Abstract: A memory stores data, the contents of which must be kept secret. A memory stores security data and a latch circuit latches key data for releasing the security. A comparison circuit compares security data with key data, outputs a coincidence signal when they coincide with each other and outputs a non-coincidence signal when they do not coincide with each other. When a coincidence signal is output from the comparison circuit, an output signal of a change bit control circuit is set to the "0" level and address changing circuits change an address signal for reading out data from the memory according to the security data supplied from the memory.

Abstract: This invention relates to a color image forming apparatus which is capable of forming a mono-color image based on the color image input data. The apparatus includes a circuit for determining the highest value of the image input data. This circuit is called the highest value image data outputting circuit. The highest input color data value is found by comparing the values of the image data for the three primary colors (yellow, magenta and cyan) and outputting the value for the color having the highest input value. The apparatus further includes a mono-color image forming portion which forms a mono-colored image based on the output of the highest value image data outputting circuit.

Abstract: A circuit for signaling an operator when a linear actuator, driven by a reversible direct current motor, has reached opposite end positions. Two normally closed series-connected switches which open at the respective positions and diodes, connected across each switch and to each other in opposition, stop the motor when the actuator reaches either position. A third switch and third diode cause a lamp to energize at one of the positions and remain energized until the actuator moves to the other position.

Abstract: In a linear actuator comprising a motor-driven screw shaft, an overload detection mechanism comprises a pair of cup-shaped spring seats with substantially cylindrical portions. The spring seats are mounted at one end of the screw shaft by a pair of bearings and have a spring therebetween under a predetermined preload. Limit switches are provided for detecting overload on the screw shaft as a result of axial movement of the spring seats. The cylindrical portions of the cup-shaped spring seats serve as strikers for said limit switch means.

Abstract: This improved driving force support is used in a linear actuator in which rotary motion of a rotating screw shaft is converted to linear motion of a travelling nut. The driving force support comprises a pair of springs surrounding the rotating shaft and held in compression between a pair of shaft bearing receivers. The receivers and bearings held thereby move axially with the rotating shaft as axial forces are applied to the shaft by the travelling nut. The bearing receivers slide axially in a hollow housing. The springs are arranged in series between seats which normally abut the respective bearing receivers and also normally abut stop surfaces in the housing. One spring has a high degree of stiffness, and the other has a comparatively low degree of stiffness.