JP3308122B2 - Image forming device - Google Patents

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 facsimile, and more particularly to an electrophotographic image forming apparatus.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus, corona discharge is performed in a latent image forming step, an image transferring step, and the like, so that ozone and NOx (nitrogen oxide) are generated in the apparatus. These discharge products adversely affect the photoreceptor and cause abnormal images such as blurred images and white spots.

[0003] Various image forming apparatuses have been proposed to prevent the effects of discharge products on the photoreceptor.

[0004]

However, in such a conventional image forming apparatus, it is intended to suppress the influence on the photoreceptor by the discharge products such as ozone and NOx generated in the apparatus. If the air introduced from the outside of the apparatus contains NOx or the like, it cannot be handled. That is, when a petroleum stove or the like is used in winter, the NOx concentration in the room increases, and may be as high as about 10 ppm. In such an environment, when an image forming apparatus configured to introduce air outside the photoconductor near the photoconductor is used, high-concentration NOx affects the photoconductor,
There is a problem that an abnormal image such as image blur or white spots occurs.

An object of the present invention is to solve the above-mentioned problems in the conventional image forming apparatus and to provide an image forming apparatus which does not generate an abnormal image such as image blur or white spots even in a high-density NOx environment. And

[0006]

According to the present invention, in an image forming apparatus having a photosensitive member and an outside air introduction mechanism, a humidifying means for humidifying introduced outside air in an outside air introduction path of the outside air introduction mechanism is provided. And a means for adjusting the humidification amount of the humidification means, and a nitrogen oxide concentration measurement means for measuring the nitrogen oxide concentration of the outside air around the device or the outside air introduced into the device. Is controlled according to the measurement result of the nitrogen oxide concentration measuring means.

Further, the present invention proposes that in order to solve the above-mentioned problem, the humidification amount adjusting means is controlled in accordance with an image forming operation.

Further, in order to solve the above-mentioned problems, the present invention proposes that the outside air introducing mechanism has a suction fan, and the humidification amount adjusting means is controlled according to the operation of the fan.

In order to solve the above-mentioned problems, the present invention further comprises a temperature measuring means for measuring the temperature inside the apparatus, wherein the humidifying amount adjusting means is controlled in accordance with the measurement result of the temperature measuring means. Suggest.

Further, the present invention proposes, in order to solve the above-mentioned problem, that the humidifying means has a storage container for storing water and a heating means for heating the water in the storage container.

Further, the present invention proposes, in order to solve the above-mentioned problem, that the humidifying means has a storage container for storing water and a means for emitting high frequency to water in the storage container. .

[0012]

The humidifying means is installed in the outside air introduction path of the outside air introduction mechanism provided in the image forming apparatus to humidify the introduced outside air.
Thus, the concentration of nitrogen oxides contained in the introduced outside air is reduced, and the influence on the photoconductor is prevented.

Other effects will be apparent from the following description of the embodiments.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a color copying machine according to an embodiment of the present invention. This color copier 100
Is composed of a color image reading unit (hereinafter, referred to as a color scanner) 1 and a color image recording unit (hereinafter, referred to as a color printer) 2.

FIG. 2 is an enlarged view showing the vicinity of the photosensitive member of the color printer 2.

Although the details of the color scanner 1 and the color printer 2 will be described later, FIG.
Is provided. That is, the photoconductor 9 disposed substantially at the center of the color printer 2
An intake duct 41 for guiding outside air to the vicinity is provided. A suction fan 40 is provided at a suction port of the duct 41. The air sucked from outside the machine by the suction fan 40 is guided to the duct 41 and is blown onto the surface of the photosensitive drum 9 from above the charger 12. This blowing system uses ozone generated by the discharge of a charger, etc.
This is for eliminating NOx and the like. Reference numeral 19
Denotes an intermediate transfer belt provided adjacent to the photoconductor 9.

By the way, a humidifying means as shown in FIG. 4 is provided in the middle of the suction duct 41. The humidifying means includes a water storage container 4 provided in the middle of the duct.
3 is installed. As the water storage container 43, for example, a can can be used. As described above, the water storage section 42 is provided in the middle of the duct 41 for guiding the outside air to the vicinity of the photoconductor 9.
By disposing the water storage container 43 with the
The inflow air can be humidified by utilizing the natural evaporation of water in the photoreceptor 3, and even if the atmosphere outside the apparatus is in a high-concentration NOx environment, the NOx concentration of the air blown to the photoreceptor 9 is reduced. Can be. For this reason, it is possible to prevent adverse effects on the photoconductor 9 due to NOx in the outside air. The reason why the NOx concentration decreases when the humidity increases is that NOx bonds with water molecules in the air. Then, when all the water in the storage container 43 has been consumed (evaporated), the container may be replaced or water may be supplied.

Since the water container is merely arranged in the suction duct 41, the inflow air can be humidified at low cost. Further, the water storage container 43 may be heated to increase the humidification amount of the inflow air. That is, as shown in FIG. 5, a heater 44 is attached to the water storage container 43 to heat water in the container. Thereby, the evaporation of the water in the container 43 is promoted, the humidity of the inflow air rises, and the decomposition of NOx is promoted.

The amount of evaporation of water changes depending on the temperature of the atmosphere in which the water is placed. That is, the evaporation amount is large in a high temperature state, and decreases in a low temperature state. Thus, if the humidification amount is controlled by detecting the temperature inside the device, water can be used without waste. As a temperature detecting method, an atmosphere temperature may be measured by providing a thermistor or the like in the apparatus, but it is preferable to measure an atmosphere temperature near a place where water is installed as much as possible.

As a configuration for controlling the humidification amount, when the water storage container 43 is not provided with a heater, the water storage container 43 or the water storage section 42 is opened and closed by a lid. That is, as shown in FIG. 6, the lid 46 is attached to the upper opening of the water storage container 43 installed in the water storage part 42 so as to be openable and closable.
The lid 46 is pivotally attached to the container 43 by a shaft 47, and a spring 45 is locked at one of the opposite ends. The other end of the spring 45 is locked to the wall surface of the water storage section 42 and the like.
6 is given a biasing force in the direction of closing the lid. Further, a solenoid 48 is installed adjacent to the water storage section 42.
The plunger 48 a of the solenoid 48 is pivotally attached to the other end 46 a of the lid 46. Therefore, when the solenoid 48 is turned on, the lid 46 is opened, and when the solenoid 48 is turned off, the lid 46 is opened.
Is closed.

Alternatively, as shown in FIG.
2 and a duct 41 are formed in a semicircular opening 5
Contact by 1a. Then, a semicircular lid 49 is attached to the bottom surface 51, and is rotated by the stepping motor 50. Thus, the opening 51a is opened and closed by the lid 49.

On the other hand, when the heater 44 is attached to the water storage container 43, the humidification amount can be accurately adjusted by controlling the temperature of the heater 44. In this case, the temperature of the water in the container is measured assuming that the temperature in the machine and the temperature of the water in the container are proportional, and when the temperature of the measured water is lower than the reference temperature compared with a preset reference temperature. It is determined that the humidification amount is insufficient, and the water in the container may be heated by the heater 44 until the reference temperature is reached.

Incidentally, if the NOx concentration in the outside air of the apparatus is measured and the humidification amount is controlled based on the measurement result, the humidification amount can be adjusted to an appropriate amount. That is, N
When the Ox concentration is high, the humidification amount is increased, and when the NOx concentration is low, the humidification amount is decreased. As the NOx concentration, the NOx concentration outside the device may be measured, or the NOx concentration of the air introduced into the suction duct 41 may be measured. As a configuration for controlling the humidification amount, when the heater is not provided, the humidification amount can be controlled by the above-described method according to FIG. 6 or 7. According to the configuration in FIG. 7, the rotation amount of the stepping motor 50 is controlled. This is advantageous because the opening and closing amount of the lid 49 can be adjusted stepwise.

Further, if the humidification amount is controlled in accordance with both the NOx concentration of the outside air and the temperature inside the apparatus, the humidification amount can be adjusted more appropriately, and the occurrence of an abnormal image due to the NOx of the outside air can be controlled under the optimum condition. Can be prevented. Also,
It is possible to prevent wasteful consumption of humidification water and reduce maintenance work.

When the humidification amount is controlled by opening and closing the lid, the suction fan 40
If the lid is opened at the time of the operation and the lid is closed at other times, the inflow air is humidified only when the outside air is actually introduced, which is effective. Alternatively, the opening and closing of the lid may be synchronized with the image forming timing. As a representative of the image forming timing, for example, an appropriate one can be selected, such as when the charging device is energized or when the photosensitive member is rotated. This is effective because the inflow air can be humidified only when actually forming an image. It is needless to say that even when the humidification amount is adjusted by controlling the heating means, the humidification amount is effectively controlled when the suction fan 40 operates or in synchronization with the image forming timing.

The following configuration can be adopted as another example of the humidifying means. That is, an evaporating dish 57 as shown in FIG. 8 is installed in the water storage section 42, and a high-frequency output device 55 such as a magnetron is arranged above the evaporating dish 57 to emit ultrasonic waves to the water W stored in the evaporating dish 57. To generate steam. In the case of this method, the humidification amount can be increased without increasing the temperature inside the apparatus, which is advantageous. Reference numeral 56 denotes a high-voltage unit for driving the high-frequency output device 55.

Alternatively, as shown in FIG. 9, a water storage recess 52 is provided on the bottom surface 51 of the suction duct 41, and the water W is stretched.
A cloth 54 such as gauze is attached to the upper wall 53 of the duct, and the lower end of the hanging cloth 54 is immersed in the water W in the recess 52. Water is sucked into the cloth 54 by capillary action. Therefore, the outside air introduced through the duct 41 is humidified by passing the air through the two cloths 54, so that the NOx concentration can be reduced. In addition, the size of the cloth 54 may be a circle of several centimeters square or several centimeters in diameter, and the humidifying means can be reduced in size. Further, the material, the number, the interval, and the like of the cloth 54 can be arbitrarily set.

Next, the details of the color scanner 1 and the color printer 2 will be described with reference to FIGS.

The color scanner 1 forms an image of the document 3 illuminated by the illumination lamp 4 on a color sensor 7 via a mirror group 5 and a lens 6, and converts color image information of the document 3 into, for example, blue or green. , Red (hereinafter, B,
G and R) and converted into electrical image signals. Then, B obtained by the color scanner 1,
Based on the G and R color separation image signal intensity levels, an image processing unit (not shown) performs color conversion processing, and black (hereinafter, described as Bk), cyan (hereinafter, described as C), magenta ( Hereinafter, color image data of M) and yellow (hereinafter, referred to as Y) are obtained. The color image data is visualized in Bk, C, M, and Y by the color printer 2 and superimposed to form a four-color full-color image.

Next, the outline of the color printer 2 will be described. The writing optical unit 8 converts the color image data from the color scanner 1 into an optical signal, performs optical writing corresponding to the original image, and To form an electrostatic latent image. The writing optical unit 8 includes a laser 8a and its light emission drive control unit (not shown), a polygon mirror 8b
And a rotation motor 8c, an f / θ lens 8d, a reflection mirror 8e, and the like.

FIG. 2 is an enlarged view showing the vicinity of the photosensitive member and the intermediate transfer belt of the color printer 2 in detail. As shown in FIG. 1, a cleaning unit (including a pre-cleaning static eliminator) 10 and a static elimination lamp 1 are provided around a photoreceptor 9.
1, charging device 12, potential sensor 13, Bk developing device 14, C
A developing unit 15, an M developing unit 16, a Y developing unit 17, a development density pattern detector 18, an intermediate transfer belt 19 and the like are arranged.

Since the constructions and operations of the respective color developing units 14, 15, 16, 17 are all the same, the Bk color developing unit will be described as a representative. The Bk color developing device 14 includes a developing sleeve 14a, a developing paddle 14b, a toner density sensor 14c, and the like. The developing paddle 14b pumps up and agitates the developer. While the developing sleeve 14a rotates,
The developer paddle 14b pumps the developer spikes into contact with the outer peripheral surface of the photoreceptor 9 to develop the electrostatic latent image formed on the photoreceptor 9. However, when in the standby state, the developing sleeve 1
Reference numeral 4a does not rotate, and the developer is in a cutting edge (development inoperative) state in which the developer is separated from the surface of the photoconductor 9.

Next, each color developing unit 14, 15, 16, 17
Will be described assuming that the developing order (that is, the color image forming order) is the order of Bk, C, M, and Y. However, the order of forming color images (that is, the order of development) is not limited to this embodiment.

First, when the copying operation by the copying machine 100 is started, reading of the Bk image data of the original 3 by the color scanner 1 is started at a predetermined timing.
Then, based on this image data, optical writing / electrostatic latent image formation is performed on the photoconductor 9 rotating counterclockwise in the figure (in the direction of arrow L) by the laser light of the writing optical unit 8 (hereinafter, referred to as “the latent image”). The electrostatic latent image based on the Bk image data is represented by B
Described as k latent image. The same applies to C, M, and Y).

In order to develop the Bk latent image formed on the photoreceptor 9 from the leading end thereof, the developing sleeve 14a is started to rotate before the leading end of the latent image reaches the developing position of the Bk developing unit 14, The developer is raised and the Bk latent image is developed with the Bk color toner. Then, the developing operation of the Bk latent image area is continued, but when the rear end of the latent image passes the developing position of the Bk developing device 14, the developer on the developing sleeve 14a is immediately cut off, and the developing operation is stopped. State. This ear cutting is completed at least before the leading end of the C latent image based on the next C image data reaches the Bk developing device 14. The cutting of the developer is performed by switching the rotation direction of the developing sleeve 14a to a direction opposite to that during the developing operation, and thereafter, the rotation of the developing sleeve 14a is stopped.

The Bk formed by developing the Bk latent image is now described.
The toner image is transferred onto an intermediate transfer belt 19 which is in contact with the surface of the photoconductor 9 and moves at a constant speed (hereinafter, referred to as the photoconductor 9).
(Transfer of the toner image from the printer to the intermediate transfer belt 19 is referred to as belt transfer.) The belt transfer is performed by applying a predetermined bias voltage to the transfer bias roller 20 while the photoconductor 9 and the intermediate transfer belt 19 are in contact with each other.

Next, reading of the C image data of the original 3 by the color scanner 1 is started at a predetermined timing. Then, in the same manner as in the case of the Bk color, laser beam writing is performed using C image data, and a C latent image is formed. The C color developing device 15 starts rotation of the developing sleeve 15a before the trailing end of the Bk latent image passes through the developing position and before the leading end of the C latent image reaches the developing position, and the developer is discharged. Make a hot stand. Then, the C latent image is developed with the C color toner.
Hereinafter, the reading of image data, the formation of a latent image, and the development with the corresponding color toner are performed for the M and Y colors, respectively. The operations are the same as the operations for the Bk and C colors described above. Is omitted.

On the intermediate transfer belt 19 onto which the Bk toner image has been transferred, C, C
The M and Y color toner images are sequentially transferred to the previous toner image while being aligned with each other, thereby forming a four-color superposed belt transfer image. Then, the four-color superimposed belt transfer image is collectively transferred to transfer paper.

Here, a unit including the intermediate transfer belt 19 will be described.

The intermediate transfer belt 19 includes a belt transfer bias roller 20, a driving roller 21, and a driven roller 25a,
and is driven by a drive motor (not shown). A belt cleaning unit 22 for cleaning the intermediate transfer belt 19 includes a brush roller 22a,
It comprises a rubber blade 22b, a mechanism 22c for contacting and separating from the intermediate transfer belt 19, and the like. The belt cleaning unit 22 is separated from the belt surface by the contact / separation mechanism 22c during the belt transfer of the second, third, and fourth color toner images after the first color Bk toner image is transferred to the belt. .

The paper transfer unit 23 for transferring the four-color superimposed belt transfer image formed on the belt 19 to the transfer paper includes a transfer bias roller 23a, a roller cleaning blade 23b, and a mechanism for contacting and separating from the transfer belt 19. 2
3c and the like. Transfer bias roller 23a
Is normally separated from the belt surface, but is pressed by the contact / separation mechanism 23c at a time when the belt-transferred image on the intermediate transfer belt 19 is collectively transferred onto the transfer paper, and is pressed against the intermediate transfer belt 19. You. Then, a predetermined bias voltage is applied, and the belt transfer image is collectively transferred onto the transfer paper P guided between the transfer bias roller 23a and the intermediate transfer belt 19. The transfer paper P is transferred to the intermediate transfer belt 19.
The paper is fed by the paper feed roller 24 and the registration roller 26 (each shown in FIG. 1) at the timing when the leading end of the upper belt transfer image reaches the paper transfer position.

By the way, the following three methods can be considered as the operation method of the intermediate transfer belt 19 after the belt transfer of the Bk toner image of the first color is completed to the rear end portion. Alternatively, the operation is performed by a combination of efficient methods according to the copy size (e.g., in terms of copy speed).

(1) Constant speed constant direction rotation method After the transfer of the Bk toner image to the belt, the rotation continues in the same direction at a constant speed.

B. Then, when the front end position of the Bk toner image on the surface of the belt 19 reaches the contact portion with the photoconductor 9 again, that is, the belt transfer position, the front end portion of the next C toner image on the photoconductor 9 is just at that position ( (Bk toner image tip position)
The image is formed in a timely manner so that As a result, the C toner image is accurately aligned with the Bk toner image, and is belt-transferred onto the intermediate transfer belt 19.

C. After that, M, Y
Proceeding to an image process, a four-color superimposed belt transfer image is obtained.

D. Following the belt transfer process of the Y toner image of the fourth color, the belt transfer image of the four-color superimposition on the surface of the belt 19 is collectively transferred onto the transfer paper P while rotating as it is.

(2) Skip constant direction rotation method When the belt transfer of the Bk toner image is completed, the photosensitive member 9
From the intermediate transfer belt 19. Then, it is skipped at a high speed in the same direction, and returns to the original rotation speed after moving a predetermined amount. Thereafter, the belt 1 is again attached to the photoconductor 9.
9 is brought into contact.

B. When the leading edge position of the Bk image on the surface of the belt 19 reaches the belt transfer position again, the photosensitive member 9
An image is formed on the top at a timing so that the leading end of the next C toner image is exactly at that position. As a result, the C toner image is accurately aligned with the Bk toner image, and is belt-transferred onto the intermediate transfer belt 19.

C. After that, M, Y
Proceeding to an image process, a four-color superimposed belt transfer image is obtained.

D. Following the belt transfer process of the Y toner image of the fourth color, the belt transfer image of the four-color superimposition on the surface of the belt 19 is collectively transferred onto the transfer paper P at the same speed.

(3) Reciprocating rotation method a. When the belt transfer of the Bk toner image is completed, the photosensitive member 9
From the intermediate transfer belt 19. Then, at the same time as the rotation is stopped, a high-speed return is made in the reverse direction. The returned belt 19 is stopped after the leading end position of the Bk image on the belt surface passes through the belt transfer position in the reverse direction and further moves by a preset distance.
Then, a standby state is set.

B. Next, when the leading end of the C toner image on the photosensitive member 9 reaches a predetermined position before the belt transfer position, the transfer belt 19 is rotated again in the initial direction. Then, the transfer belt 19 is brought into contact with the photoconductor 9 again. At this time, the C toner image is transferred to the belt 19 under a condition controlled so as to accurately overlap the Bk image on the belt 19 surface.

C. After that, M, Y
Proceeding to an image process, a four-color superimposed belt transfer image is obtained.

D. Following the belt transfer process of the Y toner image of the fourth color, it rotates at the same speed without returning,
The four-color superimposed belt transfer image on the surface of the belt 19 is collectively transferred to the transfer paper P.

The transfer paper P on which the four-color superimposed toner images are collectively transferred from the intermediate transfer belt 19 is conveyed to a fixing device 28 by a transfer paper conveyance belt 27. Then, the fixing roller 28a and the pressure roller 28b controlled to a predetermined temperature
The unfixed toner image on the transfer paper P is fused and fixed, and a full-color copy is completed. Thereafter, the transfer paper P is carried out to the paper discharge tray 29. The surface of the photoconductor 9 after the belt transfer is cleaned by the photoconductor cleaning unit 10. In addition, the static elimination lamp 1
1, the charge is removed uniformly. On the other hand, the intermediate transfer belt 19 after transferring the toner image onto the transfer paper P is
The surface of the belt 19 is cleaned by the belt cleaning unit 22 pressed and pressed against the belt 19.

In the case of a repeat copy, the first Y (4
Following the (color) image process, the reading of the document image and the formation of the latent image on the photoconductor 9 are performed at a predetermined timing, and the second Bk (first color) image process is performed. Further, in the intermediate transfer belt 19, the second BK toner image is transferred to the area where the belt surface is cleaned by the belt cleaning unit 22 following the batch transfer process of the first four-color superimposed image onto the transfer paper. Transcribed. The subsequent color image processes are the same as those for the first sheet.

The transfer paper cassette 30 shown in FIG.
Transfer papers of various sizes are stored in 31, 32 and 33. Then, the sheet is fed from the storage cassette of a size designated from an operation panel (not shown) to the registration roller 26 at a proper timing. From the manual paper feed tray 34, paper such as OHP paper or thick paper is fed.

The above description is for the copy mode for obtaining four full colors. In the three-color copy mode and the two-color copy mode, the same operation as described above is performed for the designated color and the number of times. Will be. In the case of the single-color copy mode, until only a predetermined number of sheets have been completed, only the developing device of that color is set in a developing operation (spring of developer), and the intermediate transfer belt 19 is kept in contact with the photoconductor 9. The copying operation is performed while rotating at a constant speed and the belt cleaning unit 22 is still in contact with the transfer belt 19.

[0060]

As described above, according to the image forming apparatus of the present invention, the humidifying means is provided in the outside air introduction path, and when the NOx concentration is reduced by humidifying the inflow outside air, the N of the outside air is reduced.
Since the humidification amount is adjusted according to the Ox concentration, the optimum humidification can always be performed when the NOx concentration is high and when the NOx concentration is low. Therefore, occurrence of an abnormal image such as image blur or white spots can be prevented by suppressing the influence on the photoconductor.

According to the configuration of the second aspect, the humidification amount is adjusted according to the image forming operation of the apparatus, so that humidification can be effectively performed only when necessary (at the time of image formation).

According to the third aspect of the invention, the humidification amount is adjusted according to the operation of the suction fan, so that the humidification can be effectively performed only when the outside air is introduced.

According to the configuration of the fourth aspect, the humidification amount is adjusted according to the temperature inside the apparatus, so that optimum humidification can always be performed in consideration of the difference in the evaporation amount of water depending on the temperature.

According to the fifth aspect of the present invention, since the humidifying means has the storage container for storing water and the heating means for heating the water in the storage container, the humidification amount can be easily increased.

According to the sixth aspect of the present invention, since the humidifying means has the storage container for storing water and the means for emitting high-frequency waves to the water in the storage container, it is possible to perform humidification without increasing the internal temperature. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a copying machine according to an embodiment of the present invention.

FIG. 2 is a detailed view of the vicinity of a photoconductor and a developing device of the copying machine.

FIG. 3 is a perspective view showing an air blowing system in the copying machine.

FIG. 4 is a perspective view showing a humidifying unit provided in a duct of the air blowing system.

FIG. 5 is a perspective view showing an example in which a heater is attached to the humidifying means.

FIG. 6 is a plan view showing a humidification amount adjusting mechanism of the humidification unit shown in FIG. 4;

FIGS. 7A and 7B show another example of the humidification amount adjusting mechanism. FIG. 7A is a plan view and FIG. 7B is a side view.

FIG. 8 is a side view showing another example of the humidifying unit.

FIG. 9 is a perspective view showing still another example of the humidifying unit.

[Explanation of symbols]

 1 Color Scanner 2 Color Printer 9 Photoconductor 19 Intermediate Transfer Belt 40 Suction Fan 41 Suction Duct 42 Water Storage Unit 43 Water Storage Container 44 Heater 46, 49 Lid 48 Solenoid 50 Stepping Motor 51a Semicircular Opening 52 Water Storage Concave 54 Cloth 55 High Frequency Output device 56 High-pressure unit 57 Evaporating dish 100 Color copier

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) G03G 21/20 G03G 21/00 370-540 G03G 15/00 303

Claims (6)

(57) [Claims] 1. An image forming apparatus having a photoreceptor and an outside air introduction mechanism, wherein a humidification unit for humidifying the introduced outside air is provided in an outside air introduction path of the outside air introduction mechanism, and a humidification amount of the humidification unit is adjusted. And a nitrogen oxide concentration measuring means for measuring the nitrogen oxide concentration of the outside air around the apparatus or the outside air introduced into the apparatus, wherein the humidification amount adjusting means corresponds to the measurement result of the nitrogen oxide concentration measuring means. An image forming apparatus characterized in that the image forming apparatus is controlled by: 2. The image forming apparatus according to claim 1, wherein the humidification amount adjusting unit is controlled according to an image forming operation. 3. The outside air introduction mechanism has a suction fan,
The image forming apparatus according to claim 1, wherein the humidification amount adjustment unit is controlled according to an operation of the fan. 4. The image forming apparatus according to claim 1, further comprising a temperature measuring unit for measuring an inside temperature, wherein the humidifying amount adjusting unit is controlled according to a measurement result of the temperature measuring unit. apparatus. 5. The image forming apparatus according to claim 1, wherein the humidifying unit includes a storage container for storing water and a heating unit for heating water in the storage container. 6. The image forming apparatus according to claim 1, wherein the humidifying unit includes a storage container for storing water, and a unit for emitting high-frequency waves to the water in the storage container.