JP2004061553A - Electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic apparatus preventing the dew condensation of a photoreceptor when air temperature is low. <P>SOLUTION: Power is supplied and temperature T1 when supplying the power measured by a temperature sensor 2b is captured in a control circuit 4. When the temperature T1 is lower than reference temperature T2 stored in a storage medium 5, the control circuit 4 determines time Ti for reversely rotating a fan 3 based on a relation table or correlative calculation expression between the temperature T1 stored in the medium 5 and the reversely rotating time of the fan 3. By reversely rotating the fan until the time Ti elapses, a 1st air passage (air passage from a fixing device to the photoreceptor) is formed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electrophotographic apparatus such as a printer, a facsimile, and a copying machine.
[0002]
[Prior art]
As a conventional electrophotographic apparatus, a toner image is formed on a photosensitive drum, the toner image on the photosensitive drum is transferred onto paper by a transfer unit, and then fused and pressed by a fixing device to fix the toner image. There is something.
In order to solve the problem of dew condensation on the photosensitive drum in the apparatus at a low temperature, for example, as disclosed in JP-A-10-254330 and JP-A-5-303244, 2. Description of the Related Art There is known an apparatus in which an air passage having a duct structure is formed between a fixing device and a plurality of fans or open / close valves provided on a duct to convey air heated by the fixing device to a photosensitive drum.
[0003]
[Problems to be solved by the invention]
However, in the conventional electrophotographic apparatus, since a plurality of ducts, a plurality of fans and on-off valves are required, the number of parts is increased, which causes a problem of space saving and cost.
[0004]
[Means for Solving the Problems]
The present invention has been made in view of the above problems, and includes a photoconductor that forms a toner image, a fixing device that fixes the toner image transferred onto paper, and a fan that generates an air path in the apparatus. In the electrophotographic apparatus provided, by rotating / reversing the fan in the normal direction, a first air path as an air path from the fixing device to the photoconductor and a second air path as an air path from the photoconductor to the fixing device are provided. And an electrophotographic apparatus for controlling the rotation of the fan so as to be the first air path during warm-up.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating a configuration of an electrophotographic apparatus according to the present invention, and FIG. 2 is a view illustrating an air path formed in the electrophotographic apparatus according to the present invention. The electrophotographic apparatus includes a fixing device 1 for heating and fusing and fixing a toner image transferred onto a sheet, a photosensitive drum 2a, an air temperature sensor 2b for detecting a temperature near the photosensitive drum 2a, a forward / reverse rotating fan 3, A control circuit 4 for controlling the entire apparatus, a program related to the operation of the entire apparatus, for example, a table of a reverse rotation time of the fan 3 based on the temperature detected by the temperature sensor 2b, or a non-volatile storage medium such as a ROM storing a relational expression. 5 is provided. The fixing device 1 includes a fixing roller 1b serving as a pressure roller, a heater 1a disposed inside the fixing roller 1b to heat the surface of the fixing roller 1b, and a temperature sensor 1c for detecting a temperature near the surface of the fixing roller 1b. Have.
[0006]
In this embodiment, when the fan 3 rotates in reverse, a first air path is formed in the order of the outside air, the fan 3, the fixing device 1, the photosensitive drum 2a, and the outside air, as shown by the solid arrow in FIG. During normal rotation, a second air path is formed in the order of the outside air, the photosensitive drum 2a, the fixing device 1, the fan 3, and the outside air as shown by a dotted arrow in FIG. A second air path may be formed. In this embodiment, the temperature sensor 2b is disposed near the photoconductor drum 2a to detect the temperature near the photoconductor drum 2a. However, the temperature sensor 2b detects the temperature at any position in the apparatus or the temperature outside the apparatus. It may be arranged at a position where the temperature is detected. FIG. 2 shows a state in which a hole is provided on the side opposite to the fan 3 to provide air permeability.
[0007]
The operation of the electrophotographic apparatus having such a configuration will be described with reference to the flowchart of FIG.
First, the temperature at the time of turning on the power, at the time of returning from the sleep mode, or at the time of entering the warm-up is measured by the air temperature sensor 2b during the warm-up. In the present embodiment, the case where the power is turned on (step 1) and the temperature T1 at the time of turning on the power measured by the temperature sensor 2b is taken into the control circuit 4 (step 2) is described.
[0008]
After capturing the temperature T1, the control circuit 4 determines whether or not the temperature is higher than the reference temperature T2 stored in the storage medium 5 (step 3). A second air path is formed (step 4). This is an environment in which dew condensation does not occur on the photosensitive drum 2a when the temperature is equal to or higher than the reference temperature T2, and the air heated by the heater 1a of the fixing unit 1 is formed on the photosensitive drum 2a by forming a first air path. This is because there is no need to reduce the likelihood of dew condensation by sending.
[0009]
If it is smaller than T2, a time Ti for reversing the phone 3 is determined from a relation table of the temperature T1 and the reversal time of the fan 3 stored in the storage medium 5 or a correlation formula thereof (step 5). Then, the fan is rotated in reverse until the time Ti elapses to form a first air path (steps 6 and 7), and after the time Ti elapses, the fan is rotated forward to form a second air path (step 4). ).
[0010]
As described above, by forming the first air path for the time Ti determined based on the temperature T1, the air heated by the heater 1a of the fixing device 1 is blown to the photosensitive drum 2a in a low temperature state. The photosensitive drum 2a can be warmed. In addition, by determining the formation time of the first air path by using a table or calculation as in the present embodiment, the photosensitive drum 2a is not excessively heated, and the second air path is switched to the second air path after the elapse of the time Ti. By performing the switching, it is possible to perform control for preventing an increase in the temperature inside the apparatus.
[0011]
It should be noted that the time Ti based on the table or the calculation formula may be such that the lower the temperature T1 is, the longer the time becomes. Further, the control circuit 4 reads the temperature of the fixing roller 1b by the temperature sensor 1c when the power is turned on or when returning from the sleep mode, and when the read temperature is higher than a predetermined temperature, the power supply is turned off or the sleep mode is set. By judging that the standing time after the rush has not been long, and by controlling not to reverse the fan 3, it is possible to prevent an excessive rise in the temperature of the photosensitive drum 2a and the inside of the apparatus.
[0012]
【The invention's effect】
As described above, according to the electrophotographic apparatus of the present invention, by rotating the fan forward / reverse, the first air path, which is the air path from the fixing device to the photoconductor, and the photoconductor from the photoconductor, to the fixing device. By forming a second air path, which is an air path of the photoconductor, and forming the first air path during warm-up, heat generated in the fixing device can be sent to the photoconductor even when the temperature is low. An electrophotographic apparatus capable of preventing the formation of dew condensation can be provided. Furthermore, since there is no need to provide a special duct configuration, the number of parts can be reduced, and the size of the entire apparatus can be reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram showing the configuration of an electrophotographic apparatus according to the present invention.
FIG. 2 is a view showing an air passage in the electrophotographic apparatus of the present invention.
FIG. 3 is a flowchart showing an operation of the electrophotographic apparatus of the present invention.
[Explanation of symbols]
1: fixing device 1a: heater 1b: fixing roller 1c: temperature sensor 2a: photosensitive drum 2b: temperature sensor 3: fan 4: control circuit 5: storage

Claims (4)

An electrophotographic apparatus comprising: a photoreceptor that forms a toner image, a fixing device that fixes the toner image transferred onto paper, and a fan that generates an air path in the device.
By rotating the fan forward and reverse, a first air path from the fixing device to the photoreceptor and a second air path from the photoreceptor to the fixing device are formed. An electrophotographic apparatus, wherein the rotation of the fan is controlled so as to be the first air path during the up. 2. The electrophotographic apparatus according to claim 1, wherein the rotation of the fan is controlled so that the first air path is used at an end of the warm-up or at an arbitrary time before the end of the warm-up. 3. A temperature detecting means for detecting the temperature of the outside air or the inside of the machine is provided. 2. The electrophotographic apparatus according to claim 1, wherein the rotation of the fan is controlled so as to form a wind path. 4. The electrophotographic apparatus according to claim 3, wherein a rotation time of the fan for setting the first air path is set according to a temperature detected by the temperature detection unit.

Images