JP2004054504A - Print control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quickly transfer print data by using the isochronous transfer of a UBS interface. <P>SOLUTION: Print data are added with a header, and divided into packet sizes set by a USB interface, and the packet data are copied so that a plurality of packets whose data are the same can be prepared. Those packets are assigned with numbers. The packet whose data error is detected is not basically used, and only the correctly received data are linked so that print data can be prepared. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a print control device that uses a USB interface for data transfer.
[0002]
[Prior art]
Conventionally, print data has not been transferred using the isochronous protocol of the USB serial interface.
[0003]
[Problems to be solved by the invention]
However, the above conventional example has the following problems.
[0004]
With bulk transfer, you do not know when the data is actually transferred.
[0005]
When isochronous transfer is used, a retransmission request cannot be made even if a data error occurs.
[0006]
In order to solve the above problem, the printer secures a data transfer rate higher than the transfer rate necessary for data transfer, sends out the same data packet multiple times, checks the received data on the printer side, connects the correct data, and An object of the present invention is to provide a print control device that prints data using the data.
[0007]
[Means for Solving the Problems]
The present invention has solved the above problem by providing the following configuration.
[0008]
(1) In a print control device that is connected to a host computer via a USB interface and transfers print data using an isochronous protocol,
a. A packet number is added to data divided into packets, and the same packet number is assigned to a packet containing the same data. B. Outputting a plurality of packets containing the same data repeatedly c. Determine the number of repetitions according to the designation of the number of repetitions from the print control device, and create data to be transmitted d. Outputting the above print data from the host computer e. Check the received data to see if the data was received correctly. F. Create print data by connecting correctly received data g. If all the repeated data are errors, create print data using the data of one of the packets h. Maintaining the probability of data error in data transfer i. The print control device according to any one of the above a to i, wherein the number of times the same data is repeated is changed based on the probability of a data error.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
(First embodiment)
FIG. 1 is a diagram showing a configuration of a printing apparatus according to the present invention. In the figure, 101 is a host computer for outputting print data, 102 is a print control unit, 103 is a CPU for controlling the entire print control unit 102, and 104 is control for data access from each block of the print control unit 102. 105, a USB interface unit; 106, a ROM containing an operation program and font data of the CPU 103; 107, a work memory of the CPU 103; a buffer for storing received data; and a created bitmap data. A RAM 108 is an engine interface for synchronizing with the recording unit 109 and outputting video data, and a recording unit 109 for actually printing and outputting on paper.
[0010]
With reference to FIG. 2 and FIG. 3, the flow of operations of the host computer and the printer that are generally performed will be described below.
[0011]
FIG. 2 is a flowchart of the operation of the printer driver software in the host computer in the present embodiment.
[0012]
FIG. 3 is a flowchart of the operation of the CPU 103 in the present embodiment.
[0013]
When printing is instructed by the application software of the host computer 101, the application software creates print data and requests printing to the OS of the host computer 101. The printer driver software receives the print data according to an instruction from the OS, and creates the print data so that the printer can understand the print data. In the USB interface, in order to transfer code information, a bulk mode is designated as a data transfer protocol, and print data is divided into packets and output from the host computer 101 to a printing device.
[0014]
Next, the operation in this embodiment will be described.
[0015]
First, when the printing apparatus is connected to the host computer 101, the printing control apparatus 102 communicates with the host computer 101 via the USB interface unit 105, and connects the data transfer protocol to be used in an isochronous manner. At this time, the printing device reports twice the required data transfer width to the host computer 101 as the data transfer width.
[0016]
When printing is instructed by application software of the host computer 101, the application software creates print data and requests printing to the OS of the host computer 101. The printer driver software receives print data according to an instruction from the OS, and creates bitmap data from the data. The created bitmap data is divided into a packet size reduced by the header from the packet size specified by the interface, and a header such as packet number data is added to the head of the packet. Then, the same data as the packet is copied, and print data in which the same data packet is continued is created. The created print data is sent from the host computer 101 to the 105 USB interface unit of the print control unit 102. The data received by the USB interface unit 105 is checked by CRC. The CPU of 103 checks the result of the CRC, and reads the head data of the buffer of the 105 USB interface unit. Since the first data is a header, the number of this packet is held. If the packet number is different from the packet number of the previous packet and a data error has occurred, the CPU of 103 reads and discards all the data stored in the buffer of the USB interface unit of 105. Then, the received data of the next packet is read from the buffer of the USB interface unit 105, the header is removed, and transferred to the RAM 107. If the first packet is received correctly, the CPU of 103 removes the read header from the buffer of the USB interface unit of 105, transfers it to the RAM of 107, and reads the next packet of received data without reading. The packets received as correctly as possible are connected according to the packet number in the header to make the original bitmap print data. If bitmap data that does not overrun is stored in the RMA 107 based on the received data amount, the data transfer amount, and the printing speed, the start address and the like of the bitmap data are set in the engine interface unit 108 to start up. Multiply. The activated engine interface unit 108 starts reading bitmap data from the RAM 107. On the other hand, it instructs the recording unit 109 to start printing, converts bitmap data into video data in accordance with the synchronization signal from 109, and outputs the video data. In the recording unit 109, a laser diode is issued based on the video data received from the engine interface unit 108, and printing is performed.
[0017]
(Second embodiment)
Hereinafter, the operation of the second embodiment will be described.
[0018]
The printing apparatus stores the number of times a data error has occurred in the past when receiving print data from the host computer 101, and based on the probability that the number of times the same data packet is sent and the error occurrence rate can be increased, the The case where the number of repetitions is determined is shown below.
[0019]
FIG. 4 is a flowchart of the operation of the printer driver software in the host computer according to the present embodiment.
[0020]
FIG. 5 is a flowchart of the operation of the CPU 103 in the present embodiment.
[0021]
The print control device 102 holds the error probability of the data transfer performed in the past. For example, the number of occurrences of an error with respect to the number of received packets. In a system (environment) where the error occurrence probability is high, if the same packet is still generated even if it is repeated twice, a data transfer width capable of transmitting the same data three times is requested to the host computer 101.
[0022]
The rest is executed in the same manner as in the first embodiment.
[0023]
【The invention's effect】
As described above, the printer secures a data transfer rate higher than the transfer rate necessary for data transfer, sends out the same data packet multiple times, checks the received data on the printer side, connects the correct data, and connects one print data By performing printing using the data, the data transfer speed can be determined, so that the required print data can be output at high speed. As for the capacity of the receiving buffer, if a sufficient data transfer rate can be secured, printing can be performed with a small number of buffers.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a printing apparatus according to the present invention; FIG. 2 is a flowchart of an operation of printer driver software in a host computer in a first embodiment; FIG. 3 is an operation of a CPU in the first embodiment; FIG. 4 is a flowchart of the operation of the printer driver software in the host computer in the second embodiment. FIG. 5 is a flowchart of the operation of the CPU in the second embodiment.
101 Host computer 102 Print control unit 103 CPU
104 controller 105 USB interface 106 ROM
107 RAM
108 engine interface unit 109 recording unit

Claims (1)

In a print control device that is connected to a host computer via a USB interface and transfers print data using an isochronous protocol,
a. A packet number is added to data divided into packets, and the same packet number is assigned to a packet containing the same data. B. Outputting a plurality of packets containing the same data repeatedly c. Determine the number of repetitions according to the designation of the number of repetitions from the print control device, and create data to be transmitted d. Outputting the above print data from the host computer e. Check the received data to see if the data was received correctly. F. Create print data by connecting correctly received data g. If all the repeated data are errors, create print data using the data of one of the packets h. Maintaining the probability of data error in data transfer i. The print control device according to any one of the above a to i, wherein the number of times the same data is repeated is changed based on the probability of a data error.

Images