# US 5,704,023 A · Method for interfacing electrical signals transmitted between an engine controller and a video controller > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,704,023 A - Document ID: US5704023A - Status: Granted - Kind: A - Application number: 08/551,815 - Filed: 1995-11-07 - Granted: 1997-12-30 - Earliest claimed: 1994-11-09 - Assignees: Samsung Electronics Co., Ltd. - Inventors: Gyung-Yeol Kim - Web page: https://patentgrep.com/patent/US5704023A ## CPC - G06K 15/00: Arrangements for producing a permanent visual presentation of the output data {, e.g. computer output printers}(printing or plotting combined with another operation, e.g. with conveying, G06K17/00) - G06K 2215/0091: Outputting only video data, e.g. Hard copy of CRT display - G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS ## Abstract A method for interfacing electrical signals transmitted between an engine controller and a video controller through first and second transmission lines in an image forming apparatus includes the steps of: transmitting first data indicating an engine power ready state from the engine controller to the video controller through the first transmission line when power is initially supplied to the engine controller, transmitting second data representive of a print ready state from the engine controller to the video controller through the first transmission line after performing a warm up operation on the image forming apparatus, transmitting third data representing commencement of a printing operation from the video controller to the engine controller through the second transmission line in response to an input of printing data to the video controller from an external source, transmitting fourth data representative of a request for page synchronization information from the engine controller to the video controller through the first transmission line in response to receipt of the third data by the engine controller, and transmitting fifth data representative of the page synchronization information from the video controller to the engine controller through the second transmission line in response to receipt of the fourth data by the video controller. The engine controller performs the printing operation in response to the fifth data. ## Claims ### Claim 1 A method for interfacing electrical signals transmitted between an engine controller and a video controller connected through first and second transmission lines in an image forming apparatus, said method comprising the steps of: transmitting first data indicating an engine power up state from said engine controller to said video controller through said first transmission line when power is initially supplied to said engine controller; transmitting second data from said engine controller to said video controller through said first transmission line after performing a warm up operation on said image forming apparatus, said second data indicating that said engine controller is ready to enable performance of a printing operation; transmitting third data from said video controller to said engine controller through said second transmission line in response to an input of printing data to said video controller from an external source, said third data indicating commencement of said printing operation; transmitting fourth data from said engine controller to said video controller through said first transmission line in response to receipt of said third data by said engine controller, said fourth data indicating that said engine controller is requesting page synchronization information; and transmitting fifth data representative of said page synchronization information from said video controller to said engine controller through said second transmission line in response to receipt of said fourth data by said video controller, said engine controller enabling performance of said printing operation in response to said fifth data. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein said first and second transmission lines represent an engine message transmission line and a control message transmission line, respectively. ### Claim 3 (depends on 1) The method as claimed in claim 1, further comprised of transmitting first busy signals from said engine controller to said video controller through a third transmission line electrically connecting said engine controller to said video controller, said first busy signals indicating a transmission state of said first transmission line. ### Claim 4 (depends on 3) The method as claimed in claim 3, further comprised of transmitting second busy signals from said video controller to said engine controller through a fourth transmission line electrically connecting said video controller to said engine controller, said second busy signals indicating a transmission state of said second transmission line. ### Claim 5 (depends on 1) The method as claimed in claim 1, wherein said external source comprises a personal computer. ### Claim 6 (depends on 4) The method as claimed in claim 4, wherein said external source comprises a personal computer. ### Claim 7 A method for interfacing electrical signals transmitted between an engine controller and a video controller connected through first and second transmission lines in an image forming apparatus, said method comprising the steps of: transmitting a first signal from said engine controller to said video controller through said first transmission line after performing a warm up operation on said image forming apparatus, said first signal indicating that said engine controller is ready to enable performance of a printing operation; transmitting a second signal from said video controller to said engine controller through said second transmission line in response to an input of printing data to said video controller from an external source, said second signal indicating commencement of said printing operation; transmitting a third signal from said engine controller to said video controller through said first transmission line in response to receipt of said second signal by said engine controller, said third signal indicating that said engine controller is requesting page synchronization information; and transmitting a fourth signal representative of said page synchronization information from said video controller to said engine controller through said second transmission line in response to receipt of said third signal by said video controller, said engine controller enabling performance of said printing operation in response to said fourth signal. ### Claim 8 (depends on 7) The method as claimed in claim 7, further comprised of transmitting a first busy signal from said engine controller to said video controller through a third transmission line electrically connecting said engine controller to said video controller, said first busy signal indicating a transmission state of said first transmission line. ### Claim 9 (depends on 8) The method as claimed in claim 8, further comprised of transmitting a second busy signal from said video controller to said engine controller through a fourth transmission line electrically connecting said video controller to said engine controller, said second busy signal indicating a transmission state of said second transmission line. ### Claim 10 (depends on 7) The method as claimed in claim 7, wherein said external source comprises a personal computer. ### Claim 11 (depends on 9) The method as claimed in claim 9, wherein said external source comprises a personal computer. ### Claim 12 A device for interfacing electrical signals between an engine controller and a video controller in an image forming apparatus, said device comprising: a first transmission line for transmitting said electrical signals from said engine controller to said video controller, said first transmission line transmitting a first electrical signal from said engine controller to said video controller after performing a warm up operation on said image forming apparatus, said first electrical signal indicating that said engine controller is ready to enable performance of a printing operation; a second transmission line for transmitting said electrical signals from said video controller to said engine controller, said second transmission line transmitting a second electrical signal from said video controller to said engine controller in response to an input of printing data to said video controller from an external source, said second electrical signal indicating commencement of said printing operation; said first transmission line transmitting a third electrical signal from said engine controller to said video controller in response to receipt of said second electrical signal by said engine controller, said third electrical signal indicating that said engine controller is requesting page synchronization information; and said second transmission line transmitting a fourth electrical signal representative of said page synchronization information from said video controller to said engine controller in response to receipt of said third electrical signal by said video controller, said engine controller enabling performance of said printing operation in response to said fourth electrical signal. ### Claim 13 (depends on 12) The device as claimed in claim 12, further comprising: a third transmission line electrically connecting said engine controller to said video controller for transmitting a fifth electrical signal from said engine controller to said video controller, said fifth electrical signal indicating a transmission state of said first transmission line. ### Claim 14 (depends on 13) The device as claimed in claim 13, further comprising: a fourth transmission line electrically connecting said video controller to said engine controller for transmitting a sixth electrical signal from said video controller to said engine controller, said sixth electrical signal indicating a transmission state of said second transmission line. ### Claim 15 (depends on 12) The device as claimed in claim 12, wherein said external source comprises a personal computer. ### Claim 16 (depends on 14) The device as claimed in claim 14, wherein said external source comprises a personal computer.