JPS5849869B2 - Seigiyosouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates generally to electrostatographic printing machines, and more particularly to electrostatographic printing machines that are incorporated in this type of printing machine to permanently apply powder figures in image form to sheets of support material. The present invention relates to a control device used to adjust a fusing device to deposit a target.

In the electrostatic copying method, in order to record and copy visible figures,
Forming an electrostatic latent image and utilizing it.

The field of electrostatography includes electrophotography and electrography.

Electrophotography is a type of electrostatography that uses a photosensitive medium to form an electrostatic latent image with the aid of radiation.

Electrography is a type of electrostatography that utilizes an insulating medium to form electrostatic latent images without the aid of radiation.

All of these types of electrostatography use fusing to permanently attach the powder image to a sheet of support material.

The illustrated embodiments described below employ electrophotography.

In electrophotographic printing, a charged photoconductive member is exposed to a light image of an original to be reproduced.

This records an electrostatic latent image on the photoconductive surface.

At this time, a developing device is operated to bring a developer mixture of carrier powder and toner powder into contact with the electrostatic latent image.

The toner powder is electrostatically attracted to the latent image to form a toner powder image.

This toner powder image is then transferred to a sheet of support material.

Generally, toner powders are fusible resins.

After such toner powder is transferred to a support material, the powder image is permanently affixed to the support material by heating.

In the process of applying heat to the toner powder image, the toner powder partially melts and fuses to the sheet of support material.

In multicolor electrophotographic printing, the steps of charging, exposing, developing and transferring are repeated over several cycles.

However, each development cycle deposits a different color of toner powder onto the support material in superimposition with a previously deposited layer of toner powder.

Therefore, a multilayer toner powder image is transferred onto the support material.

The multilayer toner powder image is heated to fuse and become transparent.

That is, each toner layer modulates the light passing through it to form a copy having a single composite color.

In this way, the modulated light beam passing through the toner powder image is reflected from the subsequent support material to the viewer's eye.

When heating the toner powder image, the temperature of the support material may be raised to approximately the same temperature as the toner powder O contact temperature.

The support material then acts as a heat source rather than a heat flow during the fusing operation.

Therefore, the fusing device preferably has two heat sources, one heating the support material and the other heating the toner powder image.

Various types of fusing devices have been proposed which heat the support material and apply radiant heat to the toner powder deposited thereon.

For example, a fusing device suitable for use in multicolor electrophotographic printing machines was published in U.S. Patent Application No. 30053 filed in 1972.
It is stated in No. 1.

This fusing device uses a radiant energy source and a heated transfer body for the support material.

Hereinafter, this type of q-touching device will be explained in connection with the control device of the present invention.

In operation, the radiant energy source and the moving heat source work together to fuse and adhere the multilayer toner powder image to the support material.

This is done without burning or igniting the support material.

Therefore, the radiant energy source and the moving heat source must be coupled individually and together to properly adjust the temperature of the support material on which the multilayer toner powder image is deposited.

SUMMARY OF THE INVENTION Accordingly, a principal object of the present invention is to improve a control device for regulating a fusing device arranged to permanently deposit a single or multilayer toner powder image on a sheet of support material.

Briefly, a control system according to the present invention regulates first and second heat sources arranged in cooperation with each other to maintain a moving article at a preselected temperature.

This is achieved according to the invention by a control device having a first control means and a second control means.

According to the invention, the first control means adjust the thermal energy generated by the first heat source in response to the temperature detected on the part of the article being moved.

In this manner, the first heat source is controlled to maintain the moving article at approximately the preset temperature.

Furthermore, the first control means is arranged to automatically compensate for variations in the external voltage supplied thereto.

Further in accordance with the invention, the second control means is operatively associated with the first control means to be responsive to the temperature detected in the area of the second heat source and to control the thermal energy generated by the second heat source. Adjust.

The second heat source thus cooperates with the first heat source to maintain the moving article at approximately the preset temperature.

Furthermore, the second control means is also arranged to automatically compensate for variations in the external voltage supplied thereto.

Other objects and advantages of the invention will become apparent from the following detailed description and accompanying drawings.

Although the invention will be described in conjunction with a preferred embodiment, it is not intended to limit the invention to this embodiment.

On the contrary, the intention is to cover all alterations and equivalents falling within the spirit and scope of the invention as claimed.

Although like reference numerals are used throughout the accompanying drawings to indicate like components, FIG. 1 schematically depicts a multicolor electrophotographic printing machine in which the present invention may be embodied.

The electrophotographic printer utilizes a variety of components to produce multicolor copies from color originals.

Although the control system of the present invention is particularly adapted for use in conjunction with the fusing apparatus of an electrophotographic printing machine as shown in FIG. 1, it is equally suitable for use with a variety of electrographic printing machines. It will be clear from the following discussion that the application is not necessarily limited to the particular embodiments shown.

The printing press shown in FIG. 1 uses a photoconductive member having a drum 1o, which is rotatably mounted within a machine frame (not shown).

A photoconductive surface 12 is mounted on the outer peripheral surface of the drum 10.

One suitable photoconductive material is disclosed in U.S. Pat. No. 3,655,37
It is disclosed in No. 7.

Drum 10 rotates in the direction indicated by arrow 14 to sequentially move photoconductive surface 12 through a series of processing stations.

A conventional drive motor (not shown) rotates the drum 10 at a predetermined speed relative to other actuating mechanisms.

The various mechanical actuators cooperate with each other to cause the correct sequence of operations to be performed at the appropriate processing station.

The working order within an electrophotographic printing machine is controlled by logic circuitry.

Logic timing may be controlled by individual logic elements or alternatively timed to rotation of drum 10.

If the timing of each successive operation is adjusted to 100 rotations of the drum, a timing disk (not shown)
may be attached to one end of the drum 10.

Preferably, the timing disc has a number of angularly spaced slits around its periphery.

A light source transmits light through these slits to energize the photoreceptor.

Thus, each time a beam passes through each slit, the photoreceptor is energized and, therefore, the appropriate logic is energized to initiate each step at the respective station.

Initially, drum 10 moves photoconductive surface 12 through charging station A.

Charging station A consists of a corona generator (total 16
).

The corona generating device 16 extends generally laterally across the photoconductive surface 12.

By doing so, the corona generating device 16
Photoconductive surface 12 can be easily charged to a relatively high and substantially uniform potential.

Preferably, the corona generating device 16 is as described in U.S. Pat.
It is of the type described in No. 8946.

After sowing, tram 10 (east exposure station BK) is rotated where charged photoconductive surface 12 is exposed to a chromatic light image of the document.

Exposure station B includes a moving lens system (generally indicated at 18) and a color filter mechanism (generally indicated at 20).
and includes.

A suitable moving lens system is disclosed in U.S. Pat. No. 3,062,108, and a suitable color filter arrangement is
It is disclosed in US Patent Application No. 830,282, filed in 1969.

As shown in FIG. 1, an original document 22 (eg, a sheet of paper, a book, etc.) is placed face down onto a transparent viewing platen 24. As shown in FIG.

Purchased 26 lenses, 18 lens systems, and 2 filters.
o is moved in synchronization with the drum 1o to scan the surface of the document 220 on the platen 24.

Thus, the moving beam of original document 22 is projected onto photoconductive surface 12 to record its electrostatic latent image thereon.

Filter mechanism 20 A selected color filter is inserted into the G-J optical path.

A suitable color filter acts on the light beam passing through lens 18 to create an electrostatic latent image on photoconductive surface 12.

This electrostatic latent image corresponds to a preselected spectral range of the electromagnetic wave spectrum, which will be described later as a monochromatic electrostatic latent image.

Following exposure, drum 10 moves the monochrome electrostatic latent image recorded on photoconductive surface 12 to development station C.

Developing station c consists of three independent developing units (
28, 30 and 32 respectively).

A suitable developer station using multiple developer units is disclosed in US patent application Ser. No. 2,552, filed in 1972.

Preferably, the developer units are all of the type commonly referred to as magnetic brush developer units.

A typical magnetic brush type developing unit uses a magnetized developer that is a mixture of carrier powder and toner powder.

This mixed developer is continuously passed through a directional electric field to form a brush.

The electrostatic latent image recorded on photoconductive surface 12 is developed by contact with a brush of mixed developer material.

Each developing unit contains toner powder of a different color corresponding to the residual color in the spectral range of the wavelength of the light that has passed through the filter 20.

For example, a green colored electrostatic latent image is visualized by depositing green-absorbing magenta toner powder thereon.

Also, the blue and red latent images are developed with yellow toner powder and cyan toner powder, respectively.

The drum 10, with the toner powder image electrostatically adhered to the Toko conductive surface 12, is then rotated to transfer station D.

At transfer station D, the toner powder image is finally transferred to a sheet of support material 34.

This final support material 34 may be blank paper or a thermoplastic sheet.

Transfer station D is equipped with a transfer roll (indicated generally at 36).

Transfer roll 36 is electrically biased to a potential of sufficient magnitude and polarity to recirculate support material 34 and draw toner powder from the latent image recorded on photoconductive surface 12 to the transfer roll. .

A suitable example of an electrically biased transfer roll is described in US Pat. No. 3,612,677.

Transfer roll 36 rotates in the direction of arrow 38 in synchronization with drum 10 (in this case at the same angular velocity).

Support material 34F is releasably affixed to the outer peripheral surface of transfer roll 36 and moved in a recirculating path by the transfer roll so that successive superimposed toner powder images can be transferred to the support material.

Support material 34 supports stack 40 resting on tray 42
Supplied from.

A feed roll 44 cooperates with a retard roll 46 to advance and separate the uppermost sheet from the stack 40.

The advanced sheet moves to a chute 48 and is sent to a three-way section between register rolls 50.

Thereafter, gripping fingers 52 mounted on the transfer roll 36 releasably secure the support material 34 onto the transfer roll for movement through the recirculation path.

After the plurality of toner powder images are transferred onto support material 34, support material 34 is separated from transfer roll 36.

After the gripping fingers 52 release the support material 34, the stripping bar 54 separates the support material 34 from the transfer roll 36.

After support material 34 is stripped from east transfer roll 36, it is advanced to fusing station E by endless conveyor 56.

At this fusing station E, a fusing device (indicated generally at 58) fuses the transferred powder image to support material 34.

Fusing device 58 is of the type previously described, as described in U.S. Patent Application No. 300,531, filed in 1972, and will now be described in more detail with reference to FIGS.

Returning to FIG. 1 again, a plurality of toner powder images are shown on the support material 3.
After being permanently attached to the support material +-3 endless bell 1 conveyor 60, 62 the catch tray 64
from where it can be taken out by the operator.

Although most of the toner powder is transferred to support material 34, some toner powder always remains on photoconductive surface 12.

These residual toner powders are removed at cleaning station F.

When the drum 10 passes through the cleaning station F, the residual toner powder is first carried away under the influence of a cleaning corona generating device (not shown).

This cleaning corona generator is designed to neutralize the static charge remaining on the toner powder.

The neutralized toner powder is then mechanically removed from the photoconductive surface 12 by a rotatably mounted fiber brush 66.

A suitable brush cleaning device is disclosed in U.S. Pat. No. 3,590,412.
listed in the number.

A rotatably mounted brush 66 is located at cleaning station F and is held in contact with photoconductive surface 12 .

In this manner, toner powder remaining on photoconductive surface 12 is removed from the photoconductive surface after each transfer operation.

It is believed that the foregoing description is sufficient to illustrate the general operation of an electrophotographic printing machine embodying the teachings of the present invention.

Referring now to the subject matter of the present invention, FIG. 2 shows a fusing device 58 used in the electrophotographic printing machine of FIG.
A perspective view of the figure is shown.

Fuser device 58 is shown in FIG. 2 with cover member 72 in an open position.

A conveyor 56 is associated with a fuser 58 to transport support material 34 from transfer roll 36 to the fuser.

Conveyor 55+-J1 pair of opposing and spaced apart rollers 70
It consists of a plurality of endless belts 68 worn around the .

A vacuum device blows air through holes 73 in belt 68 to maintain a low pressure to secure support material 36 to the belt.

Cover member 72 includes a radiant energy source 76 .

The lower screw member 74 defines an open-ended chamber having a pair of spaced apart rollers 78, 80 which are rotatably mounted on a moving frame disposed within the chamber. ing.

An endless belt 82 is mounted around rollers 78,80.

The endless belt 82 has a plurality of holes 84 arranged to draw air, thereby securing the support material 3 4 to the belt during passage through the DJ fusing device 58 .

Preferably, the cover member 72 has a shell made of sheet metal with a suitable insulator affixed to the inner surface.

A nylon fiber coating is sprayed on the outer surface of the cover member 72 to protect the operator.

An external reflector is suitably attached to the insulator affixed to the inner surface of the cover.

An inner reflector is attached to the outer reflector.

The inner and outer reflectors are separated from each other to allow air to circulate between them.

A detection device, ie, a thermistor 100 (FIG. 4), is installed in the space between the inner and outer reflectors to measure the temperature there.

A glass bead type thermistor is suitable for detecting the temperature of the space between the inner and outer reflectors.

The radiant energy source, or radiant heat strip 76, is preferably a nickel chromium alloy ribbon helically wrapped around a pair of opposing spaced support members, such as ceramic spools.

The thermal strip 76 is arranged to provide substantially uniform radiation.

A suitable guide, preferably a quartz woven string, guides the thermal strip 7.
6 to prevent support material 34 from contacting the thermal strip.

FIG. 3 shows a cross section of the lower housing assembly 74.

The lower housing 74 consists of a sheet metal shell with an insulator secured to its inner surface.

A transport frame is removably mounted within the shell.

The rollers 7B and 80 are rotatably mounted on this frame, and an endless belt 82 is placed around these rollers.
is installed.

An inner surface 82b of the endless belt 82 is adapted to come into contact with a plate member 86.

Plate member 86 is adapted to be heated by air moving in the direction of arrow 90.

A blade member 94 is attached to the blower motor 92, and the blade member 94 generates an air flow in the direction of the arrow 90.

The air stream is passed through the plate member 86 after being heated to a temperature by a heating device, ie, an auxiliary heater 96 .

The plate member 86 is in contact with the lower surface 82b of the endless belt 82 and transfers heat thereto.

This, in turn, increases the temperature of the support material 34 to minimize heat lost therefrom.

In this way, the radiant energy Qi. In conjunction with auxiliary heater 96, the multilayer toner powder image formed on support material 34 is fused.

Auxiliary heater 96 is preferably an 800 watt tubular high mass heater.

Sensing device, i.e. bead-shaped thermistor 1 surrounded by a can
18 (FIG. 5) is arranged to detect the temperature of the endless belt 82.

The bead-shaped thermistor 1 1 8 F is mounted on a thermally conductive shoe, which is adapted to contact the lower surface 82b of the belt 82.

Preferably, the floor motor 92 is a two-pole split capacitor motor, and is configured to maintain an appropriate pressure differential to hold the support member 34 to the outer surface 82a of the endless belt 82.

As previously mentioned, a suitable timing disk mounted on drum 10 and adapted to rotate therewith cooperates with the logic circuitry of the machine to direct fuser 58 to sheet 84.
Activates when passing.

The mode of operation of fuser 58 is summarized in Table I.

In operation, the electrophotographic printing machine is heated from a cold state to a standby state.

During warm-up, both auxiliary heater 96 and radiant energy source 76 are activated.

Initially, radiant energy source 76 operates at a full power output of approximately 1750 watts.

The endless belt 82 has a temperature of about 199°C to about 216°C (390y
The radiant energy source 76 is deenergized when the temperature rises to a preselected standby state in the temperature range (depending on humidity conditions) between 420° C. and 420° C. below.

The fusing device 58 is maintained at standby temperature by an auxiliary heater 96.

When the sheet of support material 34 enters the fuser 58, logic circuitry energizes the radiant energy source 76 at a higher power level (1750 watts in this case) and de-energizes the auxiliary heater 96.

As the sheet of support material 34 exits the fuser 58, the control logic energizes the auxiliary heater 96 and the radiant energy source 76.
Deactivate.

In the foregoing torpedo cycle, the thermistor 100 is at approximately 227°C.
(440 bottom) Continue as long as the temperature is below 《.

However, if the temperature exceeds approximately 227°C, and the sheet of support material 34 enters the fuser 58, the radiant energy source 76 is energized at a lower power level (1250 watts in this case).

In addition, auxiliary heater 96 remains energized.

Once the sheet of support material 34 exits the fuser 58, the control logic de-energizes the radiant energy source 76 while leaving the auxiliary heater 96 energized.

Additionally, when a transparent material, such as a coated thermoplastic material other than blank paper, is being passed through the fuser 58, the radiant energy source 76 is de-energized and the auxiliary heater 96 is energized.

FIGS. 4 and 5 show functional block diagrams of the control system for regulating the radiant energy source 76 and the auxiliary heating device 96, respectively.

FIG. 4 schematically depicts a second control means (generally designated 98) used to regulate the radiant energy source 76.

This second pedestal means 98 is adapted to regulate the energy output from the radiant energy source 76.

Preferably <Qi. The second control means 98 controls the radiant energy source 7
a sensing device, i.e. a thermistor 10, adapted to detect the temperature of the space between the inner and outer reflectors in the 60 zone;
has 0.

A voltage source 102 is arranged to generate a reference voltage corresponding to a predetermined temperature (227° C. in this case).

Comparison circuit 104 compares the reference voltage produced by voltage source 102 to the electrical signal produced by thermistor 100 .

The output from comparison circuit 104 is an electrical error signal representing the difference between the reference temperature and the measured temperature of the space between the inner and outer reflectors.

Voltage source 106 generates a reference voltage to which the sum of the error signals from comparator circuit 104 is compared, and a voltage proportional to the voltage that energizes radiant energy source 76 within comparator circuit 108 .

The photomod 110, consisting of an incandescent light source and a cadmium sulfide photocell, is adapted to detect and generate a voltage proportional to the voltage generated by the radiant energy source.

The resistance change in a photovoltaic cell is proportional to the voltage applied to the photovoltaic cell.

The voltage, which is thus proportional to the voltage of the radiant energy source 76, is summed with the error signal from the comparator circuit 104 and compared in a comparator circuit 108 with a reference voltage generated by the voltage source 106 to output an error signal from the comparator circuit. Generate voltage.

The error voltage from comparison circuit 108 is used to energize radiant energy source controller 112.

The radiant energy source controller 112 operates at 227°C (-440'F).
) produces 180 volts RMS when thermistor 100 is indicating a temperature less than thermistor 100.
15 when indicates a temperature greater than 227°C.
It is designed to generate 2 volts RMS.

The radiant energy source controller 112 is preferably a zero-crossover voltage controller, and when the error signal input from the comparator circuit 104 indicates that the temperature of the space between the inner and outer reflectors is less than 227°C. is designed to generate a voltage of 180 volts} RMS.

Similarly, radiant energy source 76 generates 152 volts RM when the error signal from comparator circuit 104 indicates that the air temperature between the inner and outer reflectors is greater than 227°C.
It is designed to generate an electric current of S.

Therefore, the output from the radiant energy source controller 112 is 1
Radiant energy source T6 is adapted to be energized with a pressure of either 80 volts RMS or 152 volts RMS.

Radiant energy source 76 is 1750 volts at 18 o volts rms.
Watts, adapted to generate 1250 watts at 152 volts RMS. In FIG. It shows.

Voltage reference 116 generates a voltage corresponding to one of a pair of temperature references.

In this case, when switch 111 is in position a, the voltage output corresponds to 199°C (390'F), while when switch 117 is in position b, the voltage output from voltage reference 116 is 216°C. °C (corresponds to 4202).

A thermistor 118 positioned against the lower surface 82b of the endless belt 82 generates an electrical output that is a function of belt temperature.

The electrical output from the thermistor 118 is sent to the voltage comparator circuit 12.
0 to the voltage from voltage reference 116.

This difference becomes the error voltage. photo.o
mod ) 1 2 4 produces a voltage output that is a function of the auxiliary heater 96 voltage.

Voltage reference 122 corresponds to a voltage output of approximately 180 volts RMS.

The output from photomad 124 and the error signal from comparator circuit 120 are applied to voltage reference 122 in comparator circuit 126.
and the difference therebetween becomes the error signal used to energize the auxiliary heater controller 128.

Auxiliary heater controller 128 is a zero crossover proportional voltage controller.

The controller voltage output remains approximately constant at 180 volts RMS until the error signal from comparator circuit 126 indicates that the temperature of belt 82 is 6° C. below the temperature set point.

When the belt temperature decreases by 6°C below the set point, the RMS voltage to the auxiliary heater decreases proportionally to 199°C (
At a set point of 390'F, the voltage is 151 volts R.
MS, with a voltage of 163 volts RMS at a set point of 420'F.

If the temperature of belt 82 is approximately 6 degrees Celsius above the set point, the voltage input to auxiliary heater 96 will be zero.

The above operation is sustained for external line voltage variations ranging from about 254 volts RMS to about 180 volts RMS.

Details of the circuitry used for the first control means 114 adapted to regulate the auxiliary heater 96 and the second control means 98 adapted to regulate the radiant energy source 76 are shown in FIG.

In FIG. 6, a step-down transformer (not shown) is connected to pin 132.
, 134.

A half-wave rectifier 136 and a filter capacitor 138
A DC level is applied to pin 135 of voltage regulator 140.

Voltage regulator 140 maintains a 5 volt output across resistor 142.

Therefore, 1 across resistors 142, 144 of the voltage divider network.
A voltage of 5 volts is maintained.

Capacitor 146 is a filter for the internal power supply of integrating circuit 148.

Resistor 15o limits the current to pin 135 of integrator circuit 148, and capacitor 152 corrects for the step-down transformer phase shift.

Pins 154, 156, and 158 are connected together, with pin 58 biased to a voltage level of approximately 2.9 volts.

Pin 160 is connected to resistors 162, 169 and photovoltaic cell 166 of the voltage divider network.

The resistance of photocell 166 varies as a function of the light intensity emitted by light source 168.

Photovoltaic cell 166 and light source 168 constitute photomad 124 (FIG. 5) connected across auxiliary heater 96 (FIG. 5) through resistor 170.

In this way, the resistance of photovoltaic cell 166 is a function of the voltage applied to auxiliary heater 96.

When the voltage across the auxiliary heater 96 is low and the resistance of the photovoltaic cell 166 is high, the triac gate pulse (tri
ac gating pulse) is the integrator circuit 1
48 pin 139.

If the voltage across the auxiliary heater 96 is high and the photovoltaic cell 166
If the resistance of is low, then there is no pulse.

The level at which pulsing is suppressed is controlled by a resistor (set for a 180 volt RMS input to auxiliary heater 96).

A pulse transformer 172 inverts the gate pulses to isolate the controller from the auxiliary heater strike (not shown).

The gate circuit is suppressed by applying a positive voltage to pin 141 of integrator circuit 148 through resistor 116 and diode 178.

When the contacts of relay 180 are closed, positive voltage is removed from pin 141.

Resistors 182, 184 and capacitor 186, along with unijunction transistor 188, are connected to test point 9.
It has a ramp output at o and constitutes a relaxation oscillator.

Resistor 182 is selected to adjust the oscillation period to about 1 second.

Resistor 192 is selected to adjust the amplitude to 0.5 volts.

Emitter bowls 194 and 174 are used for insulation.

Resistor 198 turns off the lamp (at about 7.5 volts above the reference)
ramp ).

Resistor 308 is connected to unijunction transistor 18
8 to compensate for temperature changes in the output.

The output of the ramp oscillator is the positive input of the threshold detector 203;
That is, it is connected to pin 148 thereof.

The resistors 204, 206, 208 are the thermistor 118 (
5) to form a voltage divider network connected to the negative input of the threshold detector 203, ie its pin 145.

If the voltage at pin 143 of threshold detector 203 is negative with respect to the voltage at pin 145, the output of this threshold detector 203 is low.

However, if the voltage at pin 143 is positive with respect to the voltage at pin 145, the output of threshold detector 203 is high.

The switch point of limit detector 203 is set by resistor 204.

Near this set point, the output of threshold detector 203 is time proportional over a range of approximately plus or minus 6 degrees Celsius.

This range corresponds to the temperature change of the thermistor.

Resistors 212 and 214 are used to set the second set point selected by switch 111.

The higher set point corresponds to 216°C and the lower set point corresponds to 199°C.

Resistors 216 and 218 constitute a voltage divider network that forward biases diode 179 and suppresses integrator circuit 148.

Pin 147 of integrator circuit 220 connects voltage divider network resistor 22
2,224 biases it to a positive value.

Resistor 226 provides voltage feedback to limit oscillations at the switch point.

Capacitor 228 is charged through resistor 230 operatively associated with diode 232 and
36 and is arranged to discharge through a resistor 234.

When the output of the integrator circuit 203 is adjusted such that 0.7 seconds low < 0.3 seconds high, the capacitor 228 is charged to the threshold voltage and the output from the integrator circuit 220 is low and the relay 2
Empower 38.

A preparation signal is then sent to the logic circuit of the printing press.

Diode 240 is a steering diode to bypass the fuser control circuit.

Capacitor 242 is a filter for the internal power supply of integrating circuit 244.

A resistor 246 limits the current to pin 149 of the integrator circuit 244, and a capacitor 248 corrects for the step-down transformer phase shift.

Pins 175, 153, and 155 are connected together, and pin 155 is biased at approximately 2.9 volts.

The pin 157 of the integrating circuit 244 is connected to the resistors 25o and 252.
and a photovoltaic cell 254 .

The resistance of photovoltaic cell 254 varies as a function of the intensity of light emitted from light source 256.

A light source 256 is connected across the radiant energy source 76 (FIG. 4) and together with the photovoltaic cell 254 constitutes a 7-tomato 110 (FIG. 4).

A resistor 258 is also connected to the light source 256 .

The resistance of photovoltaic cell 254 also varies as a function of the voltage applied to radiant energy source 16.

The voltage across the radiant energy source 76 is low and the photovoltaic cell 254
A triac gate pulse is present at pin 159 of the integrator circuit 244 when the resistance of the integrator circuit 244 is high.

The level at which the pulses are suppressed is controlled by resistor 250, which is set to maintain a voltage of 180 volts RMS across radiant energy source 76.

Resistors 260 and 262 increase the bias on pin 151 when the contacts of relay 264 are closed.

Resistor 260 connects radiant energy source 76 to 152 volts R
It is adjusted to supply the voltage of the MS.

Resistors 266 and 268 provide positive feedback around the integrator circuit 2440 on/off sensing amplifier.

Integrating circuits 244 and 148 will be explained later with reference to FIG.

Positive feedback around the on/off sensing amplifier of integrator circuit 244 provides hysteresis and reduces the period at the set point by half.

A pulse transformer 130 transforms the gate pulses to isolate the controller from the radiant energy triac (not shown).

The gate circuit is inhibited by a positive voltage applied to pin 161 of integrator circuit 244 through resistor 270.

When the contacts of relay 272 are closed, the positive voltage is removed.

Threshold detector 274 has a positive input at pin 163.

This input is biased by resistors 276, 278 in a voltage divider network.

Resistors 280, 282, 284 and thermistor 100 (FIG. 4) of the voltage divider network are connected to the negative input of threshold detector 274, pin 165.

When the voltage at pin 165 is positive with respect to pin 163, thermistor 1oO has a large resistance and the output of threshold detector 274 is low.

When pin 165 is negative with respect to pin 163, the resistance of thermistor 100 is low and the output of threshold detector 274 is high.

Resistor 330 is adapted to provide feedback to reduce oscillations near the set point.

If the temperature of thermistor 100 is above 227° C., threshold detector 274 has a high output and energizes relay 269.

The voltage input to the radiant energy source 76 is then switched to a low level.

Resistors 288 and 290 in the voltage divider network provide the necessary voltage level to forward bias diode 292, which activates transistor switch 294.

This transistor switch 294 is connected in parallel with the contacts of the relay 180, and is also connected to the single-acting auxiliary 2 heater 9.
6 is not present, the integration number 148 is activated.

Relays 180, 272, 238 are arranged to isolate the controller from the logic circuitry.

Capacitors 296 and 298 are connected to resistors 30o and 298, which prevent relay chatter with 1 kilohertz input signals.
302 limits the current, and diodes 304 and 306 act as steering diodes.

Resistor 310 working with capacitors 314, 316
, 312 limits the rate of voltage rise across the auxiliary heater and radiant energy triac and prevents the triac from turning on when transient voltages occur on the external lines.

Integrating circuits 203, 220, and 274 are operational amplifiers used in the circuit shown in FIG. 6 as a voltage comparison circuit.

Integrating circuits 148 and 244 are shown in FIG. 1 and will be described below.

In FIG. 1, an integrating circuit 148 is shown as a representative.
This integrator circuit 148 is almost identical to integrator circuit 244.

The correspondence between pins is as follows.

That is, pin 141 is connected to pin 161, pin 161 is connected to pin 169, pin 139 is connected to pin 159, pin 176 is connected to pin 173, pin 160 is connected to pin 157, pin 154 is connected to pin 175, pin 156 is connected to pin 153, pin 158
pin 155, pin 177 to pin 179, pin 13
5 corresponds to pin 149, respectively.

A voltage limiter 318 is arranged to reduce the voltage applied across pins 135, 176 to approximately ±8 volts.

Power supply 320 is removed from a half-wave rectifier that produces ±6 volts at pin 167 when an external capacitor is connected across pins 167, 176.

Zero crossing detector 822 provides an output pulse when the voltage across pins 135, 176 is less than 2 volts.

The on-off sensing amplifier 324 is connected to pins 158, 1
When 60 is input, it acts as a differential comparator.

The output from the on-off sensing amplifier 324 is at pin 160.
is higher than pin 158.

Triac gate circuit 326 includes a driver for direct triac triggering.

If all inputs to the gate circuit are high voltage,
That is, the line voltage is approximately O volts, the on/off sensing amplifier 324 has a high output, and the inverter (inverter)
ter ) 3 2 8 output is high.

The output of inverter 328 is high when the voltage at pin 141 is less than 2 volts.

Table 2 illustrates preferred nominal values for the resistor and capacitor elements of FIG.

In summary, the first control means controls the energy generated by the first heat source in response to the temperature detected in the area of the moving article to maintain the moving article at approximately the predetermined temperature. .

In a printing press, the moving article is a sheet of support material that moves along an endless conveyor belt.

This first heat source is an auxiliary heater adapted to heat the conveyor belt moving the support material.

Similarly, the second control means D'J adjusts the thermal energy generated by the radiant energy source in response to the temperature detected in the area of the second heat source (in this case the radiant energy source).

the radiant energy source cooperates with the auxiliary heater to maintain the moving article (i.e., the sheet of support material) at approximately the desired temperature;
Applying a multilayer toner powder image to a moving article.

The control system of the present invention is therefore adapted to adjust a fusing device incorporated in an electrophotographic printing machine to permanently affix a single layer or multilayer toner powder image to a sheet of support material.

Therefore, it is clear that according to the present invention, it is possible to obtain a control device that fully satisfies the above-mentioned objects and advantages.

Although specific embodiments of the invention have been described, many alterations, modifications, and variations will become apparent to those skilled in the art in light of the foregoing description.

[Brief explanation of the drawing]

1 is a schematic perspective view of an electrophotographic printing machine according to the present invention, FIG. 2 is a perspective view of a fusing device used in the printing machine of FIG. 1, and FIG. 3 is a perspective view of the fusing device of FIG. 2. 4 is a schematic diagram of the electric circuit used to adjust the radiant heater used in the welding device of FIG. 2, and FIG. 5 is a schematic diagram of the auxiliary heater of the welding device of FIG. 6 is a schematic diagram of the electrical circuit used to control the circuit; FIG. 6 is an electrical circuit diagram showing the electrical components incorporated in the diagrams of FIGS. 4 and 5; FIG. This is a schematic diagram of an integrator circuit. 10...Drum, 16...Song corona generator,
18... Lens system, 2o... Color filter mechanism, 22... Original, 24... Platen, 28, 30, 32... Development unit, 34
...Track support material sheet, 36...Transfer roll,
58... Curved fusion device, 76... One radiant energy source, 9
6... Song auxiliary heater, 1oo... Thermistor,
98...Second armature means, 102...Voltage source,
104... One comparison circuit, 106... Voltage source, 108... Comparison circuit, 114...
First control means, 118...Thermistor, 120
...Bending voltage comparison circuit, 128...Controller.

Claims (1)

[Claims] 1. In a control device for adjusting a first heat source and a second heat source arranged so as to cooperate with each other to maintain a moving article at a predetermined temperature, the first control means and the second control means wherein the first control means adjusts the thermal energy generated by the first heat source in response to a temperature detected in an area of the moving article to maintain the moving article at approximately the predetermined temperature. , and also arranged to automatically compensate for variations in the supplied external voltage, said second leg means being operatively associated with said first control means and in the area of said second heat source. adjusting the thermal energy generated by the second heat source in response to the detected temperature, such that the second heat source cooperates with the first heat source to maintain the temperature of the moving article at approximately the predetermined temperature; and wherein said second pedestal means is arranged to automatically compensate for variations in the external voltage supplied thereto.