Abstract: Provided is a vehicle speed control device with respect to which the speed at which a centrifugal brake operates can be easily changed from the outside without disassembling the device. A brake drum 11 is fixed to a vehicle body 101a. A brake shoe 23 rotates around a rotary shaft 20 of the wheel 101c, and reduces the rotation speed of the wheel 101c as a result of coming into contact with an inner circumferential side face of the brake drum 11. A spring 24 prevents contact between the brake drum 11 and the brake shoe 23 when the rotation speed of the wheel 101c is lower than or equal to a predetermined speed, and permits contact between the brake drum 11 and the brake shoe 23 when the rotation speed of the wheel 101c exceeds the predetermined speed. A position change mechanism 25 is installed within the brake drum 11, and changes the position of an end of the spring 24 on one end side.

Abstract: Provided is a vehicle speed control device with respect to which the speed at which a centrifugal brake operates can be easily changed from the outside without disassembling the device. A brake drum 11 is fixed to a vehicle body 101a. A brake shoe 23 rotates around a rotary shaft 20 of the wheel 101c, and reduces the rotation speed of the wheel 101c as a result of coming into contact with an inner circumferential side face of the brake drum 11. A spring 24 prevents contact between the brake drum 11 and the brake shoe 23 when the rotation speed of the wheel 101c is lower than or equal to a predetermined speed, and permits contact between the brake drum 11 and the brake shoe 23 when the rotation speed of the wheel 101c exceeds the predetermined speed. A position change mechanism 25 is installed within the brake drum 11, and changes the position of an end of the spring 24 on one end side.

Abstract: In a laser beam printer, automatic optical quantity (APC) control is performed based on an optical quantity detection output to generate a laser beam having a predetermined quantity of light. In each scanning cycle, APC is effected by utilizing a period (unblanking period) in which the laser device is forcibly actuated to generate a horizontal synchronization signal. The unblanking period may be changed according to the print paper size or image formation/non-image-formation periods. Also, light quantity control may be effected through a plurality of scanning cycles before image formation and may be effected by utilizing the unblanking period during the period corresponding to the intervals of print sheets. Techniques also provided to prevent a transfer unit from being contaminated by toner images formed as a byproduct of APC.

Abstract: In a laser beam printer, automatic optical quantity (APC) control is performed based on an optical quantity detection output to generate a laser beam having a predetermined quantity of light. In each scanning cycle, APC is effected by utilizing a period (unblanking period) in which the laser device is forcibly actuated to generate a horizontal synchronization signal. The unblanking period may be changed according to the print paper size or image formation/non-image-formation periods. Also, light quantity control may be effected through a plurality of scanning cycles before image formation and may be effected by utilizing the unblanking period during the period corresponding to the intervals of print sheets. Techniques also provided to prevent a transfer unit from being contaminated by toner images formed as a byproduct of APC.