JPS60126667A - Image forming device - Google Patents

Abstract

PURPOSE:To correct a developing characteristic and a sensitivity of a photosensitive body by a simple constitution by correcting a developing bias condition in accordance with an image characteristic at every image forming unit. CONSTITUTION:A constant-voltage element 7 is incorporated in an image forming unit 1. One end of the element 7 is connected to an electrode plate 8 and a terminal 11 of an image forming device body 10, the other end of the element 7 is connected to a terminal 12, and the terminal 12 is connected to a bias power source E. On the other hand, a developing device 2 is attached and detached freely to and from a holding member 13 of the device body 10, a toner of an optional specified color is contained in the developing device 2, and when changing a color of an image to be obtained, a developing device containing a toner of other color is loaded. Also, a bias voltage of the power source E is corrected in accordance with an image characteristic by every image forming unit.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an image forming apparatus that obtains images with different characteristics by replacing image forming units.

(Prior Art) In an image forming apparatus in which developers (or toners) of different colors are replaced in order to obtain images with different characteristics, for example, images with different colors, developing bias or In order to prevent image adjustment conditions such as exposure amount and charging potential from going out of order, it is necessary to make the development characteristics as consistent as possible. However, in reality, it is very difficult to make the development characteristics of different types of developers the same. This is because, for example, when toners of different colors are used, the charging characteristics generally vary depending on the color of the toner, which causes deviations in development characteristics depending on the color type of toner.

Conventionally, as a method for correcting such deviations in development characteristics, the following measures have been taken.

(1) Correction by changing the development gap.

(2) Correction by changing the doctor blade gap.

+31 31. Correction by changing the rotation speed of the image sleeve.

(4) Correction by changing the magnetic force of the magnet inside the developing sleeve.

(5) Correction by changing the rotation speed of the magnet inside the developing sleeve.

In addition, the following methods are available for adjusting the development characteristics by changing the image forming conditions.

(1) Change the charging potential.

+21 Change the exposure amount (ground potential).

However, in the former example of +11 to +51,
A disadvantage is that a completely separate developing unit is required for each type of developer. Also, the latter (l).

(In the example of 2;, the image forming conditions of the main body of the image forming apparatus are
This method requires means for switching each developing unit, and has the disadvantage that the configuration becomes complicated.

(Objective) It is an object of the present invention to provide an image forming apparatus that solves the above-mentioned problems and allows correction of development characteristics and the like with an extremely simple configuration.

(composition) The configuration of the present invention will be described below based on examples.

By the way, the apparatus of the present invention corrects the developing conditions between different types of image forming units by providing a developing bias correction means including a constant voltage element in the replaceable image forming unit including at least the developing device. This is what we do.

As such a condition correction method, for example, Japanese Patent Application Laid-Open No. 1986-
A technique as shown in Japanese Patent No. 76845 has been proposed, but in this example, the above-mentioned correction is limited to a mechanical condition setting means such as a lever. There is a drawback that the setting means must have an unnecessarily wide variable range. In addition, a technique disclosed in Japanese Unexamined Patent Publication No. 58-105168 has already been proposed, but in this example, the image forming unit itself is equipped with a condition setting means, so the device cost is reduced. There is a rising problem.

The present invention can also address these problems. FIG. 1 shows an apparatus according to an embodiment of the present invention, and in this example, the image forming unit 1, which is replaced as appropriate with respect to the main body of the image forming apparatus, is a single type having only a developing device 2. . The scooping device 2 includes a developing sleeve 5 and a doctor blade 6, which apply toner carried on the circumferential surface of a developing container 39 containing toner to a photoreceptor 4 to perform development.
It is composed of etc.

A constant voltage element 7 is incorporated in the image forming unit 1, and one end of this constant voltage element 7 is connected to a bias applying portion of the image device, that is, a developing sleeve 5 and a doctor blade 6 in this example, and , are connected to ground via a resistor R, respectively.

The other end of the constant voltage element 7 is connected to a bias power source E of the main body of the image forming apparatus.

FIG. 2 shows a specific example of the configuration of the apparatus of the present invention, in which one end of the constant voltage element 7 is connected to the terminal 11 of the main body 10 of the image forming device 10 on the electrode plate 8. , the other end of the constant voltage element 7 is connected to a terminal 12, and this terminal 12 is connected to a bias power supply E. As an example of an image forming unit, the developing device 2 is removably attached to the holding members 13 and 13K of the apparatus main body 10, and when the developing device 2 is loaded in the position shown in the figure,
One end and the other end of constant voltage element 7 are connected to terminals 11 and 12, respectively. Note that the developing device 2 shown in FIG. 2 accommodates toner of a certain specific color, and when changing the color of the image to be obtained, another developing device containing toner of a different color is used as the image forming unit. Close ii! j 11 It is designed to be loaded into the main body of the forming device.

By the way, the example of the developing device 2 shown in FIG. 1 is based on a magnetic one-component developing system using a pole sleeve as a float proposed by the present inventors.

In such a method, when a toner other than black, for example, blue, is used, the amount of magnetic material in the toner is set to be smaller than that of black toner in order to achieve clearer image colors.

By the way, FIG. 3 shows the correlation between the developing bias voltage and the background stain rank in the case of black toner (solid line A),
This is shown for the case of blue toner (broken+1IB). As mentioned above, in the case of blue toner, the amount of magnetic material in it should be set lower than that of black toner, but due to these conditions, the development characteristics of blue toner are The bias component decreases,
The state of change is shown in FIG. 3, where the black toner requires a higher bias voltage, and in the example shown in this figure, the voltage value is shifted by 50V.

Therefore, the bias voltage from the bias power supply FJ shown in FIG.
-500V), and when using a developing device containing black toner, the constant voltage element 7 is set at 50V.
If this is used, a developing bias voltage in the range of -150V to -450V can be used when black toner is used.

As described above, according to the apparatus of the present invention, the image 1 including the developing device
By simply adding one constant voltage element to the image forming unit,
The device user can obtain good images depending on the type of toner without changing any image adjustment conditions, and it is extremely easy to use as it only requires selectively replacing various image forming units. Become a good one. moreover,
In the apparatus of the present invention, it is possible to set developing bias conditions corresponding to the sensitivity characteristics of the photoreceptor, which indicates that such sensitivity correction is possible.

As described above, the present invention is characterized in that, in an image forming apparatus that obtains images with mutually different characteristics by replacing the image forming unit including the developing device with respect to the main body of the image forming apparatus, the above image forming unit A developing bias correction means including a constant voltage element is provided, and this correction means corrects the phenomenon bias voltage for each image forming unit according to the image characteristics.

In the present invention, which is characterized by the following points, the development bias is corrected according to these image characteristics in order to faithfully reproduce line images and solid images even with the same type of toner. It can also be effectively applied in cases where Also,
In the embodiment of the present invention, the image forming unit is equipped with only a developing device, but the present invention can also be applied to an image forming unit that is equipped with a photoreceptor including a developing device, a cleaning device, etc. can be applied. Furthermore, the present invention can be applied to not only I-component type developers but also two-component type developers.

(Effects) According to the present invention, it is possible to provide an image forming apparatus that can correct the development characteristics, the sensitivity of the photoreceptor, etc. with an extremely simple configuration.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a schematic configuration diagram of an apparatus according to an embodiment of the present invention, FIG. 2 is a diagram showing a specific configuration of the apparatus according to the embodiment, and FIG. FIG. 7 is a diagram showing the correlation between the developing bias voltage used and the background stain rank. 1... Image forming unit, 2... Developing device, 7...
- Constant voltage element, 10... image forming apparatus main body.

Claims (1)

[Claims] In an image forming apparatus that obtains images with different characteristics by replacing an image forming unit including a developing device with respect to an apparatus main body, the image forming unit is provided with a developing bias correction means including a constant voltage element. An image forming apparatus is provided with a special purpose of correcting developing bias conditions according to image characteristics for each image forming unit using the correction means.