JP2839789B2 - Electrophotographic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention has a light source for irradiating an original with light, a fixing device having first to third fixing rollers, and a pressure contact portion between first and second fixing rollers. 2
And an electrophotographic apparatus in which a fixing portion is formed at a pressing portion of a third fixing roller.

[0002]

2. Description of the Related Art As shown in FIG. 8, a conventional copier as an electrophotographic apparatus includes a fixing device 114 having two upper and lower parts.
There is known one provided with a plurality of heat rollers 114a and 114b. This copier is capable of black-and-white and full-color copying.
Scans an original (not shown) arranged on the original mounting table 103, and exposes the photosensitive member 105 with reflected light from the original guided through the filter 104, thereby forming an electrostatic latent image formed on the photosensitive member 105. With developing units 106 to 108
And the toner image is transferred to a sheet supplied from one of the sheet cassettes 111 to 113 via the intermediate transfer belt 110, and the sheet is fixed to the fixing device 11.
4. In the fixing device 114, the upper and lower heat rollers 114a
114b are pressed against each other, and these two heat rollers 11
The toner of the toner image is melted in a fixing section formed between the portions 4a and 114b, and the toner image is fixed on the sheet.

[0003] By the way, black-and-white copying in which gloss is not required for an image and full-color copying in which gloss is required for an image are performed by using materials of heat rollers 114a and 114b,
Different fixing conditions are required for fixing temperature etc.,
As described above, only two heat rollers 114a and 11
With a copier equipped with the fixing device 114 composed of 4b, it is impossible to completely satisfy those requirements. Therefore, there is a problem that the material of the sheet that can be used is restricted and a good image suitable for monochrome or full-color copying cannot be obtained.

Japanese Unexamined Patent Publication No. Sho 51-98036 discloses a fixing device in which three upper, middle and lower heat rollers are provided, and a first fixing portion is formed between the upper and middle heat rollers. , A second fixing section is formed between the middle and lower heat rollers, and a conveying belt for conveying a sheet to the first and second fixing sections is moved up and down according to the fixing section to be used. . According to such a configuration, the materials of the upper, middle, and lower heat rollers are appropriately selected, and a heater having a predetermined capacity is provided for each of the first and second fixing units. By adjusting the fixing temperature, black and white and full-color copying can be performed under conditions suitable for each of the sheets, regardless of the material of the sheet, and a good image can be obtained.

[0005]

However, although there was no problem with the two heat rollers 114a and 114b, in the above-described conventional fixing device having three upper, middle and lower heat rollers, Since the rated power consumption of the copying machine is limited, all heaters cannot be turned on at the same time, and it is necessary to limit the heating of the first and second fixing units.

In particular, once the heating of the first and second fixing units is completed, the first and second fixing units wait in a state where ON / OFF of each heater is repeated to maintain a predetermined temperature. doing. In such a state, when the copy start switch is turned on and the copy lamp is turned on,
There is a problem that the total power consumption of each heater and the copy lamp may exceed the maximum rated power.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to make it possible for a total power consumption of each heater and a copy lamp to be equal to a maximum rated power when the copy lamp is to be turned on. It is an object of the present invention to provide an electrophotographic apparatus capable of preventing the occurrence of an overshoot and eventually improving the operability of the apparatus.

[0008]

In order to solve the above-mentioned problems, an electrophotographic apparatus according to the present invention includes a light source for irradiating a document with light, and first to third fixing rollers. 1
A first fixing portion is formed at a pressure contact portion between the fixing roller and the second fixing roller, a second fixing portion is formed at a pressure contact portion between the second fixing roller and the third fixing roller, and the sheet conveyed to each fixing portion And a temperature adjusting means for adjusting the temperature of each fixing unit, the first to third fixing rollers each include while the heater is provided, Furka
Color copy mode and black and white copy mode separately
Set, the lighting sequence storage means for storing the priority order of lighting of the heaters, so the total power consumption of the heater and the light source being illuminated does not exceed the set power, lighting order storage means storing The copy mode to be performed
And a power control unit for turning off a heater having a lower priority order based on the priority order corresponding to the above.

[0009]

According to the configuration of the electrophotographic apparatus of the present invention, the lighting order storage means is set separately according to each copy mode.
The stored priority order of the heaters provided on the first to third three fixing rollers is stored. Then, the power control unit turns off the heaters having the lower priority order based on the priority order stored in the lighting order storage unit, and controls the total power consumption of the lit heater and the light source so as not to exceed the set power. I do.

For this reason, when the light source is turned on when the heater of the fixing roller is turned on in order to maintain the fixing temperature in the standby state, for example, the total power consumption of the heater and the light source is, for example, the maximum rated power. Exceeding the set power such as power can be prevented, and the operability of the apparatus can be improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electrophotographic apparatus according to one embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 5, a full-color copying machine (hereinafter simply referred to as a "copying machine") as an electrophotographic apparatus according to the present embodiment has a
And a reversing and retransmitting unit 2 provided below the copying machine main body 1.

The main body 1 of the copying machine has a document table 3 made of hard transparent glass on its upper surface, and an exposure optical system 4 below the document table 3. This exposure optical system unit 4
A copy lamp 5 for scanning a document (not shown) placed on the document table 3 while irradiating the document with light, a plurality of reflecting mirrors 6 for guiding reflected light from the document to the photoconductor 8, And a lens unit 7 disposed in the optical path of the reflected light. Two copy lamps 5 each having a power consumption of 300 W are provided in the above-described copy lamp 5, and the total power consumption is 600 W.

A charging charger 9 for charging the surface of the photoconductor 8 to a predetermined potential is provided on the outer periphery of the photoconductor 8, and an inter-image eraser (from the charging charger 9 in the rotation direction of the photoconductor 8) is provided. (Not shown), black developing tank 1
0, yellow developing tank 11, magenta developing tank 12, cyan developing tank 13, intermediate transfer device 14, cleaning device 15
And the static eliminator 16 are arranged in this order.

On the paper feed side of the intermediate transfer device 14, a registration roller 24, a paper feed cassette 25, and a paper feed tray 26 for supplying paper to the intermediate transfer device 14 at a predetermined timing are provided. Near the cassette 25 and the paper feed tray 26, a paper feed roller 27, a transport roller 28, and the like are provided.

In the paper output direction from the intermediate transfer device 14, a suction unit 36 for transporting the paper, a fixing device 40,
Switching gate 29, paper discharge roller 30, and paper discharge tray 3
1 is provided. The above-mentioned switching gate 29 controls the transport direction of the sheet discharged from the fixing device 40 by the discharge rollers 3.
The direction is switched between the direction of 0 and the direction of the transport path 32 below.

The transport path 32 is connected to the reversing retransmission unit 2
Extends to the intermediate tray 33 disposed inside the printer, and conveys the sheet processed by the fixing device 40, and discharges the sheet to the intermediate tray 33 with the surface on which the toner image is formed facing upward. It has become. The conveyance path 3 is provided in the intermediate tray 33.
The sheets sent by the sheet feeder 2 are stacked, and each sheet is sent to a transport path 35 by a sheet feed roller 34. The transport path 35 reverses the sheet sent from the intermediate tray 33 and transports the sheet to the registration roller 24.

As shown in FIG. 6, the intermediate transfer device 14 presses the transfer belt 17, the rollers 18, 19, and 20 that support the transfer belt 17, and the transfer belt 17 against the photosensitive member 8, and The first transfer rollers 21 and 21 transfer the toner image formed on the surface of the transfer belt 17 to the transfer belt 17, and are pressed against the roller 20 via the transfer belt 17 at the time of transfer of the toner image to the paper, and the surface of the transfer belt 17 A second transfer roller 22 for transferring the toner image on the paper.

In the suction unit 36, the transport belt 37 includes a drive shaft 38 on the paper input side and a driven shaft 39 on the paper output side.
And is supported by. Then, the drive shaft 38 is rotated by power transmitted from a belt drive motor 54, which will be described later, so that the transport belt 37 is circulated in the direction D in the drawing. The transport belt 37 is configured such that an end on the paper output side rotates up and down together with a driven shaft 39 around the drive shaft 38 by a moving mechanism (not shown).

The fixing device 40 has upper, middle and lower heat rollers 41 to 43 as first to third fixing rollers provided in parallel in the vertical direction. The upper heat roller 41 is pressed against the upper surface of the middle heat roller 42, and the lower heat roller 43 is pressed against the lower surface. In the present embodiment, the fixing when performing full-color copying is performed by the upper fixing unit as the first fixing unit formed at the pressure contact portion between the upper heat roller 41 and the middle heat roller 42, The fixing at the time of performing black-and-white copying is performed by the lower fixing unit as the second fixing unit formed at the pressure contact portion with the lower heat roller 43. Therefore, the upper heat roller 41 is formed of silicone rubber, the middle heat roller 42 is formed of Teflon rubber, and the lower heat roller 43 is formed of Teflon rubber or other rubber. . That is, the surface of the upper heat roller 41 is a very smooth surface to obtain high releasability from the three-layer toner image for obtaining a full-color image.

Each of the heat rollers 41 to 43 is hollow, and in the hollow portions of the upper heat roller 41 and the lower heat roller 43, one upper heater lamp 44a and one lower heater lamp 44d are provided for heating. In the hollow portion of the middle heat roller 42, two first middle heater lamps 44b and second middle heater lamps 44c for heating are provided. These upper, first, second, lower heater lamps 44a
For example, 650 W, 350 W, and 3
It has power consumption of 00W and 350W. Around the upper, middle, and lower heat rollers 41 to 43, thermostats (not shown) for detecting over-surface temperatures, which are incorporated in circuits of upper, middle, and lower thermistors 45a to 45c and heater lamps 44a to 44d, are shown. And cleaning rollers 46 for removing toner and the like adhering to the surfaces of the heat rollers 41 to 43, respectively. The heater lamps 44a to 44d and the thermistor 45
a to 45c, thermostat, and CPU 60 to be described later
For example, the upper, middle, and lower heat rollers 41 to 43 are heated to predetermined temperatures, for example, 210 ° C., 190 ° C., and 13 ° C., respectively.
Temperature adjusting means for adjusting the temperature to 0 ° C. is provided.

Also, around the middle and lower heat rollers 42 and 43, peeling nails 47 for peeling the paper from the roller surface are provided.
Are provided around the upper heat roller 41, and the oil application roller 4 impregnated with silicone oil is provided around the upper heat roller 41.
8 are provided. The oil application roller 48 applies silicone oil to the surface of the upper heat roller 41 to prevent color toner from adhering to the roller surface, that is, to prevent offset, thereby ensuring the releasability of the color toner image, and to form a full-color copy image. It is for giving gloss.

The oil application roller 48 is attached to one end of a roller holder 50 that rotates about a support shaft 49,
A mechanism including an eccentric cam 51 provided at the other end of the roller holder 50 and a tension spring (not shown) is configured to be in pressure contact with the upper heat roller 41 when the upper fixing unit is used. The eccentric cam 51 is driven by an oil application roller cam driving mechanism 55 described later.

The upper, middle and lower heat rollers 41 to 4
3, the middle heat roller 42 is driven, the upper and lower heat rollers 41 and 43 are driven, and the middle heat roller 42 is driven by a heat roller drive motor 53 described later to be used for upper or lower use. It rotates forward and backward depending on the fixing unit.

Further, on the paper output side of the upper fixing section and the lower fixing section in the fixing device 40, an upper conveying path 57 and a lower conveying path 5 are provided.
The upper fixing section or the lower fixing section fixes the toner image on the sheet.
7 or through the lower conveyance path 58 to the paper discharge roller 30. When performing double-sided copying, the reversing and re-transmitting unit 2 is moved from the lower conveying path 58 by the switching gate 29.
The sheet is sent to a transport path 32 following the sheet feeding.

Further, the copying machine has a suction unit 3
As shown in FIG. 7, a control device 52 composed of a microcomputer, for example, controls the fixing device 6 and the fixing device 40.
It has. The control device 52 includes a CPU (Central P
rocessing Unit) 60 and ROM (Read Only Memory) 6
1, a RAM (Randam Access Memory) 62, and an I / O unit (Input / Output Unit) 63.

The ROM 61 is a read-only memory for storing programs and data for controlling the copying machine.
The RAM 62 is a writable / readable memory having a function of temporarily storing input data, a calculation result of the CPU 60, and the like, and a main power supply of the copying machine main body 1 is operated by a battery 64 connected to the RAM 62. Even if you turn off, the stored contents are not erased. RAM6
2 includes heater lamps 44a, 44b, 44c, 44 in the full color copy mode and the black and white copy mode.
The lighting priority of d is stored, and has a function as lighting order storage means. The priority order of lighting is different between the full-color copy mode and the black-and-white copy mode, and the lighting priority of each of the heater lamps 44a, 44b, 44c, and 44d in the full-color copy mode is highest in the first medium. Heater lamp (350W)
44b, the second is the upper heater lamp (650W) 4
4a, the third is the second middle heater lamp (300W) 44
c and the fourth are lower heater lamps (350W) 44d. In the black-and-white copy mode, the lighting priority of each heater lamp is highest in the second middle heater lamp (300W) 44c, second in the first middle heater lamp (350W) 44b, and third in the lower heater lamp. Lamp (3
50W) 44d, 4th is upper heater lamp (650W)
44a.

The CPU 60 includes the upper, middle and lower thermistors 45a to 45c connected to the I / O unit 63,
The operation of the heat roller drive motor 53, the belt drive motor 54, the oil application roller cam drive mechanism 55, and the heater lamps 44a to 44d is controlled based on inputs from various sensors and various input keys (not shown). I have.

The CPU 60 controls each heat roller 41.
Upper, middle and lower thermistors 4 to detect surface temperature of ~ 43
5a to 45c, the heater lamp 44a
By turning on or off the ~ 44d,
The temperature of the middle and lower heat rollers 41 to 43 is controlled. In the copying machine of the present embodiment, 1000 W of power is supplied to the fixing device 40, and 650 W of the upper heater lamp 44a and the first middle heater are supplied to the upper fixing portion. 350 of lamp 44b
W, and a total of 1000 W, and the lower fixing unit is heated to 350 W for the first middle heater lamp 44b, 300 W for the second middle heater lamp 44c, and 3 W for the lower heater lamp 44d.
Heating is performed at a total of 1000 W, including 50 W.

Further, the CPU 60 controls the main power supply O of the copying machine.
Immediately after N, the temperature adjusting means is switched so as to adjust the temperature by giving priority to the fixing unit based on the storage in the RAM.

Further, the CPU 60 controls the RAM 62 so that the total power consumption of the heater lamps 44a to 44d and the copy lamp 5 lit in the fixing device 40 does not exceed the maximum power consumption of 1000 W as the set power.
Has a function as a power control unit for turning off the heater lamps 44a to 44d having a low priority order based on the priority order stored in the storage device.

In the above configuration, the main power supply of the copying machine is
The temperature control of the fixing device immediately after N is described with reference to the flowcharts of FIGS. First, FIG.
As shown in FIG. 5, when the main power of the copying machine is turned on (S
1) The backup data in the RAM 62 is read by the CPU 60 (S2), and based on the storage in the RAM 62, it is determined which of the fixing units is to be preferentially adjusted for the temperature (S3). When the temperature is to be adjusted with priority given to the upper fixing unit for full-color copying in S3, a heating control routine for the upper fixing unit, which will be described later, is executed (S4). On the other hand, when the temperature is adjusted with priority given to the lower fixing section for black and white copying in S3,
A heating control routine for the lower fixing unit described below is executed (S
6) When S6 is completed, a standby state (S5) is set.

Here, a heating control routine in the case where the upper fixing unit is heated first as a subroutine process will be described. As shown in FIG. 3, first, the flag is set to 0 (S11), and then the upper heater lamp 4 of the upper heat roller 41 is set.
4A (HLU) and the first middle heater lamp 44b (HLM1) of the middle heat roller 42 are turned on (S12).
Next, it is determined whether the temperature of the upper thermistor 45a (THU) is lower than 210 ° C. (S13).
If the temperature is below 0 ° C., the medium thermistor 45b (THM)
It is determined whether the temperature is 90 ° C. or higher (S14). If the temperature of the middle thermistor 45b is 190 ° C. or more in S14, the first middle heater lamp 44b (HLM1) is turned off (S15). If the middle thermistor 45b is less than 190 ° C. in S14, the process returns to S13. After S15, it is determined whether the flag is 1 (S16). If the flag is not 1, the flag is replaced with 2 (S17), and the process returns to S13. Also, S16
If the flag is 1, the full-color ready lamp (not shown) is turned on, the full-color copy is ready, and a full-color copy can be made (S21).

On the other hand, in S13, the upper thermistor 45a
If it is 0 ° C. or higher, the upper heater lamp 44a (HLU) is turned off (S18), and it is determined whether or not the flag = 2 (S19). If the flag is 2 in S19, the full-color copy is ready (S21). Also, S1
If the flag is not 2 in 9, the flag is replaced with 1 (S 20), and the process proceeds to S 14.

Subsequent to S21, the lower fixing unit is heated for monochrome copying. That is, the lower heat roller 4
3 lower heater lamp 44d (HLL) is turned on (S
22). Next, the lower thermistor 45c (THL)
It is determined whether the temperature is equal to or higher than C (S43).
If c (THL) is 130 ° C. or higher, the lower heater lamp 44d (HLL) is turned off (S24), and the process returns. Note that full-color copying can be performed during the heating of the lower fixing unit.

Next, a heating control routine as a subroutine process when the lower fixing unit is heated first will be described.

As shown in FIG. 4, after the flag is set to 0 (S31), the first middle heater lamp 44b (HLM1) of the middle heat roller 42 and the second middle heater lamp 44c are set.
(HLM2) and the lower heater lamp 44d (HLL) of the lower heat roller 43 are turned on (S32). Next, it is determined whether the middle thermistor 45b (THM) is lower than 190 ° C. (S33). If the middle thermistor 45b is lower than 190 ° C., it is determined whether the lower thermistor 45c (THL) is 130 ° C. or higher. (S34). If the lower thermistor 45c is 130 ° C. or more in S34, the lower heater lamp 44d
(HLL) is turned off (S35). On the other hand, if the lower thermistor 45c is lower than 130 ° C. in S34, the process returns to S33. After S35, it is determined whether the flag is 1 (S3).
6) If the flag is not 1, the flag is replaced with 2 (S37), and the process returns to S33. Also, the flag = 1 in S36.
If so, the ready lamp for black and white (not shown) is turned on, the black and white copy is ready, and the black and white copy can be performed (S41).

On the other hand, in S33, the middle thermistor 45b (TH
If M) is equal to or higher than 190 ° C., the first middle heater lamp 44
b (HLM1) and the second middle heater lamp 44c (HLM1).
2) is turned off (S38), and it is determined whether or not flag = 2 (S39). If the flag is 2 in S39, the black-and-white copy is ready, and the black-and-white copy can be performed (S39).
41). If the flag is not 2 in S39, the flag is replaced with 1 (S40), and the process proceeds to S34.

After S41, the upper fixing section is heated for full-color copying. That is, the upper heat roller 4
1 upper heater lamp 44a (HLU) is turned on (S
42). Next, the upper thermistor 45a (THU)
It is determined whether the temperature is equal to or higher than C (S43). If the temperature is equal to or higher than 210 C, the upper heater lamp 44a (HLU) is turned off (S43).
44) Return. Note that black and white copying can be performed during the heating of the upper fixing unit.

When the main power of the copying machine main body 1 is turned off and then turned on again, the setting data stored in the RAM 62 is read by the program stored in the ROM 61, and the fixing unit based on the setting data is first set. The temperature is adjusted.

Next, the lighting control of each heater lamp when the copy operation is started and the copy lamp 5 is turned on during the standby state after the above-mentioned temperature adjustment is completed will be described. First, as shown in FIG. 1, when a copy key (not shown) for turning on the copy lamp 5 is turned on from the standby state (S5), the CPU 60 determines the wattage of the copy lamp 5 and the current lighting state. The total power consumption Twatt with the wattage of the heater lamp that is present is calculated (S5).
2). Next, the CPU 60 determines whether or not the total power consumption Twatt exceeds the maximum rated power of 1000 W (S53). In S53, the total power consumption Twatt is 10
In the case of 00W or more, of the lit heater lamps,
The heater lamp with the lowest priority order stored in the RAM 62 is turned off (S54). Then, after S54, it is determined again whether or not the total power consumption Twatt exceeds the maximum rated power 1000W (S55). If the total power consumption Twatt is equal to or more than 1000 W in S55, the process returns to S54, the heater lamps with the lower priority order are turned off, and this process is repeated until the total power consumption Twatt becomes less than 1000W.

On the other hand, if the total power consumption Twatt is less than 1000 W in S53 and S55, the copy lamp 5 is turned on (S56), and the copy operation described later is started (S57). Next, when the copy operation is completed,
The copy lamp 5 is turned off (S58), and the standby state is set again (S59).

Next, a full-color copying operation in the copying machine will be described.

When the surface temperatures of the upper heat roller 41 and the middle heat roller 42 reach the set temperature, the heat roller drive motor 53 rotates the middle heat roller 42 counterclockwise as shown in FIG. As a result, the upper heat roller 41 rotates clockwise. Then, the eccentric cam 51 is driven by the oil application roller cam drive mechanism 55, and the oil application roller 48 is pressed against the upper heat roller 41. In addition, the suction unit 36 is driven by the moving mechanism to be held at the upper position, and the driving force of the belt drive motor 54 is transmitted to the drive shaft 38, so that the transport belt 37 moves around. The operation of pressing the oil application roller 48 against the upper heat roller 41 only needs to be performed at an appropriate time before the sheet is conveyed to the upper fixing unit.

Next, as shown in FIG. 5, the surface of the photoreceptor 8 rotating in the direction B is uniformly charged by the charging charger 9, and the first exposure of the original on the original placing table 3 by the exposure optical system unit 4. Scanning is performed. The light reflected from the original is passed through a blue color separation filter (not shown) and a slit (not shown) to an exposure point on the photoreceptor surface between the charger 9 and the inter-image eraser (not shown). To expose the photoreceptor 8 to form an electrostatic latent image.
Next, the potential of the non-image area on the photoreceptor 8 is removed by the inter-image eraser. Thereafter, the electrostatic latent image is developed by the yellow developing tank 11 to form a yellow toner image.

Next, the yellow toner image on the surface of the photoconductor 8 is transferred to the first transfer roller 21 to which a high negative voltage is applied.
As a result, the image is transferred onto the transfer belt 17 that moves around in the C direction. The residual toner on the surface of the photoconductor 8 is removed by the cleaning device 15, and the residual potential on the surface of the photoconductor 8 is removed by the charge removing device 16.

When the above-described series of operations is completed, the photosensitive member 8 is charged again by the charger 9 and the original is scanned by the exposure optical system 4 for the second time. In this case, a green color separation filter is used, and the electrostatic latent image formed on the photoconductor 8 is developed with magenta toner in the magenta developing tank 12. The magenta toner image formed on the surface of the photoreceptor is transferred to the first transfer roller 2.
By means of No. 1, the image is superimposed and transferred on the previous yellow toner image on the transfer belt. Thereafter, similarly, a third scan is performed by the exposure optical system unit 4 using a red color separation filter, and a cyan toner image is formed on the photoconductor 8 by development with the cyan toner in the cyan developing tank 13. It is formed. This cyan toner image is transferred onto the magenta toner image on the transfer belt 17.

Next, the second transfer roller 22, which has been separated from the transfer belt 17 in the operation so far, is
7, and a negative voltage higher than the surface potential of the transfer belt 17 is applied to the second transfer roller 22, so that the second transfer roller 22 is conveyed from the sheet cassette 25 or the sheet tray 26 via the registration roller 24. The three-layer toner image on the transfer belt 17 is transferred to the paper.

FIG. 6 shows the sheet on which the toner image has been transferred.
Are transported to the fixing device 40 by the transport belt 37 of the suction unit 36 shown in FIG. At this time, the transport belt 37
Is held at the upper position, the sheet is conveyed to the upper fixing section formed at the press contact portion between the upper heat roller 41 and the middle heat roller 42. In the upper fixing section, three layers of color toner images on the paper are supplied to the heater lamps 44a and 44b.
And the middle heat roller 41 heated to a predetermined temperature in
It is heated and melted by 42 and fixed on the paper.
At this time, the upper heat roller 41 is
Since the silicone oil is supplied from 8, the offset of the toner image to the upper heat roller 41 is prevented, and gloss is given to the full-color toner image on the paper. The paper discharged from the upper fixing unit is discharged to the outside of the fixing device 40 through the upper conveyance path 57, and is discharged onto the discharge tray 31 by the discharge rollers 30.

Next, the black-and-white copying operation of the copying machine will be described. The middle and lower heat rollers 42.4
When the temperature reaches a predetermined set temperature, the heat roller drive motor 53 causes the middle heat roller 42 to move as shown in FIG.
Rotates clockwise, and the lower heat roller 4
3 rotates counterclockwise. Then, the oil application roller 48 is separated from the upper heat roller 41. Further, the suction unit 36 is driven by the moving mechanism to be held at the lower position, and the driving force of the belt drive motor 54 is transmitted to the drive shaft 38 so that the transport belt 37 moves around.

The middle and lower heat rollers 42
When the temperature adjustment at 43 is completed, the surface of the photoconductor 8 shown in FIG. 5 is uniformly charged by the charger 9, and the exposure optical system unit 4 scans the original on the original table 3. The reflected light from the document is guided to the exposure optical system 4 and irradiated on the photoconductor 8 without passing through the color separation filter and the slit, and an electrostatic latent image is formed on the photoconductor 8. Thereafter, the electrostatic latent image is developed by the black developing tank 10,
The black toner image thus formed is transferred to the transfer belt 17 in the same manner as when performing full-color copying, and further transferred to the sheet supplied via the registration roller 24.

The sheet on which the toner image has been transferred is conveyed to the lower fixing section formed at the press contact portion between the middle heat roller 42 and the lower heat roller 43 by the conveyance belt 37 of the suction unit 36 held at the lower position. Then, the toner image is fixed on the paper by being heated to a predetermined temperature by the heater lamps 44b, 44c, and 44d and heated by the lower heat rollers 42 and 43.

Here, in the case of one-sided copying, the switching gate 29 operates so as to guide the sheet toward the discharge roller 30, and the sheet discharged from the fixing device 40 through the lower conveying path 58. Is discharged onto a discharge tray 31 by a discharge roller 30.

On the other hand, in the case of double-sided copying, the switching gate 29 operates so as to guide the sheet in the direction of the conveying path 32, and the sheet discharged from the lower fixing unit is transferred onto the intermediate tray 33 by the conveying path 32. Is discharged. Then, intermediate tray 3
The paper on 3 is sent out to the transport path 35 by the paper feed roller 34, is reversed by the transport path 35, and reaches the registration roller 24.

Next, the surface of the photoreceptor 8 shown in FIG. 5 is charged again by the charging charger 9, and the exposure optical system 4 scans the original placed on the original placing table 3 upside down. Next, the toner image is transferred to the back surface of the paper by the same operation as that for the front surface of the paper, and the toner image is fixed on the paper by the lower fixing unit. Thereafter, the sheet is guided toward the sheet discharge roller 30 by the switching gate 29, and is discharged onto the sheet discharge tray 31 by the sheet discharge roller 30.

As described above, in the copying machine according to the present embodiment, the RAM 62 as the lighting order storage means has the heater lamps 4 provided on the three upper, middle and lower heat rollers 41-43.
The priority order of lighting of 4a to 44d is stored. Then, the CPU 60 as the power control means operates the heater lamp 44 having the lower priority order based on the priority order stored in the RAM 62.
a to 44d are turned off, and the lit heater lamp 4
Control is performed so that the total power consumption of 4a to 44d and the copy lamp 5 does not exceed the maximum rated power.

For this reason, for example, in order to maintain the fixing temperature in the standby state, the upper, middle and lower heat rollers 41 to 4
When any one of the heater lamps 44a to 44d is turned on and the copy lamp 5 is to be turned on,
The total power consumption of any of the lit heater lamps 44a to 44d and the copy lamp 5 can be prevented from exceeding the maximum rated power, and the operability of the copying machine can be improved.

[0057]

As described above, in the electrophotographic apparatus of the present invention, the first to third fixing rollers are provided with the heaters respectively, while the full-color copy mode and the black-and-white
Lighting order storage means for storing the priority order of lighting of each heater separately set in accordance with the peak mode, and for preventing the total power consumption of the lit heater and the light source from exceeding the set power. Power control means for turning off heaters having a lower priority order based on the priority order corresponding to the copy mode to be executed, which is stored in the lighting order storage means.

Thus, it is possible to control so that the total power consumption of the lit heater and the light source does not exceed the set power. For this reason, for example, when the light source is turned on when the heater of the fixing roller is turned on in order to maintain the fixing temperature in the standby state, the total power consumption of the heater and the light source becomes, for example, the maximum rated power or the like. Exceeding the set power can be prevented, and the operability of the device can be improved.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a procedure of controlling a total power consumption of a lit heater lamp and a copy lamp so as not to exceed a maximum rated power in a copying machine according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a procedure for adjusting the temperature of a designated fixing unit after the main power is turned on in the copying machine according to the embodiment of the present invention.

FIG. 3 is a flowchart showing a procedure in a case where the temperature of an upper fixing unit is adjusted first in the copying machine.

FIG. 4 is a flowchart showing a procedure in the case where the temperature of the lower fixing unit is adjusted first in the copying machine.

FIG. 5 is an overall configuration diagram of the copying machine.

FIG. 6 is an enlarged view of a main part showing a configuration near a fixing device in the copying machine.

FIG. 7 is a block diagram showing a main configuration of a control system provided in the copying machine.

FIG. 8 is an overall configuration diagram showing a conventional copying machine.

[Explanation of symbols]

37 conveyance belt 40 fixing device 41 upper heat roller (first fixing roller) 42 middle heat roller (second fixing roller) 43 lower heat roller (third fixing roller) 44a to 44d heater lamp (temperature adjusting means) 45a to 45c thermistor (Temperature adjusting means) 57 Upper transport path 58 Lower transport path 60 CPU (Temperature adjusting means, power control means) 62 RAM (Lighting order storage means)

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Atsushi Kurimoto 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (56) References JP-A-2-191979 (JP, A) JP-A-53- 45534 (JP, A) JP-A-59-28178 (JP, A) JP-A-3-62080 (JP, A) JP-B-2-10950 (JP, B2) (58) Fields investigated (Int. Cl. ^6, DB name) G03G 13/04 G03G 13/20 G03G 15/04 G03G 15/20 G03G 21/00 398

Claims (1)

(57) [Claims] A light source for irradiating the original with light; first to third light sources;
A first fixing portion is formed at a pressure contact portion between the first fixing roller and the second fixing roller, and a second fixing portion is formed at a pressure contact portion between the second fixing roller and the third fixing roller. Is formed, and a fixing device that feeds a sheet conveyed to each fixing unit in a discharge direction by rotation of a fixing roller, and a temperature adjustment unit that adjusts a temperature of each fixing unit. In addition, a heater is provided for each of the third to third fixing rollers, while a full-color copy mode and a monochrome copy mode are provided.
Lighting order storage means, which is set separately according to the mode, stores the priority order of lighting of each heater, and in order to prevent the total power consumption of the lit heater and the light source from exceeding the set power. The actual number stored in the lighting order storage means
An electrophotographic apparatus, comprising: power control means for turning off a heater having a lower priority order based on a priority order corresponding to a copy mode to be executed .