JPH03291681A - Fixing device for printing device - Google Patents

Abstract

PURPOSE:To stably fix toner and to prevent overheating of a heating roll by housing a heating means by which the direction of the shaft is divided into a multiple number of ranges and can feed electrical power independently to each range in the heating roll, and by feeding electrical power according to the width of the recording paper by the heating means. CONSTITUTION:The control device 30, by which the heating roll 20 is controlled, energizes heating wires 23 to 25 of the range where the paper is in contact, and the electrical power by which the temperature of each range can be maintained at a set temperature is fed by signals from temperature detectors 26 to 28 provided in each range. When the recording paper with the toner adhered is ejected from the photosensitive body drum 9 in this state, and is processed to the fixing device 16, while all of the width of the recording paper is evenly heated and the toner on the surface is melted by heat with the heating roll 20, since the recording paper comes into contact with all of the heating roll 20 in the shaft direction and heat is evenly absorbed, there is no generation of a local overheating. Thus, the stable fixing can be carried out, and the overheating of the heating roll can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fixing device suitable for a printing device using an electrophotographic process.

(Prior Art) A printing device using an electrophotographic process uses a fixing roller that consists of a heating roller with a heater wire arranged in the axial direction and a pressure roller in order to thermally fuse the toner transferred by a photoreceptor drum to a recording paper. Equipped with equipment.

By the way, 1 occupies the entire width of the heating roller on the recording paper, so when printing extremely continuously on the heating roller such as on an envelope, the area in contact with the envelope as shown in Fig. 6 is The temperature of this portion rises above the set temperature, causing problems such as deterioration of the roller components due to overheating and an increase in the temperature of the device.

The present invention was made in view of these problems, and its purpose is to provide a new fixing device that can achieve stable fixing performance and prevent overheating of the heat generating roller regardless of the size of recording paper. Our goal is to provide the following.

(Means for Solving the Problems) In order to solve these problems, the present invention provides a heat generating roller and a pressure roller arranged to receive the recording paper discharged from the photoreceptor drum. The heat generating roller houses a heat generating means which is divided into a plurality of regions in the axial direction and can supply power to each region independently (this means that the heat generating means is configured to supply power in accordance with the width of the recording paper). A means of supply was provided.

(Function) Power is selectively supplied to the heating means in the area corresponding to the width of the paper to maintain the temperature necessary to soften the toner in the area commensurate with the paper size, ensuring fixing performance, and fixing. This prevents the heating roller from overheating by suppressing energization to areas that are not involved.

(Example) The details of the present invention will be described below based on illustrated examples.

FIG. 1 shows an embodiment of a printing device using the fixing device of the present invention, and reference numeral 1 in the figure is a paper feed device provided at the top of the main device, which stores two types of paper. A stacker 2.3 is provided, and a pickup roller 4.5 is provided from which the recording sheets are pulled out one by one.
The recording paper is fed one by one from the main body to the paper feed lower of the main body.

A paper detector 8 is disposed below the paper feed lower to detect when the recording paper is set at a predetermined position.
A gate roller 10.10 is provided which feeds out the feed.

Below the gate roller 10.10, in the direction of arrow A in the figure,
In other words, the photosensitive drum 9 rotates in a direction that moves the recording paper downward and receives the light beam from the optical signal generator 11.
is being distributed. Around this photosensitive drum 9, a charging unit 12, a developing unit l-13, and a transfer unit 14 are arranged.
, erase unit 15 are arranged. A fixing device N16 is arranged below the photosensitive drum 9 to melt the toner and weld it to the recording paper.

FIG. 2 shows an embodiment of the fixing device of the present invention, and reference numeral 20 in the figure is a heat-generating roller constituting the fixing device, and the cylinder has a moisturizing layer 21 made of fluororesin or the like formed on its surface. shape body 2
2, the axial direction is divided into a plurality of regions, in this embodiment, three regions, a central region and an end region, and heater wires 23, 24, and 25 that can be independently energized are housed in each region. has been done.

Reference numeral 30 denotes a control device for controlling the above-mentioned heat generating roller, which receives width data calculated based on the paper size set on the panel surface of the host device or the main body of the printer, and energizes the heater wire in the area in contact with the paper. , is configured to supply power that can maintain the temperature of each region at a set temperature based on signals from temperature detectors 26, 27, and 28 provided in each region.

In this embodiment, when a print command is input, one sheet of recording paper is pulled out from the stacker 2.3 and placed on the gate roller 1.
Sent to 0.10. In this state, the pull-out roller 4
．． 5 rotates further and the recording paper bends, the paper detector 8
is activated. As a result, the gate roller 10.10 and the photoreceptor drum 9 rotate synchronously, and the optical signal generator 11 writes print data onto the photoreceptor drum 9. The latent image formed on the photosensitive drum 9 is transferred to a developing unit 13.
is converted into a toner image. The toner forming an image on the surface of the photosensitive drum 9 comes into contact with the recording paper at the transfer unit 14 and is attracted to the recording paper by the electrostatic force of the transfer unit 14 .

On the other hand, the control device 30 controls all the heater wires 23.
24 and 25 are enabled to conduct electricity, and power is supplied so that the entire area of the heat generating roller 20 reaches the set temperature. As a result, the entire axial direction of the heating roller 20 is heated almost uniformly as shown in FIG. 3(A).

In this state, when the recording paper with toner attached is discharged from the photoreceptor drum 9 and enters the fixing device 16, the entire width of the recording paper is uniformly heated by the heating roller 20, and the toner on the surface is thermally fused. Since the heat generating roller 20 is in contact with the recording paper almost entirely in the axial direction and heat is evenly removed, local overheating does not occur.

On the other hand, when printing on a recording medium with a small width such as an envelope is selected, the control device 30 supplies power only to the heater wires 24 in an area corresponding to this width, and stops supplying power to the other heater wires 23 and 25. Abort.

In this state, when the envelope on which a toner image corresponding to the print data (this is formed) is ejected by the photoreceptor drum 9 and enters the fixing device, it is heated while contacting only the pole portion of the heating roller 20, and the toner on the surface is heated. At this time, the heating roller 20 selectively supplies power only to the heater wires 24 existing in the area through which the envelope passes, so that the power is sufficient to thermally weld the toner on the envelope. On the other hand, power is not supplied to the edge side area where the recording medium does not pass, or it does not cause overheating (Figure 3).Especially when the paper width is narrow and the fixing When printing on envelopes or postcards that require a sufficient supply of heat, the heater 24 in the center area (this selectively supplies sufficient power to ensure fusing performance, while It is possible to prevent overheating of the area.

Note that in this embodiment, electricity is not applied to the parts where fusing is not performed, but by keeping the electricity flowing to a level that maintains the temperature slightly lower than the set temperature, it is possible to avoid electricity when changing the paper size. The fixing temperature can also be raised quickly.

In addition, in this embodiment, the area to be energized is selected based on the paper size set by the host device or the panel surface, but the rate of change of the signal from the temperature sensor placed in each area It is also possible to determine the paper width based on the output difference between adjacent temperature detectors, and select the energized area based on this.

In addition, in this embodiment, the case where the center line of the paper is used as the reference is taken as an example and explained, but in the case where the side edge of the paper is used as the reference, it is sufficient to divide the area into two areas. .

In addition, in this embodiment, a heater wire is used as a heat generating means, but as shown in FIG. 31.32.3 Halogen lamp with
3, and as shown in FIG.
It is clear that the same effect can be obtained by using a heat generating roller formed by winding the heat generating wires 37, 38, 39 and coating the surface of the heat generating wire with highly lubricating resin 40.

(Effects of the Invention) As described above, the present invention includes a heat roller disposed to receive the recording paper discharged from the photoreceptor drum and a pressure roller, and the heat roller is provided with a pressure roller. The heating means is divided into a plurality of regions in the axial direction and includes a heating means capable of supplying power independently to each region, and the heating means is provided with means for supplying power in accordance with the width of the recording paper. , each heater wire built into the heating roller corresponds to the size of the recording paper (this can supply the optimum power, and maintains the heating roller at the optimum temperature regardless of the paper size to ensure a stable toner). It is possible to prevent the heating roller from overheating and to reduce the temperature rise inside the device as much as possible.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a printing device using a fixing device M of the present invention, FIG. 2 is a configuration diagram of an apparatus showing an embodiment of the fixing device M of the present invention, and FIG. ) are diagrams showing the operation of the same device, FIGS. 4 and 5 are cross-sectional views showing other embodiments of the present invention, and FIG. 6 is a diagram showing the operation of the above device, and FIG. FIG. 3 is a diagram showing the temperature distribution when printing. 9... Photosensitive drum 16... Fixing device 1
7... Heat generating roller 18... Pressure roller 2
0... Heat generating roller 21... Moisture layer 22...
...Cylindrical body 23.24.25...Heater wire

Claims (1)

[Claims] The heating roller is arranged to receive recording paper ejected from the photosensitive drum and includes a pressure roller, and the heating roller is divided into a plurality of regions in the axial direction and power is applied to each region independently. A fixing device for a printing apparatus, which houses a heat generating means that can be supplied, and includes means for supplying electric power to the heat generating means in accordance with the width of recording paper.