JPH02127665A - Image forming device - Google Patents

Abstract

PURPOSE:To satisfactorily attract transfer material on a transfer material carrying means and to eliminate trouble such as transfer defect by varying and adjusting power supplied to a transfer electrifying means based on a temperature detection signal and/or humidity detecting signal. CONSTITUTION:Based on the temperature and humidity detecting signals from a temperature/humidity detecting sensor 16, an area is designated, and the value of an attraction current supplied to an attraction electrifier 6 is controlled by using an appropriate attraction current determined corresponding to the designated area as the target value. Then, the attracting current can be supplied to the attraction electrifier 6 in response to a change in the volume resistivity value of the transfer paper P due to the fluctuation of the humidity conditions of the transfer material P and a change in the surface resistance value of a transfer material carrying belt 5. As a result, the transfer material carrying means attracts the transfer material satisfactorily and constantly, regardless of the environmental change where the image forming device is installed, and moreover trouble such as transfer defect never occurs.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention generally relates to an image forming apparatus, and particularly, for example, to electrostatically adsorb a transfer material on a transfer material supporting means to support the transfer material, and to A multicolor electrophotographic copying machine or a color printer equipped with a transfer device that transfers a visible image formed by a developer on an image carrier onto the transfer material by applying an electric field to the transfer material. The present invention relates to a color image forming apparatus such as a color image forming apparatus.

Conventionally, this type of image forming apparatus has been configured as shown in FIG. 19, for example. That is, the image forming apparatus shown in FIG. 19 is of a type equipped with a transfer material conveying belt, and includes a cleaner 9 provided around the photoreceptor drum 1 around the photoreceptor drum 1. , pre-exposure lamp 10, charger 2, developer 4. Transfer charger 8
The main components include a transfer material conveying belt 5 wound around metal rollers 13, 14, and 15. ” The details of the two-way configuration are as follows. Image exposure 3 is irradiated from an image exposure irradiation means (not shown) toward the outer circumferential surface of the photosensitive drum 1 into the gap defined by the negative charger 2 and the developer 4. . The transfer material conveying belt 5 includes a metal roller 13
．． The metal rollers 1415 are wound in a substantially triangular shape, and each of the metal rollers 13.14, l-5, is grounded. The transfer material conveying belt 5 includes a metal roller 1
By a drive motor (not shown) connected to 5,
It is designed to rotate in the direction of the arrow in FIG. 19 (ie, counterclockwise). Around the transfer material conveying belt 5,
A suction charger 6 for attracting the transfer material P to the transfer material conveying belt 5-1, an opposing row 7, a neutralizing charger 11, a fur brush cleaner 12, and the like are provided.

In the image forming apparatus configured as described above, the cleaner 9 scrapes and collects the developer remaining on the outer peripheral surface of the photoreceptor drum 1, and the pre-exposure lamp 10 scrapes and collects the developer remaining on the outer peripheral surface of the photoreceptor drum 1. After the charges are removed, the outer circumferential surface of the photoreceptor drum 1 is uniformly charged by the negative charger 2 . - After uniform charging of the outer circumferential surface of the photoreceptor drum l by the charger 2 is completed, the outer circumferential surface of the photoreceptor drum l is irradiated with image exposure 3;
An electrostatic latent image corresponding to document image information is formed on the outer peripheral surface. After forming an electrostatic latent image on the outer peripheral surface t of the photoreceptor drum l, the developing device 4 is driven to visualize the electrostatic latent image, and the electrostatic latent image is made visible by rotating the photoreceptor drum 1 (in the direction of the arrow in FIG. 19). The latent image is moved to a portion where the outer peripheral surface of the photosensitive drum 1 and the transfer charger 8 face each other, that is, to a transfer position. On the other hand, the transfer material P is fed from a paper feeding system (not shown) in the direction of the arrow in FIG. 19, and is conveyed onto the transfer material conveying belt 5. The transfer material P conveyed to the transfer material conveyance belt 5'2 is transferred to the transfer material conveyance belt 5'' by applying a DC voltage or a high voltage in which a DC voltage component is superimposed on an AC voltage component to the adsorption charger 6. 5. Transfer material conveyance belt 5
A supporting charge is injected into the attracted transfer material P by a facing roller 7 serving as a counter electrode of the attraction charger 6, and the transfer material P is brought into pressure contact with the transfer material conveying belt 5''. The transfer material P thus attracted and pressed onto the transfer material transport belt 5 is transported to the above-described transfer position by the movement of the transfer material transport belt 5, and is formed on the outer peripheral surface of the photoreceptor drum 1. The visible image is transferred onto the transfer material P by applying a high voltage having a polarity opposite to the charge of the developer forming the visible image to the transfer charger 8. The transfer material P, onto which the visible image has been transferred by the transfer charger 8, is neutralized by the charge removal charger 11 to which an AC high voltage is applied, and after being separated from the transfer material conveyance belt 5, is moved in the direction of the arrow in FIG. Then, the image is fixed by a fixing device (not shown). The developer remaining on the outer peripheral surface of the photoreceptor drum l is scraped and collected by a cleaner 9, and the residual charge on the outer peripheral surface of the photoreceptor drum l is removed by a pre-exposure lamp 10 having a sufficient amount of irradiation light. The static electricity is removed and preparations are made for execution of a new image forming process.

However, in the conventional color image forming apparatus configured as described above, the high voltage applied to the adsorption charger 6 is always constant regardless of changes in the environment in which the color image forming apparatus is installed. It is controlled to be a good value,
The transfer material P is attracted to the transfer material conveying belt 5 at this constant value. However, when the color image forming apparatus is placed under high temperature and high N conditions, the value of the volume resistivity of the transfer material P used is 60
%) When the transfer material P is paper, the amount decreases by about two orders of magnitude compared to when the transfer material P is placed below. Also, regarding the transfer material conveyance belt 5, since moisture is adsorbed on the surface thereof, the surface resistance value of the transfer material conveyance belt 5 decreases. Therefore, the voltage applied to the adsorption charger 6 is too low, and the adsorption of the transfer material P to the transfer material conveyance belt 5 is insufficient, resulting in misalignment of the transfer material P on the transfer material conveyance belt 5 and the transfer material. On the other hand, when the color image forming apparatus is placed in a low-temperature, low-humidity environment, the value of the volume resistance of the transfer material P used is more likely to occur when forming the color image. Compared to when the apparatus is placed in a normal temperature and normal humidity environment (temperature 23° C., humidity 60%), when the transfer material P is paper, the temperature rises by about two orders of magnitude. Also, regarding the transfer material conveyance belt 5, the surface resistance value of the transfer material conveyance belt 5 increases because the amount of moisture adsorbed on its surface decreases. Therefore, although it is possible to obtain a sufficient adsorption force of the transfer material P to the transfer material conveying belt 5 with the height of the heavy pressure applied to the adsorption charger 6, the above-mentioned adsorption charger 6
There was a problem in that good transfer could not be performed because the charges attached to the back surface of the transfer material conveying belt 5 and the surface of the transfer material P were conveyed to the transfer position without being attenuated due to the adsorption charge caused by the transfer material P. . The transfer failure under the low temperature and low humidity environment as described above is proven by the facts described below. That is, in general, when performing a transfer process, the transfer material conveying belt 5 before the transfer process is
The surface potential after performing the transfer process is Vz
Then, when the polarity of the transfer charge is positive, V<V
z, and the difference value between Vz and V) is Vz−V,
Experiments have shown that the value of is preferably at least 0.5 KV or more. However, when the color image forming apparatus is placed in a low-temperature paper ld environment, the voltage applied to the adsorption charger 6 is too high, so the value of surface potential No. 7 of the transfer material conveyance belt 5 is distorted. There is a tendency for the value to approach the saturation charge potential Vs of the intermediate transfer material conveying belt 5, making it impossible to satisfy Vz -V+ >0.5 KV, which causes transfer failure. Such transfer defects similarly occur in a full-color multicolor electrophotographic copying machine equipped with a transfer material conveyor, a feed belt, a transfer drum, and the like. That is, in the above-mentioned copying machine, the photosensitive drum is transferred three to four times by multiple transfer.
By transferring the visible images of each color formed on one surface onto the transfer material P, a full-color image is formed. However, if a high potential is applied to the transfer material conveying belt 5 in the adsorption charging process, for the reason mentioned above, not only the value of Vz-V but also the potential V'z before the second transfer process is and the potential V3 after performing the second transfer process, the difference value v3-v
'This value is the difference value v between the potential V'3 before executing the third transfer process and the potential v41 after executing the third transfer process.
, -v'1 value, potential V' before execution of the fourth transfer process
There is a possibility that the difference value v5-v' between the potential (v5-v') and the potential (5) after the fourth transfer step cannot be maintained at a value larger than 0.5 KV. Therefore, even in such a multicolor electrophotographic copying machine, there is a problem in that the above-mentioned transfer failure occurs.

The present invention was devised in order to solve the above-mentioned problems, and its purpose is to always maintain the transfer material of the transfer material regardless of changes in the environment in which the image forming apparatus is placed. It is an object of the present invention to provide an image forming apparatus that can perform good suction to a supporting means and that does not cause problems such as poor transfer.

The above objects are achieved by an image forming apparatus according to the present invention. In summary, the first aspect of the present invention includes an image carrier;
a transfer material carrying means for carrying a transfer material to which a visible image formed on the R1B carrier is transferred by electrostatic adsorption and transporting the transfer material to a transfer position of the image carrier; an adsorption charging means for charging the transfer material and the transfer material supporting means to be electrostatically attracted to the means; a temperature/humidity detection means for detecting temperature and/or humidity inside the apparatus body; The image forming apparatus is characterized in that it comprises a variable adjustment means for variably adjusting the amount of Ta supplied to the attraction charging means based on an output temperature detection signal and/or humidity detection signal. In a second aspect of the present invention, an image carrier and a transfer material to which a visible image formed on the image carrier is transferred are supported by electrostatic attraction and moved to a transfer position of the image carrier. a transfer material carrying means for conveying; an adsorption charging means for charging the transfer material and the transfer material carrying means to electrostatically attract the transfer material to the transfer material carrying means; and a transfer material conveyed to the transfer position. a transfer charging device that transfers the visible image to the device; a temperature/humidity detection device that detects the temperature and/or humidity inside the device main body;
It is characterized by comprising a variable adjustment means for variably adjusting the amount of power supplied to the adsorption charging means and the transfer charging means based on a temperature detection signal and/or a humidity detection signal output from the temperature/humidity detection means. It is an image forming apparatus.

1 presentation 1 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an image forming apparatus according to a first embodiment of the present invention.The image forming apparatus according to a first embodiment of the present invention has the overall configuration shown in FIG. Although it is generally similar to an image forming apparatus, its outline is as follows. That is, the image forming apparatus shown in FIG. 1 is of a type equipped with a transfer material carrying means, that is, a transfer material conveying belt. A cleaner 9, a pre-exposure lamp 10, a charger 2, and a developer 4 provided around the
The main components include a transfer charging means, that is, a transfer charger 8, and a transfer material conveying belt 5 wound around metal rollers 13, 14, and 15. The above configuration will be described in more detail as follows. A photosensitive material 5 is placed in the gap defined by the negative charger 2 and the developer 4.
Image exposure light 3 is irradiated onto the outer circumferential surface of the body drum 1 from an image exposure irradiation means (not shown).

The transfer material conveying belt 5 includes metal rollers 13.14.1
The metal rollers 13, 14, and 15 are each grounded.

The transfer material conveying belt 5 is rotated in the direction of the arrow in FIG. 1 (ie, counterclockwise) by a drive motor (not shown) connected to the metal roller 15. At the periphery of the transfer material conveyance belt 5, an attraction charging means, that is, an attraction charger 6, which attracts the transfer material P onto the transfer material conveyance belt 5, an opposing roller 7, and a counter roller 7 are provided. l! A charger 11, a fur brush cleaner 12, etc. are provided.

In this embodiment, the adsorption charger 6 has an opening width of 22 mm, and the discharge wire and the transfer material conveying belt 5 are
The distance between the two is set to be 11 mm.

The transfer material conveying belt 5 has a thickness of 150 pm.
A PVdF (polyvinylidene fluoride) sheet is used, and it rotates at a speed of 16'Omm/sec. The opposing roller 7 is made of aluminum and has a diameter of 20 mm, and is grounded and rotates when it comes into contact with the transfer material conveying belt 5. Furthermore, according to this embodiment, a temperature/humidity detection means, that is, a temperature/humidity sensor 16 is provided to detect the temperature and humidity of the atmosphere inside the color image forming apparatus. The temperature/humidity sensor 16 is disposed near the transfer material conveyance belt 5 at a position where it does not obstruct movement of the transfer material P. The temperature/humidity sensor 16 outputs a voltage signal corresponding to the temperature/humidity detected inside the device. The image forming operation in the color image forming apparatus configured as described above has already been explained with reference to FIG. 19, so the explanation thereof will be omitted.

FIG. 2 shows a control system included in the image forming apparatus according to the first embodiment of the present invention. In FIG. 2, the temperature/humidity sensor 1-6 receives a temperature detection signal ( The A/D converter 506 outputs a humidity detection signal (hereinafter referred to as "T signal") and a humidity detection signal (hereinafter referred to as "H signal"). The converter 515 converts the H signal from analog to digital and outputs the converted signal to the I10 port 507, respectively. The variable adjustment means, that is, the CPU 510, adjusts the I1 before a series of image forming operations by the image forming apparatus.
Read each signal input to the 0-board 507 and 508, refer to table 1 (shown in FIG. 3) built in the memory 511, and determine the area in which each signal is set in the table l. -■ Specify which area the object belongs to, and at the same time, the CPU 510
refers to table 2 (shown in FIG. 4) built in the memory 511, reads the adsorption current value data corresponding to the T signal and H signal from the table 2,
The read adsorption current value data is output to the D/A converter 513 via the I10 port 512. The D/A converter 513 is connected to the CPU 5 via the I10 boat 512.
After digital/analog conversion of the adsorption current value data outputted from N510, the data is outputted to a high voltage power supply device 514, whereby the data is transferred from the high voltage power supply bag N514 to the adsorption charger 6.
An adsorption current based on the adsorption current value data is supplied to the adsorption current value data.

Note that the series of processing operations by the CPU 510 described above are as follows:
As is already well known, this is performed prior to a copying operation, that is, an image forming operation.

Here, FIG. 3, FIG. 4, FIG. 5, and FIG. 6 will be explained in more detail.

FIG. 3 shows the contents of table 1 stored in the memory 511 shown in FIG. In Table 1, regions ■ to ■ are divided as appropriate by a plurality of equal moisture content curves determined by temperature and humidity, respectively.
In the same area, the charging characteristics of the developer, the charging characteristics of the transfer material P, and the moisture absorption and charging characteristics of the transfer material carrying sheet such as the transfer material conveying belt 5 are approximately equal, and in similar environments. It is believed that there is. The data shown in FIG. 4 shows details of the contents of table 2 stored in memory 511. In the table 2, when the environment such as temperature and humidity in which the image forming apparatus is installed is divided into regions ■ to ■, the most appropriate value of the adsorption current at the representative point of each of these regions is as follows. It is set corresponding to each of the above areas. The aforementioned representative point is represented by the point X shown in FIG. 3. The appropriate adsorption current values for each of the conflict areas ① to ② shown in FIG. 4 are obtained through the following process. First, the third
Set the representative points (X points shown in Fig. 3) in each environment shown in the figure areas The relationship between the adsorption force and the material conveying belt 5 was measured. Adsorption force F of the transfer material P (80g paper) to the transfer material conveying belt 5
In this embodiment, the value of ad is determined by applying an adsorption current value Iad to the adsorption charger 6 to adsorb the transfer material P onto the transfer material conveyance belt 5, as shown in FIG. Immediately attach a spring gauge to one end of the transfer material P in the conveyance direction, pull the transfer material P along the moving direction of the transfer material conveyance belt 5, and create a critical tensile force F( dyne) and the value of the measured critical tensile force F(dyne) is applied to the transfer material conveying belt 5 of the transfer material P.
It was decided to calculate by dividing by the contact area S with. FIG. 5 shows the measurement method described above for each of the areas ■ to ■.
In FIG. 5, which shows the data obtained by each execution, the point FC on the vertical axis indicates the minimum adsorption force value necessary for the transfer material conveying belt 5 to convey the transfer material P. In this example, approximately 50 dynes/
It was decided to set it to cm'. In addition, the value of the appropriate adsorption current Iad shown in FIG. 4 mentioned above should be set so as to obtain the value of the adsorption force Fad which is a slightly larger value than the value of the adsorption force FC shown in FIG. And so. or,
In region (■) of Figure 4, the appropriate adsorption current value is within the unstable desired range where discharge from the adsorption charger 6 is likely to occur and is likely to fluctuate, so the value is 40gA, which is slightly higher than the actual appropriate value. is set to the value.

As explained below, according to the first embodiment according to the present invention, the area illustrated in FIG. Since the value of the adsorption current supplied to the adsorption charger 6 is controlled by setting the appropriate adsorption current value determined according to the designated area as the target value, the value of the adsorption current supplied to the adsorption charger 6 is controlled. The rotation is to supply the adsorption charger 6 with an adsorption W flow having a magnitude corresponding to a change in the volume resistance value of the transfer material P or a change in the surface resistance value of the transfer material conveyance belt 5.

FIG. 7 shows an image forming apparatus according to a second embodiment of the present invention. In this embodiment, the facing roller 7 shown in FIG. A charger 17 was provided. The rest of the configuration is the same as that of the image forming apparatus according to the first embodiment, so a description thereof will be omitted. The above-mentioned 1.7 outer adsorption charger 17 has the same structure as the above-mentioned adsorption charger 6. That is, the outer adsorption charger 17 has an opening width of 22 mm.
mm, and the distance between the discharge wire and the transfer material conveying belt 5 is set to 11 mm.

FIG. 8 shows a control system included in an image forming apparatus according to a second embodiment of the present invention. Since the charger 17 is provided, the control system of the image forming apparatus according to this embodiment includes an I1 connected to the outer adsorption charger 17 in addition to the configuration shown in FIG.
0 baud) 516, D/A converter 517. High voltage power supply device 5
18 new editions have been added. I10 boat 516 is I
10 boat 512, the D/A converter 517 is connected to the D/A converter 513, and the high voltage power supply 518 is connected to the high voltage power supply 514.
Since these devices are compatible with each other, explanations regarding each of these devices will be omitted. A series of processing operations by the CPU 510 are also the same as those in the first embodiment, so a description thereof will be omitted. The memory 511 stores a table 3 instead of the table 2 described above. The data set in Table 3 includes the environment such as temperature and humidity in which the image forming apparatus is installed (indicated by areas ■ to ■);
The appropriate adsorption current value (Iadi) C (hereinafter referred to as "inside appropriate adsorption current value") supplied to the inner adsorption charger 6 set for each of these environments, and the appropriate adsorption current value supplied to the outer adsorption charger 17 (Iado) (hereinafter referred to as "outside appropriate adsorption current value") (see Figures 10 and 12). The appropriate adsorption current value is determined through the process described below. First, representative points (X points shown in FIG. 3) in each environment shown in regions ■ to ■ in FIG. 3 are set, and the value Iadi (Iadsorption 1nner
), the value of the outer adsorption current Iado (Iadsorpt
i.

The relationship between the adhesion force of the transfer material P (80 g paper) to the transfer material conveyance belt 5 was measured. Although various combinations of the value Iadi of the inner adsorption current and the value Iado of the outer adsorption current can be assumed, the present inventors have determined that (a) I
Iadi, Iad when ad 1=-I ado
Relationship between o and adsorption force of transfer material P (80g paper) to transfer material conveyance belt 5, (b) Iadi and transfer material P (80g paper) to transfer material conveyance belt 5 when Iado is fixed at -100gA Experiments were conducted regarding two types of relationship with adsorption force. As a result of the experiment (a) mentioned above,
Data as shown in FIG. 9 and FIG. 1O were obtained. Figure 9 shows the inner adsorption current Iadi and the outer adsorption current -
Area when Iado is changed at the same rate ■～
Inner adsorption current Iadi, outer adsorption current Iad at ■
10 shows the relationship between o and the adsorption force, and FIG. 10 also shows the inner appropriate adsorption radio wave value and the outer appropriate adsorption radio wave value set based on FIG. 9 as already explained. The curves that define each region (■ to ■) shown in FIG. An appropriate value is set for . Therefore, in reality, the ninth point indicates the critical point of adsorption force.
The adsorption force is considerably larger than the value at point FC on the vertical axis in the figure. As a result of the above-mentioned experiment (b), Figure 1J,
Data as shown in FIG. 12 were obtained. 1st
Figure 1 shows the relationship between Iadi and adsorption force when Iad o = -L 00gA, and the first
FIG. 2 shows the inner appropriate adsorption current value set based on FIG. 11. As a result of performing an image output test by operating the image forming apparatus under the conditions set in the experiments (a) and (b) described above, the results were positive, with no problems such as poor transfer or skewed transfer material. It was possible to obtain a copy image with high image quality.

As explained above, according to the second embodiment according to the present invention, the area illustrated in FIG. , the inner adsorption charger 6. sets the inner appropriate adsorption current value and the outer appropriate adsorption current value determined according to the specified area as target values. Since it was decided to control the inner adsorption charger and outer adsorption current values respectively supplied to the outer adsorption charger 17,
The inner adsorption charger 6 and the outer adsorption charger 17 apply an adsorption current of a magnitude corresponding to a change in the volume resistance value of the transfer material P due to a change in the moisture absorption state of the transfer material P or a change in the surface resistance value of the transfer material conveyance belt 5. It became possible to supply

FIG. 13 shows a color image forming apparatus according to a third embodiment of the present invention. The color image forming apparatus shown in FIG. 13 is of a type equipped with a transfer material carrying means, that is, a transfer drum, and its overall configuration is already well known, but its outline will be explained as follows. It seems so.

That is, in FIG. 13, the color image forming apparatus main body 10
A transfer drum 18 having a PVdF sheet with a thickness of 150 gm stretched over the opening area of its peripheral surface as a transfer sheet is disposed approximately at the center of the transfer drum 18 . The transfer drum 18 is rotatably supported in the direction of the arrow (clockwise) in FIG. An electric appliance 17a and a buffer 2 brush 12b are respectively provided. On the outer circumferential side of the transfer drum 18, a facing roller 7 is disposed facing the adsorption charger 6, and a transfer material static eliminator 17b is disposed facing the transfer sheet static eliminator 17a. A separate static eliminator charger 11 and a separation claw 21 are installed near the static eliminator 17b.
A transfer sheet cleaning brush 12a and a temperature/humidity sensor 16 are also provided. A transfer material supplied from a paper feed tray 22 attached to the right side of the apparatus main body lOO in FIG. The end portion of the transfer material conveyance guide mechanism in the conveyance direction is faced. A fixing device 19 is provided in a portion inside the image forming apparatus main body lOO facing the separation claw 21 (upper right in FIG. A transfer material conveying belt is provided. In the upper right part of the image forming apparatus main body 100 in FIG.
An original scanning section 3a constituting the optical system 3 is disposed in the upper area of the apparatus main body Zoo, and an upper left area of FIG. A color separation filter 3b is provided. The document scanning section 3a described above is located approximately at the center of the image forming apparatus main body 100, which includes a document illumination lamp, various reflecting mirrors, a lens system, a color image sensor, etc.
In the upper region of the main body 100 of the image forming apparatus, the image bearing member, that is, the photosensitive drum 1 is disposed such that the outer circumferential surface thereof can come into contact with the outer circumferential surface of the transfer drum 18. A developing means, that is, a horizontally movable developing device 4
is installed. Details of the horizontally moving developing device M4 will be described later. The photoreceptor drum 1 described above is rotatably supported in the direction of the arrow in FIG. Various devices necessary for this purpose include the transfer drum 18, transfer charger 8, horizontally movable developing device 4, cleaner 9, primary charger 2, etc., which have already been described. To explain the horizontally movable developing device 4 in more detail, the horizontally movable developing device 4 includes a first
FIG. 3 shows a movable body 4a that can be moved laterally and approximately horizontally, and a yellow developer 4Y, a magenta developer 4M, a cyan developer 4C, and a black developer 4 placed on the movable body 4a.
It is equipped with 8 and. Since the details of the configuration of each of the above-mentioned parts and the image forming operation are already well known, their explanation will be omitted.

FIG. 14 shows a control system included in a color image forming apparatus according to a third embodiment of the present invention. In this embodiment, the value of the attraction current supplied to the attraction charger 6 is In addition to controlling the value of the transfer current supplied to the transfer charger 8, the control system included in the color image forming apparatus according to this embodiment includes the control system shown in FIG. In the configuration, there is an I10 port connected to the transfer charger 8) 519. A D/A converter 520 and a high voltage power supply device 521 are newly added. The I10 port 519 is connected to the I10 boat 512, and the D/A converter 520 is connected to the D/A converter 51.
Third, since the high-voltage power supply device 521 corresponds to the high-voltage power supply device 514, a description of each of these devices will be omitted. Regarding a series of treatment operations by the CPU 510,
Since this is the same as in the first embodiment, the explanation will be omitted. The memory 511 stores a table 4 instead of the table 2 described above. The data set in Table 4 is based on the environment (area
) and the appropriate adsorption current value (Iad) supplied to the adsorption charger 6 set for each of these environments.
, shows appropriate transfer current values to be separately supplied to the transfer charger 8 when transferring developed images of yellow, magenta, cyan, and black to a transfer material, respectively (see FIG. 16).

The appropriate adsorption current value and appropriate transfer current value for each of the regions (1) to (2) shown in FIG. 16 are obtained through the following process. First, representative points in each environment (point X shown in FIG. 3) are set in the areas (Φ) shown in FIG. 3, and the value Iad of the adsorption current at each of these representative points The relationship between the adsorption force and the adsorption force on the transfer sheet (80g paper) was measured.As a result of this measurement, the data shown in Figures 15 and 16, respectively, were obtained. The point F'c indicates the minimum suction force required for the transfer sheet stretched over the curved opening area of the transfer drum 18 to support and convey the transfer material P. As is clear from Figure 15, approximately 55 d y
The value of the adsorption force F'c set in this example is set to a value that is slightly thicker than the value of the adsorption force Fc in both of the above examples. The reason is that the color image forming apparatus according to this embodiment differs from the image forming apparatuses according to the above embodiments in that the color image forming apparatus according to the present embodiment has a transfer drum 1.
8, the effect of curvature must be taken into account, and the influence of this curvature can prevent the transfer material P from peeling off from the transfer sheet or misaligning due to the strain the transfer material P has. This is for the purpose of reading one page. 1st
In the data shown in FIG. 6, the value of the appropriate attraction current is set to a value Iad that allows obtaining a value Fad that is slightly thicker than the attraction force Fc. (However, Fig. 15 and 1
In the region (■) shown in Fig. 6, etc., the value I of the appropriate adsorption current that provides the adsorption force shown at point F'c on the vertical axis in Fig. 15 is determined.
Since ad is within the unstable discharge region, it is desired to set the appropriate adsorption current value as high as possible (for example, about 70 gA to 80.A), but in this example, it is set to 40. It is set to a low value of A. The reason for this will be explained later)
0 In this embodiment, as is clear with reference to FIG. 16, in addition to the appropriate adsorption current values for each environment shown in regions (■) to (■), yellow, magenta, cyan, and Appropriate transfer when transferring black visible images to transfer material P separately? ! ! The flow value is set.

In this embodiment, the appropriate transfer current value shown in FIG. 16 is set as shown in FIG. 17. The horizontal axis shown in Figure 17 shows the high voltage power supply system! The transfer current value supplied from 1521 to the transfer charger 8 is set, and the transfer efficiency is set on the vertical axis of the figure. Here, the transfer efficiency refers to the outer peripheral surface of the photoreceptor drum l.

Set up a patch of 50mm x 50mm, and
Calculated from the weight of the developer when a visible image is formed on the outer peripheral surface of the photoreceptor drum 1 by adjusting the latent image forming conditions and developing conditions so that a 50 mm patch has a reflection density of approximately 1.5. This is what is required by doing. That is, when the adsorption TL flow Iad is set to 40 tiles A and the transfer material P is adsorbed onto the transfer sheet, the visible image formed with the yellow color developer (dark color developer) is transferred to the transfer material P. Figure 0 shows the relationship between the value of transfer current and the value of transfer efficiency during transfer.

In the region of 0 to 100μ, A on the horizontal axis, transfer defects occur because the value of the transfer current is small, and the horizontal axis 12
In the range of 0-320 gA.

Since the transfer radio wave value is sufficiently large, good transfer is performed. In addition, in the region of 340 pA or more on the horizontal axis in the figure, since the transfer current value is too large, the polarity of the charge of the developer drawn from the outer peripheral surface of the photoreceptor drum 1 toward the transfer material P changes. The developer is reversed by the transfer charge applied from the transfer charger 8, and retransfer begins to occur in which the developer is transferred from the transfer material P to the outer peripheral surface of the photoreceptor drum 1. From the characteristic curve (■) described above, the appropriate transfer current value (IY) in the area (■) during the transfer process of the first color developer is set to 1.
It was set to 40JLA. In FIG. 17, the curve (■) shows the magenta color developer (the first 2 shows the relationship between the transfer current value Im and the transfer efficiency value during the transfer process of the two-color developer). The characteristic curve (■) shows that in the process of sequentially executing the image forming sequence in the region (■), the adsorption current value is set to 40 A, and the transfer current value of the first color is set to 140 A.
After setting pA, an experiment was conducted in which the transfer current In of the second color was applied to the transfer charger 8, and the relationship between the value of the transfer current Im obtained as a result and the transfer efficiency is shown. . From the characteristic curve (■) mentioned above, the appropriate transfer current f* (Im) in the area (■) during the transfer process of the second color developer is determined by 2.
I set it to 40 tiles A. In FIG. 17, the curve (■) indicates that the adsorption current Iad in the area (■) is 40. A, and the value of Iy during the transfer process of the first color developer is set to 140.
The value of Im during the color developer transfer process is 240p.
3 shows the relationship between the transfer current value Ic and the transfer efficiency value during the transfer process of the cyan color developer (third color developer) when the values are set to A. In Figure 17, the curve ■ is
The adsorption current Iad is set to 40 gA in area (3), and the value of Iy during the first color developer transfer process is set to 140, A.
In addition, when the value of Im during the transfer process of the second color developer was set to 240ttA, and the value of Ic during the transfer process of the third color developer was set to 340ttA, the black developer (fourth color developer) Transfer current value I at the time of transfer T of color developer)
It shows the relationship between bk and the value of transfer efficiency. The above-mentioned characteristic curves (2) and (2) were also determined in the same manner as the characteristic curves (2) and (2). In addition, from the above-mentioned characteristic curve (■), the appropriate transfer current value (I c) during the transfer process of the third color developer is 340 pA, and from the characteristic curve (■), the appropriate transfer current value (I c) during the transfer process of the fourth color developer is determined to be 340 pA. The current value (Ibk) was set to 440 lA. Area■
For ~■, each value is set in the same manner as above. Here, in FIG. 17, the curve 1' indicates the value of the transfer current Ibk related to the fourth color developer and the value of the transfer current Ibk related to the fourth color developer in the results of the above series of experiments with the value of the adsorption current Iad set to 70 A. 0 curve ■' which shows the relationship with the efficiency value
As is clear with reference to , the value of the transfer current Ibk is I
Although there was a peak near bk=400 pot A, the transfer efficiency value was very low at 65%, and the visible image obtained at this time had white spots and was of poor image quality. In general, it is said that the transfer efficiency for obtaining a copy image with good, high-quality image quality is 75% or more, so the reason for this kind of problem is that the value of the adsorption current is set too high. This is thought to be because the charging potential of the transfer sheet has already reached the saturation charging potential of the transfer sheet in the transfer process of a visible image formed using a black developer, which is the fourth color developer. As mentioned above, when performing the so-called multiple transfer process, it is said that good transfer can be performed if the amount of increase in the surface potential of the transfer sheet for each transfer process is 0.5 KV or more. For verification purposes, those who have not yet used the color image forming apparatus should actually operate the color image forming apparatus using the appropriate adsorption current value and appropriate transfer current value set corresponding to the area (■). The surface potential of the transfer sheet was measured. As a result, data as shown in FIG. 18 was obtained. Vz- shown in Figure 18
Value of V, v3-v'Value of Z, V, -Value of V'3, v5-
When the values of v' were verified, they were found to be approximately 0.6 KV. (For reference, Iad=70gA
v5-v' when.

The value was 0.3KV. ) From the series of experimental results as described above, the data as shown in FIG. 16, that is, the memory 5 shown in FIG.
This is the result of Daple 4 stored in 11.

As explained above, according to the third embodiment according to the present invention, a multicolor copy image having good and high quality can be obtained as in the first and second embodiments. Is possible. In this embodiment, for convenience of explanation, the radio waves supplied to the adsorption charger 6 and the transfer charger 8 are subjected to constant radio wave control, but constant voltage control may also be used instead of constant current control. There is no problem, and the adsorption charge is made to have the same polarity as the transfer charge.
There is no problem even if the polarity is reversed.6 Furthermore, the area ■～
As for (2), there is no problem in increasing or decreasing it as necessary.

As explained above, according to the present invention, regardless of changes in the environment in which the image forming apparatus is installed, it is possible to always perform good adsorption of the transfer material to the transfer material carrying means, and It is possible to provide an image forming apparatus that does not cause problems such as poor transfer.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a block diagram showing a control system included in the image forming apparatus according to the first embodiment of the present invention. FIG. 3 is a diagram showing the contents of table l stored in the memory 511 shown in FIG. 2. FIG. 4 is a diagram showing the contents of table 2 stored in the memory 511 shown in FIG. 2. FIG. 5 is a diagram showing data that served as the basis for obtaining the data listed in Table 2 shown in FIG. 4. FIG. 6 is an explanatory diagram of a method of measuring the suction force to obtain the suction force Fc shown in FIG. 5. @Figure 7 is a schematic diagram showing an image forming apparatus according to a second embodiment of the present invention. FIG. 8 is a block diagram showing a control system included in an image forming apparatus according to a second embodiment of the present invention. FIG. 9 is a diagram showing data that is the basis for obtaining the data listed in Table 3 shown in FIG. 10. FIG. 10 is a diagram showing the contents of table 3 stored in the memory 511 shown in FIG. 8. FIG. 11 is a diagram showing data that is the basis for obtaining data different from the data shown in FIG. 10 described in Table 3 shown in FIG. 12. FIG. 12 shows the contents of table 3, which is stored in the memory 511 shown in FIG. 8 and incorporates data different from table 3 shown in FIG. 10. It is a diagram. FIG. 13 is a schematic diagram showing the configuration of a color image forming apparatus according to a third embodiment of the present invention. FIG. 14 is a block diagram showing a control system included in a color image forming apparatus according to a third embodiment of the present invention. FIG. 15 is a diagram showing data that is the basis for obtaining the appropriate adsorption current value data listed in Table 4 shown in FIG. 16. FIG. 16 is a diagram showing the contents of table 4 stored in the memory 511 shown in FIG. 14. FIG. 17 is a diagram showing data that is the basis for obtaining the appropriate transfer current value data listed in Table 4 shown in FIG. 816. FIG. 18 is a diagram showing data obtained as a result of operating the color image forming apparatus according to the third embodiment of the present invention and measuring the charging potential of the transfer seal I of the transfer drum along the copy sequence. . FIG. 19 is a schematic diagram showing the configuration of an image forming apparatus according to the prior art. 1: Photosensitive drum 5: Transfer material conveying belt 6: Adsorption charger 8: Transfer charger 16: Temperature/humidity sensor 18: Transfer drum LO: CPU P: Transfer material 2° 4° Temperature T (''C) Figure 5 ad (7uA) Figure 6 Figure 8 Figure 11 factor lad, σ = -100/JA Figure 14 Figure 15 factor ad (HA) Figure 16 Transfer efficiency Ol Figure 17 Figure 18 Section copying and copying

Claims (1)

[Scope of Claims] 1) Transfer in which an image carrier and a transfer material to which a visible image formed on the image carrier is transferred are supported by electrostatic adsorption and transported to a transfer position of the image carrier. a material carrying means, an adsorption charging means for charging the transfer material and the transfer material carrying means so as to electrostatically attract the transfer material to the transfer material carrying means, and a temperature sensor for detecting the temperature and/or humidity inside the main body of the apparatus. / Humidity detection means, and variable adjustment means for variably adjusting the amount of power supplied to the adsorption charging means based on the temperature detection signal and/or humidity detection signal output from the temperature/humidity detection means. image forming device. 2) an image carrier, and a transfer material carrying means for carrying a transfer material to which a visible image formed on the image carrier is transferred by electrostatic adsorption and transporting the transfer material to a transfer position of the image carrier; an adsorption charging means for charging the transfer material and the transfer material carrying means to electrostatically attract the transfer material to the transfer material carrying means; and a transfer charging means for transferring the visible image to the transfer material conveyed to the transfer position. temperature/humidity detection means for detecting temperature and/or humidity inside the apparatus main body; An image forming apparatus comprising: a variable adjustment means for variably adjusting the amount of power supplied to the transfer charging means.