JP2005037543A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus in which dew condensation can be prevented with superior economic efficiency. <P>SOLUTION: A heater 4 for dehumidification and prevention of dew condensation in a specified member inside the device, a thermostat switch 5 controlling lighting of the heater 4 provided in an energizing path of the heater 4 and a relay 3 changing over the energizing path so that the heater 4 is energized through the thermostat switch 5 are provided. When power is not connected to the apparatus, change over to the energizing path through the thermostat switch 5 is carried out. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer using an electrophotographic process, and more particularly to a temperature control technique in the apparatus.
[0002]
[Prior art]
In image forming apparatuses such as copiers, facsimiles, and printers installed at low temperatures, condensation has occurred due to changes in the surrounding environment and heat rise due to fixing of the apparatus itself, and condensation has occurred in the optical system of the writing unit and reading unit. In some cases, a phenomenon in which an image cannot be formed is caused. If condensation occurs on the photosensitive member or the transfer belt portion, image deterioration such as image flow is caused.
In order to prevent the occurrence of such condensation, dew condensation heaters are placed near the optical system, photoconductor, and transfer belt, and these heaters are turned on when the power is turned off or the energy saving mode is entered when the device is not operating. There is a device to prevent the occurrence of this. In addition, there is a device equipped with a timer for energy saving to turn on these dew condensation prevention heaters after a lapse of a certain time from power off or transition to energy saving mode, or to turn on / off the heaters according to the scheduled use time ( For example, see Patent Document 1).
[Patent Document 1] JP-A-9-269706
[Problems to be solved by the invention]
However, with the conventional method in which a heater is placed near the possibility of condensation and the condensation prevention heater is always turned on when the power saving mode is turned off or the power is turned off, it is unclear whether condensation will occur or not at night. Electricity is consumed to prevent condensation, which is not economical. In addition, when management is performed by a timer as in the prior art, this heater may not function when it is used unscheduled or when a sudden environmental change occurs, and conversely, it is necessary to turn on the heater. Even if it is not, there is a possibility of lighting, which is not preferable from the viewpoint of energy saving.
Changing the timer setting for each season can also be a cause of poor usability. Also, if the heater power is increased to such an extent that condensation does not occur even at low temperatures and the temperature of the dew condensation part in the standby state is increased, the temperature inside the machine becomes too high when the ambient temperature is high, causing toner sticking and There is concern about exceeding the heat-resistant temperature.
An object of the present invention is to provide an image forming apparatus capable of preventing condensation with excellent economic efficiency.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, the invention described in claim 1 includes a heater for dehumidifying and preventing condensation on a predetermined member in the apparatus, a thermo switch that is provided in an energization path of the heater and controls the heater to be turned on and off. An image forming apparatus that includes a relay that switches an energization path so that the heater is energized via a thermo switch and that switches to an energization path via a thermo switch when the apparatus is not turned on is the main feature.
According to the first aspect of the present invention, when the power of the device is not turned on, the heater is switched to the energization path via the thermo switch, and the heater is turned on / off by the thermo switch. Even if the temperature is low or high, you can leave the member you want to prevent dew condensation at the desired temperature, so you can prevent dew condensation at the time of restart, and there are no side effects such as toner sticking. It becomes possible to prevent degradation of the.
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the temperature detecting means separate from the thermo switch, the temperature detected by the temperature detecting means is compared with the set temperature, and the heater is turned on and off based on the result. The image forming apparatus is provided with a comparison light extinction control means that is arranged in parallel with the thermo switch for the heater, and switches to the energization path via the comparison light extinction control means in the energy saving mode. Features.
In the invention described in claim 2, since the heater is turned on / off by the comparison lighting / extinguishing control means in the energy saving mode and the heater lighting / extinguishing control is performed by the comparison lighting / extinguishing control means, the frequency of using the thermo switch while preventing condensation The life of the thermoswitch can be extended by reducing
According to a third aspect of the present invention, the image forming apparatus according to the second aspect is characterized in that the temperature threshold value for turning on / off by the thermoswitch is set wider than the temperature threshold value of the comparison lighting on / off control means.
According to the third aspect of the present invention, the temperature threshold for turning on / off by the thermo switch is set wider than the temperature threshold of the comparison lighting on / off control means, so that the thermo switch operates due to the temperature rise by the heater during temperature control in the energy saving mode. The life of the thermoswitch can be extended.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a heater control unit in an image forming apparatus according to an embodiment of the present invention. Hereinafter, the configuration will be described together with the operation.
Since the DC power source 2 is not generated when the main switch 1 of the apparatus is turned off while being connected to the commercial power source, the relay 3 in the power supply path to the dew condensation heater 4 is connected to the first contact side. In this case, a thermo switch 5 is provided in the connection path to the condensation heater 4.
The thermo switch 5 is turned on when the temperature falls below a certain temperature by the bimetal, and when the temperature reaches a predetermined temperature, the contact is turned off to stop the energization of the heater and to the condensation heater 4 while controlling the temperature within a certain range. Turn on the power.
When the main switch 1 is turned on, the relay 3 is switched to the second contact by VccE generated by the DC power source 2. Here, when the energy saving transition is made by the energy saving control signal, the output control is turned off. In other words, in the energy saving mode, the output of the thermistor (sensor) 8 and a certain temperature threshold value ref (set temperature) are compared by the comparator 7, and when the output of the thermistor (sensor) 8 falls below the set temperature, the TRIAC 6 is controlled to condense. The heater 4 is turned on, and when the temperature exceeds the set temperature, the dew condensation heater 4 is turned off. By giving hysteresis to the comparator 7, the heater is turned on / off, and temperature control is performed.
For this reason, the power supply of the triac 6, the comparator 7, and the thermistor (sensor) 8 is set to VccE generated even in the energy saving mode. On the other hand, since the internal temperature is sufficiently raised by heat such as fixing when the apparatus is turned on except in the energy saving mode, it is not necessary to turn on the dew condensation heater 4. Therefore, the comparator output is masked by the CPU heater control signal and the triac 6 is turned on. Do not turn on the heater.
[0006]
The energy-saving mode here refers to a state where the fixing heater necessary for image formation is completely turned off and only a part of the apparatus, the CPU and peripheral elements are used to stand by with low power consumption. Only necessary power supplies are generated, and other power supplies are turned off to reduce power consumption.
In such a state, since the fixing heater is turned off, the temperature inside the apparatus becomes substantially equal to the ambient environment temperature, and dew condensation is likely to occur at the time of restart. By disposing the thermistor (sensor) 8 in the vicinity of a portion where condensation may occur, condensation can be prevented at a more appropriate temperature. Further, a temperature / humidity sensor for measuring the installation environment temperature / humidity for determining the process conditions provided in the apparatus can be substituted.
[0007]
With such a configuration, the thermoswitch 5 connected when the power is turned off has a life of the number of on / off times when it has a mechanical contact structure such as a bimetal, and it is ideal that the number of on / off times is as small as possible. . From this point of view, it is preferable that the thermo switch 5 has a wide off temperature and on temperature range. For example, the cycle can be lengthened by setting the off temperature to 35 ° C. and the on temperature to 5 ° C. At such a temperature, the number of times the thermoswitch 5 is turned on is drastically reduced in a normal office environment.
The control range for turning off / on the triac 6 by detecting the temperature with the other thermistor (sensor) 8 is set to an off temperature of 30 ° C and an on temperature of 10 ° C. Control is performed to extend the life of the thermo switch 5 and to prevent the thermo switch 5 from being turned off / on even during energization.
In addition, if such a set temperature is set, it is possible to stand by at substantially the same temperature in the case of the control by the thermo switch 5 and the case of the control by the thermistor (sensor) 8. Although the dew condensation heater is described here as an example, the same effect can be obtained for the dehumidification heater by changing the temperature and humidity conditions.
[0008]
【The invention's effect】
As described above, according to the first aspect of the present invention, the heater for dehumidifying and preventing condensation on the predetermined member in the apparatus, the thermo switch provided in the energizing path of the heater, and controlling the turning on / off of the heater, the heater Is equipped with a relay that switches the energization path so that it is energized via the thermo switch, and when the device is not powered on, it switches to the energization path via the thermo switch, and the heater switch is turned on and off by the thermo switch, Even if the environment in which the device is placed when the device is turned off can be kept at the desired temperature, it is possible to prevent dew condensation during restart, even if the component that you want to prevent condensation is left at the desired temperature. By eliminating side effects such as toner fixation, it is possible to prevent image quality deterioration.
According to a second aspect of the present invention, there is provided temperature detection means separate from the thermo switch, and comparison lighting / light-off control means for comparing the temperature detected by the temperature detection means with the set temperature and controlling the heater to be turned on / off based on the result. Since the comparison light extinction control means is arranged in parallel with the thermo switch for the heater, and the energy saving mode is switched to the energization path via the comparison light extinction control means, the heater on / off control of the heater is performed by the comparison light extinction control means. It is possible to extend the life of the thermo switch by reducing the frequency of use of the thermo switch while preventing condensation.
According to the third aspect of the present invention, the temperature threshold for turning on / off by the thermo switch is set wider than the temperature threshold of the comparison lighting on / off control means, so that the thermo switch operates due to the temperature rise by the heater during temperature control in the energy saving mode. The life of the thermoswitch can be extended.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a heater control unit in an image forming apparatus according to an embodiment of the present invention.
[Explanation of symbols]
1 Main Switch 2 DC Power Supply 3 Relay 4 Condensation Heater 5 Thermo Switch 6 Triac (Comparator Point Control Control Component)
7 Comparator (Comparative point extinction control means component)
8 Thermistor (temperature detection means)

Claims (3)

A heater for dehumidifying and preventing condensation on a predetermined member in the apparatus, a thermo switch provided in an energization path of the heater for controlling turning on / off of the heater, and the energization so that the heater is energized via the thermo switch An image forming apparatus comprising: a relay for switching a path, wherein the energization path is switched through the thermo switch when the apparatus is not powered on. 2. The image forming apparatus according to claim 1, wherein a temperature detection unit separate from the thermoswitch, and a comparison on / off control for comparing the temperature detected by the temperature detection unit with a set temperature and controlling the heater on / off based on the result. An image forming device characterized in that the comparison light extinction control means is arranged in parallel with the thermo switch for the heater and is switched to the energization path via the comparison light extinction control means in the energy saving mode. apparatus. 3. The image forming apparatus according to claim 2, wherein a temperature threshold value for turning on / off by the thermo switch is set wider than a temperature threshold value of the comparison lighting on / off control means.

Images