JPS5888770A - Electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To form a good toner image, to improve transfer efficiency and to obtain copies having high image quality, by applying AC voltages having a phase between a photosensitive drum and peripheral devices, and acting periodic electrostatic forces upon a developer. CONSTITUTION:The output of the DC bias circuit 14 of an AC electric power source circuit 11 is connected to a photosensitive drum 1, a corona discharger 4, etc. and an AC voltage V1 is applied. The other end side of a transformer 17 is connected to a sleeve 9, etc. of a developing device, and an AC voltage V2 differing in phase by 180 deg. from the voltage V1 is applied. Therefore, mutual electrostatic forces are generated between the drum 1 and the sleeve 9, and the electrostatic forces act upon the developer in superposition with the electrostatic force of the latent images. According to the combined forces thereof, the developer 10 is oscillated by which good toner images are formed. Owing to the effect of the electrostatic forces generated like AC, transfer efficiency is considerably improved as compared to the prior art. Thus copying having high quality is obtained.

Description

[Detailed description of the invention] The present invention relates to an electronic copying device.

Conventionally, in electronic copying machines, the photosensitive drum is charged,
A so-called jumping method, which is a non-contact development method, is known as a method of forming a toner image by attaching a developer to an electrostatic latent image formed through various steps of exposure. In this type of conventional electronic copying device, the photosensitive drum (holding material for the photosensitive layer)
is set to the ground potential, and an alternating current voltage is applied to the peripheral devices K for the photosensitive drum such as the developing device, and the above-mentioned toner image is formed by the electrostatic force generated between the photosensitive drum and the Misakibe device. It is something to do.

However, in the conventional device described above, the toner image transfer rate is 40
60, and there is a need for something that can transfer even more efficiently. Furthermore, despite the above-mentioned jumping, there are disadvantages in that the developer is scattered in non-image areas during imaging, resulting in a decrease in image quality and the developer being wasted.

The present invention was developed under the above-mentioned circumstances, and its purpose is to more effectively adhere or remove developer in each process such as development, transfer, and cleaning, thereby improving image quality. To provide an electronic copying device which can perform good copying and eliminate waste of developer.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.
I will clarify. FIG. 1 is a schematic diagram of the electronic copying apparatus.

In the figure, the photosensitive drum 1 is a conductive drum. A photosensitive layer 3 is formed on the surface of the photoreceptor 52.

A positive corona discharger 4 for charging the photosensitive layer 3 toward the glass side is arranged around the photosensitive drum 1 as shown in the figure. A high current voltage from the DC power supply circuit 5 is applied to the corona chamber 4, and corona discharge occurs in the dark.

One photosensitive drum is rotated in a simple direction as shown in the figure, and an optical path 6 is formed at the tip of the corona discharger 4 in this rotating direction. Reflected light emitted from a light source (not shown) is introduced into the optical path 6 with respect to an original (not shown) to be copied. The charges on the photosensitive layer 3 are eliminated by the light reflected from the non-image areas of the document, while the charges on the photosensitive layer 3 are retained as they are by the light reflected from the image areas, forming an electrostatic latent image.

A magnet brush 7 is further arranged at the end of the optical path 6, which rotates counterclockwise and is close to the photosensitive drum 1. This magnetic brush 7 constitutes a part of the developing device, and attaches the developer to form a toner image.

That is, a sleeve 9 made of a non-magnetic material is provided so as to be rotatable in a counterclockwise direction with respect to a magnetic roll 8 which is fixed without being magnetized to a predetermined degree. A viewing side addition 10 is formed thinly and uniformly on the outer peripheral surface of the lens. The viewing agent in the viewing agent layer 100 is made of, for example, a magnetic component. The surface of the #D layer 3 of the photosensitive drum 1 with the developer layer 10 does not come into pressure contact and is in a state of near collapse, and even if they do come into contact, it is said to be an extremely weak contact state.

By the way, in the case of the electronic copying apparatus of this invention, the photosensitive drum 1
Then, the pressures of the cross #1 having different phases are applied to the peripheral devices for the photosensitive drum 1, that is, the developing device, etc., respectively. That is, the terminal 12 side of the AC power source 11 path 11 is grounded, and the terminal 13 side is connected to the DC iR ear circuit 14. The output side of the DC bias circuit 14 is in contact with the DC power supply circuit 5.
It is connected to the inner surface of the photosensitive drum 1 via a collector piece 15 and a drum shaft 16. As a result, an AC voltage (1), which will be described later, is applied to the inner surface of the photosensitive drum 1.

The primary coil 18 of the transformer 17 is connected to terminals 12 and 13 of the AC power supply circuit 11, which are old. One end of the secondary coil 19 of the transformer 170 is grounded, and the other end is connected to the soil F sleeve 9 via the Hayabusa piece 20. As a result, the sleeve 9 has a phase of 180° with respect to the earth=S AC voltage v1.
A nine-current voltage v2 of 9 degrees is applied.

Further ahead of the upper P magnet brush 7 is a photosensitive drum 1.
A counter electrode cover 24 is disposed close to and opposite to the photosensitive layer 3 . An upper P AC voltage (1) is applied to this counter electrode cover 24 via a DC bias circuit 14.

A corona discharger 26 for transfer to the photosensitive drum 1 is further disposed in front of the counter electrode cover 24 .

This corona discharger 26 includes a pair of insulating materials 27a and 127b that are spaced apart and firmly adhered to the photosensitive layer 3 of the photosensitive drum 1, and a chevron-shaped shield electrode 28 that is housed inside the pair of insulating materials 27a and 27b. , a corona parabolic wire 29 housed within this chevron-shaped shield electrode 28
DC power supply circuit 3 that applies high DC voltage to a and 29b
It is made up of 0. The shield electrodes 28as28b on both sides of the chevron-shaped shield electrode 28 are partially covered with corresponding insulating materials 27a127b as shown, and the central shield electrode 280 is apparently closer to the photosensitive layer 3 than the shields 11fi28a, 28b. . The chevron-shaped shield electrode 28 is connected to the secondary coil 19 with the groove 1
AC voltage ■2 is applied.

A paper feed section (
A passage 25 is formed through which the paper 7 fed from a paper source (not shown) passes. Therefore, when the paper passes through the passage 25, the charge supplied to the paper by the corona discharger 26 causes the developer attached to the visible image formed on the photosensitive layer 3 to be transferred to the paper. It will be transcribed.

Next, to explain the operation of the above embodiment, when the power switch of the electronic copying apparatus is turned on, the AC power supply port @116 starts operating. As a result, AC power is supplied to the DC bias section 14 and the transformer 17, and the power is supplied to the inner surface 1 of the photosensitive drum 1 via the current collector piece 15 and the drum shaft 16, and also to the t
The one-pole cover 24 is connected to an AC voltage v shown in FIG. 3(a).
1 is applied h1. On the other hand, the AC voltage v2 in FIG. 3(b) output from the secondary coil 19 of the transformer 17 is
The voltage is applied directly to the sleeve 9 via [7] and to the angled shield electrode 28. Therefore, as is obvious from Fig. 3 (a,) and (b), the phases of AC voltages ■1 and ■2 are 180# different, and the voltage value (as an example) and town 1 are both They snore and have an ugly relationship.

When you set the original in the normal position and start copying, the photosensitive drum 1 starts rotating in the direction of opening, and the photosensitive drum 1 starts rotating.
In synchronization with the rotational movement of step 1, the sleeve 9 starts to rotate in the opposite direction of force. Then, as the photosensitive drum 1 rotates, the photosensitive layer 36 is charged to the schisolous side by the corona plate 4, which is carried out in the dark.

In this way, the photosensitive layer 3, which has been tilted to +f111, has its charge further dissipated by the reflected light from the non-image area of the reflected light from the document introduced through the optical path 6, and on the other hand, the image As a result, electrostatic latent images corresponding to the images of the original are successively formed on the 1F photosensitive layer 3. As the photosensitive drum 1 rotates, this electrostatic latent image further spreads to the magnetic brush 7.
The toner image is developed by a developer and a toner image is formed.

By the way, as mentioned above, the AC voltage (1) is applied to the inner surface of the photosensitive drum 1, and the AC voltage (v) is applied to the twisted sleeve 9.
2 are applied respectively. Therefore, as the photosensitive drum 1 and the sleeve 9 rotate in synchronization, the photosensitive drum 1
and Sleeve 9rljlKVi mutually the song @2 shown in Figure 2
A mutual electrostatic force represented by 2 is generated. That is, in relation to the opposing distance between the photosensitive drum 1 and the sleeve 90, the mutual electrostatic force gradually increases 9 until it approaches the minimum gap position 21, and becomes maximum at the minimum gap position 21. After that, it gradually decreases. This reciprocal electrostatic force in FIG. 2 is superimposed on the h power due to the electrostatic latent image formed on the photosensitive layer 3,
The agent layer 10 on the sleeve 9 is vibrated according to the magnitude of the resultant force.

In this process, an amount of developer corresponding to the magnitude of the above-mentioned composite force adheres to the electrostatic latent image, and a toner image is formed.

The operation of the above-mentioned developing process will be further explained with reference to FIG. 3.
), the phases differ by 180 degrees, and the magnitude of the electrostatic force generated by this phase difference is a curve 23 shown in FIG. 3(0). Now, if we represent a still life and the direction in which the force acts as negative on the photosensitive drum 1 side and positive on the sleeve 9 side, the electrostatic force has a phase angle of 0 to 180, as shown in FIG. 3(0). It acts in the negative direction between 180 and 360 degrees, and it acts in the positive direction between 180 and 360 degrees.
Moreover, as shown in the figure, the change from decrease → increase → decrease, ν1.
In other words, it shows an exchange-like change. Therefore, the upper 6C developer layer 10 vibrates due to the electrostatic force that changes in an alternating current manner, and the developer particles that fly out from the developer layer 10 are attracted to the electrostatic latent image, forming a toner image. Ru. Now, even if some amount of developer particles adhere to the latent image in the non-image area, the It force AC 1
Due to this change, it is immediately pulled back to the sleeve 9 side by the repulsive force caused by the opposite phase # power, and the non-image area is no longer smudged, resulting in clogging and the contrast between the image area and the non-image area. A high quality copy of the image quality can be obtained.

As the photosensitive drum 1 rotates, the toner image (visible image) obtained as described above is further sewn against the cedar cover 24.
They move while touching each other and reach the corona discharger 26. During the movement relative to the counter electrode cover 24, the same AC voltage and pressure 1 are applied to both the photosensitive drum 1 and the counter electrode cover 24, so the above-mentioned AC electrostatic effect is canceled out and the above-mentioned The toner image is retained on the sleeve 9 as it was generated.

The toner image that has reached the position of the corona discharger 26 is transferred to the passage 25 and transferred to a sheet of paper (not shown) being transferred. In this case, the photosensitive drum 1 is supplied with alternating current -l 〇-? Voltage 1 is applied, and AC voltage 2 is applied to the corona discharger 26.
The n way of saying shown in the following is in effect. and under the action of the electrostatic force with the corona group ii*'l/i of the corona charger 2G
': The paper is charged while passing through the passage 25, but when an electrostatic force acts on the same polarity as the charging electrode of the developer, the electrostatic force of the charged paper attracts the photosensitive drum 1 to the developer. The developer is transferred to the υ term due to the repulsive force from the inner surface of the . In addition, when the electrostatic force of the opposite polarity to the bright imager is applied, the electrostatic adsorption force due to the charging of the corona box is stronger, so the bright imager once transferred onto the paper is It does not peel off from the paper and return to the photosensitive drum 1 side again.

In this way, since the toner image is transferred to the paper under the action of electrostatic force that changes AC, the coverage rate is greatly improved compared to the conventional device (~, and moreover, the transfer from the paper path 25 is Separation is also very easy.

After the transfer process, the paper is discharged to a discharge section (not shown). Note that the method of superimposing the above AC voltage is not shown.

In the above embodiment, the AC voltage 2 output from the secondary coil 19 of the transformer 170 is transferred to the sleeve 9 and the corona discharger 2.
Although a weight is applied to 6, it may be applied via a variable resistor 1 to change the applied positive pressure of 1 to 1+iJ, so that the optimum positive pressure is always supplied. In the embodiment, the AC voltage V1. The phase difference of V2 is set to 80 degrees, but this phase difference is arbitrary as long as an alternating current electrostatic force as shown in FIG. 3(0) can be obtained. Although Sugi 7 image agents having magnetic properties of -h to i were used in the above embodiments, other 9 image agents such as two-component magnetic agents may also be used. If a pressure of 1" AC is applied to the cleaning device installed on the scale of the shredded soil mU2 embodiment, the cleaning effect will be greatly improved compared to the conventional method.

As described in detail above, this invention applies an alternating current voltage with a phase difference between the lubricating drum and the reachable Buddha of the toy protection system that appears on this photosensitive drum, and E<
Since we have provided an electronic copying device that generates an electrostatic force that varies between the optical drum and the peripheral device and acts on the developer to perform electronic copying, the transfer rate of the toner image can be improved. High-quality copies can be obtained, which is significantly improved from 40 to 60% compared to conventional methods, and developer consumption is reduced, resulting in lower copy unit costs.Furthermore, developer scattering on non-oil image areas is reduced. This makes cleaning easier, so it is no problem to lengthen the period of periodic inspection, which reduces labor costs. There is also Beppu where it is easy to separate the paper from its path.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of 91b in an embodiment of the present invention, FIG. 2 is a diagram showing the relationship between the opposing distance between the photosensitive drum l and the sleeve 9 and the generated electrostatic force, and FIGS. 3(a) and (b) ) are respectively,
AC voltages v1 and v2 applied to the photosensitive drum 1 and peripheral devices
(0) is a waveform diagram of the electrostatic force generated by the above-mentioned alternating voltages v1 and v2. 1... Photosensitive drum, 4... Corona discharger, 5... Surface flow frost single source circuit, 6... Optical path, 7...・Magnetic brush, 8...Magnetic roll, 11...
... AC power supply circuit, 14 ... Direct bias circuit, 15 ... Current collector piece, 17 ... Transformer, 20 ... Current collector piece, 24・・・・・・Anti-susceptibility・
-125...Passage, 26...Corona discharger, 28...Chevron shield electrode, 30...
...DC power supply circuit. @ Applicant: Casio Meter, W Machine Co., Ltd. ID Co., Ltd. 14- Fig. 1 1, 6 Fig. 2 and 1 Fig. 3 Kine E +□11 small

Claims (1)

[Claims] A photosensitive drum to which a developer is attached to the electrostatic latent image formed in each process of charging and exposure, and a photosensitive drum that is placed near this photosensitive drum and used in each process such as development, transfer, cleaning, etc. a peripheral device that attaches or peels the developer to or from the peripheral device; and a power supply device that applies an alternating current voltage with a phase difference between the photosensitive drum and the peripheral device, and a power supply device that applies an AC voltage with a phase difference between the photosensitive drum and the peripheral device, and An electronic copying apparatus characterized in that a force is periodically generated to act on the developer.