JP2000092279A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the image forming device provided with an optical system cooler adopting a simplified mechanism that properly cools an optical system as required. SOLUTION: The optical system cooler is provided with a cooling fan drive control means 19 and two cooling fans 20, 21, which are placed this side and the depth side of the cooler with an optical axis inbetween. The control means 19 receives an applied voltage adjusted and set by a light source controller 17 and the number of copies as input information and controls driving of the cooling fans 20, 21 when the applied voltage reaches a prescribed voltage or over or the number of copies is set to a prescribed number or over.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus such as a copying machine and a printer, and more particularly to a control system for an optical system cooling device.

[0002]

2. Description of the Related Art An original is illuminated by an illumination lamp, an original image formed by an image forming optical system is formed on a photoconductive photosensitive member to form an electrostatic latent image, and the electrostatic latent image is developed. An image forming apparatus for providing an obtained visible image for image formation is widely known as an analog copying machine, a digital copying machine, or the like.

As an illumination lamp for illuminating a document in such an image forming apparatus, generally, a halogen lamp or the like that generates high heat with light emission is used. The internal temperature of the image forming apparatus depends on the environmental temperature where the image forming apparatus is placed,
It tends to increase gradually under the influence of heat generation of the lighting lamp. When the internal temperature of the image forming apparatus rises, the temperature of the photoconductor also rises with it, but the photoconductive characteristics of the photoconductor generally decrease with an increase in the temperature of the photoconductor, and as the temperature of the photoconductor rises, the formation of the photoconductor increases. In general, the contrast (potential difference between the image portion and the background portion) of the generated electrostatic latent image decreases.

For this reason, an optical system has been cooled by a cooling fan for the purpose of reducing the temperature rise inside the image forming apparatus due to the heat generated by the illumination lamp. Conventionally, the cooling method of the optical system by the cooling fan is a "temperature control method" that controls the cooling fan so that the temperature near the optical system detected by a thermistor etc. is kept below a certain temperature, and the standby of the cooling fan driving efficiency `` Cooling efficiency switching method '' that switches between time and image formation, `` control method by the number of image formation '' that cools only when the number of image forming processes exceeds a certain number of times, Various methods have been proposed, such as a "temperature prediction method" in which a temperature rise is predicted and cooling is performed when the predicted temperature exceeds a certain value.

On the other hand, since the cooling of the optical system by the cooling fan is performed by taking in cooling air from outside the image forming apparatus, fine dust taken in with the cooling air is unavoidable. Attaches to surface.
Also, when the image forming apparatus is placed in an environment where a humidifier is used in winter, fine particles in which chlorine is adsorbed to nitrite are generated, and when these are taken into the image forming apparatus, they become fine white powder. It adheres to the mirror surface and lens surface of the optical system.
If the fine dust or the fine powder adheres to the mirror surface or the lens surface of the optical system, the light transmission efficiency in the optical system decreases, and it becomes impossible to form an electrostatic latent image with high contrast.

In order to prevent the above fine dust and fine powder from entering,
A fine dust intrusion prevention filter, which is an antistatic filter, is provided in the outside air inflow path of the cooling fan to prevent the dust. However, while preventing the entry of fine dust, the cooling efficiency is reduced, and if the dirt is severe, the temperature rise inside the optical system cannot be suppressed no matter how much the cooling fan is operated, so periodic inspection, cleaning, and replacement work Is done by a service person.

In order to compensate for the deterioration of the electrostatic latent image forming function caused by the "dirty of the optical system due to cooling", the light emission amount of the illumination lamp is increased according to the dirt of the optical system, Is compensated for the reduction of the imaging light reaching.

[0008]

However, when the amount of light emitted from the illumination lamp increases, the amount of heat also increases. For example, in the above-mentioned "temperature control method", the amount of heat generated increases with the amount of light emitted from the illumination lamp. As a result, the cooling time of the cooling fan increases, and the cooling efficiency increases.As a result, the amount of fine dust and fine particles taken in increases, and the tendency of the optical system to become dirty is sped up. is there. At the same time, the anti-static filter becomes dirty, lowering the cooling efficiency, and a vicious cycle is repeated after all.

In the "cooling efficiency switching method" and the "control method based on the number of times of image formation", complicated control means is required to obtain an appropriate cooling effect when the light emission amount of the illumination lamp is changed. . Similarly, the “temperature prediction method” also requires a complicated circuit for predicting a temperature rise due to a change in light amount.

Further, at present, in order to improve the operability, the reference of the original of the copying machine is mainly one-sided (the original is positioned in front of or behind the machine for positioning). In the case of the original, the temperature of the original placing surface of the contact glass (original mounting table) is lower to some extent because the original is lower than the temperature of the contact glass, so that the operator does not feel uncomfortable. The temperature of the glass surface remains high, not only discomforting the operator, but also causing a human disaster such as a burn.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides an image forming apparatus having an optical system cooling device which can appropriately cool an optical system as required and has a simple mechanism. The purpose is to provide.

[0012]

In order to achieve the above object, the invention according to claim 1 illuminates an original with an illumination lamp that changes in light emission amount according to an applied voltage and generates heat by light emission. The optical system that forms reflected light through a lens and the electrostatic latent image forming characteristics are detected, and the voltage applied to the illumination lamp is adjusted and set so that the amount of original illumination that forms an appropriate electrostatic latent image can be obtained. In an image forming apparatus including a light source control device for controlling the temperature of the illumination lamp and an optical system cooling device for reducing an increase in temperature due to heat generated by the illumination lamp, the optical system cooling device is in a direction parallel to or substantially equivalent to the optical axis of the illumination lamp. It has an arbitrary number of cooling fans and an antistatic filter arranged in the outside air inflow path of the cooling fans, and further has an applied voltage and a copy adjusted and set by the light source control device. The cooling fan drive control means for controlling the driving of the cooling fan so that the cooling fan is driven when the number of copies is input information and the applied voltage is equal to or more than a predetermined value or the number of copies is equal to or more than a predetermined value. It is characterized by having.

According to another aspect of the present invention, there is provided a computer system comprising:
In the invention described in claim 1, two or more cooling fans are provided, and the cooling fan drive control means determines that the voltage applied to the illumination lamp is a predetermined value or more, or the number of copies is a predetermined value or more. , The applied voltage increases,
The present invention is characterized in that the number of cooling fans is driven stepwise according to the increase in the number of executions of the image forming process.

According to another aspect of the present invention, the above object is achieved.
In the invention described in claim 1, two or more cooling fans are provided, and the cooling fan drive control means determines that the voltage applied to the illumination lamp is a predetermined value or more, or the number of copies is a predetermined value or more. , The applied voltage increases,
The present invention is characterized in that each cooling fan is alternately driven in accordance with an increase in the number of times the image forming process is performed.

According to another aspect of the present invention, there is provided an electronic apparatus comprising:
According to the invention described in any one of claims 1 to 3, the cooling fan drive control means, after the end of the copy or the end of the operation of the main body driving device, on the side opposite to the original reference side around the optical axis after the end of the copy. It is characterized in that only the cooling fan is driven.

As described above, the present invention provides an optical system that illuminates a document with an illumination lamp whose light emission amount changes according to an applied voltage and generates heat by light emission, and forms an image of the reflected light through a lens. A light source control device that detects the electrostatic latent image forming characteristics and adjusts and sets the voltage applied to the illumination lamp so that an original illumination amount that forms an appropriate electrostatic latent image is obtained. An image forming apparatus provided with an optical system cooling device for reducing the amount of light is characterized by the optical system cooling device.

The optical system cooling device has a cooling fan and a cooling fan drive control device. The cooling fan includes a fan and a driving device such as a motor for driving the fan, and at least one cooling fan is provided. The cooling fan drive control unit is a unit that controls the driving of the cooling fan, and is specifically configured as a CPU, a computer, or a control circuit. The cooling fan drive control means uses the applied voltage adjusted and set by the light source control device as input information, and drives the cooling fan when the inputted applied voltage reaches a predetermined value. Control the drive. Further, an antistatic filter is provided in the outside air inflow path of the cooling fan.

Two or more cooling fans can be provided. In this case, two or more fans can be driven by a common driving device. When two or more cooling fans independently driven by independent driving devices are provided, when the voltage applied to the illumination lamp exceeds a certain value, the applied voltage increases and the number of copies increases stepwise. May be controlled to increase the number of cooling fans to be driven.

That is, when a certain value of the applied voltage to the illumination lamp is A, a predetermined applied voltage higher than a certain value: A:
B (> A), C (> B),... Are set, and if the applied voltage exceeds a certain value: A, one cooling fan is driven, for example, and if the applied voltage exceeds B, cooling is performed. By driving two fans, the number of cooling fans to be driven is increased in a stepwise manner as the applied voltage increases.

In this case, it is considered practical that the number of cooling fans is two and a predetermined applied voltage B (> A) higher than a certain value A of the applied voltage to the illumination lamp is set. When the applied voltage is lower than a certain value, the cooling fan is not driven. When the applied voltage is higher than A and lower than B, one cooling fan is driven.
It is to drive individually.

In the drive control of the cooling fan, one of the cooling fans, which is always determined, is operated under the above condition (when the applied voltage is A
As described above, since the designated cooling fan is driven when the value is less than B, only the antistatic filter corresponding to the cooling fan advances the dirt quickly. In order to prevent this, the number of executions of the image forming process (the number of copies) is managed.
In 2000 times, it is also possible to alternately drive the other cooling fan B.

As described above, the adjustment setting of the applied voltage to the illumination lamp is performed by the light source control device. The timing of performing the adjustment setting of the applied voltage can be various modes. For example, the adjustment setting of the applied voltage can be performed each time the main switch of the image forming apparatus is turned on. A practical timing for performing the adjustment setting of the applied voltage is that the adjustment is performed when the temperature of the photoconductor becomes equal to or higher than a predetermined value and / or every time the image forming process is performed a predetermined number of times.

That is, attention may be paid to the temperature of the photoreceptor, and when the temperature of the photoreceptor exceeds a predetermined value, the adjustment setting of the voltage applied to the illumination lamp may be performed. May be adjusted each time a predetermined number of times are performed.

The predetermined number of times the image forming process is performed in this case is, for example, several tens to several hundreds, or
The predetermined number of times can be set in a wide range of about 00, and the predetermined number may be changed according to the season according to the seasonal change of the environment where the image forming apparatus is placed. Alternatively, focusing on both the temperature of the photoconductor and the number of times the image forming process is performed, the image forming process corresponds to at least one of the fact that the temperature of the photoconductor has exceeded a predetermined value and that the image forming process has been performed a predetermined number of times. At this time, the adjustment setting of the voltage applied to the illumination lamp may be performed.

Next, the operation of the present invention will be described. In the present invention, the applied voltage that regulates the light emission amount of the illumination lamp is determined by the electrostatic latent image characteristic as described above. That is, the voltage applied to the illumination lamp is adjusted and set to a value such that an appropriate electrostatic latent image is formed according to the electrostatic latent image characteristics. When the voltage applied to the illumination lamp exceeds a predetermined value,
When the amount of heat accompanying the light emission of the illumination lamp exceeds a certain level, the optical system is cooled by a cooling fan. When the set value of the voltage applied to the illumination lamp is set by the above-mentioned adjustment setting, the set value is maintained until it is newly set.

In the morning, when the set value of the applied voltage is equal to or more than a certain value while the main switch of the image forming apparatus is turned on, or as a result of the adjustment setting of the applied voltage, a new adjustment setting is performed. When the applied voltage exceeds a certain value, it is conceivable to immediately drive the cooling fan,
In such a state, the illumination lamp is not always turned on. Since the cooling by the cooling fan may be performed when the illumination lamp is actually turned on, the cooling fan is driven only when the applied voltage exceeds a certain value and the image forming process is executed.

[0027]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a main part configuration diagram of an image forming apparatus showing an embodiment of the present invention. This image forming apparatus is an analog electronic copying apparatus. A reference pattern 2 is provided on a side of a contact glass 1. An exposure optical system is arranged below the contact glass 1.

The exposure optical system includes an illumination lamp 3, a mirror 4,
A roof mirror 5, an imaging lens 6, a fixed roof mirror 7, a fixed mirror 8, a dustproof glass 9, and the like are provided. A photoreceptor 10 is provided below the optical system. Around the photoreceptor 10, a charging device 11, an electrometer 12, a developing device 13, a transfer device 14, an electrometer 15, and a cleaning device 1 as electrophotographic process means.
6 and others.

Further, a light source control device 1 for adjusting and setting a voltage applied to the illumination lamp 3 so as to obtain an original illumination amount for forming an appropriate electrostatic latent image by detecting an electrostatic latent image forming characteristic.
7 is provided. The power supply 18 is controlled by the light source control device 17 to adjust the applied voltage of the illumination lamp 3. Further, a cooling fan drive control unit (hereinafter, simply referred to as a control unit) 19 and two cooling fans 20 and 21 are provided as an optical system cooling device.

The light source control device 17 and the control means 19 can be specifically configured as a CPU, a computer, or a control circuit. In terms of hardware, the light source control device 17 and the control means 19 are used as control boards on the same board. Can be assembled.

An original O to be copied is placed on the contact glass 1. The illumination lamp 3 illuminates and scans the original while moving rightward in the figure together with the mirror 4.
The reflected light flux from the original is turned back by the roof mirror 5 which is displaced rightward in the figure at half the moving speed of the mirror 4, is transmitted back through the imaging lens 6, is turned back by the fixed roof mirror 7, and is returned by the fixed mirror 8. Is reflected by Then, an original image is formed on the photoconductive photoconductor 10 via the dustproof glass 9 provided on the partition plate 24.

The partition plate 24 prevents stray light from the side of the exposure optical system at the upper portion of the apparatus from affecting the photosensitive member 10 and, at the same time, radiates heat from the illumination lamp 3 in the exposure optical system as much as possible. Is provided so as not to affect.

The photosensitive member 10 is drum-shaped, rotates clockwise at a constant speed when the above-described exposure is performed, and is uniformly charged to a predetermined potential by the charging device 11. That is, the charging potential of the photoconductor 10 is detected by the electrometer 12, and the charging device 11 is controlled so that the detected potential gives a predetermined potential. When the uniformly charged photoreceptor 10 is irradiated with the image of the original as described above, an electrostatic latent image corresponding to the original image is formed.

This electrostatic latent image is developed by the developing device 13 to become a visible image. The transfer paper S is sent to a transfer section by a belt-type transfer device 14 in synchronization with the movement of the visible image due to the rotation of the photoconductor 10, and the visible image is transferred. The transfer paper S to which the visible image has been transferred is fixed with the visible image by a fixing device (not shown) and is discharged out of the device. The above is the outline of the image forming process.

FIG. 2 is a top view of the image forming apparatus shown in FIG. This figure shows the exposure optical system and the cooling fans 20 and 2
1 illustrates a positional relationship between the electrostatic filter 1 and the electrostatic filters 22 and 23 and a state where cooling air is passed by the cooling fans 20 and 21.
When the cooling fans 20 and 21 are driven, air sucked from outside the device flows as cooling air as shown by arrows, and cools the optical system. The cooling fans 20, 21 are arranged before and after the machine with the optical axis as the center. In the case of FIG. 2, the document O is abutted against the document reference (back left) and is placed on the contact glass 1.

Next, referring to FIG.
The detection of the electrostatic latent image forming characteristic and the adjustment setting of the voltage applied to the illumination lamp 3 will be described. The detection of the electrostatic latent image forming characteristic is performed when the image forming process is not performed.
At this time, the photoconductor 10 is uniformly charged to a predetermined potential: V0 by the charging device 11, and then the exposure lamp 3 irradiates the image of the reference pattern 2. The reference pattern 2 has a predetermined reference density. The irradiation of the reference pattern 2 causes the formed electrostatic latent image to move with the rotation of the photoconductor 10 without being developed, and is detected by the electrometer 15 as a reference ground potential: VL.

The potential detected by the electrometer 15: VL
Is input to the light source control device 17. Light source control device 17
Calculates the potential difference: ΔV = (V0−VL). potential:
Since V0 is constant, the potential difference: ΔV changes in accordance with the potential: VL, and the smaller the potential difference: ΔV, the worse the electrostatic latent image forming characteristics.

As described above, there are two main causes of the deterioration of the electrostatic latent image forming characteristic. One is dirt on the mirror surface and the lens surface in the exposure optical system, and one is a rise in the temperature of the photosensitive member 10. Is a decrease in photoconductive properties.

Therefore, the temperature T of the photoconductor 10 is input to the light source control device 17 together with the potential VL.
Temperature: T is detected by a thermistor. The light source control device 17 previously determines the photoconductor temperature: T and the potential difference: ΔV,
To form a proper electrostatic latent image in the current situation,
A table of applied voltages to be applied to the illumination lamp 3 or an arithmetic expression for calculating the applied voltage based on the photoconductor temperature: T and the potential difference: ΔV is stored.
Appropriate applied voltage based on input value of T and potential difference: ΔV:
Determine V. Then, the determined applied voltage: V is set in the power supply 18. The power supply 18 may be a DC power supply or an AC power supply. The above is the adjustment setting of the voltage applied to the illumination lamp 3.

FIG. 3 is a flowchart showing an example of the adjustment setting of the voltage applied to the illumination lamp. When the power is turned on (S
0), the temperature: T of the photoconductor 10 is detected by the thermistor, and this temperature: T is set to a predetermined temperature: t
(Temperature at which substantial degradation of the photoconductive property starts) (S1).

When T ≧ t (Y in S1), the above-described electrostatic latent image forming characteristic is always detected (S2), and the adjustment setting of the voltage applied to the illumination lamp 3 is performed (S3). When T <t (N in S1), the number of times the image process is executed: N (counted by the counter and reset to 0 when the applied voltage is newly adjusted and set) is 1000.
It is determined whether the number of times has been reached (this determination is performed by the light source control device 17) (S4).

Even when the condition of N = 1000 is satisfied (Y in S4), the above-described electrostatic latent image forming characteristics are always detected, and the adjustment setting of the voltage applied to the illumination lamp 3 is performed. When T <t (N in S1) and N <1000 (N in S4), the applied voltage adjusted and set last time is maintained (S5).

FIG. 4 is a flowchart showing a first example of drive control of the cooling fan. When the copy start key for executing the image forming process is turned on in a state where the power of the image forming apparatus is on (S10), the same as the voltage applied to the illumination lamp 3 is set to the power supply 18 The applied voltage: V is transmitted from the light source control device 17 to the control unit 1.
9 and the control means 19 compares a predetermined value of the voltage: v with the input voltage: V (S1).
1).

If V <v (N in S11), the amount of light emitted from the illumination lamp 3 is relatively small and the amount of heat generated is also small (v is set to satisfy such a condition). Then, the copying operation is started (S14) without driving the cooling fans 20, 21 and keeping the cooling fan off (S12).

When V ≧ v (Y in S11), since the amount of light emitted from the illumination lamp 3 is large, the control means 19
The cooling fans 20, 21 are driven (S13). Then, in this state, the copy operation is started (S14).

FIGS. 5 and 6 show a second example of the drive control of the cooling fan.
It is a flowchart which shows the example of. In the control means 19, 2
Two applied voltage values: v, w (> v) are set, and when the input voltage: V satisfies w> V ≧ v (S20, S
21, Y in S22, Y in S23), drive the cooling fan 20 (S24), and when V ≧ w (N in S23), drive the cooling fans 20, 21 together (S25).
By doing so, it is possible to perform cooling more in accordance with the amount of heat generated by the illumination lamp 3. If V is smaller than v (S2
2 and N), the cooling fans 20 and 21 are turned off (S2).
6). Then, the copy starts (S27).

Alternatively, in each of the above cases (when a certain value of the voltage is v, v, w), when the input voltage: V exceeds a certain value: v, the input voltage: V increases. Accordingly, the rotation speed of cooling fan 20 and / or cooling fan 21 may be increased stepwise and / or continuously.

When copying is completed (S28), the original size: X is compared with a predetermined original size: x (S29). If X> x (Y in S29), both cooling fans 20, 21 are set. The machine is stopped (S30), and then the machine is also stopped (S31). If X ≦ x (N in S29),
The cooling fan 21 is operated (S32), and operates for a predetermined operation time, and thereafter, is stopped. The operation time is a few seconds and the operation is not performed for a long time.

The determination of the document size is performed based on a document size detection (not shown) or a signal from a document feeder. Thus, the temperature difference between the surface of the contact glass where the document is not placed (the hatched portion in FIG. 2) and the surface of the contact glass where the document is placed (the other portion in FIG. 2) is not widened. Can be.

[0050]

According to the first aspect of the present invention, the cooling fan is provided only when the heat generation of the illumination lamp is constant while satisfying the condition that an appropriate electrostatic latent image is formed on the photoconductive photosensitive member. , Driving of the cooling fan can be minimized, energy consumption can be suppressed, and the configuration of the image forming apparatus can be simplified.

According to the second aspect of the present invention, when driving the cooling fan, it is possible to perform cooling according to the heat generated by the illumination lamp.

According to the third aspect of the present invention, since each cooling fan is driven in response to an increase in the number of executions of the image forming process, unidirectional contamination of the antistatic filter can be prevented.

According to the fourth aspect of the present invention, the operability can be improved without giving the operator handling the document an uncomfortable feeling due to the heat on the contact glass.

[Brief description of the drawings]

FIG. 1 is a main part configuration diagram of an image forming apparatus showing an embodiment of the present invention.

FIG. 2 is a top view of the image forming apparatus shown in FIG.

FIG. 3 is a flowchart illustrating an example of an adjustment setting of a voltage applied to an illumination lamp.

FIG. 4 is a flowchart showing a first example of drive control of a cooling fan.

FIG. 5 is a flowchart (part 1) illustrating a second example of drive control of the cooling fan.

FIG. 6 is a flowchart (part 2) illustrating a second example of drive control of the cooling fan.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Contact glass 2 Reference pattern 3 Illumination lamp 4 Mirror 5 Dach mirror 6 Imaging lens 7 Fixed roof mirror 8 Fixed mirror 9 Dustproof glass 10 Photoreceptor 11 Charging device 12, 15 Electrometer 13 Developing device 14 Transfer device 16 Cleaning device 17 Light source control Device 18 Power supply 19 Control means 20, 21 Cooling fan 22, 23 Electrostatic filter

Claims (4)

[Claims] 1. An optical system that changes the amount of light emission according to an applied voltage and illuminates a document with an illumination lamp that generates heat by light emission, forms an image of reflected light through a lens, and detects an electrostatic latent image forming characteristic. And a light source control device that adjusts and sets the voltage applied to the illumination lamp so as to obtain an original illumination amount that forms an appropriate electrostatic latent image, and an optical system for reducing a temperature rise due to heat generation of the illumination lamp. An image forming apparatus having a cooling device, wherein the optical system cooling device is arranged so as to draw in outside air from a direction parallel to or substantially equivalent to the optical axis of the illumination lamp, and an arbitrary number of cooling fans and cooling fans. It has an antistatic filter arranged in the outside air inflow path, and further uses the applied voltage and the number of copies adjusted by the light source control device as input information, and the applied voltage is a predetermined value or more, or As several drives a cooling fan when it is above a certain value of a given image forming apparatus characterized by having a cooling fan drive control means for controlling the driving of the cooling fan. 2. The cooling fan drive control unit according to claim 1, wherein two or more cooling fans are provided, and the cooling fan drive control means determines that the voltage applied to the illumination lamp is equal to or higher than a predetermined value or the number of copies is equal to or higher than a predetermined value. An image forming apparatus that drives a number of cooling fans according to an increase in an applied voltage and an increase in the number of executions of an image forming process. 3. The cooling fan according to claim 1, wherein two or more cooling fans are provided, and the cooling fan drive control means determines that the voltage applied to the illumination lamp is equal to or more than a predetermined value or the number of copies is equal to or more than a predetermined value. An image forming apparatus that drives each cooling fan alternately according to an increase in an applied voltage and an increase in the number of executions of an image forming process. 4. The cooling fan drive control means according to claim 1, wherein the cooling fan drive control means is provided on the side opposite to the document reference side with respect to the optical axis after the copy or the operation of the main body drive device. An image forming apparatus characterized by being driven only.