JP2806295B2 - Printing system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing system, and more particularly to a printing system for printing out image data transferred from a personal computer (hereinafter referred to as a PC).

When image data from a PC is printed out by a printer, a PC control circuit for performing print control on the PC side and a printer control circuit for performing print control on the printer side are connected via a cable.
Printing is performed by performing mutual control based on a certain protocol.

When such printing control is performed, erroneous printing on the printer side based on the quality of the cable and erroneous recognition and display of the printer state on the PC side, which occur with the speeding up of data transfer, occur. It is necessary that it does not occur.

[0004]

2. Description of the Related Art FIG. 2 shows a configuration of a conventional print system. The PC control circuit includes a protocol control unit 1 and a data transfer control unit 2. The protocol control unit 1 controls transmission and reception of commands and responses accompanying data transmission and reception with the printer control circuit based on a certain protocol. The data transfer control unit 2 performs data transfer processing to the printer control circuit.

[0005] The printer control circuit comprises an interface control unit 11. The interface control unit 11
Controls transmission and reception of data to and from the PC control circuit and transmission and reception of commands and responses at this time. The cable 21 is connected between the PC control circuit and the printer control circuit, and is used for transmitting and receiving data, commands, and responses between each other.

A similar technique is disclosed in Japanese Patent Application Laid-Open No. 5-18 / 1993.
In Japanese Patent No. 3697, one of a plurality of resolutions is input from a printer controller or a data line via a connection cable, the input resolution is determined in the printer device, and the resolution is determined based on the designated resolution. It describes that an image is printed at a specified resolution by setting the rotation speed of a drum.

[0007] Further, in Japanese Patent Application Laid-Open No. Hei 5-219332, the image quality required on the transmitting side from the receiving side is reduced.
Sends function parameters such as transmission image size and resolution,
It describes that an image is transmitted on the receiving side with image quality, transmission image size, resolution, and the like specified by parameters.

[0008]

In the conventional printing system, the PC side has a constant transfer speed and resolution regardless of the quality of the cable connected between the PC control circuit and the printer control circuit. The rasterized image data has been transferred to the printer and printed out.

[0009] Nevertheless, in the past, the data transfer speed was low, so that the performance of the cable did not matter so much, so that accidents such as erroneous printing did not occur. However, recently, when a low-quality cable is used with the speeding up of data transfer, erroneous printing on the printer side and erroneous recognition and display of the printer state on the PC side occur. The problem of becoming unusable has arisen.

An object of the present invention is to solve such a problem of the prior art. In a print system for printing and outputting image data from a PC to a printer, a communication state between the PC and the printer is determined. By feeding back the determined communication status to the control performed by the PC control circuit, erroneous printing on the printer side, erroneous recognition of the printer status on the PC side, and erroneous display occur even when a low-quality cable is used. The purpose is to provide a print system that does not have any problem.

[0011]

Means for Solving the Problems In order to solve such problems of the prior art, the present invention has the following configuration. This aims to achieve the above-mentioned object.

(1) A personal computer (PC) control circuit and a printer control circuit are connected via a cable 21. In the PC control circuit, the data transfer control unit 2
The printer controller performs processing to transfer the generated image data to the printer control circuit, and the protocol controller 1 controls transmission and reception of commands and responses to and from the printer control circuit based on a predetermined protocol. In a printing system in which the interface control unit 11 controls the transmission and reception of data with the PC control circuit and the transmission and reception of commands and responses at this time, the printer control circuit sends dummy data to the printer control circuit based on the instruction of the interface control unit 11. Data generating unit 12 that generates
And a communication status determination unit 3 for determining, in the PC control circuit, the communication status based on the quality of the cable 21 based on the dummy data transferred from the printer control circuit.
And a communication status determination result feedback unit 4 for feeding back the determined communication status to the control performed by the PC control circuit.

In the case of (1) , when the communication status determination result feedback unit 4 has a retransmission instruction generation unit 5 and receives a retransmission request command from the communication status determination unit 3, the PC sends it to the printer 1 The printer sends a command to the protocol control unit 1 requesting that the printer make a plurality of responses to one command.

[0014]

In the case (1) , the communication status determination result feedback unit 4 includes a resolution switching unit 7, and when the communication status determination unit 3 determines that the resolution of the image data is inappropriate, the resolution is changed. Switch.

[0016]

[0017]

In a printing system in which a PC control circuit and a printer control circuit are connected via a cable, processing for switching the transfer speed and resolution of image data is performed in accordance with the performance of the cable. The process of transferring data while confirming the correctness of the response is performed, so that even if the cable is of low quality, the transferred signal is not degraded or affected by disturbance. Therefore, stable transmission and reception of data and transmission and reception of commands and responses can be performed.

[0018]

FIG. 1 shows the configuration of an embodiment of the present invention. Hereinafter, a print system according to the present invention will be described with reference to FIG.

In FIG. 1, a protocol control unit 1 controls transmission / reception of data with a printer control circuit and transmission / reception of a command such as a retransmission command and a response associated therewith based on a predetermined protocol.

The data transfer control unit 2 performs data transfer processing to the printer control circuit in accordance with the transfer speed and resolution of the image data set in the communication status determination result feedback unit 4.

The communication status determination unit 3 sends a dummy data transmission request to the printer control circuit, and based on the result of the fast Fourier transform of the dummy data transferred from the printer control circuit, a communication status determination result feedback unit. It is determined whether the current settings for the image data transfer speed and resolution in 4 are suitable for the cable 21. If the result of the determination is that it is not optimal, the communication status determination result feedback unit 4 is instructed to perform required processing.
The content of the instruction differs depending on the determination result. Further, in response to a command sent from the PC to the printer, a response sent from the printer to the PC is confirmed.

The communication status judgment result feedback unit 4
It has a retransmission instruction generating unit 5, a transfer speed switching unit 6, and a resolution switching unit 7.

When receiving a retransmission request command from the communication status judging unit 3, the retransmission command generation unit 5 responds to the command sent from the PC to the printer a plurality of times from the printer to the PC. Is issued to the protocol control unit 1.

When a request to switch the data transfer rate is issued from the communication status judging section 3, the transfer rate switching section 6 switches the transfer rate of image data and sends the data transfer rate to the data transfer control section 2. Sends a signal to notify.

When a request to switch the resolution is issued from the communication status judging unit 3, the resolution switching unit 7 switches the resolution of the image data, and switches the data transfer control unit 2.
Sends a signal to notify the data transfer control unit 2 of the resolution.

In the printer control circuit, an interface control unit 11 controls transmission and reception of data with the PC control circuit and transmission and reception of commands and responses, and instructs a dummy data generation unit 12 to generate dummy data. Perform The dummy data generator 12 generates dummy data in this manner, and the generated dummy data is sent to the PC control circuit via the interface controller 11.

The cable 21 is connected between the PC control circuit and the printer control circuit, and is used for transmitting and receiving data, commands, and responses. In the case of the present invention, any quality can be used.

The operation of the embodiment shown in FIG. 1 will be described below. A personal computer (PC) and a printer are connected via a cable, and the image data rasterized on the PC side is transferred to the printer side for printing and output, and the PC is connected to the printer via the bidirectional interface protocol. In a print system that monitors the status, the cable is of a low quality that is not suitable for high-speed data transfer, so that erroneous printing occurs on the printer side, or erroneous recognition or display of the printer state on the PC side. Occurs, the PC instructs the PC control circuit to start the maintenance operation. The start of the maintenance operation may be manually instructed from outside, for example.

When the maintenance operation is instructed, the communication status determination unit 3 in the PC control circuit issues a command to the printer control circuit to request generation of dummy data for determining the communication status. The data is sent to the printer control circuit via the protocol control unit 1 and transmitted to the dummy data generation unit 12 via the interface control unit 11.

As a result, the dummy data generator 12
Predetermined dummy data is generated, and the dummy data is sent from the interface control unit 11 to the PC control circuit via the cable 21 and is input to the communication status determination unit 3.

The communication status determination unit 3 analyzes the frequency components of the input data by means of a fast Fourier transform in order to check whether or not the input dummy data is within a predetermined data format allowable range. Then, the distortion of the waveform, the distribution and the intensity of the noise component are examined. Further, it is checked whether the voltage level of the input signal is within an allowable range in an analog manner.

If all of them are within the allowable range, the communication status judging unit 3 instructs the transfer speed switching unit 6 to set a high transfer speed, and the resolution change unit 7 While instructing the transfer as it is, it instructs the retransmission instruction generator 5 not to issue a response retransmission request for confirming the correctness of the response from the printer. Therefore, in this case, high-speed data transfer is possible, and high-speed printing can be performed. In addition, the printer status can be monitored in a state close to real time.

When the communication status determining unit 3 determines that any of the waveform distortion, the noise component, and the voltage level is out of the allowable range, the communication status determining unit 3 lowers the data transfer speed. Request that the input image data be converted to lower-resolution data and transferred, or that the printer responds to the command multiple times for one command sent from the PC to the printer. It is determined whether to issue a command to execute. Data necessary for making such a determination is stored in advance in the communication status determination unit 3.
And a communication status determination unit 3 based on the
Can make either determination.

When the communication status determining unit 3 determines that the transfer speed of the image data is inappropriate, the transfer speed switching unit 6 is instructed to lower the transfer speed. In this case, the transfer speed switching unit 6 performs switching so as to reduce the image data transfer speed, notifies the switched transfer speed to the data transfer control unit 2, and the data transfer control unit 2 thereafter performs the switching. The transfer of image data is controlled at the set transfer speed.

When the communication status determining unit 3 determines that the resolution of the image data is inappropriate, the resolution switching unit 7 is instructed to lower the resolution. In this case, the resolution switching unit 7 converts the input image data into
While converting and transferring to lower resolution data,
The data transfer control unit 2 is notified of the switched resolution, and the data transfer control unit 2 thereafter controls the transfer of image data at the switched resolution.

When the communication status determination unit 3 determines that both the transfer speed and the resolution of the image data are inappropriate, the transfer speed switching unit 6 is instructed to lower the transfer speed, and the resolution is reduced. An instruction to lower the resolution is issued to the switching unit 7. In this case, the transfer speed switching unit 6
Performs switching so as to reduce the image data transfer speed, notifies the data transfer control unit 2 of the switched transfer speed, and the resolution switching unit 7 converts the input image data into data having a lower resolution. And transfer the resolution to the data transfer control unit 2.
Thereafter, the data transfer control unit 2 controls the transfer of the image data at the switched transfer speed and resolution.

When the communication status determination unit 3 determines that it is necessary to instruct the printer to respond a plurality of times to one command from the PC, the retransmission instruction generation unit 5 The user is instructed to give an instruction to that effect. In this case, the retransmission instruction generating unit 5 causes the printer control circuit to instruct the printer control circuit via the protocol control unit 1 to make a plurality of responses from the printer to one instruction from the PC, Thereafter, the PC prevents the erroneous recognition and display of the printer status by confirming a plurality of responses from the printer to one command from the PC.

[0038]

As described above, according to the present invention, dummy data sent from a printer control circuit to a PC control circuit via a cable is analyzed and determined by fast Fourier transform, and the data transfer speed is determined based on the result. Erroneous printing in the printer by switching the resolution, and requesting a response from the printer multiple times for one command from the PC and confirming it.
The printer status is prevented from being erroneously recognized and displayed, so that even if the cable is of low quality, erroneous printing or erroneous recognition or display of the printer status does not occur, and the operation of the printing system can be improved. It is possible to provide a printing system that can be made stable and reliable and has an unprecedented superior effect.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a conventional print system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Protocol control part 2 Data transfer control part 3 Communication status judgment part 4 Communication status judgment result feedback part 5 Retransmission instruction generation part 6 Transfer speed switching part 7 Resolution switching part 11 Interface control part 12 Dummy data generation part 21 Cable

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI H04N 1/32 B41J 29/00 C

Claims (2)

(57) [Claims] 1. A personal computer (hereinafter abbreviated as PC) control circuit and a printer control circuit are connected via a cable. In the PC control circuit, a data transfer control section converts image data generated on the PC side into a printer. The protocol control unit performs a process of transferring the data to the control circuit.
A printer control circuit for controlling transmission / reception of a response, wherein the interface control unit controls transmission / reception of data to / from a PC control circuit and transmission / reception of commands and responses at this time. A dummy data generation unit that generates the dummy data based on an instruction of the interface control unit; and the PC control circuit has a communication status based on the quality of the cable by the dummy data transferred from the printer control circuit. A communication status determination unit for making a determination; and a communication status determination result feedback unit for feeding back the determined communication status to control performed by the PC control circuit , wherein the communication status determination result feedback unit transmits a retransmission instruction.
It has a live part and receives a retransmission request command from the communication status determination part
When one command sent from the PC to the printer is
Request that the printer respond multiple times.
A print command for sending a print command to the protocol control unit . 2. A PC control circuit and a printer control circuit are connected to each other.
Connected to the PC control circuit.
The transfer controller controls the image data generated by the PC.
Performs processing to transfer to the printer control circuit and
The controller controls the printer control circuit based on a certain protocol.
Control the transmission and reception of commands and responses between
In the printer control circuit, if the interface control unit is P
Transmission and reception of data to and from the C control circuit
System that controls transmission and reception of commands and responses
In the printer control circuit, the interface control unit
Dummy data for generating the dummy data based on an instruction;
A printer generation unit, and transferred to the PC control circuit from the printer control circuit.
Communication based on the quality of the cable using dummy data
A communication status determination unit for determining a status;
Feedback of communication status to control performed by the PC control circuit
And a communication status determination result feedback unit that performs resolution switching.
The communication status determination unit
If the resolution is determined to be inappropriate, cut off the resolution.
A printing system characterized by changing.