Sharp FO-2970M Service Manual - Page 54

FO-2970MU k. Top margin control Top margin is set according to the number of lines (the number of HSYNC interrupt) from detail paper Pin On to LASER input. The interval between Pin On and point D is 52.6747 mm. The interval between Point D and point B is: 27.33 (C-D) + 8.3769 (B-C) = 35.7069 mm If top margin is 4 mm, 52.6747 - 35.7069 + 4 = 20.9678 m In case of the actual software processing, chattering of the sensor is considered to be observed for 9 msec. The processing speed is 50 mm/sec; while chattering is being observed, paper is fed by 0.45 mm (9 x 50/1000 = 0.45 mm). In order to gain top margin of 4 mm, printing data should be processed after paper is fed by 20.5178 mm (20.9678 - 0.45 = 20.5178 mm) following PIN On detection. The base machine resolution in the sub-scanning direction is 391.16 dpi; If the value 20.5178 mm is converted into the number of lines, 315.9 lines are obtained from 391.16 x 20.5178/25.4. Accordingly the software set value is considered to be based on 316 lines. Similarly, considering from the fact that resolution of PC printing is 600 dpi, the number of lines is 484.6 lines (600 x 20.5178/25.4=484.6). The software set value is based on 485 lines. Pout sensor Paper exit roller LASER Process speed 50mm/sec OPC drum speed 49mm/sec=(50x0.98) Discharge brush nip 5.7523mm Fusing 9.3389mm(A-B) 8.3769mm(B-C) B C A OPC drum Developing roller nip 2.7693mm Diameter ø24mm D 27.33mm(C-D) Pin sensor Paper feed roller 30.3522mm(D-A) Transfer 52.6747mm(from Pin On) roller ø13.4(13.7) 40.0697mm(from Pin Off) 100.4mm(from Pin On) 37.2mm (until Pin On) 123.8410mm(from Pin On until Pout On) 207.875mm(from Pin Off) Fig. 21 (4) MODEM control block 1) INTRODUCTION Conexant's FM336 modem is a V.34 half-duplex modem. It supports Group 3 facsimile transmission/reception at speeds up to 33,600bps in the V.34 half-duplex mode. In order to optimize the modem configuration for the line conditions, this modem uses V.34 technology. It connects at an optimally selected data rate so that speeds from 2,400bps to 33,600bps can be supported. This modem can be used on the general public telephone network using a network control unit (NCU) line termination device. This modem conforms to ITU-T V.17, V.21, V.23, V.27ter, V.29, and V.34 specifications. It also complies with V.8 and T.30 binary signaling conditions. This modem supports HDLC internally. Therefore, products using built-in error correction and the T.30 protocol do not need an external serial input/ output (SIO) line on DTE. This modem can execute HDLC framing, as specified in T.30, at all data rates. Since it can perform zero insertion/ deletion and CRC tasks, this allows enhanced SDLC/HDLC frame operation. The FSK flag pattern detector facilitates FSK detection during high-speed reception. This modem features a programmable DTMF transmitter/receiver that operates in tone mode, and three programmable tone detectors. This modem is primarily suited to use in small system designs in such environments as work plants, offices, and homes because of its low power consumption and small size. This modem is packaged in a 100-pin PQFP. 2) FEATURES • Two-wire, half-duplex fax modem that supports transmission/recep tion speeds up to 33,600bps - V.17, V.27ter, V.29, V.34, and V.21 2 channel - Short train option in V.17 and V.27ter • Two-wire, full-duplex data modem mode V.21 and V.23 (75bps TX/1,200bps RX or 1,200bps TX/75bps RX) • PSTN session start - V.8 signaling • HDLC supported at all the speeds - Flag sending, 0 bit insertion, ITU CRC-16 or CRC-32 calculation and sending - Flag detection, 0 bit deletion, ITU CRC-16 or CRC-32 checksum error detection - FSK flag pattern detection (during high-speed reception) • Tone mode and function - Programmable single or dual tone transmission - DTMF reception - Tone detection using three programmable tone detectors • Serial synchronous data • Parallel synchronous data • V.34 half-duplex and Automatic Rate Adaptation (ARA) • TTL- and CMOS-compatible DTE interface - ITU-T V.24 (EIA/TIA-232-E) (data/control) - Microprocessor bus (data/configuration/control) • Reception dynamic range: 0dBm ~ -43dBm (V.17, V.33, V.29, V.27ter, and V.21) -9dBm ~ -43dBm (V.34 half-duplex) • Programmable RLSD turn-on and turn-off thresholds • Programmable transmission level: 0 ~ -15dBm • Adjustable speaker output for monitoring communication signals • DMA support interrupt line • 16 byte FIFO data buffer (2) for transferring burst data, can be ex panded up to 255 bytes • NRZ1 encoding/decoding • Diagnostic function • +3.3V operation (+5V input possible) • +5V analog signal interface • Standard power consumption: - Sleep mode: 20mW - Normal mode: 250mW • 100-pin PQFP package 5 - 18