High-speed Serial Transmission Technology

In the printing market, there have recently been increasing expectations toward digital presses, which eliminate the step of creating printing plates and allow for high-speed printing. Because of this, there is demand for digital presses that are capable of processing large amounts of image data quickly while also having increased intra-system data transmission speeds and high image quality approaching that of offset printing. Fuji Xerox has developed a new high-speed serial transmission technology, one of our core electronics technologies, in order to make it possible for our digital presses to achieve the high speed and high image quality demanded by the printing market. With this technology, a new high-speed image path is made possible in which image data generated in the external controller is sent to the digital press through high-speed serial transmission, then image processing is performed by the digital press's new image processing ASIC (application-specific integrated circuit), and the image is finally printed with the VCSEL exposure system at a resolution of 2400 dpi × 1 bit.

In order to deliver improved speed and image quality, our newly developed high-speed serial transmission technology takes advantage of the technologies implemented in our high-frequency circuitsNote 1 to achieve a vastly improved transmission speed of 8.5 Gbps (4.25 Gbps x 2 channels) for each color. In addition, because the technology allows for an image path with uncompressed native 1200 dpi x 10 bit resolution plus a screen control tag of 4 bits using the newly developed Ultra HD (High Definition) technology, the quality of text and tone reproduction has been improved, thus delivering higher image quality.

Fig. 1: Comparison of before and after the introduction of the newly developed Ultra HD (High Definition) technology

Furthermore, for the transmission configuration used to send data from the external controller to the digital press, we adopted an asymmetrical transmission configuration consisting of four channels for sending and one channel for receiving per two colors, which is the optimal configuration for a digital press. This allows data to be sent and received efficiently and reliably.

Fig. 2: A configuration diagram of the image path

When processing large amounts of data at high speeds, it is important to have a transmission system that is highly reliable. Because of this, we implemented cutting-edge electronics technologies in our high-frequency circuits in order to achieve an extremely high quality of transmission, with a transmission system BER (bit error rate)Note 2 of 10-14 or less. Furthermore, we also independently developed a hardware protocol that is optimized for digital presses, equipping it with error detection/correction and diagnostic functions to further improve the quality of transmission and increase the reliability of the transmission system.

  • Note 1 This refers to the technologies used in our circuits to ensure the signal quality of gigahertz-band serial transmission, consisting of artwork (printed circuit design), signal waveform equalization control, and signal integrity simulation/modeling.
  • Note 2 The BER (bit error rate) is an index of the quality of transmission over transmission lines or data transmission circuits inside electronic devices. It is defined as the rate at which erroneous bits are received after digital data is transmitted. The value listed here was achieved in evaluations conducted by Fuji Xerox.