Integrated raster image processor and electro-photographic engine controller
View Patent ↗This invention comprises a converged printer architecture for controlling both electro-photographic (EP) processing and raster image processing (RIP) of data for laser modulation over a video line. By converging EP process control with image processing control, significant advantages in cost, image quality, and output stability are achieved. A digital signal processor (DSP) serves as the central processing resource of the architecture. The DSP is well suited for the dual role of image processing and real-time feedback process control. The DSP can operate in open loop motor/motion control, print process control, and in closed loop feedback control including image processing adaptations for quality and stability enhancements.
1. A printer controller comprising:
at least one input port for receiving print data in a page descriptive language format;
a digital signal processor connected to said at least one input port;
a print engine controller bidirectionally coupled to said digital signal processor, said print engine controller supplying print control signals to a print engine under control of said digital signal processor and receiving printer sensor signals from the print engine for supply to said digital signal processor;
said printer sensor signals includes at least one optical density sensor of a printed page; and
wherein said digital signal processor is programmed to:
convert said print data from said page descriptive language format into print data for supply to the print engine via said print controller, said conversion including screening,
provide real time feedback control of a print process of the print engine via control of said print control signals in response to said printer sensor signals, and
respond to said at least one optical density sensor to adjust screening in said conversion of said print data from said page descriptive language format into print data for supply to the print engine to maintain uniform optical density in the printed page.
2. The printer controller of claim 1 , further comprising:
a paper controller bidirectionally coupled to said digital signal processor, said paper controller supplying paper movement control signals to the print engine under control of said digital signal processor and receiving paper position sensor signals from the print engine for supply to said digital signal processor; and
wherein said digital signal processor is further programmed to provide real time feedback control of paper movement of the print engine via control of said paper movement control signals in response to said paper position sensor signals.
3. The printer controller of claim 1 , wherein:
said printer sensor signals includes a paper smoothness sensor;
said digital signal processor is further programmed to respond to said paper smoothness sensor to adjust said paper movement control signals for supply to the print engine to maintain uniform paper movement velocity.
4. The printer controller of claim 1 , further comprising:
a control panel interface bidirectionally coupled to said digital signal processor, said control panel interface receiving operator input signals from a control panel and supplying control panel display signals to the control panel under control of said digital signal processor; and
wherein said digital signal processor is further programmed to:
control printer operation in response to operator input signals; and
supply display data corresponding to current printer status to an operator via said control panel display signals.
5. The printer controller of claim 1 , wherein:
said print control signals includes a photoconductive drum charging high voltage signal;
said printer sensor signals includes a photoconductor drum charging sensor; and
said digital signal processor is further programmed to respond to said photoconductor drum charging sensor to maintain a uniform photoconductive drum charging high voltage signal.
6. The printer controller of claim 1 , wherein:
said print control signals includes a photoconductive drum drive signal; and
said digital signal processor is further programmed to maintain a uniform photoconductive drum velocity.
7. The printer controller of claim 1 , wherein:
said print control signals includes a laser modulation signal;
said printer sensor signals includes at least photoconductor drum motion sensor; and
said digital signal processor is further programmed to respond to said at least photoconductor drum motion sensor adjust said laser modulation to maintain a uniform print density.