Abstract: A heating device includes a heater, a holder, a device frame, a primary positioner, a secondary positioner, and a tertiary positioner. The heater includes a heat generator. The holder holds the heater. The device frame is configured to support the holder. The primary positioner is configured to position the heater and the holder in a longitudinal direction of the heater. The secondary positioner is configured to position the holder and the device frame in the longitudinal direction of the heater. The tertiary positioner is configured to position the device frame and a body of an image forming apparatus in the longitudinal direction of the heater. The primary positioner and one of the secondary positioner and the tertiary positioner are disposed on an identical side defined by a center of the heat generator in the longitudinal direction of the heater.

Abstract: An image forming apparatus includes a fixing device including a fixing device frame, a chute rotatable between a path forming position and a path opening position, an optical sensor including a light-emitting element, and an actuator. The actuator has a shaft, a first lever configured to contact an anti-pivot rib, and a second lever configured to shield light emitted from the light-emitting element. The actuator is movable to a position where the first lever contacts the anti-pivot rib when the chute is at the path forming position, a position where the first lever and the anti-pivot rib are separated from each other when the chute is at the path forming position, and a position where the first lever and the anti-pivot rib are separated from each other when the chute is at the path opening position. The actuator and the optical sensor are supported by the fixing device frame.

Abstract: A heating unit includes a cylinder which rotates about an axis parallel to a first direction. A heater has a first surface abutting on an inner surface of the cylinder at a nip position. A support member is on a second surface of the heater and also contacts the cylinder. A first heating element is in the heater at a first position along the first direction. A second heating element in the heater is at a second position spaced from the first position. A first temperature sensor is above the first position. A locking portion of the heater is at a third position along the first direction. The locking portion engages the support member and restricts movement of the heater in the first direction. The first position is near a first outer edge of the cylinder. The second position is closer to a central portion of the cylinder.

Abstract: A slipring assembly comprises a slipring module having at least one slipring track which is in electrical contact with at least one slipring brush. The slipring module includes an isolating body holding the at least one slipring track. Furthermore a heating element is embedded in the slipring module to generate heat within the slipring module and to increase the temperature of the at least one slipring track. This allows increasing the temperature of the slipring module to an optimum operation temperature and further to remove humidity from the surface of the slipring track.

Abstract: An image heating apparatus includes first rotatable member and second rotatable member; a heater provided in the second rotatable member; a moving mechanism for integrally moving the second rotatable member and the heater between a contact position in which the second rotatable member is contacted to the first rotatable member and a separation position in which the second rotatable member is separated from the first rotatable member; and an electrical connecting piece for electrically connecting an electric energy supplying portion of the heater and an electric wire under pressure application. A direction of the electrical connecting piece is set so that a smaller angle formed between a longitudinal direction of the electrical connecting piece in cross section of the electric wire and a movement direction of the electrical connecting piece during an operation by the moving mechanism is 45 degrees or less.

Abstract: A safe product transfer apparatus that heats refrigerated food products and then hold those heated food products in a hold drawer until they can be transferred to a heater merchandizer, preferably a roller grill as needed. The apparatus features a control assembly. A pre-heat indicator indicates when the preheat temperature has been reached so that the food products can be loaded into an operable drawer. The apparatus can heat a refrigerated product from 34° F. to greater than or equal to 140° F. in 35 minutes or less. The apparatus has a safe product transfer apparatus that has a heating cavity ranging from 250° F. to 425° F. The apparatus provides a safe product transfer apparatus that can hold the products stored therein at a safe holding temperature (ranging from greater or equal to 140° F. to not more than 205° F.), that is, not hot enough to continue heating or degrading the food product.

Abstract: A dryer uses conduits to carry a heating medium, such as steam, to heat the outer surface of the dryer. The volume of steam is successfully reduced to non-explosive levels and the shell need not be designed to prevent an explosion. Conduits may be formed through the shell itself or grooves may be formed on the inner surface of the shell, with the conduits retained within the grooves. Also, the conduits can be placed against the inside surface of the dryer and a material, such as zinc, can be filled in about the conduits. The material serves to both retain the conduits in place and thermally couple the conduits to the dryer to assure efficient heat transfer between the conduits and dryer. These modifications relieve the dryer from the Unfired Pressure Vessel classification to the classification of a piping assembly under ASA code regulations. This results in savings in operation safety, installation cost and operating costs due to the absence of costly inspections.

Abstract: The invention provides for an inkjet printhead having a plurality of micro-electromechanical vapor bubble generators. Each bubble generator includes a nozzle in fluid communication with an ink chamber, and a heater positioned in thermal contact with ink in the chamber. Each generator also includes drive circuitry configured to provide a modulated pulse to the heater to generate a vapor bubble in the ink in said chamber, the pulse comprising a pre-heat series of a predetermined number of pulses separated by a predetermined period, followed by a trigger pulse of a period twice that of said predetermined period.

Abstract: An elastic roll is used in a fixing device of an image forming apparatus. The elastic roll includes an elastic layer and a covering layer disposed on an outside of the elastic layer. The covering layer is made of a heat-resistant resin or a metal, which has higher rigidity than a material of the elastic layer.

Abstract: Apparatuses useful for printing and methods for controlling the temperature of media in apparatuses useful for printing are disclosed. An embodiment of the apparatuses includes a heated first roll including a first outer surface; a heated second roll including a second outer surface; a third roll including a third outer surface; a temperature sensor for sensing the temperature of the third outer surface; a belt supported on the first roll and the second roll and disposed between the first outer surface and the third outer surface, the belt including an inner surface and an outer surface; a nip between the third outer surface and the outer surface of the belt at which the belt heats media which include a surface, marking material on the surface and an interface between the surface and marking material; and a positioning device coupled to the second roll.

Abstract: A heater element is provided adapted to heat a belt in a fuser assembly. The heater element comprises laterally spaced-apart features extending beyond a center section provided between the features. The features and center section are adapted to face an inner surface of the belt.

Abstract: Provided is a printing device comprising a hot roller having an inside surface and an outside surface. A heating element is present within the hot roller. The inside surface has a first region, wherein the first region is coated with a first type of material. The inside surface has a second region, wherein the second region is coated with the first type of material, and wherein second region is of a different dimension than the first region. The inside surface has a third region, wherein the third region is coated with a second type of material.

Abstract: The heating apparatus of a surface-heating type, includes a rotary member, an opposing member that forms a nip with respect to the rotary member, and a heating member for heating a portion of a rotary member surface other than the nip, in which temperature used for heating the rotary member by the heating member is controlled, and a heating material inserted in the nip to be nipped and conveyed therein is heated using heat of the rotary member. Accordingly, after insertion of the heating material in the nip starts, control temperature of the heating member is increased before the rotary member rotates by one revolution, thereby preventing an uneven heating phenomenon of the heating material in the first revolution and the second revolution or later, and preventing uneven gloss due to the uneven heating phenomenon in the fixing apparatus.

Abstract: A MEMS vapour bubble generator that uses a heater in thermal contact with a liquid to generate a bubble. The heater is energized by an electrical pulse that is shaped to have a relatively low power, sub-nucleating portion and a high power portion that nucleates the bubble. The thermal energy transferred to the liquid by the sub-nucleating portion speeds up the nucleation of the bubble across the surface of the heater during the nucleating portion. This produces larger, more stable bubble having a regular shape.

Abstract: A fusing device (23) has heat reflectors (238) and (239) positioned in consideration of the fact that convective heat loss from respective outer surfaces of the heat reflectors (238) and (239) depends on orientation of the outer surfaces. More specifically, each of the heat reflectors (238) and (239) are positioned so as to have a convective heat transfer coefficient ? of up to 0.9. The convective heat transfer coefficient ? is given by the following expression: ?=(Su+0.77Sh+0.54Sd)/(Su+Sh+Sd), were Su is a projected area of an outer surface of each of the heat reflectors on an upper horizontal plane, Sh is a projected area of the same on a vertical plane, and Sd is a projected area of the same on a lower horizontal plane.

Abstract: A fixing apparatus and an image formation apparatus are disclosed. The fixing apparatus includes two or more heaters with temperature detecting function that generate heat with electric current and detect temperature; a heating unit that includes the heater with the temperature detecting function; a film, a surface of which slides on the heating unit; a thermal fixing unit that is heated by the heating unit through the film for fusing a toner image that is yet-to-be fixed on a recording paper at a predetermined fixing temperature; a pressurization roller for pressing the recording paper to the thermal fixing unit; and a temperature control unit for controlling the temperature of the heater to be a predetermined temperature based on the temperature of the heater detected by the heater with the temperature detecting function.

Abstract: A heater includes: a hollow tube sealed hermetically and reduced in pressure, the interior of the hollow tube being divided by at least one partition wall into a plurality of regions arranged side by side in a longitudinal direction of the tube; an electron source provided in each of the divided regions, the electron source being supported inside the hollow tube in an electrically insulated state from the hollow tube; a power supply that applies a voltage between the hollow tube and the electron source with the electron source as a negative polarity side; and the electron source emitting electrons toward an inner periphery surface of the hollow tube to heat the hollow tube.

Abstract: A resistive heater adapted for heating a fuser belt is provided. The heater comprises a substrate, a first resistive trace formed over the substrate, and a second resistive trace formed so as to at least partially overlap the first resistive trace.

Abstract: A roller grill assembly for cooking human food has a plurality of horizontally aligned roller tubes which can be arranged to extend at an angle of about 3° to 5° are rotatably mounted to a housing frame. A sealing assembly comprises a bearing member and an annular sealing member. A drive chain engages an idler sprocket to rotate the tubes. The housing has a cavity that receives a sliding compartment assembly that has a frame comprising track members and a cross strut shaped to support a pan for holding food. The tubes have heating elements with compact spiraled configuration at the ends. A cover is pivotally mounted by a biased pin or two legged spring to cover a control panel.

Abstract: A temperature controlled apparatus comprising: an object having a surface and being rotatable about an axis; an electrical heater assembly thermally coupled to the surface of the object; a temperature sensor assembly mounted on the object for sensing the temperature of the object surface and for producing temperature signals representative of the sensed temperatures; a microprocessor non-rotatably mounted with respect to the rotatable object; an optical communication link for transmitting the temperature signal to the microprocessor; and a temperature control assembly, non-rotatably mounted with respect to the rotatable object for controlling the flow of electrical power to the heater in response to control signals from the microprocessor as a function of the transmitted temperature signals.

Abstract: A fusing roller having an electrical connection between the heater and the external power supply of an electrophotographic image formation apparatus is provided. The fusing roller having an electrical connection between the heater and the external power supply includes an electrically insulating cap and a conductive slip ring installed near the cap. The slip ring is supplied with current from an external power supply and transmits the current to a heater disposed within a hermetically sealed fusing roller by a pair of conducting caps. Due to such a structure, durability and safety can be considerably improved against many stresses such as an electrical current stress, a mechanical residual heat stress and a thermal shock according when an electrical connection between the heater and the external power supply of a fusing roller is employed.

Abstract: A heated roll and a method for heating of a roll, in particular of a press roll or calender roll in a paper or board machine. The roll has a hollow, tubular roll mantle. The roll is heated with electric current by means of electrical resistors fitted inside the body material of roll mantle. The heating is preferably applied to the roll substantially at the proximity of the face of the roll mantle, and the electric current may be supplied to the electrical resistors from the ends of the roll through glide rings.

Abstract: A roller grill assembly for cooking human food has a plurality of roller tubes rotatably mounted to a housing frame. A sealing assembly comprises a bearing member, and an annular sealing member. The bearing has a bore for receiving a roller tube. The bearing bore has a part with an annular recess for receiving the sealing member, so that the sealing member can be held against the outer surface of the tube. An idler sprocket is associated with the frame. A drive chain engages the idler sprocket and the sprockets on the tubes, to rotate them. The housing has a cavity that receives a sliding compartment assembly. The compartment assembly has a frame comprising track members and a cross strut, shaped to support a pan for holding food. A wall is spaced above the housing cavity and beneath the tubes. The tubes have heating elements with spiraled configuration, with the spacing at the ends more compact than in the central part of the heating element.

Abstract: In a conductive board heater using metal as the board, since thermal expansion is large, and expansion and shrinkage are repeated in a heating apparatus, there is a defect that the electrode portion to which a power supply spring contact point on the power supply connecter side is pressurized and contacted is worn and contact inferior occurs and it is easy to break. Furthermore, since the position of the resistor pattern of the heating body varies, excessive heating, insufficient heating, uneven heating at an end portion, or uneven curl unevenness at a paper end is occurred. A heater in an image heating apparatus is provided so as to prevent a contact defect between an electrode and a connecter of image heating apparatus.

Abstract: A heater includes a substrate having a high heat conductivity; a resistive layer on the substrate, for generating heat up on electric power supply; an output electrode on the substrate; and a temperature sensing element having an output portions placed on top of the output electrodes.

Abstract: A method and a device for controlling the temperature of hot tap-water, which is heated on the secondary side of a heat exchanger. In order to achieve a quick response and a good temperature stability, the changes of the temperature and the flow of the hot tap-water are sensed on the secondary side of the heat exchanger, these sensed variations controlling a regulator which in turn controls a setting device regulating the flow on the primary side of the heat exchanger.

Abstract: An apparatus, system, and method for processing photothermographic elements. The apparatus thermally develops a photothermographic element by heating the photothermographic element between a heated member, having a resilient layer, and a plurality of rollers. The apparatus can be a component of other apparatus and systems including those having the ability to expose the photothermographic element to form a latent image.

Abstract: A heated roller assembly (10) is disclosed having a rotatable roller (12). The roller (12) has a generally cylindrical section (20) with an outer diameter D and includes an inner insulative layer (36) thereover, a conductive layer (38) over the inner insulative layer (36), and an outer insulative layer (40) over the conductive layer (38). The roller assembly (10) also has an inwardly projecting conical portion (22) adjacent the cylindrical section (20) of the roller (12) with the inner insulative layer (36), conductive layer (38) and outer insulative layer (40) respectively thereover. A portion (A) of the conductive layer (38) on the conical portion (22) of the roller (12) is exposed. An external contact body (14) has at least one electrically conductive outer surface (46) that projects towards and contacts the conductive layer (38) of the conical portion (22) while piercing an imaginary plane P1 formed by an extending outer diameter (D) of the cylindrical section (20).

Abstract: When the surface temperature of a heating roller exceeds a predetermined temperature, bearings that rotatably support the heating roller melt. Thus, a pressuring roller causes the heating roller to move toward a temperature detecting device. Thus, the heating roller comes in contact with the temperature detecting device. Consequently, when a defect takes place, the warm-up time after the temperature detecting device works until the power to the heater is shut off can be reduced. In addition or in the alternative, an electrode plate has edges electrically contacting and connecting the heater in the heating roller and a power supply. As the heating roller moves, electrical contact between the heater and the electrode plate is broken and the power from the power supply to the heater is disconnected. As a result, an electrophotographic printing apparatus can be prevented from getting defective, thereby improving the reliability thereof.

Abstract: A heating element having an electrically heatable layer comprises a support tube (16) provided with an electrically resistive heating layer (14), and electrodes for applying a voltage to the resistive heating layer (14). At least one electrode is provided as an elastic electrode, having a contacting side for engaging the resistive heating layer (14) and being adapted for arrangement on the support tube (16), with the contacting side of the electrode abutting the resistive heating layer (14). The contacting side has free ends comprising a plurality of projections having abutment faces, abutment lines or abutment points for contacting the resistive heating layer (14).

Abstract: In the apparatus (10) and the method according to the invention, two temperature treatment devices (e.g., laminating rollers 14, 16) which are to be contacted with an element to be subjected to heat treatment (e.g., proof 50 with color particles 52), are temperature-controlled. One of the treatment devices (laminating roller 14) is provided with a heating means (22). For tempering the second treatment device (laminating roller 16), the second treatment device is brought into contact with the directly heated treatment device (laminating roller 14). This is carried out as soon as the temperature of the not directly heated treatment device (laminating roller 16) has dropped below a predetermined desired temperature or a predetermined desired temperature range.

Abstract: An ink jet printer has multiple print heads for ejecting ink in response to signals supplied in sequence to cause ejection of ink in forming an image. The ink is ejected upon an ink transfer medium, and an energy source is adapted for application of heat to the surface of the ink transfer medium. A pressure application assembly places the printing substrate in contact with the ink transfer medium in forming an image by transfer of ink. Ejection of ink may occur from multiple ink jet print heads simultaneously.

Abstract: A temperature sensor for use in connection with a heat and pressure roll fuser which minimizes the problem of gloss variation due to fuser roll wear caused by sensor contact with the fuser roll surface. To this end, one or more Resistance Temperature Detector (RTD) sensors are used. Each sensor is encapsulated or embedded in a polyimide material in any desired form such as a tape. The polyimide tape including the RTD is supported in contact with the surface of the heated fuser roll. The load required for this operation is substantially less than that for a bead thermistor and the area of the sensor structure is relatively large for distributing the load over a larger surface area of the roll contacted as compared to the area of contact of a bead thermistor.

Abstract: Described is a godet (2) for guiding and advancing endless filament yarns, which comprises one or several heating zones along its casing (3), the heat that is applied by the heating elements (7-10) to the godet casing (3) being scanned by a multiple temperature sensor (12), so as to control the temperature of godet casing (3) in zones. In accordance with the invention, the temperature sensor (12) consists of a flat circuit arrangement of resistors and conduction bands, which are enclosed by a coating resistant to even high temperatures. The exposed tapping contacts (18) lead to the outside of godet (2) and are connected, via measuring lines, with an evaluation unit, whereas the temperature sensor (12) itself is attached to the inside surface of the rotatably driven godet casing (3).

Abstract: In a heating roller, electrode members come in contact with power supplying members for supplying power to a heating element. The electrode members are resiliently fitted to the heating element. Power is supplied from the power supplying members to the heating element through the electrode members. In this heating roller, it is possible to solve problems about cracks, etc. caused by thermal expansion, etc. of each of the heating element, the electrode members and an electric conductor formed by materials having different coefficients of thermal expansion. Accordingly, reliability of the heating roller is high and the heating roller is safe.

Abstract: A wear resistant member is loosely disposed about a thermistor in contact with a thermistor bead such that it is between the bead and a heated fuser member and completely surrounds the components of the thermistor. The wear resistant member is in the form of a strap or tape having an opening adjacent one end through the opposite end is insertable. The inserted end is configured such that once it is inserted it can't be withdrawn through the opening. The strap is loosely supported in its operative position and can be easily removed, for example, by cutting through the strap and then withdrawing the strap from around the thermistor. Thus, a worn strap can be removed and a new one installed without discarding the thermistor and more importantly discarding the thermistor assembly.

Abstract: A fixing roller device which is capable of dividing the heating area into a plurality of separately heatable different parts both in the circumferential direction of the heater roller, as well as in the direction parallel to the axis of the heater roller. As a result, the heating area can be varied according to various image fixing requirements, as well as for varying initial warm-up requirements. In addition, the temperature of the heating roller can be controlled by varying the density of heating chips or heating elements which are supplied with power within a heated area. Further, temperature control can also be accomplished utilizing a control arrangement based upon the current passing through the heater chips or heater elements, since the current varies with temperature, and thus external temperature sensors for monitoring the temperature of the fixing roller are not required.

Abstract: The invention relates to a technique which enables good electric contact to be surely made between a heat roller and conducting terminals serving as feed means. The heat roller comprises a heating portion and shaft portions which are integrally molded from the same material in the form of a molded member at least both end portions of which are hollow. The conducting terminals are capable of elastically expanding and contracting in the radial direction and are closely fitted into the hollow portions at both ends of the molded member.

Abstract: A heat pipe roller includes a rotatable outer tube having a primary internal chamber for containing a fluid, a heater operable to heat the fluid and hence the tube, and a sensor. The sensor has a movable member which communicates with the primary chamber and is mounted on the tube for rotation therewith, and a fixed member situated in the region of the axis of rotation of the tube and so mounted relative to the tube that rotation of the tube does not rotate the fixed member. The fixed member is adapted to be connected to equipment for measuring an electrical characteristic of the sensor. The arrangement is such that, in use, the movable member moves in response to a temperature change or temperature related physical change in the primary chamber, thereby causing a corresponding change in the electrical characteristic of the sensor.

Abstract: A heating device, which can be used in the fixing unit of an image forming apparatus, such as an electrophotographic copying or printing machine, for fixing a toner image on a sheet of image transferring medium, includes a ceramic heat roller whose body is formed of a resistor material having positive temperature coefficient of resistance (PTC), capable of self-heating and self-regulating the temperature.

Abstract: An image recording apparatus comprising a heat roll for fusing an toner image transferred onto a sheet by heating; a switching device for starting conduction of a heater installed within the heat roll; a temperature control device for controlling the surface temperature of the heat roll in a first predetermined temperature by controlling conduction of the heater when the switching device has been turned on and for controlling the surface temperature of the heat roll by increasing the surface temperature from a first temperature to a second predetermined temperature being different from the first temperature in response to a control signal; and a control device for applying the control signal to the temperature control device to approximately maintain the surface temperature of the heat roll in at least one of the first temperature and the second temperature.

Abstract: The drawroll unit has a heatable galette in which the shaft of the gallette is mounted in bearings which, in turn, are mounted via vibration damping devices in a stationary housing. The vibration damping devices may be in the form of bodies of interlaced wire, O-rings or the like. The vibration damping devices serve to damp vibrations of the shaft in a critical speed range within the normal speed range of the rotor so that the galette can be operated at any speed within the normal speed range.

Abstract: A mill roll having a pair of ceramic, hollow rollers with the chambers defined in each filled with a plurality of particles with spaces defined therebetween including means to enter fuel therein to be burned to heat the rollers to incandescent temperatures.

Abstract: In a roll with a roll shell or jacket which is rotatable about a support or beam, the inner side of the rotatable roll shell or jacket is heated by means of an induction coil which is operated at high frequency and provided, for example, at a support element. The heating is effected directly at the press or work nip or in the proximity thereof without substantial loss of energy and without the use of a thermo-sensitive hydraulic medium.

Abstract: The surface temperature of a fusing roller is controlled by sensing both the surface temperature and the temperature of a source of heat for said roller. Each temperature is compared to a nominal temperature for each to derive two error signals. The two error signals are combined to give a combined error signal, which is used to control the amount of energy applied to the source. The source can be an internally heated core or heated external roller riding on the fusing surface.

Abstract: A temperature control device adapted to increase the roll surface temperature to the fusing temperature after initiation of power supply. When the roll surface temperature is to be increased from a level below a reference temperature, the current is supplied until the roll surface temperature reaches a predetermined temperature lower than the fusing temperature, and when the roll surface temperature is to be increased from a level higher than the reference temperature, the current is supplied for a predetermined time which is set according to the roll surface temperature at the initiation of power supply.

Abstract: The present invention relates to an apparatus for connecting appliance lines to cooking plates, hobs or hotplates. Our of the bottom of the electric hotplate, connecting pins (19b) extend for connection to connecting members (33) of a connecting piece (31) that is part of the appliance line. From a passage through an insulating member (20b) in the bottom of the hotplate, the connecting pins (19b) project outwards towards the circumference of the hotplate body (2b). In a transportation mode the pins can be resiliently and completely countersunk in the underside of the hotplate. In the vicinity of the front end of the connecting members (33) of the appliance plug, the connecting piece (31) of the plug has a threading and guidance apparatus for the connecting pins (19b) that does not project beyond the outer circumference of hotplate body (2b), thereby ensuring an automatic, positonally correct connection between the connecting piece (31) and connecting pins (19b).

Abstract: A temperature control device uses a thermo-sensitive element to detect the temperature of an imaging system heated fixer device member. A comparator compares the potential generated by the thermo-sensitive element corresponding to the detected temperature with a reference voltage to set the temperature of the heated member to a predetermined level. A signal representing the comparison result is used for controlling the temperature of the heated member. Any abnormality of the heated member is detected on the basis of the output signal from an oscillator producing a signal which changes the reference potential at predetermined periods and from the comparator output signal.

Abstract: A temperature sensitive control circuit for an electrically heated rotatable drum (11) including an internally disposed electric heater (27) and an electric temperature sensor (28) and, outside of the drum, an electric supply (30) for heating the heater and a D.C. supply (31) for producing a constant electric current through the sensor, wherein the electric connections with the drum occur through two sliding contacts (89, 90) only and a diode (29) bypasses the voltage of the heating supply around the temperature sensor. The heater current supply and the sensor current supply operate alternatively and the sensor measures drum temperature while the heater current is interrupted.

Abstract: A directly heating type fixing apparatus for use in an image forming device such as an electronic copying machine, has a heating roll which includes an heat generating electric resistance layer and a toner releasing layer both formed on the surface of a cylindrical body thereof, and a pressure roll which is arranged to contact the heating roll under pressure. Current collecting bearings made of an electrically conductive material are provided on both sides of the heating roll, respectively. These current collecting bearings and the heat generating electric resistance layer of the heating roll are electrically connected with each other.