JP2003295738A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of reducing the power consumption as a whole by supplying power to a dehumidifying heater even in the ON state of a power supply switch and, when the power supply to the dehumidifying heater is unnecessary, stopping the power supply. <P>SOLUTION: In the image forming apparatus having a dehumidifying heater consisting of any one or a combination of a fixing heater 14 for heat-fixing an image transferred to transfer paper, a dew condensation preventing heater 15 for preventing dew condensation on an exposure lamp, a fed paper dehumidifying heater 16 for preventing the humidification of transfer paper, and a photosensitive body heater 17 for stabilizing the temperature environment of a photosensitive body or a combination of two or more heaters, and is capable of controlling the dehumidifying heater by supplying power to the dehumidifying heater by branching the power from the reverse contact of a fixing heater ON/OFF control element 12 for controlling the ON/OFF of the fixing heater 14, a dehumidifying heater ON/OFF control element 22 is arranged on a power supply line to the dehumidifying heater. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer and a fax machine having a dehumidifying heater.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, when there is a temperature difference between the temperature of the mechanical parts of each part and the temperature of the operating environment, especially in the early morning when it is cold, the mechanical parts are condensed. This causes the following problems. That is, when dew condensation occurs on the lens or mirror of the optical system, no image is captured. Further, if the charging system or the photoconductor drum is condensed, an image may not be captured, the image may be blurred or thinned, and a paper jam (jam) may occur. Further, if the paper feeding system is condensed, paper jam occurs.

In order to prevent various problems caused by such dew condensation, conventionally, a heater for warming each mechanical part is arranged in each part, and the heater is operated at night when the image forming apparatus is not used. ing. In general, the wattage (capacity) of this heater is determined so as to reach an appropriate temperature after temperature saturation. Therefore, the heater remains energized without any control, and when the power switch of the image forming apparatus is off, that is, at night, the heater always consumes power, which is uneconomical.

In order to solve such a problem, for example, a technique disclosed in Japanese Patent Laid-Open No. 9-269706 is known. In the image forming apparatus disclosed in this publication, power is supplied to the dehumidifying heater by the branch provided in the power switch.

[0005]

However, in such a conventional apparatus, power is supplied to the dehumidifying heater only when the power switch is turned off, and the dehumidifying heater is used in an image forming apparatus such as a FAX that is in a night standby state. It is impossible to supply electricity to. Further, there is a problem that the power switch with the switching mechanism is expensive.

The present invention has been made in order to solve the above problems, and when the power of the dehumidifying heater is supplied even when the power switch is turned on, and the power supply to the dehumidifying heater is not required, An object of the present invention is to provide an image forming apparatus in which supply is stopped and power consumption is reduced as a whole.

[0007]

In order to achieve the above object, the invention according to claim 1 is to prevent dew condensation of a fixing heater for thermally fixing an image transferred on a transfer paper and an exposure lamp. , A dehumidifying heater made of any one or a combination of a heater for dehumidifying paper, a heater for dehumidifying a sheet for preventing the transfer sheet from absorbing moisture, and a heater for a photosensitive member for stabilizing the temperature environment of the photosensitive member. In the image forming apparatus for controlling the dehumidifying heater by branching from the reverse contact of the fixing heater on / off control element for controlling the on / off of the fixing heater to supply the power to the dehumidifying heater, the power supply line to the dehumidifying heater is connected. An image forming apparatus equipped with a dehumidifying heater on / off control element is the main feature.

According to a second aspect of the present invention, the dehumidifying heater is turned on /
The image forming apparatus according to claim 1, further comprising an external operation section for operating the off control element from the outside.

According to a third aspect of the invention, the dehumidifying heater is turned on /
The image forming apparatus according to claim 1 or 2 is characterized by using a switch as the off control element.

In a fourth aspect of the invention, the dehumidifying heater is turned on /
The image forming apparatus according to claim 1 or 2 is characterized by using a relay element as the off control element.

According to a fifth aspect of the present invention, the dehumidifying heater is turned on /
5. The image forming apparatus according to claim 1, wherein the OFF control element is provided independently for each of the dew condensation prevention heater, the paper feed dehumidification heater, and the photoconductor heater, or is provided commonly to the two heaters. Characterize.

According to the invention of claim 6, the dehumidifying heater is turned on /
The image forming apparatus according to any one of claims 1 to 5, wherein the off control element is provided on the hot line, the neutral line, or both lines.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. First, the image forming operation of the digital copying machine which is one of the image forming apparatuses according to the present invention will be described. Generally, an image forming operation of a digital copying machine (hereinafter referred to as "copying machine") is started by placing a document on a document table (contact glass) and pressing a copy start key. By illuminating the original with an exposure lamp and guiding the reflected light through a mirror and a lens to a CCD (charge coupled device) image sensor, the image information and character information written on the original are converted into electrical signals. To be done. Predetermined image processing is applied to this electric signal to obtain image data. A polygon mirror that controls the light emission of the laser diode based on the image data and rotates the light beam from the laser diode at high speed.
Deflection is performed using a lens or the like to scan the surface of the photoconductor.

A charging device, a developing device, a transfer belt, and a cleaning device are provided around the rotating photosensitive member. The surface of the photosensitive member is cleaned by the cleaning device and then a predetermined height by the charging device. It is uniformly charged by the electric potential. When the surface of the charged photoconductor is scanned by the above light beam, the surface potential on the photoconductor changes according to the intensity of the irradiated light, and an electrostatic latent image is formed. This electrostatic latent image becomes a toner image visualized by the developing device.

On the other hand, the transfer sheet is fed from the sheet feeding section at a timing so as to overlap the toner image on the photoconductor. This transfer paper is conveyed by a transfer belt to which a high voltage is applied, and the toner image on the photoconductor is transferred to the transfer paper at the contact portion with the photoconductor. The transfer paper on which the toner image is transferred is conveyed to the fixing device and fixed. The fixed transfer paper is discharged to the outside of the image forming apparatus, and the image forming operation ends.

The copying machine executes the image forming operation in the above steps, but DC power from the DC power supply is necessary for executing the image forming operation, detecting the state of each part, and controlling. The DC power supplied to each unit in the copying machine is commercial power obtained by a switching regulator. Further, the fixing device of the copying machine adopts a heating roller fixing system, and the fixing system does not convert commercial power into DC power, and supplies the commercial power directly to the fixing device by using a lighting control circuit. Is.

The fixing control of the copying machine according to the present invention will be described below. FIG. 1 is a block diagram of the fixing control device. As the heater power source 1, a commercial AC power source is usually used, and power is supplied to the heater 2 through the switch 7. Switch 7
Is a semiconductor switching element transistor or SCR capable of high-speed switching. The temperature of the heater 2 is detected by the temperature sensor 3 and the temperature detection circuit 4. The arithmetic circuit 5 calculates the resistance of the heater from the temperature of the heater 2 and determines the control voltage to the heater 2 so that the current flowing from the heater power supply 1 to the heater 2 does not exceed a preset value. The control circuit 6 generates a switching signal of the supply voltage to the heater 2 from the control voltage to the heater 2 and controls so that the supply voltage to the heater 2 does not exceed the control voltage.

An embodiment of claim 1 will be described. Figure 2
FIG. 3 is a heater control block diagram in the image forming apparatus according to the first embodiment of the present invention. A power plug 11, a relay 12 for controlling ON / OFF of a heat fixing unit, a heat fixing control circuit 13, a fixing heater 14 (heater 2 in FIG. 1), a dew condensation preventing heater 15, a paper feed dehumidifying heater 16, a drum heater 1.
7, power switch 18, PSU 19, DC load 20, on / off control circuit 2 for controlling on / off of the heat fixing unit
1. A heater switch 22 which is an element for controlling on / off of the dehumidification heater (condensation prevention heater 15, paper feed dehumidification heater 16, drum heater 17).

The operation of the image forming apparatus of this embodiment will be described. Commercial power source (ex. 100V-2
When 40 V) is supplied, electric power is supplied to the dew condensation preventing heater 15, the paper feed dehumidifying heater 16 and the drum heater 17, which are connected to the normally closed side of the relay 12. When the power switch 18 is turned on, the commercial power source becomes PSU19.
To start power supply to. PSU powered by commercial power
19 performs AC / DC conversion and supplies DC power (ex. 5V, 24V, etc.) to the DC load 20.

The DC load 20 supplied with the DC power supply starts the given control, drives the relay 12 from the ON / OFF control circuit 21, and connects it to the normally open side. As a result, commercial power supplied from the power plug 11 is supplied to the thermal fixing control circuit 13, and the thermal fixing control circuit 13
Then, the lighting control of the fixing heater 14 is started.

In addition, when the fixing heater 14 does not need to be turned on, such as in a night standby state of the FAX, and there is a temperature difference between the temperature of the mechanical parts of each part and the temperature of the operating environment, especially in the early morning in cold weather, When the parts are in a state of causing dew condensation, the heat fixing control circuit 13 and the relay 12 are turned off, and the dew condensation prevention heater 15, the paper feed dehumidification heater 16,
Commercial power is supplied to the drum heater 17. Since the power switch 18 is turned on at this time, the PSU 19 operates and the DC load 20 can continue the given control.

However, even in the apparatus having such a configuration, it is necessary to stop the power to the dehumidifying heater depending on the environmental conditions used or to suppress the power consumption. Therefore, by installing the heater switch 22 and connecting the relay 12 to the normally closed side, even when commercial power is supplied to the dehumidifying heater side, the power supply to the dehumidifying heater can be stopped.

An embodiment of claim 2 will be described. Figure 3
FIG. 6 is a heater control block diagram in the image forming apparatus according to the second embodiment of the present invention. In the second aspect, the heater switch 22 is operated by the external operation section 23. This makes it possible to easily turn off the heater switch 22 by operating the external operation unit 23 and stop the power supply to the dehumidifying heater.

An embodiment of claim 3 will be described. In the third embodiment of the present invention, a switch (heater switch 22) is used as an element for controlling on / off of the dehumidifying heater, as shown in FIGS.

An embodiment of claim 4 will be described. In the embodiment of claim 4, a relay element is used as an element for controlling on / off of the dehumidifying heater.

An embodiment of claim 5 will be described. Figure 4
FIG. 6 is a heater control block diagram in an image forming apparatus according to a third embodiment of the present invention. In the present embodiment, the dew condensation preventing heater 15, the paper feed dehumidifying heater 16 and the drum heater 1 are used.
Heater switches 22-1, 22-
2, 22-3 are installed. Thereby, the dew condensation prevention heater 15, the paper feed dehumidification heater 16, the drum heater 1
It is possible to supply electric power to only the necessary heaters in 7. A heater switch may be provided commonly to the two heaters.

An embodiment of claim 6 will be described. In the sixth embodiment, the heater switch 22 is provided on the hot line of the relay 12, the neutral line, or both lines.

[0028]

As described above, according to the first aspect of the present invention, the fixing heater for thermally fixing the image transferred on the transfer paper and the condensation preventing heater for preventing the condensation of the exposure lamp. , A dehumidification heater composed of one or a combination of a paper feed dehumidification heater for preventing the transfer paper from absorbing moisture and a photoconductor heater for stabilizing the temperature environment of the photoconductor, and the fixing heater is turned on. In the image forming apparatus that controls the dehumidification heater by branching from the reverse contact of the fixing heater on / off control element for controlling the on / off, the dehumidification heater is turned on / off in the power supply line to the dehumidification heater. Since the control element is installed,
(EN) An image forming apparatus that enables power supply without waste, supplies power to a dehumidification heater, and stops power supply when power supply to a dehumidification heater is not needed, and can perform night standby such as FAX. be able to.

According to the second aspect of the present invention, the dehumidifying heater on / off control element is provided with an external operation section for operating it from the outside. Therefore, power can be supplied without waste, and power can be supplied to the dehumidifying heater. It is possible to provide an image forming apparatus capable of performing night standby such as FAX while stopping the power supply when the power supply to the dehumidifying heater is unnecessary.

According to the third aspect of the invention, since the switch is used as the dehumidification heater on / off control element, it is possible to supply power without waste, supply power to the dehumidification heater, and supply power to the dehumidification heater. It is possible to provide an image forming apparatus that can stand by at night such as FAX while stopping the power supply when unnecessary.

According to the fourth aspect of the invention, since the relay element is used as the dehumidification heater on / off control element,
(EN) An image forming apparatus that enables power supply without waste, supplies power to a dehumidification heater, and stops power supply when power supply to a dehumidification heater is not needed, and can perform night standby such as FAX. be able to.

According to the fifth aspect of the present invention, the dehumidification heater on / off control element is provided independently for each of the dew condensation prevention heater, the paper feed dehumidification heater, and the photoconductor heater, or is provided commonly to the two heaters. Therefore, it is possible to supply power without waste, supply power to the dehumidifying heater, and stop power supply when power supply to the dehumidifying heater is not necessary.
It is possible to provide an image forming apparatus such as an AX that can stand by at night.

According to the sixth aspect of the present invention, since the dehumidifying heater on / off control element is provided in the hot line, the neutral line, or both lines, power can be supplied without waste and the dehumidifying heater can be supplied. It is possible to provide an image forming apparatus that can supply electric power and stop the electric power supply to the dehumidifying heater when the electric power is not needed, and can perform night standby such as FAX.

[Brief description of drawings]

FIG. 1 is a block diagram of a fixing control device.

FIG. 2 is a heater control block diagram in the image forming apparatus according to the first embodiment of the present invention.

FIG. 3 is a heater control block diagram in the image forming apparatus according to the second embodiment of the present invention.

FIG. 4 is a heater control block diagram in an image forming apparatus according to a third embodiment of the present invention.

[Explanation of symbols]

12 relay (fixing heater on / off control element) 14 fixing heater 15 dew condensation prevention heater 16 paper feed dehumidification heater 17 drum heater (photosensitive heater) 22 heater switch (dehumidification heater on / off control element)

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H027 DA01 DA12 DA14 DE07 EA11                       EA12 EA13 EA16 EC06 EF01                       EF15 EJ18 JA12 JA16 JB19                       JC01 JC04 JC08 JC09 JC11                 2H033 AA35 BA30 CA08 CA11 CA23                       CA45                 2H035 CZ03                 2H076 AA68 EA09                 3F343 FA02 FC19 MA05 MA09 MB05                       MC14

Claims (6)

[Claims] 1. A fixing heater for thermally fixing an image transferred onto a transfer sheet, a dew condensation preventing heater for preventing dew condensation of an exposure lamp, a paper feed dehumidifying heater for preventing moisture absorption of a transfer sheet, and a photosensitive member. A dehumidifying heater including any one or a combination of a plurality of photosensitive body heaters for stabilizing the body temperature environment, and branched from the reverse contact of the fixing heater on / off control element for controlling the on / off of the fixing heater An image forming apparatus for supplying power to a dehumidifying heater to control the dehumidifying heater, wherein an dehumidifying heater on / off control element is installed on a power supply line to the dehumidifying heater. 2. The image forming apparatus according to claim 1, further comprising an external operation section for externally operating the dehumidification heater on / off control element. 3. A dehumidifying heater on / off control element,
The image forming apparatus according to claim 1, wherein a switch is used. 4. A dehumidifying heater on / off control element,
3. A relay element is used, according to claim 1 or 2.
The image forming apparatus described. 5. A dehumidifying heater on / off control element is provided independently for each of the dew condensation preventing heater, the paper feed dehumidifying heater, and the photoconductor heater, or is provided commonly to the two heaters. 5. The image forming apparatus according to any one of 4 to 4. 6. The image forming apparatus according to claim 1, wherein the dehumidifying heater on / off control element is provided on a hot line, a neutral line, or both lines.