Abstract: A liquid crystal device is constituted by disposing a chiral smectic liquid crystal between a pair of substrates each provided with an electrode and a uniaxial alignment film. The chiral smectic liquid crystal is placed in such a quasi-smectic A alignment state that the liquid crystal molecules will have a single average molecular axis under no electric field application on a lower temperature side within chiral smectic C phase range, wherein the single average molecular axis can be confirmed as a position providing the darkest state when observed through cross nicol polarizers. Such a quasi-smectic A alignment state is effective in providing a liquid crystal device (or display apparatus) having an improved shock resistance and a good low-temperature storage properties.

Abstract: A liquid crystal device including: a pair of substrates and a chiral smectic liquid crystal disposed between the pair of substrates. Each of the pair of substrates has an electrode for applying a voltage to the liquid crystal. The pair of substrates is provided with respective uniaxial alignment axes extending in directions which are parallel to each other or intersect each other at a prescribed angle. The chiral smectic liquid crystal is placed in such an alignment state that the liquid crystal assumes at least two stable states and provides a pretilt angle .alpha. (degrees), a tilt angle H (degrees), an inclination angle .delta. (degrees) of the liquid crystal layer, and an apparent tilt angle .theta.a satisfying the following relationships (I) and (II) in a temperature range of 10.degree.-55.degree. C.:H<.alpha.+.delta. and .delta.<.alpha. (I), andH>.theta.a>H/2 (II).The liquid crystal provides a tilt angle H (degrees), an inclination angle .delta.

Abstract: A liquid crystal device for gradational display, comprising: a pair of substrates each provided with an electrode, and a liquid crystal layer comprising a chiral smectic liquid crystal disposed between the substrates; the pair of substrates each having thereon alignment control layer provided with a uniaxial alignment axis, wherein aid liquid crystal layer comprises a striped region and a non-striped region where (1) the striped region and the non-striped region each assume a homogeneous alignment state, (2) the striped region extends in a direction perpendicular to the direction of the uniaxial alignment axis, and (3) each of liquid crystal molecules within the striped region and the non-striped region show bistability; and the liquid crystal molecules within the striped region have a threshold voltage, for switching between two stable states, different from that given by the liquid crystal molecules within the on-striped region.

Abstract: A liquid crystal device with little temperature-dependence of drive characteristics, such as response speed, and with good storage stability, can be produced by using a liquid crystal composition, successively assuming SmA (smectic A) phase and SmC* (chiral smectic) phase on temperature decrease. The layer spacing composition has a temperature-dependence of layer spacing d in smectic phase such that the layer spacing d increases, is constant or decreases on temperature decrease in SmA phase temperature range, assumes a first transition point where the layer spacing d abruptly decreases on temperature decrease in vicinity of transition temperature from SmA phase to SmC* phase, and assumes a second transition point where the layer spacing d commences to increase on further temperature decrease below the first transition point in SmC* temperature range.

Abstract: A liquid crystal device is constituted by disposing a chiral smectic liquid crystal between a pair of substrates each provided with an electrode and a uniaxial alignment film. The chiral smectic liquid crystal is placed in such a quasi-smectic A alignment state that the liquid crystal molecules will have a single average molecular axis under no electric field application on a lower temperature side within chiral smectic C phase range, wherein the single average molecular axis can be confirmed as a position providing the darkest state when observed through cross nicol polarizers. Such a quasi-smectic A alignment state is effective in providing a liquid crystal device (or display apparatus) having an improved shock resistance and a good low-temperature storage properties.

Abstract: A liquid crystal (composition) containing a ferroelectric liquid crystal shows a layer inclination angle .delta. in smectic phase providing a specific temperature dependence. The inclination angle .delta. increases on temperature decrease down to a mediate temperature and decreases on temperature decrease below the mediate temperature. The inclination angle .delta. keeps a positive value in an ambient temperature or starts to increase again on further temperature decrease before it reaches zero degrees. The liquid crystal (composition) is usable for providing a liquid crystal device or apparatus with decreased temperature dependences of driving conditions and improved low-temperature storage properties.

Abstract: A liquid crystal device showing improved uniform alignment characteristic and switching characteristic is constituted by a pair of an upper substrate and a lower substrate, and a chiral smectic liquid crystal disposed between the upper and lower substrates. Each of the upper and lower substrates has thereon an electrode for applying a voltage to the liquid crystal and a uniaxial alignment film. The alignment films on the upper and lower substrates are provided with uniaxial alignment axes which cross each other so that the direction of crossing of the uniaxial alignment axes from the lower substrate to the upper substrate is identical to the direction of helical twist in cholesteric phase of the chiral smectic liquid crystal, and the chiral smectic liquid crystal is disposed in such an alignment state that the liquid crystal shows a pretilt angle .alpha., a cone angle H, an inclination angle .delta. of SmC.sup.* layer, and an apparent tilt angle .theta.a satisfying relationships of: H<.alpha.+.delta.

Abstract: A chiral smectic liquid crystal composition is formed by including at least one species of a mesomorphic compound represented by the following formula (I): ##STR1## wherein X denotes F, Cl, Br, CF.sub.3, NO.sub.2 or CN; Y denotes a single bond, ##STR2## --CH.sub.2 O-- or --OCH.sub.2 --; and R denotes a linear or branched alkyl group having 1-20 carbon atoms optionally substituted. The composition shows improved switching characteristics and, when used in combination with an alignment film providing a high pre-tilt angle, provides an increased contrast at a large drive margin and with little tendency of monostabilization of a memory state.

Abstract: A liquid crystal device with a decreased temperature-dependence of response speed is obtained by using a liquid crystal composition having a temperature range where the composition assumes chiral smectic C phase. The temperature range of chiral smectic C phase includes a) a first temperature range where the liquid crystal composition shows a cone angle in chiral smectic C phase which increases on temperature decrease down to a mediate temperature, and b) a second temperature range, below the first temperature range, where the liquid crystal composition shows a cone angle in chiral smectic C phase which decreases on further temperature decrease below the mediate temperature.

Abstract: An image forming apparatus so composed that it can be furnished with a plurality of developers, can change the developer opposed to the photosensitive body by integrally moving the corresponding developers and can compensate for the position of the corresponding developer at the compensating position thereof while changing developers. Furthermore, in the image forming apparatus, the developers are moved by a motor, the position of the developers is only compensated for when the predetermined compensating position is on a shortest moving path when changing one of the developers to another developer and the developers are always changed through the shortest moving path.

Abstract: An arrangement for communication between two CPUs which allows diagnosis of whether the cause of an interrupt in communication between the CPUs is due to a routine interrupt or a failure in the communication line. Timers generate overflow signals in the event that data from one or the other CPU is late in arriving. Lateness is determined by comparing the timer values to stored values in memory. Control units respond to the timers and switch the transmission level of the CPUs so that they pass a predetermined signal pattern between themselves, indicating that the interrupt is in effect but that communication lines are still open. When one of the CPUs fails to detect the confirmation signal, the CPU causes a communication failure to be indicated.

Abstract: A transfer unit of an image forming apparatus includes a transfer device, a pressing member, and a regulative member. The transfer device is provided adjacent to a photoconductor of the image forming apparatus and is separable from the photoconductor under its own weight. The pressing member presses the transfer device against the photoconductor. The regulative member regulates the distance by which transfer device is separated from the photoconductor when the pressing member disengages the transfer device therefrom. In this transfer unit, if a printing sheet is large, the pressing member disengages the transfer device after a given transfer operation. As a result, the transfer device separates from the photoconductor under its own weight, with the distance separating the transfer device from the photoconductor being regulated by the regulative member. Then, the transfer device idles in the separated state, wherein preparation for a subsequent transfer operation is made.

Abstract: A nipping device is provided in a transfer unit having a fixed support and rotating element rotatably supported by the fixed support. The nipping device retains a printing sheet against the circumferential surface of the rotating element, and separates the printing sheet from the transfer unit. The nipping device includes a nipper, a pivoting lever device and a drive device. The nipper is disposed pivotally on the circumferential surface of the rotating element, and retains the feed-leading edge of the printing sheet. The levers of the pivoting lever device are disposed within the rotating element, pivotal on an axes intersecting the circumferential surface of the transfer unit, and functions therein to open and close the nipper by which the printing sheet is nipped against and separated from the transfer unit. The drive device is disposed in the fixed support, and functions to turn the pivoting levers.

Abstract: A document reader in which means for feeding in/out feeds a document into the fixed reading position and feeds it out from there, a reading unit reads the document by scanning, and means for scanning/returning makes the reading unit scan along the document and makes it return to its home position.

Abstract: In an image forming apparatus in which toner is fed to a developer unit from a toner storage container through toner conveying means provided between the toner storage container and the developer unit, the image forming apparatus comprises a toner remaining amount detector for detecting not more than a predetermined amount of toner in the toner storage container, a toner density detector for detecting the density of toner in the developer unit, and means for interrupting the image forming operation to feed the toner to the developer unit from the toner storage container through the toner conveying means when the amount of the toner in the toner storage container is larger than the predetermined amount and the density detected by the toner density detector is lower than a predetermined density.

Abstract: A scanning-member-stop positioning device for the image forming apparatus, wherein a document in contact with a document glass plate is exposed due to the movement of a scanning member consisting of an optical section or a document glass plate, will execute a precise braking control in which a suitable degree of the brake power determined by the actual run to stop the scanning member just at the home position. Accordingly the present invention should be characterized about what the brake power, started at the timing of the passage over the fixed position against the scanning member running back toward the home position in the fixed velocity, is changed the degree, and about what the suitable degree of the brake power is determined by operation corresponding to the moving distances given as a result of the change.