|Thursday, 19 October 2006|
Fax machines are able to send and receive arbitrary image data to and from a remote communication device. A fax machine scans an original document, transmits an image of the document to a remote fax receiver, and reproduces the received image on a printer of the receiver. Facsimile machines operate by encoding an image on a paper into a series of tones that are then transmitted over the telephone network to a receiving facsimile machine. The transmitters of the fax machines scan the images and data, encode and convert the images and data into appropriate signal waves and then send them to receiver fax machines at a remote end via wire or wireless channels. The receiving facsimile machine decodes the transmitted message and reconstructs the image. A fax machine divides a still image, such as characters, photographs and pictures, into picture elements through scanning, and converts them into electrical signals for the purpose of transmission. In addition to this operation, the facsimile machine performs reception in which the original image transmitted is realized, after receiving the electrical signals transmitted from a long distance. Standard facsimile protocols for effectuating communications between facsimile machines have been defined, and most facsimile machines operate using one or more such protocols. Before a facsimile image is transmitted from an originating facsimile machine to a terminating facsimile machine, the originating and terminating facsimile machines send messages between the machines to negotiate transmitting and receiving modes for transmitting fax data. This process is to specify a set of parameters that are agreed upon prior to transmitting facsimile data. These parameters may include a data bit rate, a page size, the number of pixels per line, the number of lines per page, and whether or not any fill characters are added to a line so that the terminating facsimile machine has time to print each line. Generally facsimile machines are capable of two types of transmission. With the first type, the facsimile machine transmits encoded data immediately to a remote device. In the second type of transmission, the facsimile machine stores encoded data in a memory and transmit it at a later time. This first type of the facsimile transmission is called direct transmission and the second type of transmission is called memory transmission.
A fax machine comprises a feed roller driven to feed sheets of paper individually, and a transmission roller driven to deliver fed sheet of paper at a higher speed. The feed roll assembly generally comprises an axle, a roll fixedly mounted around the axle in the middle, a transmission gear revolvably mounted around one end of the axle and coupled to a motor drive, a coupling wheel mounted around the axle adjacent to the transmission gear and turned with the axle, and a spring mounted around the coupling wheel and connected to the transmission gear. Fax machines typically use a special paper which is installed in rolls and which tends to curl. The printed pages accumulate in the stacker until they are removed manually. The capacity of the stacker differs from one facsimile machine to another, but in any case, the printed pages should be removed often enough to keep the stacker from becoming full. If the facsimile machine is out of paper, the facsimile machine temporarily stores received messages in a memory and then prints the stored message received when paper is added to the machine. Most fax machines today have the capability to warn the user when the end of the paper roll is near or the paper has been exhausted. This warning is done through audible alarms and/or display messages on the fax machine. If the receiving facsimile machine is interfaced to a personal computer, incoming image data can be transferred to the personal computer system. Most facsimile machines include a microprocessor-based controller that monitors various inputs and controls the overall operation of the facsimile machine. The controller also controls when the facsimile machine transitions between the main operating mode and the standby mode. The facsimile machine is also provided with an operating panel where various keys for transmitting operation instructions are disposed. This operating panel is provided on the top of the upper guide member so as not to interfere with the feed or discharge of a document being transmitted. On the operating panel, there are disposed various function keys, such as dial number keys, automatic dial call keys for calling stored dial numbers of destinations, keys for setting the image quality of the document to be transmitted, a redial key for calling a previously dialed destination again; and a conversation reserve key. Various types of standby power sources are used depending upon the requirements of a particular application. Some facsimile machines use a second, smaller power supply for standby mode that consumes less power than the main power supply. Other facsimile machines use a battery-based standby power supply. In the standby mode, the main power supply is de-energized to conserve power and to extend the life of various parts and equipment in the facsimile machine.
A facsimile machine for transmitting and receiving via telephone line images generally comprises an image reader for reading images on the original as image information, a printer for printing the read image information on paper, and a transmission-reception device for transmitting and receiving via the telephone line the image information. The image reading unit of a facsimile transmitter typically employs a contact image sensor (CCD image sensor) for reading information on the original documents and converting them into electrical signals. To read information from an original document, the document is fed in an auxiliary-scanning direction by the stepping motor while the image scanner optically scans the original document in a main-scanning direction perpendicular to the auxiliary-scanning direction. The information optically read during these scans is photoelectrically converted into an electric signal. Fax machines have various functions, such as an image capturing function, a printing function, a communication function, a multi-copying function, an auto-answer function, a memory transmission function, and a scheduled transmission function, etc. The facsimile machine has not only a function of transmitting and receiving image data of an original in a standard mode which corresponds to a low resolution, but also a function of transmitting image data in a fine or super fine mode which correspond to higher resolution. Facsimile machines which are provided with a copying function and a reducing function have been practically used. The multi-copying function is capable of generating plural sets of copies of the original documents upon reading the original documents with the scanner. A facsimile machine with a copying function has many keys in an operation unit in order to instruct details of copying operation, and facsimile operation. A facsimile machine may be capable of receiving information from one remote facsimile machine and forwarding the information to a different target facsimile machine. The facsimile machine can be inputted with the telephone number of the target facsimile machine either directly using the operation panel of the facsimile machine or by remote control from a remote facsimile machine. Some facsimile machines are provided with a mailbox function. While the facsimile machine is in its answering machine mode, a caller from a remote telephone or facsimile machine, by performing operations at the remote device, can access confidential data, such as voice data or image data, stored in mailboxes formed in a memory of the facsimile machine. Control programs for the various functions of the facsimile machine and for data transfer between the facsimile machine and its associated personal computer are stored in a read-only memory (ROM) equipped in the facsimile machine.
In addition to the traditional facsimile functions of the transmission and reception of image data, the fax machines which are connected to personal computers or workstations are also provided with a variety of functions which enable them to be used as printers for such information processing devices, as scanners, as modems and as copiers. In this facsimile-personal computer system, the fax machine can function as a scanner for the personal computer if it is used to scan an image and send it to the personal computer. The personal computer then modifies or processes the image data. The fax machine can also function as a printer for the personal computer if it is used to receive image data from the personal computer. The fax machine can further function as a modem for the personal computer if it is used to receive and send image data from and to a remote communication device. Network facsimile machines have been developed which exchange email with other terminals via a local area network and the Internet and, in addition, exchange facsimile data with other facsimile machines via a public switched telephone network using facsimile communications procedures. Such facsimile machines can relay facsimile image information to a destination facsimile machine in response to receiving, over a local area network of the Internet, e-mail that contains such facsimile image information and a telephone number for the destination facsimile machine. Via the network, a fax machine receives an electronic mail message from the internet and extracts the image attachment. The fax machine then prints the image. If the fax machine sends the facsimile to a computer, the facsimile is received as an electronic mail message at the computer. The computer user can then open the message and view or print the attached image file.