JPH06208273A - Exhaust fan controller for image forming device - Google Patents

Abstract

PURPOSE:To provide the exhaust fan controller for an image forming device which is operated without receiving the limitation on the discharge rate from a housing even if the image forming device is disposed in a place where discharge is insufficient. CONSTITUTION:Both flanks of the housing 1 are provided with a first discharge aperture 20 and a second discharge aperture 21 held closed by an opening/closing means 25. An air quantity detecting means 29, a variable speed driving means for driving an exhaust fan 4, a rotating speed detecting means for the fan 4, an energizing means 27 for changing over the opening/closing means 25 to an open state and a warning means indicating the insufficient state of the exhaust rate are connected to a control means. This control means opens the opening/closing means 25 by detecting that the rotating speed of the fan exceeds the upper limit of the rotating speed by a set value, thereby opening the second exhaust aperture 21 and increasing the discharge air quantity. The warning means is energized if the detected air quantity in this state is not restored within the set value width of the air quantity.

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 or a laser printer, for discharging heat generated by an illumination system in the housing of the apparatus, a photoconductor charger, a transfer charger, etc. The present invention relates to an exhaust fan control device that discharges ozone generated from the outside.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus of the type in which a photosensitive member is subjected to corona charging, exposure, development, transfer, peeling and fixing processes, the exposure device is turned on and heat generated by the fixing device causes Since the temperature inside the housing rises and the electrostatic characteristics of the photoconductor fluctuate, which significantly affects the image quality, a cooling fan that constantly rotates at a constant speed is provided inside the housing to suck the outside air and cool the inside of the housing. I am trying.

Since this cooling fan always rotates at a constant speed, it constantly scatters a certain level of noise to the surroundings and causes a problem that the photosensitive member or the like is contaminated by suction of a certain amount of dust. In JP-A-3-144667, the temperature inside the housing is detected by a thermistor or the like, the detected values are compared by a multistage comparison circuit, and the rotation speed of the cooling fan is controlled according to the comparison result. Further, in a normal copying machine, since the exhaust air from the exhaust port is hot air or is exhausted with ozone having a peculiar irritating odor generated from a corona charger, a transfer charger, etc., normally, The housing is provided with only one exhaust port so as not to cause discomfort to the operator or people around.

[0004]

However, when the copying machine is installed by arranging the exhaust port provided in the housing close to the wall or the back surface of the locker, the temperature inside the housing is detected and the detected result is obtained. Even if the fan rotation control is performed accordingly, exhaust cannot be performed sufficiently because the wall becomes an obstacle and the exhaust volume is limited, which causes deterioration of image quality and temperature rise. Accordingly, there is a problem that the safety device operates. In particular, in the case of a small machine, since it is easy to move, it is apt to be installed in a corner from the viewpoint of space saving, which results in a reduction in exhaust volume and the above-mentioned problems.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to operate the image forming apparatus without being restricted by exhaust gas even if the image forming apparatus is arranged in a place where exhaust gas is insufficient. Another object is to provide an exhaust fan control device for an image forming apparatus.

[0006]

SUMMARY OF THE INVENTION According to the present invention, the internal air is provided from a first exhaust opening provided on one side surface of the housing with a fan driven by a variable speed driving means provided in the housing. In an exhaust fan control device for an image forming apparatus that exhausts air outside the body, a second exhaust opening provided on a side surface different from one side surface of a housing, an opening / closing means for opening and closing the second exhaust opening, and a control means. In addition, the control means includes an air volume detection means for detecting the exhaust air volume from the housing, a rotation speed detection means for detecting the rotation speed of the fan driven by the variable speed drive means, and an opening / closing means in a closed state. Is connected to an urging means for switching from the open state to the open state and a warning means for indicating an insufficient state of the exhaust air volume from the first and second exhaust openings, and the control means controls the exhaust air volume detected by the air volume detection means to the air volume. Within the set value range The rotation speed of the variable speed drive means is controlled so as to enter, and when the fan rotation speed detected by the rotation speed detection means exceeds the rotation speed upper limit set value, the biasing means is biased to open the opening / closing means. Then, the second exhaust opening is opened, and the second exhaust opening is opened to control the warning means when the air volume detected by the air volume detection means does not return to within the air volume set value range.

[0007]

In the state where the first exhaust opening of the housing is arranged close to the wall, the wall serves as an obstacle to the first exhaust opening, so that the air volume detected by the air volume detecting means is reduced, but the variable speed is variable. The fan speed is increased by controlling the rotation speed so that the drive means falls within the air volume setting price range. When the first exhaust opening is arranged closer to the wall, the decrease in the air volume due to this is detected, and the rotation speed of the variable speed drive means is increased. When this rotation speed exceeds the rotation speed upper limit value, the urging force is applied. The means is urged to open the opening / closing means, and the second exhaust opening is also used for exhaust. If the detected air volume does not return to within the air volume set value range even if the second exhaust opening is opened, the warning means is activated.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below based on the embodiments shown in the accompanying drawings. 1 is a front view of a copying machine according to an embodiment of the present invention, FIG. 2 is a plan view of the copying machine installed close to a wall when viewed from the direction of arrow P in FIG. 1, and FIG. 3 is an electric circuit of an exhaust fan control device. It is a block diagram. In FIG. 1, an illumination lamp 2 for document exposure is provided in an upper portion of a casing 1 of a copying machine, which is partitioned by a partition wall 11.
In the lower part of 1, there is provided a photoconductor 7 having a charger 5 and a transfer charger 6 arranged on the outer periphery thereof. And the partition wall 11
Exhaust device 3 for exhausting heat M1 generated from the illumination system in the upper part of the casing and ozone M2 generated at the time of charging by the chargers 5 and 6 in the lower part of the partition wall 11 to the outside of the housing 1 together with the sucked outside air. Is provided. In the figure, reference numeral 4 is a fan of the exhaust device 3, 8 is a paper guide portion, 9 is a fixing device, and 10 is a paper receiver after fixing.

FIG. 2 shows a state in which the rear side of the casing 1 of the copying machine shown in FIG. 1 is disposed close to the wall 19, and the heat inside the casing 1 is provided on the rear side of the casing 1. Also, a rear exhaust port 20 for exhausting ozone to the outside is provided, and a side exhaust port 21 for increasing the exhaust air volume is also provided on the side surface of the housing 1. A case 23 is disposed so as to face the back exhaust port 20 and the side exhaust port 21, and a back opening 22 and a grid are provided on the side surface of the case 23 that faces the back exhaust port 20 and the side exhaust port 21. Side opening 2 with a large number of ventilation openings
4 is provided, and an ozone decomposition filter 28 and an exhaust fan 4 are sequentially arranged from the exhaust air upstream side. Further, on the side surface of the case 23 on the upstream side of the exhaust fan 4, for example, an orifice (measuring fluid throttle mechanism used in the flow meter) is provided, the fluid pressures on the upstream side and the downstream side are detected, and the difference between them is detected. A differential pressure type air volume detector 29 of the type that detects the air volume from the pressure is provided. A shutter 25 having a large number of ventilation holes is provided in a space between the side exhaust port 21 and the side opening 24 so as to be openable and closable, and one end of the shutter 25 has a spring 26 connected to a fixing member provided in the case 23.
The other end of the shutter 25 is connected to a solenoid 27 fixed to the side wall of the housing 1. Then, when the solenoid 27 is excited, the shutter 25 is displaced downward, the ventilation hole of the side opening 24 and the ventilation hole of the shutter 25 are aligned, and the internal air is exhausted to the outside. In addition,
Reference numerals 20A and 21A in the figure denote wind deflecting members.

In FIG. 3, an air volume detector 29 is connected via an amplifier 31 to the input side of a control unit 32 formed by a memory and a CPU, and the output side thereof is connected to the air volume detector 29. PWM that modulates to a pulse width signal corresponding to the amplitude of the deviation signal between the air volume detection signal and the air volume setting value
A variable speed motor 36, which receives a control signal output from the modulator through a filter 34 and a power amplifier 35, is connected to control the rotation speed so that the control signal is within the air flow rate set value range.
The fan 4 is attached to the motor 36, and
For example, a photoelectric conversion type rotation speed detector 37 that detects the rotation speed of the fan is provided, and a detection signal of the rotation speed detector 37 is input to the control device 23. And the rear side opening 20
The rotation speed of the fan 4 is increased so that the exhaust air flow rate from the air flow rate falls within the air flow rate setting value range (F ₀ ± α), and when the fan rotation speed exceeds the rotation speed upper limit value N _L , the solenoid 27 is excited. Control signal to solenoid 2 via driver 40
6 is input, the shutter 25 is opened, and the side exhaust port 21 can also exhaust gas. Shutter 25 described above
Even if the air is exhausted from the side exhaust port 21 by driving, the amount detected by the air volume detector 29 is within the air volume set value range (F ₀ ±
If it does not return to α), the excitation signal is input to the light emitting diode 39 provided on the console panel via the driver 38.

FIG. 4 is a functional block diagram of the control device 32. The PWM control section 32C includes a detection signal from the air volume detector 29 and an air volume set value (F ₀ ± α) in the air volume set value storage section 32B. Is compared in the air volume comparison unit 32A, the deviation signal is compared in amplitude with a triangular wave generator (not shown) of the PWM control unit 32C, the comparison result signal is input to the variable speed motor 36, and the fan 4 is output. Within the air flow setting value range (F ₀ ± α)
Rotation speed control is performed so that it enters.

The rotation speed comparison unit 32D compares the rotation speed detection signal of the fan 4 from the rotation speed detector 37 with the upper limit rotation speed N _L stored in the upper limit rotation speed storage unit 32E of the fan 4, and When it exceeds the upper limit rotation speed value N _L , control is performed to output an excitation signal to the solenoid 27 that opens the shutter 25. Then, in the failure determination unit 32F, when it is determined that the solenoid 27 is excited to open the side exhaust port 24 and exhaust from the rear side exhaust port 20 and the side exhaust port 21 does not reach the air volume set value range. Outputs an excitation signal to the light emitting diode 39, and the variable speed motor 3
6 and the solenoid 27 are turned off.

The operation of the apparatus constructed as described above will be described with reference to FIG.
6A to 6C, and (I) air volume, (II) fan rotation speed, (II)
This will be described with reference to (I) solenoid output and (IV) timing chart of display output. As shown in FIG. 6A, when the back side of the casing 1 of the copying machine is not installed near the wall, the variable speed motor 36 is driven at time t0 (step S1), and the variable speed motor 36 is controlled by PWM. Three
In No. 6, the rotation speed is controlled so that the air volume detected by the air volume detector 29 is within the air volume installation value range (F ₀ ± α), and when it is within the set air volume value range, it is rotationally driven at the rotation speed N _0. (Step S2).

FIG. 6B shows that the housing 1 is placed on the wall 19 at time t1.
When the housing 1 is brought close to the wall 19 at time t1, the wall 19 becomes an obstacle to the exhaust air from the rear exhaust port 20, so that the air volume is increased. The air volume from the detector 29 does not return to within the set value range (F ₀ ± α) (step S2).
The rotation speed of the variable speed motor 36 is gradually increased from 2 (step S3), and when it is determined that the rotation speed of the fan 4 does not exceed the upper limit set value N _L (step S3).
4), the decreased detected air volume is within the air volume setting value range (F ₀ ± α)
It is discriminated whether or not the operation has been returned to step S6, and if YES (step S5), the operation is continued in this state thereafter.

Next, FIG. 6 (C) shows a case in which the casing 1 is further brought closer to the wall 19 at the time t1 and the copying machine is arranged. During the time t0 to t2, FIG. ), But since the wall 19 becomes a larger obstacle to the exhaust of the fan 4, the detected air volume further decreases from the time t1,
In step S2, it is determined that the variable speed motor 36 has not reached the air volume set value range, and in step S3, the variable speed motor 36 is gradually increased in speed from the time t2. Nevertheless, step S4
At time t3, if it is determined that the rotation speed of the motor 36 exceeds the upper limit value N _L , the solenoid 27 is turned on at time t4.
To the side surface exhaust port 21 of the housing 1 and the side surface opening 24 of the case 23 to communicate with each other (step S6). As a result, in addition to the exhaust from the rear exhaust port 20 in the direction of the dotted arrow A, the exhaust from the side exhaust port 21 in the direction of the dotted arrow B,
For this reason, the flow quickly returns to within the air volume setting value range (F ₀ ± α) (step S7).

FIG. 7 shows that even if the operation shown in FIG.
It shows the case where an exhaust obstacle is located at the side exhaust port 21 or the shutter 25 fails to open sufficiently,
Since the rotational speed of the fan 4 exceeds the upper limit value N _L at time t3, even if the excitation signal is input to the solenoid 27 and the shutter 25 is opened in step S6, the detected air volume is within the air volume installation value range (F ₀ Since it has not returned to (± α) (step S7), an excitation signal is input to the light emitting diode 39 to display a warning (step S8), and the variable speed motor 3
6. The voltage applied to the solenoid 27 is cut off.

In this embodiment, the fan rotation speed is directly detected and controlled. However, the fan rotation speed is detected by a current value or a voltage value which is a substitute characteristic, and the detected value is an upper limit value. The operation of the biasing means may be controlled depending on whether or not it exceeds. Also,
In this embodiment, the side surface opening is provided on the transfer paper discharge side, but the side surface opening may be provided on the opposite side surface. In this case, the operability of the shutter does not adversely affect the storability of the discharged transfer paper. Also, instead of the optical display, it is also possible to display a warning display by a warning sound.

[0018]

As described above, according to the present invention, in addition to the first exhaust opening which is always open in the housing of the image forming apparatus, the second opening which is always closed by the opening / closing means and opened when necessary. Since the exhaust opening is provided, even if the image forming apparatus is installed in a location where the exhaust state of the first exhaust opening is poor, the fan rotation speed driven by the variable speed drive means is the upper limit of the rotation speed. After opening, open and close the opening and closing means
It is possible to open the exhaust opening of, and to exhaust from the second exhaust opening in addition to the exhaust from the first exhaust opening.
The image quality is maintained in a predetermined state, and the image quality is not adversely affected. Further, when the exhaust air volume does not return to within the air volume set value range even if the second exhaust opening is opened, the downtime of the image forming apparatus can be shortened by issuing an abnormality warning.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a device according to an embodiment of the present invention seen through from the front.

FIG. 2 shows a main part of an apparatus according to an embodiment of the present invention as indicated by arrow P in FIG.
It is the top view seen from the direction.

FIG. 3 is an electric circuit block diagram of an apparatus according to an embodiment of the present invention.

FIG. 4 is a functional block diagram of a control device of the device according to the embodiment of the present invention.

FIG. 5 is a flowchart of an apparatus according to an embodiment of the present invention.

6A to 6C show a case where the apparatus of the embodiment of the present invention is normal, a case where the back side of the housing is arranged close to the wall, and a case where the case back is arranged closer to the wall. It is a control timing chart.

FIG. 7 is a control timing chart in the case of displaying an abnormality of the device according to the embodiment of the present invention.

[Explanation of symbols]

1 copier housing, 2 exposure lamp, 3 exhaust device, 4
Fans 5 and 6 charger, 7 photoconductor, 9 fixing device, 20 rear exhaust port, 21 side exhaust port, 22 rear opening provided in case 23, 24 side opening provided in case 23, 25 shutter, 27 solenoid, 28 ozone decomposition filter, 29 air flow detector, 32 controller, 36 variable speed motor, 39 light emitting diode.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03B 27/52 B 8102-2K

Claims (1)

[Claims] 1. An image forming apparatus in which internal air is exhausted to the outside of a housing from a first exhaust opening provided on one side surface of the housing by a fan driven by a variable speed drive means provided in the housing. And a second exhaust opening provided on a side surface different from the one side surface of the housing, an opening / closing means for opening and closing the second exhaust opening, and a control means. The control means includes
Air volume detection means for detecting the exhaust air volume from the housing, rotation speed detection means for detecting the rotation speed of the fan driven by the variable speed drive means, and energizing for switching the opening / closing means from the closed state to the open state. Means and warning means for indicating an insufficient state of the exhaust air volume from the first and second exhaust openings are connected, and the control means controls the exhaust air volume detected by the air volume detection means within the air volume set value range. The rotation speed of the variable speed drive means is controlled so as to enter, the fan rotation speed detected by the rotation speed detection means is detected to exceed the rotation speed upper limit set value, and the biasing means is biased to open / close means. To open the second exhaust opening and open the second exhaust opening to control the warning means when the air volume detected by the air volume detection means does not return to within the air volume set value range. Featuring Exhaust fan controller in forming apparatus.