Electrical computers and digital processing systems: multicomput – Computer-to-computer session/connection establishing – Network resources access controlling
Reexamination Certificate
1999-12-08
2003-04-15
Geckil, Mehmet B. (Department: 2142)
Electrical computers and digital processing systems: multicomput
Computer-to-computer session/connection establishing
Network resources access controlling
C358S001150
Reexamination Certificate
active
06549947
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a print system and a host device for the print system.
The present application is based on Japanese Patent Application No. Hei. 10-351085, which is incorporated herein by reference.
2. Description of the Related Art
There has already been known a print system comprising a host device, such as a personal computer, and a printer which performs printing operation upon receipt of print data from the host device. Functions and performance required of the print system are growing increasingly sophisticated. In some cases, a printer is equipped with a high-performance CPU, large-capacity memory, and a high-speed/high-performance engine, thus tending to become increasingly large. In other cases, a printer has only the minimum required functions; for example, typically a printer is equipped with only the basic function of performing only printing operation upon receipt of bitmapped image data. There exists a reasonable level of demand for this type of printer (called a dumb printer or host-based printer), because of its low price.
One of the major factors which make the dumb printer attractive to users resides in low price, and another major factor resides in negating the need for laborious operation of a control panel. In contrast, the major drawback of the dumb printer resides in low-grade functionality. In designing a dumb printer, in order to minimize price the manufacturer must inevitably make efforts to use low-level components, completely eliminate a control panel, and embody the greatest-possible print performance and functions.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a high-performance print system employing a dumb printer.
Accordingly, the present invention provides a print system including a printer and a host device which is connected to the printer in a communicable manner and controls the printer. The printer comprises memory used as a receiving buffer; receiving means which receives print data transmitted from the host device and stores the thus-received print data into the receiving buffer; print means which performs print operation on the basis of the print data stored in the receiving buffer; status data means which determines the current status of or an error in the printer, prepares status data representing the thus-determined status or error, and retains the thus-prepared status data; and response means which, in response to an individual command sent from the host device, prepares a reply including the currently-retained status data and sends the reply back to the host device. Further, the host device comprises print data preparation means for preparing the print data; data transmission means which divide the thus-prepared print data pertaining to a single job into a plurality of fractional data sets, prepares a plurality of data transmission commands, each of which includes a corresponding one of the fractional data sets, and sequentially transmits the data transmission command to the printer; status acquisition means which receives a reply transmitted from the printer in response to each of the data transmission commands and acquires the status data included in the thus-received reply; and user interface means which informs the user of the status of or error in the printer, on the basis of the thus-acquired status data.
In the print system, the host device divides print data into a plurality of fractional data sets (for example, band data divided on a per-page basis or a per-band basis). The fractional data sets are transmitted to the printer in the form of data transmission commands. Every time the host device transmits a data transmission command, the host device receives a reply from the printer, thus determining the current status of or an error in the printer. The thus-determined status or error is reported to the user. Hence, the user can ascertain the current status of the printer on a user interface screen of the host device. Further, the host device utilizes the thus-determined status or error in determining whether to continue, suspend, or resume transmission of subsequent data, or in determining whether to delete subsequent data. Accordingly, although the printer per se is inexpensive and has a simple structure, the host device can effect considerably-sophisticated print control.
Preferably, the host device further comprises status request means which sends, to a printer, a status request command for requesting status data when the host device fails to send any data transmission command. By virtue of this status request means, even before transmission of print data or when transmission of print data is suspended for reasons of occurrence of an error, the host device can keep track of the status of the printer, whenever necessary, and determine the next appropriate operation.
Preferably, the printer further comprises means for notifying the host device of the capacity of the memory in response to an inquiry about memory capacity transmitted from the host device. The host device further comprises means which transmits the inquiry about memory capacity to the printer before preparation of the print data pertaining to a single print job and which receives the memory capacity from the printer. The print data preparation means of the host device prepares print data by expanding all the image data into a bit image. At this time, a plurality of transmission modes having different resolutions or levels of halftone are prepared with regard to the bit image. An appropriate transmission mode is selected from the plurality of transmission modes in accordance with the memory capacity reported by the printer. As a result, for example, in a case where the memory is of small capacity, there is prepared a bit image having lower resolution and a lower level of halftone. Thus, there can be prepared print data which can be processed by the printer; i.e., which can be processed within the range of capacity of the memory of the printer. Therefore, even when the capacity of the memory of the printer is small, normal printing can be effected.
Preferably, the fractional data sets correspond to band data into which each page is divided on a per-band basis. The print means of the printer initiates printing operation when the printer has received band data pertaining to a predetermined number of bands smaller than the number of bands corresponding to a single page of the beginning of print data pertaining to a single print job. The print means of the printer initiates printing operation when the receiving buffer becomes full before receipt of the band data pertaining to the predetermined number of bands. Accordingly, the printer can perform normal printing even when the memory of the printer is of small capacity.
Preferably, buffer-full data representing whether or not the receiving buffer is full are included in a reply returned from the printer. When the buffer-full data included in the reply returned from the printer represents that the receiving buffer is full, the data transmission means temporarily suspends transmission of a subsequent data transmission command, the status request means repeatedly sends to the printer the status request command, and, on the basis of a replay returned from the status request command, the host device determines whether or not the receiving buffer has been released from a full state. When the receiving buffer has been released from a full state, the data transmission means resumes transmission of the subsequence data transmission command.
The print data are divided into a single or a plurality of fractional data sets on a per-page basis. Before transmission of the data transmission command pertaining to a certain page, the host device transmits a page start declaration command including designation of the number of copies to be printed. Further, the host device determines whether or not all the data transmission commands pertaining to the page can be stored in the receiving buffer of the printer (that is, whether convention
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