Abstract: A sheet reversing and discharging device of the present invention conveys each of a tab sheet and an ordinary sheet in a particular manner. Before a tab sheet enters a reversal tray, a drive roller is driven in the reverse direction while a driven roller is lowered into contact with the drive roller beforehand. The drive roller and driven roller pull in the tab sheet in the direction of conveyance until the tab of the tab sheet moves away from the tip of a path selector. The drive roller and driven roller surely convey the tab sheet to the reversal tray after the tab has moved away from the above tip. Whether or not the tab has moved away from the tip is determined on the basis of a period of time elapsed since a sheet sensor adjoining the inlet of the device has sensed the trailing edge of the tab sheet.

Abstract: A duplex recording method for an image forming apparatus stores page-by-page image data in a storage in the order of page and records, among the image data, two consecutive pages of image data on the front and rear of a recording medium, respectively. At this instant, the method records the image data on the rear of the recording medium carrying an image on the front and a new recording medium alternately by using an interleaf control system. Assume that images are continuously recorded on the fronts of n consecutive recording media at the initial stage of printing. Then, the method continuously records images on the fronts of n+1 consecutive recording media at the final stage of printing. An apparatus for practicing the method is also disclosed.

Abstract: A sheet conveying device includes conveying means respectively located at an upstream side and a downstream side on a sheet conveyance path. First drive means rotates the upstream conveying means at a constant speed while second drive means rotates the downstream conveying means at a variable speed. When the second drive means accelerates the rotation of the downstream conveying means, speed adjusting means causes the conveying speed of the upstream conveying means to reflect the acceleration. The sheet conveying device insures smooth, reliable conveyance even when a sheet extends over both of the upstream and downstream conveying means.

Abstract: A sheet guide device to guide a sheet being conveyed in a sheet conveying path of the device includes a device to adjust widthwise sheet positioning by regulating side edges of the sheet. The adjusting device is provided in a curved part of the sheet conveying path. The sheet guide device further includes a sheet conveying roller to convey the sheet. The adjusting device is positioned on a shaft of the sheet conveying roller and is slidable along the shaft. The sheet conveying roller reverses a conveying direction of the sheet. The adjusting device unitarily includes a guide member to guide the side edges of the sheet.

Abstract: A tester detects an abnormality in a quiescent power supply current of a device under test. In the tester, a programmable voltage generation source controls a power supply unit, providing a device under test with power. A test pattern generator applies test patterns repeatedly to the device under test. Power supply current to the device under test is converted into voltage values by a detection resistor. A spectrum analyzer unit finds a differential between voltage values occurring between opposite ends of the detection resistor, and voltage values proportional to power supply current values of a device known to perform properly, as measured beforehand. The spectrum analyzer ouputs a power of a fundamental wave of a frequency spectrum obtained by applying the EFT method to the differential.

Abstract: A miniature duplex sheet feeding device for an image forming apparatus is disclosed. A duplex unit is positioned above an ordinary sheet feed tray loaded with a stack of sheets. The duplex unit has an intermediate tray for stacking sheets each carrying an image on one side thereof, and a bottom plate movable back and forth in an intended direction of sheet refeed. The sheet feed tray and duplex unit share a single sheet pay-out means. The bottom plate includes separators for retaining the leading edge of the sheet stack and allowing the stack to be bodily shifted to a preselected refeed position.