HP Color LaserJet CM4730 Service Manual - Page 219

3. The fusing sleeve and the fusing pressure roller fuse the toner onto the media. The media is then delivered from the fuser. 4. The image fusing media sensor (SR1) detects the media delivered from the fuser, and then delivers the media to the face-down tray or other output device. NOTE: If the face-down tray is full of media, the delivery tray paper-full sensor (SR2) detects that it is full. The DC controller determines the face-down tray media is full, notifies the formatter, delivers the media currently printing from the MFP, and stops the printer engine. When the stack of media on the face-down tray is removed, the SR2 detects the media absence and the printing operation resumes. Loop control The media is delivered from the ETB to the fusing pressure roller maintaining the specified warp for the media type, to prevent image and media transport defects. The feeding speed of the fusing pressure roller and the ETB are not exactly the same. The following problems might occur when the media is fed into the fuser. ● If the rotational speed of the fusing pressure roller is slower than that of the ETB, the media warp increases and an image defect or media crease might occur. ● If the rotational speed of the fusing pressure roller is faster than that of the ETB, the media warp decreases and a color misregistration in the sub-scanning direction occurs as the fusing pressure roller pulls the media. To resolve these issues, two sensors are used depending on the media type specified by the formatter. The sensors bifurcate the warp amount for thick paper and thin paper. The DC controller monitors the paper loop sensor 1 (SR13) and the paper loop sensor 2 (SR14) to maintain the paper warp at specified amount by changing the rotational speed of the fusing pressure roller. Figure 4-42 Loop control on page 200 illustrates this process. ENWW Pickup/feed system 199