JPH064003A - Electrophotographic copying device - Google Patents

Abstract

PURPOSE:To prevent the power consumption of respective heaters and a copying lamp from exceeding the maximum rated power by providing the plural heaters on three fixing rollers and turning off the heater whose priority is low based on the priority stored in a turning-on order storage means so that the power consumption of the turning-on heater and the turning-on copying lamp does not exceed the set power. CONSTITUTION:When the copying lamp is turned on, the total amount of the power consumption of the wattage of the copying lamp and the wattage of the heater lamps 44a-44d which are turned on at present is calculated by a CPU 60. Then, it is judged whether the total amount of the power consumption exceeds the maximum rated power or not. When it exceeds, the heater lamp of the lowest priority stored in a RAM 62 among the turning-on heater lamps is turned off. It is judged again whether the total amount of the power consumption exceeds the maximum rated power or not. Then, such a processing is repeatedly executed until the total amount of the power consumption becomes under the maximum rated power. Besides, when it is judged that the total amount of the power consumption is under the maximum rated power, the copying lamp is turned on and a copying action is finished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a light source for illuminating an original, and a fixing device provided with three fixing rollers, namely, first to third fixing rollers. Two
The present invention also relates to an electrophotographic apparatus in which a fixing portion is formed on the pressure contact portion of the third fixing roller.

[0002]

2. Description of the Related Art In a copying machine as a conventional electrophotographic apparatus, as shown in FIG.
It is known that each of the heat rollers 114a and 114b is provided. This copying machine is capable of black-and-white and full-color copying, and has a light source lamp 102 of an optical system 101.
Scans a document (not shown) placed on the document table 103, exposes the photoconductor 105 with the reflected light from the document guided through the filter 104, and thereby the electrostatic latent image formed on the photoconductor 105. To the developing devices 106 to 108
Color toner or the black toner of the developing device 109, the toner image is transferred onto a sheet supplied from any of the sheet cassettes 111 to 113 via the intermediate transfer belt 110, and this sheet is fixed.
4 to supply. In the fixing device 114, the upper and lower heat rollers 114a
114b are pressed against each other and both heat rollers 11b
The toner of the toner image is melted at the fixing portion formed between 4a and 114b, and the toner image is fixed on the sheet.

By the way, in the black-and-white copy in which the image does not require glossiness and the full-color copy in which the image requires glossiness, the materials of the heat rollers 114a and 114b,
Different fixing conditions such as fixing temperature are required,
As mentioned above, only two heat rollers 114a.
A copying machine having the fixing device 114 composed of 4b cannot completely meet these requirements. Therefore, there are problems that the material of the sheet that can be used is limited and a good image suitable for black-and-white or full-color copying cannot be obtained.

Therefore, in Japanese Patent Laid-Open No. 51-98036, a fixing device is provided with three upper, middle and lower heat rollers, and a first fixing portion is formed between the upper and middle heat rollers. It has been proposed that a second fixing unit is formed between the middle and lower heat rollers, and a conveyor belt that conveys a sheet to the first and second fixing units is moved up and down according to the fixing unit used. . According to such a configuration, the materials of the upper, middle and lower heat rollers are appropriately selected, and further, heaters having predetermined capacities are provided for the first and second fixing sections, and these heaters respectively set predetermined heaters. By adjusting the fixing temperature to 1, the black and white and full-color copying can be performed under conditions suitable for each without being limited by the material of the sheet, and a good image can be obtained.

[0005]

However, although there is no problem with the two heat rollers 114a and 114b, in the structure of the fixing device having the above-mentioned three upper, middle and lower heat rollers, Since the rated power consumption of the copying machine is limited, all the 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 portions is completed, the first and second fixing portions wait in a state in which each heater is repeatedly turned on / off to maintain a predetermined temperature. is doing. In this state, when the copy start switch is turned on and the copy lamp lights up,
There is a problem that the total power consumption of each heater and the copy lamp may exceed the maximum rated power.

The present invention has been made in view of the above conventional problems, and an object thereof is to make the total power consumption of each heater and the copy lamp reach the maximum rated power when the copy lamp is about to light. An object of the present invention is to provide an electrophotographic apparatus capable of preventing the excess and eventually improving the operability of the apparatus.

[0008]

In order to solve the above-mentioned problems, an electrophotographic apparatus of the present invention has a light source for irradiating a document with light, and three fixing rollers, first through third, 1
The first fixing portion is formed at the pressure contact portion between the fixing roller and the second fixing roller, the second fixing portion is formed at the pressure contact portion between the second fixing roller and the third fixing roller, and the sheet is conveyed to each fixing portion. In the electrophotographic apparatus provided with a fixing device that sends out the sheet in the discharging direction by the rotation of the fixing roller and a temperature adjusting unit that adjusts the temperature of each fixing portion, a plurality of fixing rollers are provided for the first to third fixing rollers. While the heater is provided, lighting order storage means for storing the priority order of lighting of each heater,
In order to prevent the total power consumption of the turned-on heater and the light source from exceeding the set power, a power control means is provided for turning off the heater having a lower priority order based on the priority order stored in the lighting order storage means. It is characterized by

[0009]

According to the structure of the electrophotographic apparatus of the present invention, the lighting order storage means stores the priority order of lighting of each heater provided in the first to third fixing rollers. Then, the power control means turns off the heaters of lower priority order based on the priority order stored in the lighting order storage means, and controls so that the total power consumption of the turned-on heater and the light source does not exceed the set power. To do.

Therefore, for example, when the heater of the fixing roller is turned on to maintain the fixing temperature in the standby state, when the light source is turned on, the total power consumption of the heater and the light source is, for example, the maximum rating. It is possible to prevent the set power such as electric power from being exceeded, and thus improve the operability of the device.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electrophotographic apparatus according to an 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 copying machine body 1 as shown in FIG.
And a reversing and retransmitting unit 2 provided under the copying machine body 1.

The copying machine main body 1 has an original placing table 3 made of hard transparent glass on the upper surface thereof, and an exposure optical system section 4 under the original placing table 3. This exposure optical system section 4
Is a copy lamp 5 that scans a document (not shown) placed on the document table 3 while irradiating it with light, a plurality of reflecting mirrors 6 that guide reflected light from the document to the photoconductor 8, And a lens unit 7 arranged in the optical path of the reflected light. Two copy lamps 5 having a power consumption of 300 W are provided, 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. Further, an interimage eraser (from the charge charger 9 in the rotating 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 is arranged in this order.

A registration roller 24, a paper feed cassette 25, and a paper feed tray 26, which feed the paper to the intermediate transfer device 14 at a predetermined timing, are provided on the paper feed side of the intermediate transfer device 14. A paper feed roller 27, a transport roller 28, and the like are provided near the cassette 25 and the paper feed tray 26.

In the paper output direction from the intermediate transfer device 14, a suction unit 36 for conveying the paper, a fixing device 40,
Switching gate 29, paper ejection roller 30, and paper ejection tray 3
1 is provided. The switching gate 29 is arranged so that the sheet ejected from the fixing device 40 is conveyed in the conveying direction.
The direction 0 is switched to the direction of the lower transport path 32.

The above-mentioned conveying path 32 is the reverse retransmission unit 2
So that the sheet processed by the fixing device 40 is conveyed and the sheet on which the toner image is formed faces up and is discharged to the intermediate tray 33. It has become. The transport path 3 is provided in the intermediate tray 33.
The sheets sent by 2 are stacked, and each sheet is sent out to the conveying path 35 by the sheet feeding roller 34. The conveyance path 35 is adapted to reverse the sheet sent from the intermediate tray 33 and convey it to the registration rollers 24.

As shown in FIG. 6, in the intermediate transfer device 14, the transfer belt 17, the rollers 18, 19 and 20 for supporting the transfer belt 17, and the transfer belt 17 are brought into pressure contact with the photoconductor 8 to make the photoconductor 8 Surface of the transfer belt 17, which is pressed against the roller 20 via the transfer belt 17 when the toner image formed on the surface of the first transfer roller 21 is transferred to the transfer belt 17, and when the toner image is transferred to the sheet. The second transfer roller 22 that transfers the toner image of No. 2 to the sheet is provided.

In the suction unit 36, the conveyor belt 37 has a drive shaft 38 on the paper input side and a driven shaft 39 on the paper output side.
It is supported and configured by. The drive shaft 38 is rotated by the power transmitted from a belt drive motor 54, which will be described later, so that the conveyor belt 37 is moved in the D direction in the drawing. Further, the transport belt 37 is configured such that an end portion on the paper output side is vertically rotated together with the driven shaft 39 about 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 thereof. In the present embodiment, the fixing at the time of performing a full-color copy is performed by the upper fixing unit as the first fixing unit formed in the pressure contact portion between the upper heat roller 41 and the middle heat roller 42, while the middle heat roller 42 is fixed. The lower fixing unit, which is a second fixing unit formed in the pressure contact portion with the lower heat roller 43, fixes the black-and-white copy. Therefore, in the surface layers of the upper, middle and lower heat rollers 41 to 43, the upper heat roller 41 is made of silicone rubber, the middle heat roller 42 is made of Teflon rubber, and the lower heat roller 43 is made of Teflon rubber or other rubber. . That is, the surface of the upper heat roller 41 is a very smooth surface in order 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 one upper heater lamp 44a and one lower heater lamp 44d for heating are provided in the hollow portions of the upper heat roller 41 and the lower heat roller 43, respectively. In the hollow portion of the middle heat roller 42, two first middle heater lamps 44b and a second middle heater lamp 44c for heating are provided. These upper, first, second, and lower heater lamps 44a
~ 44d are, for example, 650W, 350W, and 3 respectively.
It has power consumption of 00W and 350W. Around the upper, middle and lower heat rollers 41-43, a thermostat (not shown) for detecting the surface temperature of the upper, middle and lower thermistors 45a-45c and heater lamps 44a-44d for preventing overheating is installed. No.) and a cleaning roller 46 for removing the toner and the like adhering to the surfaces of the heat rollers 41 to 43, respectively. Then, the heater lamps 44a to 44d and the thermistor 45.
a-45c, thermostat, and CPU 60 described later
The upper, middle and lower heat rollers 41 to 43 at predetermined temperatures, for example 210 ° C., 190 ° C. and 13 ° C., respectively.
A temperature adjusting means for adjusting the temperature to 0 ° C. is configured.

Around the middle and lower heat rollers 42 and 43, a peeling claw 47 for peeling the paper from the roller surface.
On the other hand, the oil applying 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 the color toner from adhering to the roller surface, that is, to prevent the color toner image from being peeled off, and to form a full-color copy image. It is for imparting luster.

The oil applying roller 48 is attached to one end of a roller holder 50 which rotates about a support shaft 49.
A mechanism composed of an eccentric cam 51 provided at the other end of the roller holder 50 and a tension spring (not shown) makes a pressure contact with the upper heat roller 41 when the upper fixing portion is used. The eccentric cam 51 is driven by an oil application roller cam drive mechanism 55 described later.

The above-mentioned upper, middle and lower heat rollers 41 to 4
In the rotation of 3, the middle heat roller 42 is driven and 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 to be described later and is used in an upper or lower direction. It is designed to rotate in the normal direction according to the fixing unit.

Further, on the paper output side of the upper fixing section and the lower fixing section of the fixing device 40, the upper conveying path 57 and the lower conveying path 5 are provided.
8 is provided, and the paper on which the toner image is fixed by the upper fixing unit or the lower fixing unit is the upper conveyance path 5
7 or through the lower conveyance path 58 to the discharge roller 30. When performing double-sided copying, the reversing retransmitting unit 2 is moved from the lower conveyance path 58 by the switching gate 29.
The paper is fed to the conveyance path 32 following the.

Further, this copying machine is provided with a suction unit 3
6 for controlling the fixing device 40 and the fixing device 40, as shown in FIG.
Is equipped with. The control device 52 includes a CPU (Central P
rocessing unit) 60 and ROM (Read Only Memory) 6
1, an RAM (Randam Access Memory) 62, and an I / O unit (Input / Output Unit) 63.

The ROM 61 is a read-only memory that stores programs and data for controlling the copying machine.
The RAM 62 is a memory that has a function of temporarily storing input data, a calculation result of the CPU 60, and the like and can be written / read at any time, and a battery 64 connected to the RAM 62 allows a main power supply of the copying machine main body 1. Even if you turn off the memory contents will not disappear. RAM6
The heater lamps 44a, 44b, 44c, 44 in the full-color copy mode and the monochrome copy mode are shown in FIG.
The lighting priority order of d is stored, and it has a function as a 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 priority of lighting of the heater lamps 44a, 44b, 44c, 44d in the full-color copy mode is highest in the first order. Heater lamp (350W)
44b, the second is the upper heater lamp (650W) 4
4a, the third is the second middle heater lamp (300W) 44
The lower heater lamp (350W) 44d is at the 4th position. In addition, the priority of lighting of each heater lamp in the black-and-white copy mode is highest in the second middle heater lamp (300W) 44c, the second is the first middle heater lamp (350W) 44b, and the third is the lower heater. Lamp (3
50W) 44d, 4th is upper heater lamp (650W)
44a.

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

Further, the CPU 60 controls each heat roller 41.
Upper, middle and lower thermistors 4 to detect surface temperature of ~ 43
In response to the signals from 5a to 45c, the heater lamp 44a
By turning on or off ~ 44d,
The temperature of the middle and lower heat rollers 41 to 43 is controlled. In the copying machine of this embodiment, 1000 W of electric 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. Lamp 44b 350
The heating is performed at a total of 1000 W and W, and the lower fixing portion is heated to 350 W of the first middle heater lamp 44b, 300 W of the second middle heater lamp 44c, and 3 W of the lower heater lamp 44d.
Heating is performed at a total of 1000 W of 50 W.

Further, the CPU 60 controls the main power source O of the copying machine.
Immediately after N, the temperature adjusting means is switched so as to preferentially adjust the temperature of the fixing unit based on the memory of the RAM.

Further, the CPU 60 ensures that the total power consumption of the heater lamps 44a to 44d and the copy lamp 5 that are turned on in the fixing device 40 does not exceed the maximum power consumption of 1000 W as the set power.
It has a function as an electric power control means for turning off the heater lamps 44a to 44d having a low priority order based on the priority order stored in the table.

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

A heating control routine for heating the upper fixing portion first will be described as a subroutine process. As shown in FIG. 3, first, after setting flag = 0 (S11), 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 judged whether or not the upper thermistor 45a (THU) is lower than 210 ° C. (S13), and the upper thermistor 45a is set to 21.
If the temperature is below 0 ° C, the medium thermistor 45b (THM) becomes 1
It is determined whether the temperature is 90 ° C. or higher (S14). If the temperature of the middle thermistor 45b is 190 ° C. or higher in S14, the first middle heater lamp 44b (HLM1) is turned off (S15), while if the temperature of the middle thermistor 45b is less than 190 ° C. in S14, the process returns to S13. After S15, it is determined whether or not the flag = 1 (S16). If the flag = 1 is not satisfied, the flag = 2 is replaced (S17), and the process returns to S13. In addition, S16
If flag = 1, the full-color ready lamp (not shown) is turned on, the full-color copy becomes ready, and full-color copy can be performed (S21).

On the other hand, at S13, the upper thermistor 45a becomes 21
If it is 0 ° C. or higher, the upper heater lamp 44a (HLU) is turned off (S18), and it is determined whether or not flag = 2 (S19). If the flag = 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 (S20), and the process proceeds to S14.

Subsequent to S21, the lower fixing portion for black and white copying is heated. That is, the lower heat roller 4
Lower heater lamp 44d (HLL) of No. 3 is turned on (S
22). Next, the lower thermistor 45c (THL) is 130
It is determined whether or not the temperature is ℃ or more (S43), the lower thermistor 45
If c (THL) is 130 ° C. or higher, the lower heater lamp 44d (HLL) is turned off (S24), and the process returns. It is also possible to perform full-color copying during the heating of the lower fixing section.

Next, as a subroutine process, a heating control routine for heating the lower fixing portion first will be described.

As shown in FIG. 4, first, after setting flag = 0 (S31), the first middle heater lamp 44b (HLM1) of the middle heat roller 42 and the second middle heater lamp 44c.
(HLM2) and the lower heater lamp 44d (HLL) of the lower heat roller 43 are turned on (S32). Next, it is determined whether or not the middle thermistor 45b (THM) is lower than 190 ° C (S33), and if the middle thermistor 45b is lower than 190 ° C, it is determined whether or not the lower thermistor 45c (THL) is 130 ° C or higher. (S34). If the temperature of the lower thermistor 45c is 130 ° C. or higher in S34, the lower heater lamp 44d
(HLL) is turned off (S35), while if the lower thermistor 45c is lower than 130 ° C. in S34, the process returns to S33. After S35, it is determined whether or not the flag = 1 (S3
6) If flag = 1 is not set, it is replaced with flag = 2 (S37), and the process returns to S33. Further, in S36, flag = 1
In this case, a black and white ready lamp (not shown) is turned on, the black and white copy becomes 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 190 ° C or higher, the first middle heater lamp 44
b (HLM1) and the second middle heater lamp 44c (HLM
2) is turned off (S38), and it is determined whether or not flag = 2 (S39). If the flag = 2 in S39, the black-and-white copy becomes ready, and the black-and-white copy is possible (S
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 for full color copying is heated. That is, the upper heat roller 4
The upper heater lamp 44a (HLU) of No. 1 is turned on (S
42). Next, the upper thermistor 45a (THU) is 210
It is determined whether the temperature is higher than or equal to ℃ (S43), and if it is higher than 210 ℃, the upper heater lamp 44a (HLU) is turned off (S43).
44) and returns. It is also possible to make a black-and-white copy during the heating of the upper fixing unit.

When the main power source 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. It is designed to adjust the temperature.

Next, the lighting control of each heater lamp when the copy operation is started and the copy lamp 5 is lit during the standby state after the above 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 turns on the wattage of the copy lamp 5 and turns it on. Calculate the total power consumption Twatt with the wattage of the heater lamp present (S5
2). Next, the CPU 60 determines whether the total power consumption Twatt exceeds 1000 W which is the maximum rated power (S53). Total power consumption Twatt is 10 in S53
If it is over 00W, of the heater lamps that are lit,
The heater lamp with the lowest priority stored in the RAM 62 is turned off (S54). Then, after S54, it is again determined whether or not the total power consumption Twatt exceeds the maximum rated power of 1000 W (S55). When the total power consumption Twatt is 1000 W or more in S55, the process returns to S54, and the heater lamp having the lowest priority is turned off, and this process is repeated until the total power consumption Twatt is less than 1000 W.

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). Then, when the copy operation ends,
The copy lamp 5 is turned off (S58), and the standby state is restored again (S59).

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

When the surface temperature of the upper heat roller 41 and the middle heat roller 42 reaches the set temperature, the heat roller drive motor 53 causes the middle heat roller 42 to rotate 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 brought into pressure contact with the upper heat roller 41. Further, the suction unit 36 is driven by the moving mechanism and held at the upper position, and the driving force of the belt driving motor 54 is transmitted to the driving shaft 38, so that the conveying belt 37 moves in a circular manner. It should be noted that the pressing operation of the oil applying roller 48 against the upper heat roller 41 may be performed at an appropriate time before the sheet is conveyed to the upper fixing section.

Next, as shown in FIG. 5, the surface of the photoconductor 8 rotating in the B direction is uniformly charged by the charging charger 9, and the exposure optical system unit 4 makes the first exposure to the original on the original table 3. Scanning is performed. The reflected light from the document passes through a blue color separation filter (not shown) and a slit (not shown), and is an exposure point on the surface of the photoconductor between the charger 9 and the inter-image eraser (not shown). The photoconductor 8 is exposed to light to form an electrostatic latent image.
Next, the potential of the non-image area on the photoconductor 8 is removed by the inter-image eraser, and then 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 photosensitive member 8 is transferred to the first transfer roller 21 to which a negative high voltage is applied.
Thus, it is transferred to the transfer belt 17 that moves 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 eliminating device 16.

When the above series of operations is completed, the photoconductor 8 is charged again by the charging charger 9, and the document is scanned by the exposure optical system section 2 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 by the magenta toner in the magenta developing tank 12. The magenta toner image formed on the surface of the photoconductor is formed by the first transfer roller 2
1 causes the image to be transferred onto the previous yellow toner image on the transfer belt in an overlapping manner. After that, in the same manner, the red color separation filter is used to perform the third scanning by the exposure optical system unit 4, and the cyan toner image is formed on the photoconductor 8 by the 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 separated from the transfer belt 17 in the operation so far is transferred to the transfer belt 1.
When the sheet is pressed against 7 and a negative voltage higher than the surface potential of the transfer belt 17 is applied to the second transfer roller 22, the sheet is conveyed from the sheet feeding cassette 25 or the sheet feeding tray 26 through the registration roller 24. The three-layer toner image on the transfer belt 17 is transferred onto the paper.

The above-mentioned paper on which the toner image is transferred is shown in FIG.
The conveyance belt 37 of the suction unit 36 shown in FIG. At this time, the conveyor belt 37
Is held at the upper position, the sheet is conveyed to the upper fixing portion formed at the pressure contact portion between the upper heat roller 41 and the middle heat roller 42. In the upper fixing unit, the three layers of color toner images on the paper are transferred to the heater lamps 44a and 44b.
Upper and middle heat rollers 41 heated to a predetermined temperature by
-It is heated and melted by 42 and is fixed on the paper.
At this time, the upper heat roller 41 is attached to the oil application roller 4
Since the silicone oil is supplied from 8, the offset of the toner image on the upper heat roller 41 is prevented, and gloss is imparted to the full-color toner image on the paper. The paper output from the upper fixing unit passes through the upper transport path 57 and is discharged to the outside of the fixing device 40, and is discharged onto the discharge tray 31 by the discharge rollers 30.

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

The middle and lower heat rollers 42 and
When the temperature adjustment of 43 is completed, the surface of the photoconductor 8 shown in FIG. 5 is uniformly charged by the charging charger 9, and the exposure optical system unit 4 scans the document on the document table 3. The reflected light from the document is guided to the exposure optical system unit 4 and irradiates the photoconductor 8 without passing through the color separation filter and the slit, and an electrostatic latent image is formed on the photoconductor 8. Then, 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 as in the case of performing a full-color copy, and is further transferred to the sheet supplied via the registration roller 24.

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

Here, in the case of one-sided copying, the switching gate 29 is operated so as to guide the paper toward the paper discharge roller 30, and the paper discharged from the fixing device 40 through the lower conveyance path 58. Are discharged onto the discharge tray 31 by the discharge rollers 30.

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

Next, the surface of the photoconductor 8 shown in FIG. 5 is recharged by the charging charger 9, and the exposure optical system section 4 scans the original placed on the original placing table 3 inside out. Next, the toner image is transferred to the back surface of the paper by the same operation as the case of the front surface of the paper, and the toner image is fixed on the paper by the lower fixing unit. After that, 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 of this embodiment, each heater lamp 4 is provided with the RAM 62 as the lighting order storage means provided on the three upper, middle and lower heat rollers 41 to 43.
The priority order of lighting of 4a to 44d is stored. Then, the CPU 60 as the power control means causes the heater lamp 44 having a low priority order to be based on the priority order stored in the RAM 62.
Heater lamp 4 is turned on by turning off a to 44d
The total power consumption of 4a to 44d and the copy lamp 5 is controlled so as not to exceed the maximum rated power.

Therefore, for example, in order to maintain the fixing temperature in the standby state, the upper, middle and lower heat rollers 41 to 4 are provided.
When any one of the heater lamps 44a to 44d of No. 3 is turned on when the copy lamp 5 is turned on,
It is possible to prevent the total power consumption of any of the lit heater lamps 44a to 44d and the copy lamp 5 from exceeding the maximum rated power, and thus improve the operability of the copying machine.

[0057]

As described above, in the electrophotographic apparatus of the present invention, a plurality of heaters are provided on the first to third fixing rollers, and the lighting for storing the priority order of lighting of each heater is performed. Electric power for turning off the heaters of lower priority order based on the priority order stored in the lighting order storage means so that the total power consumption of the order storage means, the heaters that are turned on, and the light source does not exceed the set power. The control means is provided.

As a result, the total power consumption of the turned-on heater and the light source can be controlled so as not to exceed the set power. Therefore, for example, when the heater of the fixing roller is turned on to maintain the fixing temperature in the standby state, when the light source is turned on, the total power consumption of the heater and the light source is, for example, the maximum rated power. There is an effect that it is possible to prevent the set power from being exceeded, and consequently to improve the operability of the device.

[Brief description of drawings]

FIG. 1 is a flowchart showing a procedure of controlling a total power consumption of a heater lamp and a copy lamp that are turned on 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 of 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 the case where the temperature of the upper fixing unit is first adjusted in the copying machine.

FIG. 4 is a flowchart showing a procedure when the temperature of the lower fixing unit is first adjusted 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 transport 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 adjustment means) 57 Upper conveyance path 58 Lower conveyance path 60 CPU (temperature adjustment means, power control means) 62 RAM (lighting sequence storage means)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Kurimoto 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka

Claims (1)

[Claims] 1. A light source for irradiating an original with light, and first to third light sources.
The first fixing portion is formed at the pressure contact portion between the first fixing roller and the second fixing roller, and the second fixing portion is formed at the pressure contact portion between the second fixing roller and the third fixing roller. An electrophotographic apparatus comprising: a fixing device that forms a sheet and is conveyed to each fixing unit in a discharge direction by rotating a fixing roller; and a temperature adjusting unit that adjusts the temperature of each fixing unit. Through the third three fixing rollers, a plurality of heaters are provided, and a lighting order storage unit that stores the priority order of lighting of each heater, and the total power consumption of the lit heater and the light source are set. An electrophotographic apparatus, comprising: power control means for turning off a heater having a low priority order based on the priority order stored in the lighting order storage means so as not to exceed the power.