JPH05100534A - Image forming device - Google Patents

Abstract

PURPOSE:To provide the image forming device where transfer can be carried out well regardless of environmental change of temperature and humidity. CONSTITUTION:A developing current measuring circuit 24 is connected between a developing sleeve 4CS and a developing bias electric power source 23, and a transfer control circuit 25 is connected between the developing current measuring circuit 24 and a transfer electric power source 26. Then, data showing the relationship of the developing current and an appropriate transfer current with respect to the change of the temperature and the humidity is stored in the transfer control circuit 25, and setting is carried out so that the most appropriate transfer current is selected and the transfer electric power source 26 is controlled based on the developing current detected by the developing current measuring circuit 24. Thus, the change in the quantity of electrification of the toner can be directly detected and the transfer condition can be controlled appropriately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used as a black-and-white, mono-color or full-color electrophotographic copying machine, printer, etc., and a toner image formed on a latent image carrier formed by an electrophotographic system or an electrostatic recording system. The present invention relates to an image forming apparatus that obtains an image by applying a transfer electric field to a transfer material and transferring the transfer material.

[0002]

2. Description of the Related Art Conventionally, various full-color image forming apparatuses have been proposed, but as a representative one, a full-color electrophotographic apparatus equipped with a developing device as shown in FIG. Examples include copying machines.

In FIG. 10, reference numeral 1 is a photosensitive drum which is a latent image carrier, and is rotatably supported in the direction of the arrow. A primary charger 2 is arranged above the photosensitive drum 1 to uniformly charge the surface of the photosensitive drum 1. Further, an exposing means 3 composed of a laser beam exposing device or the like is arranged above the primary charging device 2, and a color-separated optical image on the surface of the charged photosensitive drum 1 or an equivalent thereof is provided. An electrostatic latent image is formed by irradiating a light image that changes. Further, a rotary developing device 4 is disposed on the downstream side in the rotation direction of the photosensitive drum 1 with respect to the irradiation position of the optical image, and visualizes the electrostatic latent image.

The rotary developing device 4 includes four developing devices 4Y, 4M and 4C which respectively accommodate four color developers of yellow color developer, magenta color developer, cyan color developer and black developer. , 4BK are held in a substantially cylindrical housing rotatably supported, and a desired developing device is conveyed to a position opposed to the outer peripheral surface of the photosensitive drum 1 to electrostatic latent image on the photosensitive drum 1. Is performed to perform full-color development for four colors.

A transfer drum 5 serving as a transfer means is rotatably supported below the photosensitive drum 1, and a transfer material P is carried on the surface of the transfer drum 5 to transfer the toner image on the photosensitive drum 1. It is adapted to be transferred onto the material P. As shown in FIG. 11, the transfer drum 5 has cylinders 5a and 5b arranged at both ends and a connecting portion 5c that connects the both cylinders 5a and 5b, and is located in the outer peripheral surface opening area of the cylinders 5a and 5b. A dielectric sheet 53 as a transfer material carrying member is stretched. As the dielectric sheet 53, a film-like sheet such as polyethylene terephthalate or polyvinylidene fluoride resin film is usually used. Further, a transfer material gripper 6 for gripping the transfer material P fed from the paper feeding device shown in FIG. 10 is provided in the connecting portion 5c. In addition, as shown in FIG.
As shown in FIG. 5, a transfer discharger 7, an inner charge-eliminating discharger 8 and an outer charge-eliminating discharger 9, which are charge-eliminating means, are arranged, and are separated on the downstream side of the outer charge-eliminating discharger 9 in the rotational direction of the transfer drum 5. A separating discharger 10 and a separating claw 11 as a means are sequentially arranged. Further, at the lower position substantially symmetrical to the transfer / separation position, the cleaning means 1 is provided outside the transfer drum 5.
The cleaning assisting means 13 is disposed so as to face the cleaning means 12 on the inner side thereof. A cleaning device 14 for cleaning the surface of the photosensitive drum 1 is disposed further downstream than the position where the photosensitive drum 1 and the transfer drum 5 face each other in the rotation direction of the photosensitive drum 1.

Further, a registration roller 15 is provided in front of the transfer drum 5 (on the right side in FIG. 10) to supply the transfer material P to the transfer drum 5, and above the paper supply device. A conveyor belt 16 for conveying the transfer material P separated from the transfer drum 5 is provided, and a fixing device 17 is provided in front of the conveyor belt 16.

In the above-mentioned full-color electrophotographic copying apparatus, a full-color image is formed as follows.
First, when the surface of the photosensitive drum 1 is uniformly charged by the primary charger 2, the light image E corresponding to the image information is obtained from the exposure means 3.
Is irradiated and an electrostatic latent image is formed on the photosensitive drum 1. The electrostatic latent image is developed by a rotary developing device 4 with a toner having a resin as a base material and visualized as a toner image on the photosensitive drum 1. On the other hand, the transfer material P is sent to the transfer drum 5 by the registration rollers 15 in synchronism with the image, gripped by the gripper 6 or the like at its tip, and conveyed by the transfer drum 5 in the direction of the arrow in the figure. Then, the toner image on the photosensitive drum 1 is transferred from the rear surface of the dielectric sheet 53 of the transfer drum 5 by a corona discharge having a polarity opposite to that of the toner from the back surface of the dielectric sheet 53 of the transfer drum 5 in the area contacting the photosensitive drum 1. Transcribed on. After the transfer process is performed the required number of times, the transfer material P is separated from the transfer drum 5 by the action of the separation claw 11 while being discharged by the separation discharge device 10, and is conveyed to the fixing device 17 by the conveyance belt 16. Then, after being fixed by heat and pressure in the fixing device 17, it is discharged to the outside of the machine. On the other hand, after the residual toner on the surface of the photosensitive drum 1 is cleaned by the cleaning device 14, the photosensitive drum 1 is subjected to the image forming process again. Also, the transfer drum 5
The dielectric sheet 53 is subjected to static elimination by the static eliminators 8 and 9, and then is cleaned by the action of the cleaning device 12 and the cleaning assisting means 13 such as a fur brush, and is again subjected to the image forming process.

In the above conventional example, in order to obtain an optimum image prior to the image forming process, a temperature / humidity sensor is provided in the vicinity of the photosensitive drum, and the surface potential, the image exposure amount, the developing bias are set in accordance with the respective measured values. , The transfer current, etc. are controlled. This is because the potential characteristics of the photosensitive drum, the charging characteristics of the toner in the developer, and the transfer characteristics to the transfer material are greatly influenced by the temperature and humidity.
6-77850, 57-26858, 57-3587
1,57-84463, Japanese Patent Publication No. 2-53790, 2-5
3791 and the like, respectively.

[0009]

However, according to the above-mentioned conventional example, although the control of the image forming condition with respect to the constant temperature and humidity is satisfactorily performed, the temperature and humidity are controlled due to the rapid change of climate and the air conditioner. If there is a sudden change, or if the temperature rise inside the machine or the air flow changes depending on the usage status of the main body (continuous operation or start of use after leaving), the transfer, separation, and static elimination characteristics deviate from the optimum conditions. There is a problem in that an optimum image cannot be stably obtained due to image scatter and a decrease in image density.

This is the same as the above-mentioned conventional control method.
When various image forming conditions are controlled by making use of the fact that the amount of charge of toner greatly changes depending on humidity, if the temperature and humidity are steady and there is almost no change, the temperature and humidity of the environment being measured are The toner charge amount corresponds to that shown in FIG. 12, but it was found that when the temperature and humidity drastically change, the toner cannot sufficiently follow the change and changes with a time delay. ..

For example, when the humidity is drastically increased due to the effect of dusk or the like in the dry state, the sensor cannot immediately respond to the change in the charge amount of the toner even if the sensor follows the change, and the humidity is low. The state, that is, a high charge amount is maintained.
However, since the control of the main body is optimized so that the toner charge amount is immediately low in accordance with the sensor output, there is a problem that the image quality is deteriorated.

Further, even if the environment outside the machine is steady, a difference between the temperature and humidity at the sensor position and the temperature and humidity at the space in contact with the toner may occur due to the temperature rise of the main body.

It has been found that the phenomenon as described above has an influence on the development and transfer conditions controlled on the basis of the charge amount of the toner, but particularly has a great influence on the transfer, separation and charge elimination conditions. In latent images and development, various conditions can be determined by changes in the chargeability of toner, but in transfer, transfer paper and dielectric sheets have the same resistance value as toner as shown in FIG. 13 in addition to toner. This is because it changes with temperature and humidity, and the responsivity of changes in resistance value with respect to changes in temperature and humidity has the same characteristics as toner.

Further, the transfer paper and the dielectric sheet, which have received an electric charge during the transfer, are charged differently depending on the resistance value thereof, and when the photosensitive drum and the transfer paper and the dielectric sheet and the transfer paper are separated from each other. If the charge cannot be properly removed, paper jams due to image distortion and separation defects are likely to occur, and image unevenness occurs unless the dielectric sheet is sufficiently discharged before and after image formation. Had.

The present invention solves the above-mentioned problems and provides an image forming apparatus capable of favorably performing transfer or favorably performing separation and charge removal without being influenced by environmental changes such as temperature and humidity. The purpose is to do.

[0016]

According to the present invention, the above object is to provide a latent image carrier having an endlessly movable surface and carrying an electrostatic latent image on the surface, and carrying the latent image. A developing device having a developer carrying member arranged facing the body, a developing voltage supplying means for applying a predetermined voltage to the developer carrying member, and the latent image carrying member rather than the developer carrying member. A transfer means having a transfer electrode disposed so as to face the latent image carrier on the downstream side in the moving direction of the surface, and a transfer voltage supply means for applying a voltage to the transfer electrode. In the image forming apparatus, a developing current measuring unit connected to the developing voltage supplying unit to measure the developing current, and a developing current detecting unit connected to the developing current measuring unit and the transfer voltage supplying unit and the transfer voltage supplying unit. Control for transfer that controls the output of the means And a stage, the transfer control means,
It is provided with data representing the relationship between the developing current that changes with respect to changes in temperature and humidity and the output of the transfer voltage supply means suitable for the temperature and humidity when obtaining the developing current. This is achieved by setting the output of the transfer voltage supply unit corresponding to the detected developing current based on the above data.

[0017]

According to the present invention, when the charge amount of the developer changes due to changes in temperature and humidity, the developing current generated when the developer moves from the developer carrying member to the latent image carrying member corresponds to it. The developing current changes, and the developing current is detected by the developing current measuring means. Then, the transfer control means selects the output of the transfer voltage supply means for the detected developing current based on the data stored in advance. The data represents the relationship between the developing current that changes depending on the temperature and the humidity and the output of the transfer voltage supply means suitable for the temperature and the humidity when the developing current is obtained. The output of the voltage supply means becomes appropriate at the temperature and humidity at that time. Thus, even if the environment of temperature and humidity changes, the transfer condition is controlled in accordance with the change of the charge amount of the developer, and a good image is obtained.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First to fifth embodiments of the present invention will be described with reference to the drawings. In addition, the same parts as those of the conventional apparatus shown in FIGS.

<First Embodiment> First, a first embodiment of the present invention will be described with reference to FIGS. The present embodiment is characterized by the control method of the transfer section, and unless otherwise specified, each means and device and their control method are the same as those of the conventional example of FIG.

In FIG. 1, reference numeral 1 denotes a photosensitive drum which is a latent image carrier, and a temperature / humidity sensor 18 which is a temperature / humidity detecting means is arranged in the vicinity of the photosensitive drum 1. The temperature / humidity sensor 18 is connected to a temperature / humidity measuring circuit 19 and outputs a signal indicating temperature and humidity via the temperature / humidity measuring circuit 19. This signal is input to a control circuit 20 connected to the temperature / humidity measuring circuit 19, and the control circuit 20 controls each power source against environmental changes in temperature and humidity. That is, the control circuit 20 includes the primary charging power source 2
1, an exposure power source 22, and a developing bias power source 23, which is a developing voltage supply unit, are connected to control so that charging and exposure / development can be performed well regardless of environmental changes.

In the conventional method, the transfer power source is controlled by the control circuit 20 in addition to the respective power sources. However, as described above as a problem of the conventional example, the temperature / humidity sensor and the toner with respect to environmental changes are used. Due to the occurrence of the deviation of the reaction speed and the change of the resistance value of the transfer material and the dielectric sheet, proper control was not performed. Therefore, in the present invention, the developing device 4 (in FIG. 1, 4C is shown as a representative of each developing device.
This is the developing device 4C. ) Is applied to control the transfer power supply by measuring the developing current generated when the toner moves to the photosensitive drum 1. This focuses on the fact that the developing current changes depending on the toner charge amount. That is, the toner is saturated to a predetermined charge amount by sufficient frictional charging in the developing device 4C. However, this saturated value depends on the environment (temperature and humidity).
When it changes as shown in 2, the developing current generated by the movement of the toner also changes. Therefore, the toner charge amount can be accurately detected by measuring the developing current, and the transfer power source can be appropriately controlled.

In this embodiment, as shown in FIG. 1, a developing current measuring circuit 24, which is a developing current measuring means, is connected between the developing bias power source 23 and the developing sleeve 4CS which is a developer carrying member of the developing device 4C. Measuring the current. A transfer control circuit 25, which is a transfer control means, is connected to the developing current measuring circuit 24 to determine an optimum transfer current based on the developing current and a transfer power source 26 connected to the transfer control circuit 25. The output of is controlled to be the optimum value in the environment (temperature and humidity) at that time. Further, as shown in FIG. 1, a conductive brush 27 as a transfer electrode is connected to the transfer power source 26, and the conductive brush 27 is located at a transfer position in contact with the photosensitive drum 1 inside the dielectric sheet 53. It is arranged so as to be in contact with the dielectric sheet 53.

In the transfer control circuit 25, the relationship between the proper transfer current and the developing current as shown in FIG. 2 is stored in advance as a mathematical expression or a table. The relationship between the proper transfer current and the developing current shown in FIG. 2 is obtained by an experiment in which the environment of temperature and humidity is changed and the change of the developing current and the optimum transfer condition in the apparatus of this embodiment are investigated.
The optimum transfer current is obtained in consideration of not only the change in the charge amount of the toner due to temperature and humidity but also the change in the resistance value of the transfer paper and the dielectric sheet as shown in FIG.

The experimental conditions for obtaining the data of FIG. 2 are as follows. Photosensitive drum 1: OPC drum using negative polarity organic photoconductive layer Toner: Negative polarity charged polyester toner having a volume average particle size of about 8 to 10 μm Dielectric sheet 53: 150 μm thick polyvinylidene fluoride (PVdF) sheet Conductivity Brush 27: Volume resistivity of about 10 ¹⁵ in which carbon is kneaded and dispersed in rayon resin fiber having a diameter of about 20 to 30 μm.
Ω · cm It should be noted that the optimum transfer current value may be different if the material of each means is different, so that it may be obtained by an appropriate experiment. As a means for measuring the developing current, a high voltage ammeter may be used, but a resistor may be connected in series to obtain the voltage drop.

Next, the conductive brush 27 used in this embodiment.
The configuration will be described in detail with reference to FIG. The material of the brush is as described in the conditions of the above experiment, and the brush is biased by the dielectric elastic sheet 28 such as a 125 μm thick polyethylene terephthalate (PET) sheet and the dielectric sheet 5 is pressed.
It is arranged so that the tip portion contacts the inner surface of 3. On the other hand, an electric field restricting member 29 made of a dielectric sheet such as a PET sheet having a thickness of 50 μm is arranged in a portion other than the contact portion on the side facing the inner surface of the dielectric sheet 53, and is located on the upstream side of the transfer area. It is designed to block the electric field. Although this conductive brush 27 is connected to the transfer power source 26 described above, there is no current that flows to the shield and does not directly contribute to transfer unlike the conventional corona discharger, and the transfer power source current controlled by the transfer control circuit 25 is Since all contribute to the transfer charging current, the control of the present invention described above can be performed accurately.

Next, the operation of the apparatus of this embodiment as described above will be described. First, when temperature and humidity data is transmitted to the control circuit 20 by the temperature / humidity sensor 18 and the temperature / humidity measuring circuit 19, the control circuit 20 appropriately controls the primary charging power source 21 and the exposure power source 22, and the photosensitive drum 1 is exposed. To form a good latent image. Similarly, the control circuit 20
The output of the developing bias power source 23 controlled by is applied to the developing sleeve 4CS of the developing device 4C via the developing current measuring circuit 24. Then, a potential difference is generated between the latent image on the photosensitive drum 1 and the developing sleeve 4CS, which causes the toner to move to the photosensitive drum 1. At this time, a developing current flows, and this is detected and measured by the developing current measuring circuit 24. On the other hand, the transfer material fed by the registration roller 15 is sent to the transfer drum 5, the tip portion of which is gripped and conveyed by the transfer drum 5 in the direction of the arrow in the figure. Then
The transfer control circuit 25 appropriately controls the transfer power supply 26 based on the detected and measured developing current, and its output is applied to the conductive brush 27. Then, in the transfer area in contact with the photosensitive drum 1, an electric field having a polarity opposite to that of the toner is generated from the back surface of the dielectric sheet 53 by the conductive brush 27, and the photosensitive drum is transferred through the dielectric sheet 53, the transfer material, and the toner layer. A transfer charge current is applied to 1. As a result, the transfer material is adsorbed at the same time that the dielectric sheet 53 is charged, and the toner image on the photosensitive drum 1 is transferred onto the transfer material.

In the multicolor image forming apparatus as in this embodiment, the transfer process is performed a necessary number of times on the transfer material, but the method of sequentially increasing the transfer power supply output after the second color is the optimum image. Is effective in obtaining. In that case, it is important to control the transfer power output amount calculated as described above as a reference.

When an image is output in various environments using the apparatus of this embodiment as described above, the current required for direct transfer can be output even in a sudden environmental change, and the image is scattered. An optimum image was stably obtained with high image quality without a decrease in density.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, as shown in FIG. 4, a transfer belt 30 is used instead of the transfer drum 5.
Is different from the first embodiment in that the corona discharger 31 is used instead of the conductive brush 27.

Further, in order to accurately control the optimum transfer current by the corona discharger 31, a means for detecting the total discharge current and electrically insulating the shield of the discharger to detect the discharge current flowing into the shield is provided. There is. As a result, the transfer current in the photosensitive drum direction, which is the difference current between the total discharge current and the inflow current, can be calculated, and accurate control can be performed. In addition,
Other control methods are the same as those in the first embodiment.

Also in the present embodiment, by detecting and measuring the developing current and controlling the transfer current, an optimum image of high quality can be obtained in the same manner as in the first embodiment, regardless of any environmental (temperature and humidity) changes. Was given.

<Third Embodiment> Next, a third embodiment of the present invention will be described with reference to FIG. The same parts as those of the first and second embodiments are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, as shown in FIG.
The difference from the first and second embodiments is that the transfer belt 30 is not used. The method of controlling the transfer current is the same as in the first embodiment.

Also in this embodiment, by detecting and measuring the developing current and controlling the transfer current, an optimum image of high quality can be obtained in the same manner as in the first embodiment, regardless of any changes in the environment (temperature and humidity). Was given.

<Fourth Embodiment> Next, a fourth embodiment of the present invention will be described with reference to FIGS. 6 and 7. The same parts as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

This embodiment is different from the first embodiment in that, as shown in FIG. 6, the static elimination power supply 32 as the static elimination voltage supply means and the separation power source 33 as the separation voltage supply means are controlled in the same manner as the transfer power source 26. .. Further, the control circuit 20 and the transfer control circuit 2
The point that the high voltage output control circuit 34 is formed by combining 5 into one is also different from the first embodiment.

In this embodiment, in addition to the data showing the relationship between the proper transfer current and the developing current, the data showing the relationship between the proper separation charge-eliminating voltage and the developing current as shown in FIG. It is stored in the circuit 34. As a result, not only transfer but also separation and charge removal can be properly performed regardless of environmental changes in temperature or humidity.

The conditions of the experiment were the same as those described in the first embodiment, but a corotron discharger having an opening width of 3 cm and a wire height of 15 mm from the shield top plate was used as a discharger for separation and static elimination. .. Note that, in the experiment, the fact that not only the change in the charge amount of the toner but also the change in resistance of the transfer paper and the dielectric sheet is taken into consideration is the same as in the first embodiment.

By using the data thus obtained, the optimum transfer current and separation charge-eliminating voltage can be obtained in any environment (temperature and humidity).

The operation of the apparatus of this embodiment is the same as that of the first embodiment until the end of transfer, but the proper separation voltage and the proper charge removal voltage calculated by the high voltage output control circuit 34 based on the developing current measured at the time of development are After transfer, it is applied to the separation power source 33 and the static elimination power source 32. Therefore, the separating discharger 10 neutralizes the transfer material with an appropriate voltage and discharges the dielectric sheet 53.
Peel it off. In addition, the electric dischargers 8 and 9 for electric charge elimination also eliminate the electric charge on the dielectric sheet 53 with an appropriate voltage to make the residual potential zero.

In separation and static elimination, it is not necessary to perform as strict control as in transfer, and in separation, static electricity needs to be eliminated while unfixed toner remains on the transfer material. Is desirable.

When images were displayed under various environments using the apparatus of this embodiment as described above, optimum images could be stably obtained with high image quality even under rapid environmental changes. That is, problems such as image scattering and density reduction during transfer, image distortion and paper jam during separation, and image unevenness due to poor charge removal did not occur.

<Fifth Embodiment> Next, a fifth embodiment of the present invention will be described with reference to FIG. The same parts as those of the first and fourth embodiments are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, as shown in FIG.
This is different from the fourth embodiment in that the transfer belt 30 is used in place of the above, and the corona discharger 31 is used in place of the conductive brush 27. Further, in order to accurately control the optimum transfer current by the corona discharger 31, means for detecting the total discharge current and electrically insulating the shield of the discharger to detect the discharge current flowing into the shield are provided. As a result, the transfer current in the photosensitive drum direction, which is the difference current between the total discharge current and the inflow current, can be calculated, and accurate control can be performed. The other control methods are the same as those in the fourth embodiment.

Also in this embodiment, by detecting and measuring the developing current and controlling the transfer current and the separation voltage, it is possible to optimize the image quality in the same manner as in the fourth embodiment in spite of any changes in the environment (temperature and humidity). An image was obtained.

<Sixth Embodiment> Next, a sixth embodiment of the present invention will be described with reference to FIG. The same parts as those of the first and fourth embodiments are designated by the same reference numerals and the description thereof will be omitted. This embodiment differs from the fourth and fifth embodiments in that the transfer drum 5 and the transfer belt 32 are not used as shown in FIG. The method of controlling the transfer current and the separation voltage is the same as in the fourth embodiment.

Also in this embodiment, by detecting and measuring the developing current and controlling the transfer current and the separation voltage, it is possible to optimize the image quality in the same manner as in the fourth embodiment regardless of any changes in the environment (temperature and humidity). An image was obtained.

[0048]

As described above, according to the present invention,
Since the change of the charge amount of the developer is detected by the developing current and the transfer condition is optimized without using the temperature / humidity sensor, even if the reaction speed with respect to the environmental change of the temperature / humidity sensor and the developer varies, It can detect the charge amount of the developer, and is not affected by environmental changes in temperature and humidity.
It is possible to stably obtain a high-quality and good optimum image without deteriorating the image quality due to developer scattering, transfer omission, transfer unevenness, low density, and the like. In addition, since the separation / static elimination conditions are controlled in the same manner, image irregularity at the time of separation, paper jamming, and image unevenness due to poor static elimination do not occur.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a relationship between a developing current and an appropriate transfer current with respect to temperature and humidity changes, which is stored in a transfer control unit of the apparatus shown in FIG.

FIG. 3 is a partially enlarged view showing a schematic configuration of a transfer electrode of the apparatus shown in FIG.

FIG. 4 is a diagram showing a schematic configuration of a second embodiment device of the present invention.

FIG. 5 is a diagram showing a schematic configuration of an apparatus according to a third embodiment of the present invention.

FIG. 6 is a diagram showing a schematic configuration of an apparatus according to a fourth embodiment of the present invention.

FIG. 7 is a diagram showing a relationship between a developing current and an appropriate transfer current and an appropriate separation / electrification voltage relationship with respect to temperature and humidity changes, which are stored in the control means of the apparatus shown in FIG. 6;

FIG. 8 is a diagram showing a schematic configuration of a fifth embodiment device of the present invention.

FIG. 9 is a diagram showing a schematic configuration of an apparatus according to a sixth embodiment of the present invention.

FIG. 10 is a sectional view showing a schematic configuration of a conventional device.

11 is a perspective view showing a schematic configuration of a transfer unit of the apparatus shown in FIG.

FIG. 12 is a diagram showing a relationship of changes in the charge amount of the developer with respect to changes in humidity.

FIG. 13 is a diagram showing a relationship of changes in resistance values of a transfer material and a transfer material carrying member with respect to changes in humidity.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensitive drum (latent image carrier) 4C, 4Y, 4M, 4BK Developing device 4CS Developing sleeve (Developer carrier) 5 Transfer drum (transfer means) 8, 9 Discharging discharger (discharging means) 10 Separation discharger (Separation Means) 23 Development Bias Power Supply (Development Voltage Supply Means) 24 Development Current Measurement Circuit (Development Current Measurement Means) 25 Transfer Control Circuit (Transfer Control Means) 26 Transfer Power Supply (Transfer Voltage Supply Means) 27 Dielectric Brush (Transfer electrode)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeo Tsunami 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (3)

[Claims] 1. A latent image carrier having an endlessly movable surface for carrying and transporting an electrostatic latent image on the surface, and a developer carrier arranged opposite to the latent image carrier. A developing device having the same, a developing voltage supplying means for applying a predetermined voltage to the developer carrying member, and the latent image carrying member downstream of the developer carrying member in the moving direction of the surface of the latent image carrying member. In the image forming apparatus provided with a transfer means having a transfer electrode arranged so as to face the transfer electrode, and a transfer voltage supply means for applying a voltage to the transfer electrode, the image forming apparatus is connected to the developing voltage supply means. A developing current measuring means for measuring the developing current; and a transfer controlling means connected to the developing current measuring means and the transferring voltage supplying means for detecting the developing current and controlling the output of the transferring voltage supplying means. However, the transfer control means is It is provided with data representing the relationship between the developing current that changes with respect to changes in temperature and the output of the transfer voltage supply means suitable for the temperature and humidity when the developing current is obtained, and is detected by the developing current measuring means. An image forming apparatus, wherein an output of a transfer voltage supply unit corresponding to a developing current is set to be selected based on the data. 2. A separation means having a separation electrode for separating the transfer from the latent image carrier or the transfer means side, a separation voltage supply means for supplying a voltage to the separation electrode, a developing current measuring means and the separation. A separating control unit connected to the separating voltage supplying unit for detecting a developing current and controlling an output of the separating voltage supplying unit, wherein the separating control unit is a developing unit that changes in response to changes in temperature and humidity. Data for representing the relationship between the current and the output of the separating voltage supply means suitable for the temperature and humidity when obtaining the developing current is provided, and the separating voltage supply corresponding to the developing current detected by the developing current measuring means is provided. The image forming apparatus according to claim 1, wherein the output of the means is set so as to be selected based on the data. 3. A transfer material carrying member for carrying a transfer material for transfer, charge removing means having a charge removing electrode for removing charge from the transfer material carrying member after transfer, and charge removing for supplying a voltage to the charge removing electrode. And a discharging current control unit connected to the developing current measuring unit and the discharging voltage supplying unit for detecting the developing current and controlling the output of the discharging voltage supplying unit. Is provided with data representing the relationship between the developing current that changes with changes in temperature and humidity and the output of the static elimination voltage supply means suitable for the temperature and humidity when the developing current is obtained. 3. The image forming apparatus according to claim 1, wherein the output of the charge eliminating voltage supply means corresponding to the developing current detected by the means is set to be selected based on the data.