JP2003162200A - Image forming device - Google Patents

Abstract

(57) [Abstract] [Problem] To save energy of an image forming apparatus. SOLUTION: The image forming apparatus has a plurality of fixing units, and has means for changing characteristics (for high speed and low speed) of each fixing unit and predicting and calculating power consumption of each fixing unit when inputting the number of copies. Select the fixing device that consumes the least amount of power during copying and copy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic copying machine, a printer, a facsimile, etc., which is provided with a fixing device for forming an unfixed toner image on a transfer material and heating the unfixed toner image to fix it on the transfer material. Image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, a heat roller fixing is mainly used in a fixing device of an image forming apparatus. In general,
The heat roller fixing is a transfer material carrying an unfixed toner image in a nip part formed by pressing a pressure roller having a surface made of an elastic material such as silicon rubber against a heated fixing roller by a heat source such as an infrared heater. Fixing is performed by sandwiching and conveying. The toner is formed of resin-based powder, and the surface temperature of the fixing roller must be maintained at about 150 ° C. to 200 ° C. to fix the toner on the transfer material. A large-scale machine with a large number of copies per minute and a large number of prints (hereinafter referred to as “throughput”) has to have a large fixing unit in order to support high-speed printing with durability and a large amount, and the heat capacity of the fixing roller also inevitably increases. . Accordingly, the warm-up time of the fixing device is long, and even if the power is turned on, it is necessary to wait a few minutes without immediately entering the copying or printing operation. Therefore, there is a drawback that the amount of power consumption becomes excessively large especially when printing a small number of prints. On the other hand, in a small machine with a small number of copies and prints per minute, the heat capacity of the fixing roller can be reduced, so the warm-up time is short and the power consumption can be minimized.
However, when printing a large number of sheets, the operating time becomes long, and conversely the power consumption becomes excessive.

From such a background, in recent years, a heating device by a film heating system, which has a short warm-up time and can cope with a certain speed, has been devised and utilized, which greatly contributes to energy saving. It is known from Japanese Patent Application Laid-Open No. 63-313182, Japanese Patent Application Laid-Open No. 2-157878, etc. related to the applicant's earlier proposal. However, this system has not been realized at a throughput of 40 sheets / minute or more.

An image forming apparatus having a plurality of fixing devices is also known from Japanese Patent Application Laid-Open No. 07-121938.

[0005]

As described above, in the fixing device compatible with a small throughput, the power consumption amount at the time of printing a large number of sheets becomes excessive, and there is a problem that power saving is hindered. On the other hand, in a fixing device compatible with multi-throughput, there has been a problem that the amount of power consumption when printing a small number of sheets becomes excessive. Further, even in an image forming apparatus having a plurality of fixing devices, since there is no mechanism for selecting a fixing device to be used, power consumption may be increased depending on the number of copies.

The present invention solves the above-mentioned conventional problems,
An object of the present invention is to provide an image forming apparatus capable of saving power when printing any number of sheets.

[0007]

In order to solve the above problems, the present invention comprises a fixing device for forming an unfixed toner image on a transfer material and heating the unfixed toner image to fix it on the transfer material. In the image forming apparatus, the fixing device includes a plurality of fixing devices, and a calculating unit for calculating the amount of electric power used by each fixing device during image formation.

In such an image forming apparatus, it is more effective that the maximum power consumption of at least one of the plurality of fixing devices differs from the maximum power consumption of the other fixing devices.

Further, it is more effective that the rising time of at least one of the plurality of fixing devices is different from the rising time of the other fixing devices.

At least one fixing device of the plurality of fixing devices includes a heating member fixedly supported, a film, and
A pressurizing member which is driven to rotate by being pressed against a heating body while sandwiching the film, and is upstream between the film and the pressing member in a press-contact nip portion formed by the heating body and the pressing member with the film sandwiched therebetween. By introducing the material to be heated conveyed from the processing unit on the side and slidingly moving the film to the heating body by driving rotation of the pressing member, the film and the material to be heated are nipped and conveyed by the pressure contact nip portion together. A fixing device that applies the heat of the heating element to the material to be heated through the film is more effective.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment 1) Hereinafter, an embodiment of the present invention will be described with reference to FIG. 1 described above.

FIG. 1 is a schematic view showing a main part of an image forming apparatus to which the present invention is applied. Reference numeral 41 is an organic photosensitive drum which is an image carrier, 42 is a charging roller which is a charging member, and 43. Is a laser exposure device, 44 is a developing sleeve, a developing blade, a developing device including one-component magnetic toner, and 45 is a transfer roller, and these constitute image forming means. 48 is a cleaning blade, 53
Is a registration roller, and 55 is a front / rear edge detection sensor at the position immediately after the registration roller of the recording paper. Further, the image forming apparatus according to the present exemplary embodiment includes two fixing devices A, B, and the selection path 47 that conveys the transfer material is provided in either one of the fixing devices. The fixing rollers 1 and 3 and the pressure rollers 2 and 4 constitute fixing devices A and B.

In the fixing device A, the core metal of the fixing roller has a thickness of 5 mm, a diameter of about 50 to 60 mm, and 1500 to 2
A 000 W heater is built in. On the other hand, in the fixing device B, the core metal of the fixing roller 1 has a thickness of 0.5 to 2 mm and a diameter of 2
A heater of 700 to 900 W having a length of 0 to 40 mm is built in. Therefore, the performances of the fixing device A and the fixing device B are largely different, and the fixing device of the fixing device A requires a rise time of 2-3 minutes to enable fixing after the power is turned on at room temperature, but 60 sheets or more per minute. It has the processing ability of. On the other hand, the fixing device of the fixing device B is in a printable state in a short time with a startup time of about 20 seconds, but has a processing capacity of about 10 sheets per minute.
In the case of the present embodiment, the power is not input to the fixing device when the power of the main body is turned on, but the power is input only to the fixing device selected when the number of copies is input.

In the image forming apparatus, the power consumption (W) of each fixing device from the start to the end during copying is set.
A fixing device is selected with a device for predicting and calculating s).

A specific calculation method will be described. The throughput at this time is (A sheets / s).

For example, the startup time is t (h), the power consumption at that time is W1 (Ws), and the power consumption at the time of printing is W (Ws).
In the case of the fixing device of 2 (Ws), the power consumption Wall (Ws) at the time of copying x sheets is expressed by the following formula. Wall = W1t + W2x / A At this time, the start-up time t naturally varies greatly depending on the temperature of the fixing roller at the start of energization. For example, immediately after the end of the printing operation, the fixing roller maintains a certain temperature, so the start-up time becomes short. On the contrary, if a long time has passed since the previous printing operation, the fixing roller is sufficiently cooled, and the start-up time becomes longer accordingly.

When predicting this t, it is assumed that the energization time t is proportional to the temperature rise T of the fixing roller, and is approximately assumed by using the following equation. T = a · t (a is a constant) T0 is raised from the fixing roller temperature of 0 ° C. to the target temperature T0
The constant a is a = T0 / t0 when the time taken to reach .degree.

Therefore, when the initial temperature of the fixing roller at the start of energization is T1, the startup time t1 is t1 = (1− (T1 / T0)) · t0.

At this time, t0 is determined by each fixing device, and T0 is unique to the toner.
1 is obtained only by the initial temperature of the fixing roller.

Power consumption Wal that can be calculated as described above
By predicting 1 for each fixing device and predicting, selecting, and printing the fixing device that consumes the least amount of power in that situation, it is possible to always perform a printing operation with minimum power consumption without waste. it can.

The value of W2 may be changed depending on the thickness of the paper.

(Embodiment 2) In the image forming apparatus shown in the figure, in this example, the first fixing device 10 and the second fixing device 20 are both fixing rollers 11 and 21 and a pressure roller 1.
A heat roller type fixing device having Nos. 2 and 22 is provided.
The first fixing unit 10 has a core metal of the fixing roller 11 having a thickness of 5 mm, a diameter of 60 mm, and a built-in heater of 1500 W. Therefore, the power consumption at the start-up is 1500 W, and the power consumption at the time of paper feeding is 10 on average.
It becomes about 00w. On the other hand, the second fixing unit 20 has a core metal of the fixing roller 21 having a thickness of 1 mm, a diameter of about 40 mm, and a built-in heater of 800 W. Therefore, the power consumption at startup is 800 W, and the power consumption at paper passing is 500 W on average. Therefore, the performances of the fixing devices provided in the first fixing unit 10 and the second fixing unit 20 are largely different, and if the target temperature T0 for rising is set to 200 ° C. depending on the toner used, the first fixing unit 1
0 fixing device has a rise time t1 from 0 ° C to 200 ° C
Although a requires 200 seconds, it has a processing capacity of 60 sheets (1 sheet / s) per minute. 20 ° C to 20 ° C in the second fixing unit
The rise time t1b up to 0 ° C. is 20 seconds, but the processing capacity is 12 sheets per minute (0.2 sheets / s).

In this image forming apparatus, the relationship between the power consumption of each fixing device, the initial temperature T0, and the number of printed sheets x is calculated by using the above equations (1) and (3). Fixing device A: WallA = 300000-1500T1
+ 1000x (T1 <200) Fixing device B: WallB = 16000-80T1 + 25
00x (T1 <200) From this result, if the initial temperature T1 is 0 ° C., Wa
The number of prints for which llA <WallB is x> 189.3, and when the number of prints is 190 or more, the fixing device A
It can be seen that power saving can be achieved by selecting.

In this way, power saving can be achieved by selecting the fixing device by performing the above calculation when inputting the number of prints.

(Third Embodiment) Next, a third embodiment will be described.

By adopting the heating system of the film overheating system as the fixing device B of the image forming apparatus described above, it is possible to further reduce the power consumption when copying a small number of sheets, which is effective.

Specifically, t0 (rise time) in the above calculation formula is about 5 seconds, and the power consumption at the time of start is small. Further, when the power of the main body is turned on, a small amount of electric power is input to the fixing device B by the film heating method to preheat the heat, so that t0 can be further reduced, and the power consumption is hardly increased. The copy time at the time of printing can be shortened.

[0028]

As described above, by having a plurality of fixing devices and pre-calculating the power consumption of each fixing device for each copy operation, the copy operation is always performed with the minimum power consumption. It becomes possible.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a main part of an image forming apparatus to which the present invention is applied.

[Explanation of symbols]

1 Fixing roller of fixing device A 2 Pressure roller of fixing device A 3 Fixing roller of fixing device B 4 Pressure roller of fixing device B 41 Organic photosensitive drum 42 Charging roller 43 Laser exposure equipment 44 Developer 45 transfer roller 46 cleaning blade 47 Fixer Selective Transport Route 53 Registration roller A fuser A B fixing device B

Claims (5)

[Claims] 1. An image forming apparatus comprising a fixing device for forming an unfixed toner image on a transfer material and heating the unfixed toner image to fix the toner image on the transfer material, wherein the fixing device has a plurality of fixing devices. An image forming apparatus, further comprising: a calculating unit for calculating the amount of electric power used by each fixing device during image formation. 2. The image forming apparatus according to claim 1, wherein the maximum power consumption of at least one of the plurality of fixing devices is different from the maximum power consumption of the other fixing devices. 3. The image forming apparatus according to claim 1, wherein the rising time of at least one of the fixing devices is different from the rising time of the other fixing devices. . 4. The image forming apparatus according to claim 1, 2 or 3, wherein at least one fixing device of the plurality of fixing devices includes a heating member fixedly supported, a film, and a heating device sandwiching the film. It has a pressure member that is pressed against the body and driven to rotate, and is conveyed from the processing unit on the upstream side between the film and the pressure member in the pressure contact nip portion formed by the heating body and the pressure member with the film sandwiched between them. The heat of the heating body is transferred by introducing the heated material to be heated and slidingly moving the film to the heating body by the driving rotation of the pressure member, and by conveying the film and the heating material together while sandwiching the pressure contact nip portion. An image forming apparatus, characterized in that the image forming apparatus is a fixing device which applies the material to a material to be heated via a fixing device. 5. The image forming apparatus according to claim 1, 2 or 3, wherein the throughput is changed for each fixing device.