4) x 8 = 120
．． 9 = 6120 (round down) Maximum number of characters on one page = (7 lines of characters) x (line/page) = 80
If it is specified using a Kanji code according to the HS C6226) standard, one character is specified by a 2-byte character code, so the amount of data is as follows.

Number of character data/page = 9,600 X2 = 19,20
0 byte Furthermore, control codes as defined in JIS C6220, i.e. CR, L added at the end of each line.
Including the F coat and the FF coat added at the end of the page, the total amount of data for one page is as follows.

Total data volume/page/character code tens of lines x (
CR+LF)+FF=19,200+80X2+1=19,361 bytes In the case of a multiport printer as shown in FIG. 2, there are five receiving buffers, so the total capacity is as follows.

Total buffer capacity = total data amount/page x number of ports = 19.361 Usually, one page of print data is completed in about 2,000 characters, that is, about 4,000 bytes. Therefore, considering this point, about 20 ODD bytes will be sufficient for 5 bits. For this reason, in the case of the conventional printer shown in FIG. 2, the usage efficiency of the reception buffer is actually about 21%, posing the problem that the expensive memory is hardly used.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a printer in which the use efficiency of the reception buffer is sufficiently increased.

(Means for Solving the Problems) A printer of the present invention receives print data included in different pages from a plurality of ports in a time-sharing manner, and prints each page based on each print data. In the printer, a receiving buffer, a write control means for controlling writing of the print data to the receiving buffer, and selecting the print data included in the same print page from the receiving buffer for printing one page. and read control means for reading out the print data received from one of the ports, and the write control means for receiving the print data received from any of the ports, indicating the port name and the writing order of the print data within the same print page. data ranking and
A reception port identification code including an indication of the reception data capacity is added, and a page separator code is added to the print data received last within the same print page, and the data is stored in the reception buffer, and the readout control is performed. The means is characterized in that the print data is sequentially read out according to the order of the received data up to the print data to which the page delimiter code has been added.

(Operation) When the printer described above receives print data included in separate pages from a plurality of ports, it writes the data into one reception buffer in the order in which it is received. A plurality of pieces of print data included in the same print page are also stored separately in the reception buffer. In this case, each print data includes
For identification purposes, the receiving port name, the rank of received data within the same print page, and the capacity of the received data are displayed. Print data is written one after another from a plurality of ports until the receive buffer is full. On the other hand, the readout control means reads print data included in the same page in order and transfers them to the printer control unit in accordance with the reception order. With this configuration, the receive buffer can be used efficiently and the memory capacity of the entire receive buffer can be made relatively low.

(Example) Hereinafter, the present invention will be explained in detail using embodiments shown in the drawings.

FIG. 1 is an operational explanatory diagram showing an embodiment of the printer of the present invention.

Before explaining this FIG. 1, first, the configuration of the printer of the present invention will be explained.

FIG. 4 is an embodiment block diagram for explaining the configuration of the printer of the present invention.

In the figure, this device has five ports P1 to P1, for example.
It is equipped with 5. These ports are connected to an internal bus 11 of the printer via a changeover switch 10. This internal bus 11 includes a CPU 12 and an RO
M13, RAM 14, prefix buffer 15, reception buffer 16, page buffer 17, and printer control unit 18 are connected. Further, a print section 19 is connected to the printer control section 18 .

The CPU 12 is composed of a microprocessor and the like that controls the overall operation of this printer. Also, ROM1
3 is a read/reader which stores the operating program of the CPU 12.
Consists of only memory elements. RAM14 is CPU1
It consists of a random access memory, etc. that temporarily stores parameters used during the operation of step 2. The front buffer 15 is a memory consisting of a random access memory element or the like that temporarily stores print data received from any port via the changeover switch 10.

The reception buffer 16 is provided as an alternative to the reception buffers B and -B5 shown in FIG. 2, and is also a circuit consisting of a random access memory or the like. In this embodiment, the reception buffer 16 is constituted by a so-called ring buffer in which an address counter endlessly sets the address. The page buffer 17 is a memory that stores one screen worth of print data to be transferred to the printer control unit 18. The printer control unit 18 includes a timing control circuit that controls the printing mechanism and the like in the print unit 19 and the transfer of print data.

Further, the changeover switch 10 is constituted by a switching circuit that switches the connection destination so as to receive print data from ports P+ to P in a time-division manner.

In the above apparatus, the CPU 12 controls the changeover switches 10 in order while managing the memory capacity of the prefix buffer 15, and stores print data from any port in the prefix buffer 15. And prefix buffer 1
When the amount of print data stored in the receiving buffer 16 reaches a predetermined amount, it is stored in a predetermined area of the receiving buffer 16 with a port identification coat to be described later. When the page delimiter code (FF code) is received, the print data of that port number is sequentially read from the reception buffer 16 and written to the page buffer 17. Thereafter, the printer control unit 18 controls the print unit 19 based on the print data to print one page.

Returning to FIG. 1, a detailed explanation of the operation of the printer of the present invention will be given.

In FIG. 1, a changeover switch 10 and a pre-buffer 15
and the receiving buffer 16 are exactly the same as those described in FIG. Further, the write control means 21
The CPU I2 and ROM13 explained in FIG.
The RAM 14 and the like are collectively represented as one block. Further, the readout control means 22 collectively represents the page buffer 17, printer control section 18, and the like.

In the figure, the changeover switch 10 has ports P, ~P
, time-divisionally receives print data sent from hosts H8 to H5 connected to .

FIG. 5 is a time chart showing an example of the receiving operation of such a printer.

In (a) to (e) of the same figure, print data received from the hosts H1 to H6 are shown as bands in the time axis direction, respectively.

For example, from host H+, from time t1 to t2 and time t
From t4 to t5, one page worth of print data is received twice, and an FF coat is added to the end.

Thereafter, part of other print data is received from the host H1 from time 0 to time to. On the other hand, host H
2, predetermined print data is received from time t to t6 and after time t12. Also, from host H3,
From time t2 to t3, from time ty to ta, from to to tl
During the period o, print data for one page is received in three parts. An FF coat is added to the end of the print data. From time t3 to t4 from host H4
and from time t11 to t12, from host H6 to time t6
to t7 and time tl.

Part of the print data of each predetermined page is received between the time and the tth time.

The changeover switch IO shown in FIG. 1 operates to switch the receiving port each time, such as at times j+, jz, 'ea...t1□, as shown in FIG.

Further, the front buffer 15 shown in FIG. 1 is for temporarily storing a predetermined amount of print data while receiving it from one host. At this time, the write control means 21 adds a port identification coat 31 to the beginning of the print data 30. Actually, an area for storing the port identification code 31 is provided in advance in the pre-buffer 15, and the code is written there at the same time as the changeover switch 10 switches the port.

FIG. 6 shows an explanatory diagram of control data created and used by the write control means according to the present invention. The specific structure of the port identification coat 31 is shown in FIG.

This port identification coat 31 is composed of a port name 31a, a received data rank 31b, and a received data capacity 31c.

The port name 31a is a numerical value representing the number of the port that received the print data. Received data rank 31
b represents the reception order of print data included in the same print page. For example, if we look at the print data received from the host H1 shown in FIG. 5(a), the reception order from time tI to t2 is The data order is 1", and the received data order from time t4 to time t is "2". Also,
The reception data capacity 31c indicates the data length of the print data written to the reception buffer every time, for example, the fifth
From time 1+ received from host H3 in Figure (a) to t2
If the print data up to - is written into the reception buffer all at once, the total amount of data is shown.

In addition to this, data as shown in FIG. 6(b) is stored in the RAM 14 shown in FIG. 4 as necessary control data.

This data stores control data such that each print data stored in the reception buffer 16 has already been stored four times for port P1, for example. actually,
When print data is received from any port, this port reads the number of stored received data and adds "1" to it to obtain the received data order 31b shown in FIG. 6(a) of newly written print data. . Each time print data is written into the reception buffer, the number of stored port reception data is counted up by one.

Next, the data actually written to the reception buffer 16 will be explained.

As shown in FIG. 1, the reception buffer 16 is a ring buffer, and each received print data 30
A port identification coat 31 is added to and written on.

Here, in the figure, an area 31' for an identification coat and a vacant space 30
The area indicated by ' is an area in which no print data has been written yet, or an area in which a port identification code and print data have already been written, and after which printing has been completed and storage is no longer necessary. In reality, the size of this area is determined by the received data volume of the previously received print data.

Therefore, the free area 3 in which the next print data should be written in advance
0' and the size A of that area as the pre-buffer 15.
The maximum capacity that can be written to is limited. This operation is controlled by the write control means 21. The write control means 21 receives print data from one of the hosts, stops receiving the print data when the print data reaches a predetermined limit amount in the prefix buffer 15, and writes the print data to the prefix buffer 15. The received port identification coat 31 and print data 30 are transferred to the reception buffer 16 as they are. Then, it searches for a free area 30' that can store the next print data, controls the capacity of the prefix buffer 15 to, for example, B, and starts receiving print data from the port again.

Next, the reading operation from the receiving buffer for printing by the printer of the present invention will be described.

FIG. 7 shows an explanatory diagram of the operation of the read control means.

During the reception operation as described above, if an FF coat is added to the print data received from any host, the write control means 21 in FIG. On the other hand, it instructs to read all the print data included in the same print page received from that port.

Here, as explained earlier, in this embodiment, the reception buffer 16 is a ring buffer, so the storage location of the print data received from a specific port (in the example shown, the port name is Port No. 1) is , the address order is random as shown in FIG. Therefore, first, the read control means 22 finds the port identification coat 31 with the first received data order, and finds the received data capacity C.
While recognizing this, the print data following the port identification code is sequentially read out and stored in the page buffer 17. next,
Search for the port identification coat 31 with the second rank of received data,
The print data is stored in the page buffer again.

Thereafter, in the same way, all print data included in the same page are stored in the page buffer in order based on their contents fic, D, and E, and when the print data with the FF coat added is finally written, printing is executed. do.

In the above device, the specific memory capacity required for the reception buffer is as follows.

First, the capacity of the memory buffer needs to be larger than the total data for one page. That is, for example, a maximum of 9.60
In the case of 0 characters/page, the memory capacity at this time is 19,361 bytes as described above. Therefore,
It is sufficient if it exceeds this value.

On the other hand, in order not to reduce the throughput of the system during normal operation, it is required that the amount of print data be greater than the total amount of print data from each port during normal operation. That is, as explained above, if the normally received print data is 4,000 bytes/page, 20,000 bytes/page is equivalent to 5 bots.
Becomes a part-time worker. Therefore, it is sufficient to have a capacity exceeding this value.

From the above conditions, it can be seen that the reception buffer only needs to have a capacity of at least 20,000 bytes.

On the other hand, there are basically no major restrictions on the memory capacity of the prefix buffer 15. However, considering normal usage conditions, it is preferable that the print data be about 1/2 of one page's worth of print data, that is, about 2,000 bytes.

Therefore, the sum of the prefix buffer 15 and the reception buffer 16, ie, the total capacity of the reception buffer, is as follows.

Total receive buffer capacity = Pre-buffer capacity + Receive buffer capacity = 2,00
0+20,000 = 22000 bytes Compare this with the conventional method.

In the conventional case, the total capacity of the receiving buffer is 96,805
It was a part-time job. Therefore, if we take the difference from the total capacity of the receive buffer of the present invention, this becomes 74.805 bytes.

That is, the reduction rate is approximately 77%, and the reception buffer usage efficiency during normal operation is approximately 91%. However, strictly speaking,
The total receiving buffer capacity varies depending on the system environment in which this multiport page printer is used.

Therefore, by limiting the conditions, it is possible to further improve the utilization efficiency.

Also, during operation, if the total amount of received data from all ports exceeds the above receive buffer capacity, any port currently receiving data, for example, if the amount of written data is the largest The port data is transferred to the page buffer at that point. In this way, the free area in the receive buffer is increased, and data subsequently received from the same port is transferred directly from the pre-buffer to the page buffer until the FF code is received.

By adding such a function, even if the reception buffer capacity is kept low, there is a very low possibility that the capacity will be exceeded and cause any harm.

The present invention is not limited to the above embodiments.

Although we have shown an example in which the receive buffer is a ring buffer, in reality any memory configuration can be used as long as it is possible to find an empty area within the receive buffer and store a series of data there in sequence. do not have. Furthermore, although the explanation has been given using an example in which a prefix buffer is provided, if the write control means finds an empty area in the receive buffer and directly writes the print data received from the host together with the port identification code, the prefix buffer is not necessarily provided. There is no need to provide a storage buffer.

However, the print data will be received according to the size of the free space,
The above embodiment has a more practical configuration in that the print data can then be written into the reception buffer with a simple transfer operation.

(Effects of the Invention) As explained above, the printer of the present invention is capable of identifying the reception port name, the reception order of the print data, and the reception Since the data is stored in the reception buffer with a port identification code that includes the data capacity, it is possible to mix print data in one reception buffer, select and read it at any time, and print it. . By adopting such a configuration, the capacity of the reception buffer can be made sufficiently small, and the memory usage efficiency can be extremely high, and costs can also be reduced.

[Brief explanation of the drawing]

FIG. 1 is an operational explanatory diagram showing an embodiment of the printer of the present invention;
FIG. 2 is a block diagram showing an example of a conventional multiport printer, FIG. 3 is an explanatory diagram of the print data reception operation of a conventional general multiport printer, and FIG. 4 is a block diagram showing an embodiment of the printer of the present invention. FIG. 5 is a time chart of the receiving operation of the printer, FIG. 6 is an explanatory diagram of control data of the apparatus of the present invention, and FIG. 7 is an explanatory diagram of the operation of the readout control means of the apparatus of the present invention. DESCRIPTION OF SYMBOLS 10... Changeover switch, IS... Prefix buffer, 16... Reception buffer, 21... Write control means, 22... Read control means, 30... Print data, 31... Port Identification coat, H8-H5...Host, P1-P5...Port.

Claims (1)

[Scope of Claims] 1. A printer that receives print data included in different pages from a plurality of ports in a time-sharing manner and prints each page based on each print data, comprising: a reception buffer; a write control unit that controls writing of the print data into the reception buffer; and a read control unit that selects and reads out the print data included in the same print page from the reception buffer for printing one page. and the write control means writes the print data received from any of the ports,
Add a reception port identification code that includes the port name, the reception data order indicating the writing order of the print data within the same print page, and the reception data capacity, and A page separator code is added to the received print data and stored in the reception buffer, and the read control means reads the print data according to the order of the received data up to the print data to which the page separator code is added.
A printer characterized by sequential reading. 2. A pre-buffer is provided to temporarily store print data received from a port and before being stored in the receive buffer, and the write control means writes the print data in the receive buffer into the pre-buffer. When a free area in which all or part of the print data can be stored is selected, the print data is allowed to be stored in the prefix buffer by the capacity of the free area, and the print data that has been stored is transferred to the reception buffer. The printer according to claim 1, characterized in that: