JP2003186317A - Electrically conductive roller used for image forming device, method for detecting temperature and humidity of the same and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device that can give conditions suitable for forming images, especially ones for developing the images, even without adding a temperature and humidity sensor and obtain a high-quality image. <P>SOLUTION: An electrically conductive roller is composed of ion electrically conductive material. The image forming device with the roller is provided with a transfer power supply and a voltmeter impressing specific electric power to this roller, an ammeter measuring transfer current, and ROM storing the V-I characteristics data for specifying environment. A specific voltage is impressed on the electrically conductive roller, the current value is detected, and the temperature and humidity degree is calculated from the V-I characteristics data for specifying the environment memorized in ROM, thus detecting the environment where the image forming device is placed. <P>COPYRIGHT: (C)2003,JPO

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 having an image forming means for electrostatically forming a toner image on a transfer material, such as a PPC, a printer or a facsimile, regardless of whether it is a single color or a color. The present invention relates to an image forming apparatus using a roller.

[0002]

2. Description of the Related Art Conventionally, an image carrier and a transfer roller which are in pressure contact with the image carrier are provided, and a transfer material is passed between the two, and at this time, a voltage is applied to the transfer roller so that the toner on the image carrier side. An image forming apparatus configured to transfer an image onto a transfer material has already been proposed.

The image forming apparatus employing such a contact transfer system is advantageous in terms of cost since it does not require a high voltage power source, as compared with the one using a corona discharger which has been widely used conventionally. Since there is no corona wire electrode, there are no obstacles due to its contamination, there are various advantages such as generation of ozone due to high-pressure discharge and generation of nitride, and little deterioration of the image carrier and image quality due to these. But,
On the other hand, it is known that the VI characteristic of the transfer roller greatly changes depending on the environment.

Therefore, constant voltage control and constant current control (ATVC, Active Tr) are applied to the transfer roller disclosed in Japanese Patent No. 2614309 previously filed by the present applicant.
The Transfer Voltage Control) is being performed. This is an image forming apparatus having an image carrier and a transfer roller that forms a nip between the image carrier and the image on the image carrier is transferred to a transfer material at the nip. A constant current control is performed on the transfer roller when there is no transfer material in the nip portion, and a voltage value V corresponding to the voltage value V ₁ generated on the transfer roller during the constant current control when image transfer to the transfer material is performed. ₂ (where V ₂ > V ₁ ) controls the transfer roller at a constant voltage. As a result, even if the VI characteristic of the transfer roller changes depending on the environment, it is possible to obtain stable and good transferability at all times. However, this ATVC control is for coping with the change in the resistance value of the transfer roller, and does not specify the environment, but the developing characteristics may change depending on the environment, and the image may also change.
Therefore, even in the image forming apparatus equipped with the ATVC control, in order to deal with the developing characteristics that change according to the environment,
It is necessary to separately provide a temperature / humidity sensor, which requires space and cost. In addition, since this temperature / humidity sensor used separately is placed away from the image carrier around which image formation is actually performed, it cannot respond to accurate temperature and humidity changes around the image carrier, and is always stable. It may not be possible to obtain high quality images.

Further, a conductive roller conventionally used for an image forming apparatus or the like is EPDM (ethylene propylene rubber).
Conductive rollers made of the above materials have been used. However, the resistance value of this roller changes depending on the environment, and the resistance value of the transfer material also changes. Therefore, when used in an image forming apparatus or the like, a temperature / humidity sensor that is separately used to obtain high-quality transferability and images. It has been used by detecting the environment by a temperature / humidity detecting means such as the above, and applying a transfer voltage corresponding thereto. However, since this temperature / humidity sensor used separately is placed away from the area around the image carrier on which image formation is actually performed, it cannot respond to accurate changes in temperature / humidity around the image carrier and is always stable. It may not be possible to obtain high quality images. In addition, since the resistance value of each roller during mass production varies, apply a constant voltage to this roller and apply the optimum transfer voltage for that roller based on the current value at that time. Has been used.

[0006]

In the conventional example of the image forming apparatus described above, by performing the ATVC control, even if the VI characteristic of the transfer roller changes depending on the environment, stable and good transferability is always obtained. You can get it. However, this ATVC control is for coping with changes in the resistance value of the transfer roller, and does not specify the environment. Therefore, when detecting the temperature and humidity in the image forming apparatus, it is necessary to separately provide the temperature and humidity sensor even in the image forming apparatus having the ATVC control. However, since the temperature / humidity sensor used separately is placed away from the image carrier around which image formation is actually performed, it cannot respond to accurate temperature / humidity changes around the image carrier and is always stable. It may not be possible to obtain high quality images.

When a conductive roller made of EPDM or the like is used as the conductive roller in the above image forming apparatus, means for detecting the temperature and humidity by a separately used temperature and humidity sensor or the like is required. Further, the temperature and humidity detecting means has a large variation in the resistance value among the individual rollers due to the VI value that specifies the current value obtained through the roller and the environment by applying a constant voltage to the roller. It is impossible because it overlaps with the change in value.

From the above, in the conventional image forming apparatus, the image carrier, the developer, the transfer material, etc. are affected by the environment in which the image forming apparatus is placed, and the sensitivity of the image carrier is
The image forming device itself has an environment detection device such as a temperature / humidity sensor against the effects on the image due to changes in the charging load of the developer and the resistance value of the transfer material. A high-quality image is obtained by changing the image condition or providing a switch for inputting various conditions in the image forming apparatus main body, and changing the image forming condition by operating the switch. Since this temperature / humidity sensor is installed in a place away from the area around the image carrier on which actual image formation is performed, consider the optimum installation location for the temperature / humidity sensor and then find the optimum image formation conditions for the operating environment. Etc. are necessary. Therefore, the number of steps in designing is increased, cost and space are increased, and the degree of freedom in design is reduced.

[0009]

A conductive roller made of an ion conductive material such as NBR or urethane, which has a small variation in individual resistance values during mass production and whose resistance value changes according to changes in the environment. The image forming apparatus equipped with this roller is further equipped with a transfer power source and a voltmeter for applying a constant voltage to the roller, an ammeter for measuring the transfer current, and a ROM for storing the VI characteristic data for specifying the environment. Is equipped with. A constant voltage is applied to the conductive roller, the current value is detected, the temperature and humidity are calculated from the VI characteristic data for specifying the environment stored in the ROM, and the image forming apparatus is installed. Detects the environment in which it is present.

[0010]

[Purpose] The applicant has invented a conductive roller disclosed in Japanese Patent Laid-Open No. 2000-337353. However, this conductive roller has the property that the resistance value of the roller itself changes depending on the environment in which it is placed, and that the resistance value of each roller during mass production has little variation. This roller can be used as a transfer roller of an image forming device, and it is possible to give development process conditions suitable for the environment without adding a temperature / humidity sensor separately. A forming apparatus is provided.

[0011]

The roller of the present invention may be a conductive roller made of NBR, a conductive roller made of urethane, or the like. The conductive roller made of NBR material has an elastic layer provided on a roller core metal, and the elastic layer contains acrylonitrile-butadiene rubber and alkoxyethyl adipate.
Further, the conductive roller made of urethane material has an elastic layer provided on a roller core metal, and the elastic layer contains urethane foam.

Since these rollers have small variations in resistance value due to individual rollers and large changes in resistance value due to the environment, a constant voltage is applied to a conductive roller made of an ion conductive material such as NBR or urethane. The temperature and humidity can be calculated from the current value obtained through this roller and the VI characteristic for specifying the environment.

According to the second aspect of the present invention, a constant voltage is applied to a conductive roller made of an ion conductive material such as NBR or urethane, and the temperature and humidity are calculated from the current value obtained through this roller. Is a method for detecting temperature and humidity.

The relationship between the voltage applied to a conductive roller made of an ion conductive material such as NBR and urethane and the current flowing through the roller greatly changes depending on the environment. Further, there is almost no variation in individual rollers during mass production. Due to these two characteristics, it is possible to apply a constant voltage to the conductive roller and calculate the temperature and humidity from the current value obtained through this roller.

According to a third aspect of the present invention, a constant voltage is applied to a conductive roller made of an ion conductive material such as NBR or urethane, and a V value for specifying the current value and environment obtained through this roller. An image forming apparatus characterized by calculating temperature and humidity from -I characteristics.

The relationship between the voltage applied to the conductive roller made of an ion conductive material such as NBR and urethane and the current flowing through the roller greatly changes depending on the environment. Further, there is almost no variation in individual rollers during mass production. From these two characteristics, a constant voltage is applied to the conductive roller, and the temperature and humidity are calculated from the current value obtained through this roller and the VI characteristic for specifying the environment. With this, it is possible to detect the environment in which the image forming apparatus is placed without separately installing a temperature / humidity detection device such as a temperature / humidity sensor. It is possible to give suitable developing conditions and obtain a good quality image. That is, in an image forming apparatus or the like that uses a conductive roller made of an ion conductive material such as NBR or urethane, it functions as a temperature / humidity sensor, and further the temperature / humidity around the image carrier on which image formation is actually performed. Can be detected, and a high-quality image can be obtained while saving space and reducing costs.

According to the inventions of claims 4 to 14, a constant voltage is applied to a conductive roller made of an ion conductive material such as NBR or urethane, and the current value and environment obtained through this roller are specified. The image forming apparatus is characterized in that the temperature and humidity in the image forming apparatus are calculated from the V-I characteristics for changing the developing condition based on the information.

This eliminates the need for a temperature / humidity sensor which has been conventionally required to obtain a high-quality image, and the temperature / humidity sensor can be obtained by using a conductive roller made of an ion conductive material such as NBR or urethane. In addition, it is possible to detect the temperature and humidity around the image carrier on which actual image formation is performed, and it is possible to obtain high quality images while saving space and cost. .

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] FIG. 1 is a schematic view of an example of an image forming apparatus having a conductive roller and temperature / humidity detecting means according to the present invention.

Reference numeral 1 denotes an image bearing member as a member to be charged. This example is a drum type image bearing member having a conductive substrate such as aluminum and a photoconductive layer formed on the outer peripheral surface thereof as a basic structure. is there. It is rotationally driven around the spindle at a predetermined peripheral speed (process speed) in the clockwise direction in the drawing. 3 is in contact with the surface of the image carrier 1 so that the surface of the image carrier has a predetermined polarity.
It is a charging roller that performs a primary charging process uniformly to the electric potential. The image carrier 1 is provided with an exposure device 6 that forms an electrostatic latent image, a developing unit 5, a transfer unit 4, and a transfer roller 2 that contacts the image carrier 1. The conductive roller according to the invention is used as the transfer roller 2.

The transfer unit 4 is provided with a transfer power source for applying a voltage to the transfer roller, a voltmeter for measuring the applied voltage, an ammeter for measuring the current flowing through the transfer roller, and a ROM, and a CPU 7 is added. ing.

The transfer section 4 and the transfer roller 2 transfer the toner image on the surface of the image carrier 1 to a transfer material passing through a contact portion between the image carrier 1 and the transfer material. The ROM stores VI characteristic data for specifying the environment.

The CPU 7 compares the VI characteristic data for identifying the environment read from the ROM with the current value flowing through the transfer roller to determine the environment in which the image forming apparatus is placed. To do.

FIG. 2 shows the relationship between the environment and the transfer voltage when a certain transfer current is applied. This graph is
This is the change in voltage value due to the environment when a transfer current of 2.5 μA is applied to the transfer roller. High voltage value in L / L environment (15 ° C / 10%), next high N / N (23 ° C / 50%) environment, low voltage value in H / H (30 ° C / 80%) environment I understand things. Further, it can be seen that the difference in voltage value due to the environment of the roller of the present invention is larger than that of the conventional roller. It can be seen that the conventional roller changes only about 0.3 kV, but the roller of the present invention changes about 2.5 kV, and the voltage value changes greatly depending on each environment. Therefore, in the conventional roller, since the resistance value of the roller itself varies, it is impossible to detect the temperature and humidity based on the difference in the resistance value depending on the environment, but the roller of the present invention detects the temperature and humidity. Is possible.

As described above, when the transfer material enters the contact portion between the image carrier and the transfer roller to form an image, a constant voltage is applied to the transfer roller and the value of the current flowing through the roller is detected. . By comparing the detected current value and the VI characteristic data for specifying the environment stored in the ROM, the image forming apparatus can be operated without separately installing the temperature / humidity detecting device of the temperature / humidity sensor. It can detect the environment in which it is placed. Based on this detected environment, development bias,
High-quality images can be obtained by changing the developing conditions suitable for the environment such as the sleeve peripheral speed and the contact pressure of the elastic blade. Thus, by using a conductive roller made of an ion conductive material such as NBR or urethane, it is possible to obtain a high quality image while saving space and cost.

[Embodiment 2] In the second embodiment, the case where the image forming apparatus described in Embodiment 1 updates or holds environment information of temperature and humidity and developing conditions suitable for the environment will be described. When the environmental information and the developing conditions are to be captured and held, the environmental information and the developing conditions are controlled to be held in the image forming apparatus. When the user selects to hold the setting state, the environmental information and the developing conditions are held in the image forming apparatus even when the power of the image forming apparatus is turned off.

When the power of the image forming apparatus is turned on, it is checked whether or not the environment information and the developing conditions are held, and if these information and conditions are held, the information is held. The control is performed according to the existing environmental information and development conditions. Since the other configurations and controls are the same as those in the above-described embodiment, detailed description will be omitted. Environmental information,
If the developing conditions are not held, the power is reset and the environment information and developing conditions are updated when the power is turned on. However, if there is a considerable difference between the pre-update environment information and the development conditions, the user will be confirmed.

By controlling as described above, it is possible to always obtain a high quality image in an environment that changes daily. Moreover, a high-quality image can be obtained regardless of the environment in which the image forming apparatus is used. For this reason, it is not necessary to consider a defect due to the environment at the time of designing, the number of steps is reduced, cost is reduced, and the degree of freedom in designing is increased.

[Third Embodiment] Next, in the image forming apparatus described in the first and second embodiments, a good image is obtained by changing the developing condition in the electrophotographic forming process which is changed based on the environmental information. The third embodiment according to the present invention will be described. Also in the third embodiment, the basic configuration is substantially the same as the configuration shown in FIG. 1 of the first embodiment described above. However, in the third embodiment, since the developing conditions are controlled to control a good image, the configuration related to the developing device will be described in more detail. In FIG. 3, the developing device 5 in the configuration shown in FIG. 1 of the above-described first embodiment is shown in more detail.

In the third embodiment, a case where the developing device 5 adopts a jumping developing method using a one-component magnetic negative toner will be described as an example. The developing device 5 contains a one-component magnetic negative toner 5B. The toner 5B is conveyed as the aluminum developing sleeve 5A rotates in the direction of the arrow in the figure, and is supplied onto the electrostatic latent image formed on the photosensitive drum 1.

A magnet is installed in the developing sleeve 5A and has a function of holding the magnetic toner on the sleeve. Further, 5C is a blade made of urethane rubber, which is brought into contact with the developing sleeve 5A at a predetermined pressure, and uniformizes the toner layer on the sleeve and imparts an electric charge to the toner. Developing sleeve 5A and photosensitive drum 2
Is installed with a gear tape of about 300 (μm), the photosensitive drum side equipment is grounded, and the AC + DC potential is superimposed on the developing sleeve side. The dark portion potential V _D of the photosensitive drum portion at this time is −7.
00 (V), the write portion potential _VL is about -100 (V), and the AC component of the developing bias has V _pp of 1600.
(V) and the frequency is 1800 (Hz).

In general, there is a possibility that as the humidity becomes higher, the ability to give electric charge to the toner in the developing device is lowered, and thereby the image density is lowered. Therefore, in the third embodiment, a constant voltage is applied to a conductive roller made of an ion conductive material such as NBR and urethane, and the current value and environment obtained through this roller are specified. Calculate the temperature and humidity from the VI characteristics of
In accordance therewith, the development contrast is raised to prevent a decrease in density.

Low humidity and normal condition (humidity value less than 70%)
In the case of No, no correction is performed, and the development contrast is set as in the initial setting. In the case of high humidity, the developing contrast is changed to a setting of raising 50V.

An example of controlling the developing contrast in the third embodiment including the correction processing by the above control will be shown. V _D is a dark portion potential on the photosensitive drum 1, and V _{d C} is a developing bias value applied to the developing sleeve. In the third embodiment, the dark portion potential Vd _C on the photosensitive drum 2 is changed as a means for changing the development contrast.

As described above, according to the third embodiment,
A constant voltage is applied to a conductive roller made of an ionic conductive material such as NBR or urethane, and temperature and humidity are calculated from the current value obtained through this roller and the VI characteristic for specifying the environment. It is possible to obtain a good image by changing the development contrast in the electrophotographic forming process which is changed based on the environmental information.

[Embodiment 4] In the above description, a good image was obtained by changing the development contrast. However, the present invention is not limited to the above example, and an optimum image can be obtained by changing the peripheral speed of the developing sleeve as the developing condition. A fourth embodiment according to the present invention that obtains an optimum image by changing the peripheral speed of the developing sleeve as the developing condition will be described below.

In the fourth embodiment, in order to change the peripheral speed of the developing sleeve 5A with respect to the photosensitive drum 2, a driving means (not shown) dedicated to the developing sleeve 5A is provided, which is connected to the motor via the communication means. Connection control is performed with the control unit.

Next, the control for changing the peripheral speed of the fourth embodiment will be described. When the humidity is low (less than 30%) or normal (30 to 70%), the correction is not performed, and the sleeve peripheral speed with respect to the drum peripheral speed is maintained at 100%. On the other hand, when the humidity is high (70% or more), the sleeve peripheral speed is 150
Speed up to become%. As a result, it is possible to prevent the concentration from decreasing in a high humidity environment. This is because when the humidity becomes high, the electric charge of the toner becomes small, the developing performance deteriorates, and the toner supply amount for the case where the density is decreased is increased, and the density is prevented. This increases the amount of toner supplied to the latent image on the drum to prevent the density from decreasing.

As described above, according to the fourth embodiment,
By changing the peripheral speed of the developing sleeve as the developing condition,
The optimum image can be obtained.

[Fifth Embodiment] As a change in developing condition,
A constant voltage is applied to a conductive roller made of an ionic conductive material such as NBR or urethane, and the VI value for specifying the current value and environment obtained through this roller is converted into temperature and humidity information. A fifth embodiment according to the present invention in which the pressing force of the developing blade is changed will be described below.

In the fifth embodiment, the developing blade 5
A means 5D for changing the pressing force of C on the developing sleeve is provided, and the means 5D for changing the pressing force on the developing sleeve uses, for example, driving by a motor, and this motor is controlled by the motor controller via the communication means. To be done.

FIG. 4 is a diagram showing in detail the blade pressure varying means of the fifth embodiment. In the figure, the developing blade 5C is a rubber blade made of urethane rubber, and the developing blade 5C is fixed to the blade mounting plate 5F by adhesion or the like. The blade mounting plate 5F is provided with a gear train, and the blade mounting plate 5F includes a small-diameter gear screwed to the gear train and a large-diameter gear screwed to the gear 5E fixed to the motor drive shaft. By rotating a motor (not shown) via the arranged gear shaft 5D,
It is configured to move up and down. That is, by controlling the rotation of the motor, the gear 5E fixed to the drive shaft also rotates as shown by the arrow in FIG. Then, the gear shaft 5D also rotates as shown by the arrow in the figure. This rotation is the blade mounting plate 5F
Of the blade mounting plate 5F, and the blade mounting plate 5F moves up and down in response to the rotation of the motor.

Generally, when the humidity is high, the electric charge of the toner is low and the developing performance is deteriorated. On the contrary, when the humidity becomes low, the toner causes charge-up, which also causes the deterioration of the developing performance. Therefore, when the humidity is low, it is necessary to lower the blade pressure to reduce the charge giving ability to the toner to prevent the charge gap, and when the humidity is high, it is necessary to raise the blade pressure to enhance the charge giving ability to the toner. For this reason,
In this embodiment, when the information of low humidity (less than 30%) is given, the blade pressure is reduced to 20 (gf / cm) to control the pressing of the developing blade.

On the other hand, when the information about the normal environment (30 to 70%) is given, the normal setting pressure without correction is 30 (gf /
cm) controls the pressing of the developing blade. When the information of high humidity (70% or more) is given, the blade pressure is increased to 40 (gf / cm) to control the pressing of the developing blade.

As described above, according to the fifth embodiment,
As a developing condition, a constant voltage is applied to a conductive roller made of an ion conductive material such as NBR or urethane, and a current value obtained through this roller and a VI characteristic for specifying the environment are used. By changing the pressure applied to the developing sleeve based on the environmental information obtained by calculating the temperature and humidity, a good image can be obtained without being affected by the surrounding environment.

[Sixth Embodiment] As a change in developing condition,
A sixth embodiment according to the present invention will be described below in which the developing contrast is reduced based on the paper type information from the host, the amount of toner deposited on the image portion is suppressed, and electrostatic offset is prevented. Specifically, thick paper (100 g / m ² or more) and OHP
In this case, the development contrast is lowered, the amount of toner deposited on the image portion is suppressed, and electrostatic offset is prevented. Electrostatic offset means that when the unfixed image passes through the nip of the fixing device, the electrical holding force of the paper on the toner weakens, or when the toner is attracted to the fixing roller side by the electrostatic force, This is development in which the toner image is transferred to the fixing roller side.

This development tends to occur as the amount of toner in the image area increases and the temperature decreases. This is related to the fixability, and when the toner amount is large, the heat is not evenly transferred to the entire area of the toner on the image, and the incompletely melted freener toner adheres to the fixing roller side. Also, when the temperature is low, the fixing roller and the pressure roller are hard to warm, and thus offset is likely to occur.

NB in the sixth embodiment according to the present invention
A constant voltage is applied to a conductive roller made of an ion conductive material such as R and urethane, and the temperature and humidity are calculated from the current value obtained through this roller and the VI characteristic for specifying the environment. The developing contrast is reduced based on the environmental information, and the amount of toner deposited on the image portion is suppressed to prevent electrostatic offset. In the case of L / L (15 ° C./10%), the development contrast is lowered (for example, lowered by 100 V) to control the development contrast to reduce the amount of toner adhered to the image area.

On the other hand, when the temperature is other than these, the correction is not performed and the control is performed with the normal development contrast.
In the sixth embodiment, Vd _C is shifted by 100 V in order to reduce the development contrast. This amount of shift has a sufficient effect for preventing offset.

As explained above, according to the sixth embodiment,
A constant voltage is applied to a conductive roller made of an ionic conductive material such as NBR or urethane, and temperature and humidity are calculated from the current value obtained through this roller and the VI characteristic for specifying the environment. By controlling the development contrast based on the environmental information, it is possible to obtain a good image without being affected by temperature and humidity.

[Seventh Embodiment] A constant voltage is applied to a conductive roller made of an ion conductive material such as NBR or urethane, and the current value and environment obtained through this roller are specified. A seventh embodiment according to the present invention will be described below in which a development frequency is controlled based on environmental information obtained by calculating temperature and humidity from VI characteristics to obtain a good image.

In the seventh embodiment, high temperature and high humidity (30
In the case of ℃ / 80%, the background fog is low temperature and low humidity (15 ℃).
/ 10%), the reversal fog is conspicuous, so the operation to increase the developing frequency is performed. In other cases, the correction is not performed,
The feature is that the initial setting is left as it is.

It is known that the fog is reduced as the developing frequency is increased, but if the frequency is excessively increased, the developing performance is lowered and the image density is lowered. Therefore, in order to secure a solid black area density of 1.3 (measured with a Macbeth densitometer) as a practically acceptable level, the upper limit of the development frequency is 20.
It is desirable to set it to about 00 Hz. Considering the above, 7th
In the embodiment, the development frequency is kept at the default setting frequency (1800 Hz) except for high temperature and high humidity and low temperature and low humidity, and the development frequency is increased to 2000 Hz for high temperature and high humidity and low temperature and low humidity. As a result, fog can be reduced without being affected by temperature and humidity and without impairing image quality.

Although the present invention has been described based on the preferred embodiments, a conductive roller made of an ionic conductive material such as NBR or urethane and a temperature / humidity detecting means using this roller are also included in the present invention. Included in the range. Further, a conductive roller of the present invention and a temperature / humidity detecting means using this roller,
The image forming apparatus and the image forming method provided with the conductive roller are not limited to the above-described embodiment, and the image forming apparatus and the image forming method in which various modifications and changes are made from the above-described embodiment are also included. Within the scope of the present invention.

[0055]

As described above, the present invention is different from the ATVC control that has been conventionally used, and is optimal for variations in individual resistance values and for changes in roller resistance values due to the environment. In addition to setting various transfer conditions, by using a conductive roller made of an ion conductive material such as NBR or urethane, the environment in which the image forming apparatus is installed is detected and the development conditions are also set. You can get higher quality images regardless of the environment. That is, according to the present invention, it is possible to detect the environment in which the image forming apparatus is placed without separately installing a temperature / humidity sensor,
It is possible to obtain high-quality images while saving space and reducing costs. Further, a temperature / humidity sensor or the like becomes unnecessary, and it is possible to detect the temperature / humidity around the image carrier on which an image is actually formed. Also, it is not necessary to consider the optimum installation location of the temperature and humidity sensor and then find the optimum transfer conditions for the usage environment. Therefore, the number of steps in designing is reduced, cost is reduced, and the degree of freedom in designing is increased.

[Brief description of drawings]

FIG. 1 is a schematic side view showing an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a diagram showing a VI characteristic due to an environment difference according to the embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of an image forming apparatus according to a third embodiment of the invention.

FIG. 4 shows a detailed configuration of a main part in a fifth embodiment according to the present invention.

[Explanation of symbols]

1 photoconductor 2 Transfer roller 3 charging roller 4 Transfer part 5 development department 5A developing sleeve 5B 1-component magnetic negative toner 5C blade Means for changing the pressure on the 5D developing sleeve 5E motor drive shaft 5F blade mounting plate 6 Exposure equipment 7 CPU P transfer material

Continued front page    F-term (reference) 2H027 DA01 DA11 DA14 DE04 DE07                       EA04 EA05 EC06 EF01                 2H073 BA04 BA13 BA33                 2H077 AD02 AD06 AD13 AD17 DA18                       DA31 DA57 DA82 DB08 DB25                       EA13 EA16                 2H200 FA01 GA23 GA44 GA54 GA57                       HA02 HA28 HB12 HB22 HB45                       HB46 JA02 JA25 JA26 JA29                       JA30 MA03 MA13 MA20 MB01                       PA03 PB05 PB27 PB28

Claims (14)

[Claims] 1. A nip portion is formed between an image carrier and a transfer roller, and a predetermined voltage is applied between the image carrier and the transfer roller to form an image on the image carrier at the nip portion. In an image forming apparatus that transfers to a transfer material, by using a conductive roller composed of an ion conductive material, a constant voltage is applied to this roller, and the current value obtained through this roller is detected, A conductive roller characterized by calculating the temperature and humidity at which the image forming apparatus is placed. 2. A nip portion is formed between the image carrier and the transfer roller, and a predetermined voltage is applied between the image carrier and the transfer roller to form an image on the image carrier at the nip portion. In an image forming apparatus that transfers to a transfer material, a constant voltage is applied to a conductive roller made of an ion conductive material,
A temperature / humidity detecting means for detecting a current value obtained through the roller and calculating a temperature / humidity in which the image forming apparatus is placed. 3. A nip portion is formed between the image carrier and the transfer roller, and a predetermined voltage is applied between the image carrier and the transfer roller to form an image on the image carrier at the nip portion. In an image forming apparatus for transferring onto a transfer material, a constant voltage is applied to a conductive roller made of an ion conductive material, a current value obtained through this roller is detected, and the image forming apparatus is installed. An image forming apparatus, which is characterized by calculating temperature and humidity. 4. The image forming apparatus according to claim 1, wherein
An image forming apparatus characterized in that environmental information such as temperature and humidity is updated when the power is turned on and is retained in the apparatus until the apparatus is powered off. 5. The image forming apparatus according to claim 1, wherein
An image forming apparatus characterized in that when environmental information such as temperature and humidity is updated when the power is turned on, the user is prompted to confirm if there is a considerable difference between the environmental information before and after updating. 6. A nip portion is formed between the image carrier and the transfer roller, a predetermined voltage is applied between the image carrier and the transfer roller, and an image on the image carrier is formed at the nip portion. In an image forming apparatus for transferring onto a transfer material, a constant voltage is applied to a conductive roller made of an ion conductive material, a current value obtained through this roller is detected, and the image forming apparatus is installed. An image forming apparatus characterized in that the temperature and humidity that are present are calculated, and the development process conditions are changed accordingly. 7. The image forming apparatus according to claim 1, wherein the change of the developing process condition changes a developing bias. 8. The image forming apparatus according to claim 1, wherein the change of the developing process condition changes a voltage of an AC component of a developing bias. 9. The image forming apparatus according to claim 1, wherein the change of the developing process condition changes a frequency of an AC component of a developing bias. 10. The image forming apparatus according to claim 1, wherein the change of the developing process condition changes a voltage of a direct current component of the developing bias. 11. The image forming apparatus according to claim 1, wherein the change of the developing process condition changes a developing sleeve peripheral speed. 12. The image forming apparatus according to claim 1, wherein the change of the developing process condition changes a contact pressure of the elastic blade. 13. The image forming apparatus according to claim 7, wherein temperature and humidity environment information or developing condition information is updated when the power is turned on and is retained in the apparatus until the power is turned off. Image forming apparatus. 14. The image forming apparatus according to claim 7, wherein when the environmental information of temperature and humidity or the information of the developing condition is updated when the power is turned on, there is a considerable difference between the environmental information and the developing condition before and after the updating. An image forming apparatus that prompts the user to confirm if there is.