Abstract: An image forming apparatus includes an image carrier, a cleaning unit, a development device, and a control unit. The development device includes a toner collection mechanism having a developer carrier and a filter. The control unit is capable of executing a scattered toner recovery mode at non-image forming time, in which the filter is vibrated, a potential difference is generated in the direction for the toner to move from the developer carrier to the image carrier, the developer carrier is rotated in a reverse direction to that at image forming time, and the image carrier is rotated in the same direction as that at the image forming time, so that scattered toner, which has dropped from the filter and adhered to the developer carrier, is recovered by the cleaning unit via the image carrier.

Abstract: An image forming apparatus includes a development device, and a control unit that controls the development device. The development device includes a toner collection mechanism having a duct, a filter, and an exhaust fan. The duct is connected to a conveyance chamber of the development container and allows air in the conveyance chamber to flow through. The filter is disposed at a connecting part between the duct and the conveyance chamber, and collects toner flowing into the duct from the conveyance chamber. The exhaust fan makes the air in the conveyance chamber flow to the outside via the duct. The control unit changes rotational frequency or operation frequency of the exhaust fan based on current detected by a current detection unit at non-image forming time.

Abstract: A threading device of sewing machine is disclosed, wherein the upper thread extended from a thread supply mounted on a sewing machine body may be easily and smoothly guided into engagement with a thread holder simultaneously when the threading device is operated to pass the upper thread through the eye of needle attached to the lower end of needle bar, the thread holder being arranged between the thread supply and the needle.

Abstract: A threading device of sewing machine is disclosed, wherein the upper thread extended from a thread supply mounted on a sewing machine body may be easily and smoothly guided into engagement with a thread holder simultaneously when the threading device is operated to pass the upper thread through the eye of needle attached to the lower end of needle bar, the thread holder being arranged between the thread supply and the needle.

Abstract: A devised shank is provided to a presser foot of a sewing machine in addition to an ordinary shank, such that a special presser group for straight stitching along a fabric edge is attached to the devised shank only, in which the presser foot is attachable to a presser holder, and the ordinary shank is for such as zigzag stitching, and the devised shank is different in an attaching width from the ordinary shank. Signal generating parts are provided to the presser holder, which each issue a signal in response to when the presser foot is attached, and the signal is discriminated with a signal issued in response to a pattern group belonging to patterns selected by a pattern selecting means so that the sewing machine is driven only when the presser group and the pattern group is met.

Abstract: The invention is to provide an electrical indication of improper thread tension to enable the sewing operation to be exactly accomplished.

Abstract: The tension of the sewing machine's upper thread is varied automatically, in a variety of ways not requiring conscious participation on the part of the user of the machine. When one of a set of selectable stitch-patterns is selected by the user, an appropriate thread-tension value is automatically established, although the user retains the ability to adjust the automatically established tension value if he wishes. When the user swings the presser-foot lever of the machine up, to raise the cloth presser foot up from the cloth, e.g., for basting work, the thread tension is automatically lowered to a predetermined value suitable for basting, although still adjustable by the user if he thinks necessary. Where a stitch-pattern is implemented using an addressable ROM, tension command data for each stitch of the stitch-pattern may be stored in the ROM, for variation of thread tension from constituent stitch of the pattern to the next.

Abstract: A rows-and-columns array of indicator lamps, each lamp associated with a selectable stitch pattern, is provided on the machine housing, with one pushbutton switch per column of indicator lamps. In a first embodiment, when a particular column and row contain the single illuminated one of the lamps, depression of the pushbutton switch associated with a different column terminates illumination of the presently lighted lamp and instead effects illumination of the lamp of the same row but in the column associated with the newly depressed pushbutton switch, whereupon repeated pressing of the newly pressed switch causes the illuminated state to shift, lamp by lamp, along such column. Alternatively, when the illuminated-lamp indication is located in a particular row and column, depression of the pushbutton switch associated with a different column causes the illuminated-lamp indication to jump to that column, and in particular always to a predetermined lamp within that column, e.g., the first therein.