Facsimile and static presentation processing – Static presentation processing – Communication
Reexamination Certificate
1997-07-31
2003-12-16
Garcia, Gabriel (Department: 2624)
Facsimile and static presentation processing
Static presentation processing
Communication
C358S001160, C358S001170
Reexamination Certificate
active
06665082
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a printer system constituted by a printer controller and a printer interconnected by a bus. The printer controller constituting the printer system supplies the printer with image data via the bus, and the printer prints the image, which is represented by the image data supplied by the printer controller, at a constant speed. The present invention further relates to the printer and printer controller that construct this printer system. The present invention relates to a method of controlling the operation of the printer system, a method of controlling the operation of the printer and a method of controlling the operation of the printer controller.
2. Description of the Background Art
Parallel communication using a Centronics interface or an SCSI (Small Computer System Interface) and serial communication using an RS232C, RS422 or USB (Universal Serial Bus) are utilized to transmit image data from a printer controller to a printer. With these communication schemes, image data is transmitted from the printer controller to the printer irrespective of the printing speed of the printer. It is required that the printer be provided with an image memory having enough storage capacity to store image data representing at least one frame of an image (the image printed on one sheet of paper). This makes it difficult to lower the cost of the printer.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to make it possible to construct a printer using an image memory having a comparatively small storage capacity.
In order to supply a printer with image data from a printer controller, the present invention utilizes IEEE (Institute of Electrical and Electronic Engineers, Inc.) Standard 1394 for high-speed serial transmission. With IEEE Standard 1394, which is currently under consideration in the art, isochronous transfer and asynchronous transfer are possible.
With isochronous transfer, data referred to as cycle-start packet data is in principle generated at an isochronous cycle (125 &mgr;s) by any of a plurality of nodes connected by a bus. Data is transmitted from a certain node (this node is a cycle master, as will be described later) to another node every isochronous cycle. Isochronous transfer, which makes it possible to perform data transmission without fail within the isochronous cycle, transmits data unilaterally from the transmitter to the receiver. Asynchronous transfer is such that when the receiver receives transmitted data, a signal indicating that the data has been received is sent back to the transmitter.
A first aspect of the present invention provides a printer system constituted by a printer and a printer controller. The printer and the printer controller in this printer system are connected by a bus, and the printer controller supplies the printer with image data via the bus. The printer prints the image, which is represented by image data supplied by the printer controller, at a constant speed.
The printer is equipped with a buffer memory having an image-data storage capacity smaller than the quantity of image data representing one frame of the image, the buffer memory temporarily storing the image data supplied by the printer controller. Either the printer or the printer controller is provided with a device for generating a start signal which indicates start of supply of the image data.
The printer controller has image-data transmission start control means (an image-data transmission start controller) for starting transmission of image data to the printer in packet units upon elapse of a predetermined period of time from generation of the start signal, and image-data transmission control means (an image-data transmission controller) for repeating, in packet units, the transmission of image data to the printer in such a manner that the image data that has been stored in the buffer memory will not be emptied from the buffer memory.
The printer has storage control means (a storage controller) for receiving image data transmitted from the printer controller and storing this image data in the buffer memory, and printing control means (a printing controller) for reading out the image data that has been stored in the buffer memory and printing an image, which is represented by the image data read out, at a constant speed.
The first aspect of the present invention also provides an operation control method suited to the printer system described above. Specifically, there is provided a method of controlling operation of a printer system constituted by a printer controller and a printer connected by a bus, wherein the printer controller supplies the printer with image data via the bus and an image, which is represented by image data supplied by the printer controller, is printed in the printer at a constant speed. The printer is provided with a buffer memory having an image-data storage capacity smaller than the quantity of image data representing one frame of the image, the buffer memory temporarily storing the image data supplied, and either the printer or the printer controller generates a start signal.
The method further includes starting transmission of image data from the printer controller upon elapse of a predetermined period of time from generation of the start signal, repeating, in packet units, the transmission of image data from the printer controller in such a manner that the image data that has been stored in the buffer memory will not be emptied from the buffer memory, and, in the printer, receiving image data transmitted from the printer controller, storing this image data in the buffer memory, reading out image data that has been stored in the buffer memory and printing an image, which is represented by the image data read out, at a constant speed.
In accordance with the first aspect of the present invention, the printer is provided with the buffer memory having a storage capacity capable of storing image data the amount of which is less than the amount of image data representing one frame of an image (which means, as described above, the image printed on one sheet of paper).
In the printer controller, transmission of image data to the printer from the printer controller in packet units is started upon elapse of a predetermined period of time from generation of the start signal, and transmission of the image data to the printer from the printer controller in packet units is repeated in such a manner that the image data that has been stored in the buffer memory will not be emptied from the buffer memory.
The image data that has been transmitted is received by the printer in packet units and is stored temporarily in the buffer memory of the printer. The image data that has been stored in the buffer memory is read out and the image represented by the read image data is printed at a constant speed.
The printer need not be provided with a memory having a large storage capacity capable of storing the quantity of image data representing one frame of an image. It will suffice to provide the printer with a buffer memory of small capacity, thereby lowering the cost of the printer.
The continuity of image data can be maintained because succeeding data is transmitted from the printer controller before the data already in the buffer memory vanishes. Accordingly, the printer used can be one which prints images at a constant speed.
Printing speed data representing the printing speed and storage capacity data representing the storage capacity of the buffer memory may be stored in the printer. In such case the stored printing speed data and storage capacity data would be transmitted to the printer controller.
The printer controller receives the printing speed data and storage capacity data transmitted from the printer and determines the amount of image data included in a packet based upon the printing speed data and storage capacity data received.
The printing speed and the storage capacity of the buffer memory may be entered into the printer controller. In such case the amount of d
Funazaki Fumihiro
Takeoka Yoshiki
Watanabe Mikio
Birch & Stewart Kolasch & Birch, LLP
Fuji Photo Film Co. , Ltd.
Garcia Gabriel
Tran Douglas
LandOfFree
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