Facsimile and static presentation processing – Static presentation processing – Emulation or plural modes
Reexamination Certificate
1995-03-29
2002-08-20
Garcia, Gabriel (Department: 2624)
Facsimile and static presentation processing
Static presentation processing
Emulation or plural modes
C358S001110
Reexamination Certificate
active
06437869
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a printer apparatus and a control method therefor in which data received from, for example, a host computer, is analyzed so that an output process is performed.
2. Related Background Art
In a conventional printer apparatus characters, graphics and/or images are formed in accordance with a command issued from a host computer so as to output a document or to control the printer apparatus, such as printer initialization.
Another conventional printer apparatus has a function for responding to a host computer through a bidirectional interface in accordance with a command transmitted from a host computer. The response provides information indicating the state of the printer apparatus, the set environment of the printer apparatus, the progress of the document output and font to be used.
The foregoing function for transmitting various information items about the printer apparatus to the host computer is called, for example, a “status response”.
A variety of bidirectional interfaces have been used in the status response, as exemplified by a known RS-232C, Bi-Centronics, Ethernet and the like developed recently.
In recent printer apparatuses, any of the foregoing bidirectional interfaces have been employed as a standard interface in place of the conventional mono-directional interface.
It is considered that a printer system performing the status response by means of the foregoing bidirectional interface will be widely used.
Use of the status response function will enable the host computer to recognize the state of the connected printer.
For example, a status response indicating whether or not the printer apparatus is able to print out data at present, or information supply indicating occurrence of a problem, such as wanting of paper or paper jamming, will eliminate a necessity for a user to go to the position at which the printer apparatus is located, to confirm the state of the printer apparatus, even if the printer apparatus is located remotely from the host computer.
If information about fonts which can be used with the printer apparatus, about type of graphics which can be formed, and about the printer languages which can be executed, is status-responded, the information serves as instructions to use a proper font and to form an image by using a printer language when document data to be output is processed.
With the conventional monodirectional-interface printer apparatus, the host computer cannot recognize whether or not the printer apparatus has correctly formed an image and whether or not the printing operation is stopped due to a problem after the host computer has transmitted data to the printer apparatus. When data is processed, the host computer must process image data to be formed on an assumption of the fonts and image-forming functions of the printer apparatus. Therefore, it is considered that a system, using both a bidirectional interface and the status response function and causing the host computer to acquire information of the printer apparatus to perform administration, will be usually used.
In a case where the status response is performed by using the bidirectional interface, a command for the status response is issued from the host computer to the printer apparatus.
The printer apparatus analyzes the language in the command to recognize that the command orders a status response, followed by examining information about the subject printer apparatus. Obtained information is described in a format of data to be transferred, and the information is transmitted to the host computer.
The host computer receives the information, and analyzes data so as to recognize the state of the printer apparatus.
As described above, the interface between the host computer and the printer apparatus is established in two directions, one of which runs from the host computer to the printer apparatus, and another of which runs from the printer apparatus to the host computer.
The foregoing two-directional data communication is performed by a method determined depending upon the method of the bidirectional communication. For example, a method is employed in which transmission and receipt are performed at individual timings, or a method is employed in which either of the transmission or the receipt can be performed at a time, and switching is performed between transmission and reception as the need arises.
In the printer apparatus, a major portion of the data communication is shared by transmission of data from the host computer to the printer apparatus.
Therefore, greater importance is placed on data transference from the host computer to the printer apparatus than transference from the printer apparatus to the host computer, and the data flow is intended to be performed efficiently by adjusting the algorithm of the interface and the hardware.
As a result, transmission and reception are not always performed at the same timing. For example, in a case where output data including a status response has been transmitted, the structure, in which the output process is given priority, sometimes inhibits return of the status response until the output data is processed to a certain extent. To perform the response, receipt of the output data must be temporarily stopped, or a portion of the performance of the CPU must be used to perform the response operation. As a result, an efficient printing process cannot be performed.
The transmitting and receiving portion of the host computer has a similar problem.
Generally, the process for the host computer to receive a response from the printer apparatus has lower priority than that given to the process for transmitting output data. Also the transference rate of the operation of receiving data from the printer is usually lower than that of the operation of transmitting data to the printer.
As described above, the usual printer apparatuses focus on data transfer from the host computer to the printer apparatus, and the response is given low priority. Therefore, even if a command for the status response is issued, its response is not always returned immediately.
To prevent delay due to the difference in the processing speed and processing timing among the host computer, the interface for transmitting/receiving data and the printer apparatus, a data buffer is generally disposed at each contact.
For example, a data buffer, called a “receiving buffer” is provided to adjust data transference from the host computer to the printer apparatus through the interface, the receiving buffer being disposed at the inlet port of the printer apparatus. Data transmitted through the interface is temporarily stored in the foregoing buffer. Since the foregoing storage process is performed in synchronization with the processing speed and the processing timing for the interface, load on the interface can be reduced, and thus the process can be performed under the most proper condition for the interface.
Also the printer apparatus is able to receive data from the receiving buffer at the processing speed and processing timing thereof. Thus, the printer apparatus is able to perform the process thereof under the most proper condition.
However, the temporal storage of data inhibits immediately processing of data transmitted from the host computer, but causes a somewhat long time to take place before start of the process.
Even if the host computer issues a command for the status response, command data is temporarily stored in the receiving buffer or the like, and then the printer apparatus sequentially reads the buffers. When the printer apparatus receives the command data, the process is started.
Therefore, the presence of a buffer of the foregoing type in a data conveyance passage will cause a certain time to be taken from the issue of the command for the status response to the receipt of the response.
A status response process to be performed in the printer apparatus will now be described.
It sometimes takes a long time to take information of a response depending upon the contents of the response. An assump
Fitzpatrick ,Cella, Harper & Scinto
Garcia Gabriel
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