Abstract: An excitation operation brake includes a braking shaft, an armature that rotates integrally with the braking shaft, and a field core including a disc portion facing the armature. The disc portion includes an outer magnetic shielding portion and an inner magnetic shielding portion, which make a magnetic flux flowing through the disc portion bypass to the armature a plurality of times. The outer magnetic shielding portion includes a low-magnetic resistance path having a magnetic resistance smaller than the magnetic resistance of a magnetic path that bypasses to the armature.

Abstract: An excitation operation brake includes a braking shaft, an armature that rotates integrally with the braking shaft, and a field core including a disc portion facing the armature. The disc portion includes an outer magnetic shielding portion and an inner magnetic shielding portion, which make a magnetic flux flowing through the disc portion bypass to the armature a plurality of times. The outer magnetic shielding portion includes a bypass magnetic path having a magnetic resistance smaller than the magnetic resistance of a magnetic path that bypasses the armature.

Abstract: An electromagnetic clutch includes a field core including a coil storage groove, and a rotor including a core storage groove. The coil storage groove is formed by an inner cylindrical portion, an outer cylindrical portion, and a bottom portion. The bottom portion of the field core wholly projects to the outside of the core storage groove. The outer peripheral surface of the inner cylindrical portion and the inner peripheral surface of the outer cylindrical portion include a first transition surface and a second transition surface, respectively, on the bottom portion side. Each of the first transition surface and the second transition surface includes a tilting surface that gradually narrows the groove width of the coil storage groove along with an increase in a distance from the side of the opening of the coil storage groove.

Abstract: A yoke includes an annular groove in which an exciting coil is stored, and a first through hole formed in the bottom of the annular groove. A terminal housing includes a boss portion fitted in the first through hole and a connecting concave portion located on the opposite side of the annular groove with respect to the boss portion. The boss portion includes a second through hole extending in a direction parallel to the center line of the first through hole. An external connecting terminal is buried in the terminal housing. The external includes a coil extraction hole continuing to the second through hole. The extraction end of the exciting coil is soldered to the terminal in a state in which the extraction end is passed through the second through hole and the coil extraction hole.

Abstract: An electromagnetic clutch includes a field core including a coil storage groove, and a rotor including a core storage groove. The coil storage groove is formed by an inner cylindrical portion, an outer cylindrical portion, and a bottom portion. The bottom portion of the field core wholly projects to the outside of the core storage groove. The outer peripheral surface of the inner cylindrical portion and the inner peripheral surface of the outer cylindrical portion include a first transition surface and a second transition surface, respectively, on the bottom portion side. Each of the first transition surface and the second transition surface includes a tilting surface that gradually narrows the groove width of the coil storage groove along with an increase in a distance from the side of the opening of the coil storage groove.

Abstract: A yoke includes an annular groove in which an exciting coil is stored, and a first through hole formed in the bottom of the annular groove. A terminal housing includes a boss portion fitted in the first through hole and a connecting concave portion located on the opposite side of the annular groove with respect to the boss portion. The boss portion includes a second through hole extending in a direction parallel to the center line of the first through hole. An external connecting terminal is buried in the terminal housing. The external includes a coil extraction hole continuing to the second through hole. The extraction end of the exciting coil is soldered to the terminal in a state in which the extraction end is passed through the second through hole and the coil extraction hole.

Abstract: A power transmission device includes a pulley (4) and a hub (11) that are arranged on the same rotation axis, and a connecting member (13) that connects these rotation bodies. The power transmission device includes a first connecting structure (14) that connects one end portion (13a) of the connecting member to the pulley so that one end portion (13a) cannot be separated, and a second connecting structure (15) that connects the other end portion (13b) of the connecting member to the hub so that the other end portion (13b) can be separated. The second connecting structure includes a columnar body (21) that extends through the other end portion (13b) of the connecting member (13) in the axial direction, a head portion (28) that is provided on the columnar body (21), a slit (22) of the connecting member (13), and a belleville spring (29) that presses the connecting member (13) against the rotation body.

Abstract: An electromagnetic clutch includes a rotor, armature hub, armature, magnetic body and first permanent magnet, field core, excitation coil, and second permanent magnet. The rotor is rotatably disposed in the housing of a driven device. The armature hub is fixed to the rotating shaft of the driven device, the armature movable in an axial direction. The magnetic body is incorporated in the rotor. The first permanent magnet connects the armature to the rotor. The field core is attached to the housing and inserted in the rotor to be in noncontact with it. The excitation coil is disposed in the field core and excited, when cutting off power transmission, to cancel a magnetic force of the first permanent magnet, thus releasing the armature from the first permanent magnet. The second permanent magnet separates the armature from the rotor, when cutting off power transmission, to move the armature toward the armature hub.

Abstract: An electromagnetic clutch includes a rotor, armature hub, armature, magnetic body and first permanent magnet, field core, excitation coil, and second permanent magnet. The rotor is rotatably disposed in the housing of a driven device. The armature hub is fixed to the rotating shaft of the driven device. The armature is disposed on the armature hub to be movable in an axial direction. The magnetic body is incorporated in the rotor. The first permanent magnet connects the armature to the rotor. The field core is attached to the housing and inserted in the rotor to be in noncontact with it. The excitation coil is disposed in the field core and excited, when cutting off power transmission, to cancel a magnetic force of the first permanent magnet, thus releasing the armature from the first permanent magnet. The second permanent magnet separates the armature from the rotor, when cutting off power transmission, to move the armature toward the armature hub.

Abstract: A fixing member having the form of a film or belt which is multi-layer constructed to have at least a base layer and a surface layer. The base layer is formed of a material having radiation-transmitting properties, capable of transmitting radiation coming from a radiation source disposed on the back side of the base layer in non-contact with the fixing member. Also disclosed is a fixing assembly having this fixing member and a radiation source disposed on the internal side of the fixing member. Even though the radiation source is disposed on the internal side of the fixing member, the fixing member can perform good surface heating in a good heat response.

Abstract: A fixing member having the form of a film or belt which is multi-layer constructed to have at least a base layer and a surface layer. The base layer is formed of a material having radiation-transmitting properties, capable of transmitting radiation coming from a radiation source disposed on the back side of the base layer in non-contact with the fixing member. Also disclosed is a fixing assembly having this fixing member and a radiation source disposed on the internal side of the fixing member. Even though the radiation source is disposed on the internal side of the fixing member, the fixing member can perform good surface heating in a good heat response.

Abstract: An image forming apparatus comprises an image bearing member for bearing an image, and a movable member which is abutted against the image bearing member and onto which the image on the image bearing member is transferred. The movable member includes a substrate, a sheet-like member, and an elastic layer disposed between the substrate and the sheet-like member and compressed to a predetermined thickness before the movable member is abutted against the image bearing member.

Abstract: An image forming apparatus has a recording medium bearing member bearing a recording medium thereon and rotatable, the recording medium bearing member having in the surface thereof a recess extending in the direction of the rotary shaft thereof, image formation being effected on the recording medium born on the recording medium bearing member, and a rotatable member abutted against the recording medium bearing member, the rotatable member being provided with a abutting portion abutted against the recording medium bearing member, and a regulating portion adapted to abut against the recording medium bearing member when the recess and the rotatable member become opposed to each other. Thus, the distance between the recess and the bearing portion, is regulated the rotatable member being movable between a first position in which the abutting portion abuts against the recording medium bearing member and a second position in which the regulating portion abuts against the recording medium bearing member.

Abstract: An image forming apparatus includes an image bearing member, an image forming means for forming a toner image on the image bearing member, a rotary member contacted with a surface of the image bearing member, a transfer member for transferring the toner image from the image bearing member to the rotary member, and a cleaning member for removing residual toner from the image bearing member. Wherein a longitudinal width of a contact area between the image bearing member and the rotary member is smaller than the length of the cleaning member.

Abstract: An image forming apparatus has an image bearing member bearing images thereon and movable, and a transfer medium bearing member provided in pressure contact with the image bearing member and bearing a transfer medium thereon and rotatable. The transfer medium bearing member has a sheet member for bearing the transfer medium thereon, and an elastic layer supporting that area of the sheet member bearing the transfer medium thereon from the inside of the sheet member. A voltage is applied to the transfer medium bearing member to transfer the images on the image bearing member to the transfer medium born on the sheet member. The sheet member has an area not fixed to the elastic layer. The transfer medium bearing member is rotated with a potential difference created between the image bearing member and the sheet member before the operation of transferring the images on the image bearing member to the transfer medium born on the sheet member is started.

Abstract: An image forming apparatus including image forming unit for forming an unfixed image on a recording medium, a pair of fixing rotary members for fixing the unfixed image on the recording medium, a cleaning member for cleaning surfaces of the fixing rotary members, the fixing rotary members and the cleaning member being an integral unit separable from the apparatus, detection unit for detecting remaining quantity of the cleaning member, and a unit for requesting the exchange of the integral unit of the fixing rotary member pair and the cleaning member in response to the output of the detection unit.

Abstract: A fixating device has a first rotatable member in contact with an unfixated image borne on a recording medium, a second rotatable member forming a nip together with the second rotatable member, a first heater for heating the first rotatable member, a second heater for heating the second rotatable member, and power supply controlling means for controlling the supply of electric power to the first heater and the second heater. The power supply controlling means is adapted to control the supply of electric power so that when the electric power supplied to the first heater is Wa and the electric power supplied to the second heater is Wb and the ratio when the recording medium is nipped between and conveyed by the first rotatable member and the second rotatable member is Dp=Wa/Wb and the ratio during standby is Ds=Wa/Wb, there may be established Dp>Ds.

Abstract: The present invention provides an image forming apparatus with an image bearing member capable of rotating while bearing a toner image thereon, a transfer device for transferring the toner image from the image bearing member to a recording material at a transfer position, recording material bearing member capable of rotating while bearing the recording material thereon and adapted to convey the recording material to the transfer position, a pair of rotary members arranged at an upstream side of the recording material bearing member in a recording material conveying direction and adapted to pinch and convey the recording material, and a separation device for separating the recording material from the recording material bearing member at a separation position.

Abstract: This disclosure relates to an image forming apparatus in which an image is formed by deflecting a light beam a minute distance in a sub-scanning direction every pixel of image data. By controlling the emission intensity of the light beam utilizing a .gamma. correction, and by controlling the emission time of the light beam utilizing PWM control, the beam spot can be adjusted to control the dot size of the image. Accordingly, the dot density in image formation can be raised by minute deflection in the sub-scanning direction, and the reproducibility of characters and graphics is improved, particularly in the oblique direction. Furthermore, tone reproducibility of multi-tone image data is enhanced by minute deflection in the sub-scanning direction and adjustment of image dot size.

Abstract: There is disclosed an apparatus for obtaining image signal by tonal processing of an input signal. Pulse-width modulation of the input signal is achieved thorugh comparison with a second signal of a predetermined shaped, for example a triangular signal. In order to avoid the influence of fluctuating factors in pulse-width modulation, the apparatus also has a third signal generator, and the pulse-width modulated signal or a pattern signal generated by the third signal generator is selectively used for image formation.