JPS6361267A - Image forming unit - Google Patents

Abstract

PURPOSE:To make constant provision of two sets of developing devices and transfer charger use transforming devices unnecessary by installing selectively two sets of image forming units containing toners each different in polarity in accordance with a copying system. CONSTITUTION:As for a developing unit, two kinds consisting of a first developing unit 5a for positive-positive (P-P) copying, and a second developing unit 5b for negative-position (N-P) copying are prepared. First of all, when the unit 5a is installed to a copying machine body 20, a minus side of a DC voltage which is rectified by a rectifier 57 is applied to a transfer charger 7 through terminals A1, C1. In such a state, P-P copying can be execute. Subsequently, when the second developing unit 5b is installed to the body 20, a plus side of the DC voltage which is rectified by the rectifier 57 is applied to the charger 7 through terminals B1, C1. In such a state, N-P copying can be executed. As a result, as for the charger 7, one set will suffice, and a relay for a high voltage is also unnecessary, therefore, the manufacturing cost of an image forming unit can be suppressed. Also, as to a developing device, as well, one set will surface.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image forming unit used in an image forming apparatus capable of performing both positive-positive copying and negative-positive copying functions.

(Prior Art) Conventionally, a toner image is formed by supplying charged toner from a developing device to an electrostatic Ti latent image formed on the surface of an electrostatic latent image carrier, and at the same time, a toner image is formed on the electrostatic latent image carrier. As a type of image forming device, the toner image is transferred to the sheet by applying an electric charge of a polarity different from that of the toner from the transfer device to the sheet sent between the sheet and the transfer device facing the toner. Copy function to obtain a positive image (hereinafter referred to as P-P copy)
and a copying function to obtain a positive image from a negative original (hereinafter referred to as
Electrophotographic copying machines and league printers have been provided that have both functions (referred to as NP copying), and these devices employ one of the configurations described below to perform the above functions.

One is that two developing units are installed, each containing toner that has a tendency to charge up outside the bottle when it comes into contact with a carrier. This configuration is equipped with a transformer for transfer charting.

In addition to using an electrostatic latent image carrier that is sensitive to both positive and negative polarities,
: Two L devices are provided, and one is used for positive polarity charging and the other for negative polarity charging.

(Problems to be Solved by the Invention) However, in the former case, two developing devices and a transfer charger transformer are required, and in the latter case, two charger transformers are required. The accommodating space for each machine has increased by 2 units, and the recent trend has been to make the equipment smaller and more compact. Additionally, in order to switch the output from the two transformers to the charger, an expensive high-voltage relay and its attached switches are required, making the configuration complex and expensive. Was.

However, the electrostatic latent image carrier used in the latter case has the problem that there are only a few types and the range of selection is limited, and that it is expensive.

Furthermore, the B-copying method generally used by users is P-P copying, and N-7) copying is currently only required in very rare cases and in limited industries and fields.

(Means for solving the problems) The present invention was made in view of the above problems and the current situation.
An electrostatic latent image carrier, a developing device that supplies charged toner to the electrostatic latent image formed on the surface of the electrostatic latent image carrier to form a toner image, and In an image forming apparatus having a shift transfer device for transferring the toner image to a notebook, at least the developing device is constructed as an image forming unit and is removably attached to the image forming apparatus. When the image forming apparatus is attached to the image forming apparatus, the electric power is supplied from the image forming apparatus main body, and the electric power is transformed, and a voltage of a polarity different from that of the toner housed inside is applied to the acid 3T! A power supply means is provided to apply power to the transfer device.

In other words, by selectively installing two image forming units containing toners of different polarities depending on the copying method of full/positive copying or negative/full copying, a voltage of the opposite polarity to that of the toner can be applied to the transfer chart. This is what I did to get the voltage applied.

(Example) The present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a copy 14 (1) obtained by (iii) of a phenomenon unit (5) as an image forming unit according to the present invention,
First, the general configuration and operation of the copying machine (1) will be explained.

While the photoreceptor drum (2) is being rotated at a constant speed in the direction of arrow (a), first, the DC type z1λ (3
The negative side of 1) is connected to the charger (3).
), the surface of the photoreceptor drum (2) is negatively charged (-500V).

Next, when light is irradiated from the optical system (4) to the 1 quintillion manuscript placed on the platen glass (13), the reflected light is exposed to the surface of the photoreceptor drum (2) and the manuscript is placed still on the platen glass (13). A 1"U latent image is formed, and then a 1"U latent image is formed in the subsequent developing unit (5).
A toner image corresponding to the electrostatic latent image is formed.

On the other hand, the copy note (I)) is from the sleeve, Ushibe (6) to the arrow (
b), the toner image is transferred in the transfer area (S) by discharge of the transfer charger (7), and then separated from the surface of the photoreceptor drum (2) by a separation claw (8), The toner image is conveyed to a fixing device (II), where the toner image is fixed, and then discharged to a discharge section (12).

The photoreceptor drum (2) continues to rotate in the direction of arrow (a), residual toner is removed by a cleaning device (9), and residual charge is removed by an eraser lamp (10).

Next, the developing unit (5) according to the present invention will be described in detail.

The developing unit (5) is an independent unit as shown in Figure 2, and is detachably attached to the copying machine (1).
51) includes a developing sleeve (52) with a built-in magnetic roller (53) and a packet roller (54),
Are these the developing unit (5)? By attaching it to the U-photographer (1), it is connected to the drive system of the main body.

And the development Unisol R (5) is 1 summer photo 1? When the print switch (not shown) is turned on while the packet roller (54) is in the state where it is loaded on i(+), the packet roller (54) moves in the direction of the arrow (
d), mixes and agitates the two-component developer consisting of a mixture of toner and carrier housed inside, triboelectrically charges the toner with the carrier, and transfers a portion of it to the surface of the developing sleeve (52). supply to. The developer supplied to the surface of the developing sleeve (52) is conveyed in the direction of arrow (C) in the form of a magnetic brush, and rubs against the surface of the photoreceptor drum (2) to develop the electrostatic latent image as described above. to form a toner image.

Further, the developing unit (5) includes a first developing unit (5a) for P-P copying (see FIG. 3) and a second developing unit (5a) for N-P copying.
Two types of developing units (5b) are available, each with a power transformer (55), a unit side connector (58a),
(58b), and a first developing unit (5a
) contains a first developer (De+) consisting of a positively charged toner and a carrier, and a second developer unit (5b)
A second developer (De2) consisting of a negatively charged toner and a carrier is housed in the developer.

The substation device (55) has a transformer (56) and a regulator (
57), the alternating current voltage input to the transformer (56) is transformed into a high voltage, and then rectified into direct current by a rectifier (57). In addition, developing units (5a) and (5b)
The unit side connectors (58a) and (58t+) respectively have nine terminals A, 2 to . A, B, to B9 are provided, respectively.

In the first developing unit (5a) shown in FIG. 3, the terminal A1 is the negative terminal of the rectifier (57), A, .
A is connected to the transformer (56), A4 is connected to the positive terminal of the rectifier (57), A5 is connected to the developing sleeve (52), A8 and A7 are connected to each other, and 7\8. A. is in the oven.

On the other hand, in the second developing unit (5b) shown in FIG. 4, B1 is the positive terminal of the rectifier (57).

B3 is connected to the transformer (56), B4 is connected to the negative terminal of the rectifier (57), B5 is connected to the developing sleeve (52), I3e and I37 are connected to the oven, and B
8°B9 are interconnected.

On the other hand, the first and second developing units (5a) and (5b)
The copying machine main body (20) to which the is installed has a main body side connector (
21) is a provision.

The main body side connector (21) also has nine terminals C1, -, C0, and the terminal CI is the corona wire of the transfer charger (7), C
t, C3 is the power terminal D t of the control unit (22),
D3 and C4 are ground, C5 is the developing bias power supply (23
), Ca, C7, Cs, Co are terminals D a, D ? of the control section (22), respectively. ,
Connected to De, D-. In addition, the control unit (2
Terminal D5 of 2) is connected to a developing bias power supply (23).

In the above configuration, when the first developing unit (5a) is attached to the copying machine main body (20), the unit side connector (5a) is attached to the copying machine main body (20).
The terminals (AI, to, 8) of 8a) are respectively connected to the terminals (C, to, C3) of the main body side connector (21).

As a result, the power terminal B3 of the control unit (22) is connected to the primary side of the transformer (56), and the rectifier (57) on the secondary side is connected to the primary side of the transformer (56).
) is applied with a transformed high voltage, and the negative side of the rectified DC voltage is applied to the transfer charger (7) via terminals A, C,. On the other hand, the positive side of the rectifier (57) is A4. Connected to ground via C4.

Further, terminals D e and D 7 of the control section (22) are terminals C
6゜A,,A? , C, and the copying machine main body (
20), it is detected that the first developing unit (5a) is attached to the terminal D5, and a signal corresponding to the developing bias power supply (23) is outputted via the terminal D5.

The developing bias power supply (23) sets the voltage for the first developing unit (5a) when the signal is input, and outputs the voltage to the terminal C.
The potential of the developing sleeve (52) is set to +50V via S and As.

In this way, the first developing unit (5a) is connected to the copying machine main body (
20), it becomes possible to perform copying, and the image creation process will be explained with reference to FIG.

First of all, the surface of the photoreceptor drum (2) is connected to the charger (
3) After being stained by 1500cm by corona discharge,
The light irradiated from the optical system onto the positive original is transferred to the photoreceptor drum (2
) is exposed to light to form a positive static 7Ljj+'j phenomenon, and the potential of the non-image area is dropped to ~ll0V! t7. .

Next, blastable toner is supplied from the first phenomenon unit (5a) and adheres to the image area, where the surface of the developing sleeve (52) has a lower potential (-150) than the non-image area.
"v'), the positive polarity toner does not adhere to the non-image area.

Thereafter, in the transfer area (S), when the sort (P) is charged to negative polarity by the negative discharge of the transfer charger (7), the positive donor in the image area is electrostatically transferred to the note.

Obtaining a positive image from a positive original as described above pp)
9 shots will be executed.

Next, attach the second developing unit (5b) to the 19-photograph machine body (20
) to)? As shown in FIG. 4, the connector on the unit side (58b) is connected to the connector on the main body side (21) 4+, terminals Bl, ~, r3. are respectively terminal C1°~,
Each is connected to C8.

As a result, the power terminals D 2 and D of the control unit (22)
3 is connected to the primary side of the transformer (56), and the transformed high voltage is applied to the rectifier (57) on the secondary side, where the positive side of the rectified DC voltage is connected through terminals n, , c, is applied to the transfer charger (7). On the other hand, the rectifier (57)
The negative side of is connected to ground via terminal B4A:a.

Terminals D a and D s of the control unit (22) are terminal Cs
, BR, B a .

Electrical conduction is established through C8, and it is detected that the second developing unit (5b) for NP copying is attached to the copy (+) f2.

Then, the control unit (22) outputs a signal corresponding to the phenomenon bias "HE't (23) via the terminal D5, and the developing bias power supply (23) sets the voltage for NP? summer photography,
This is connected to the phenomenon sleeve (5) via terminals Cs and B5.
2) Set the surface potential to -=150V.

In this way, the second phenomenon unit (5b) is attached to the copying machine (1).
N-P copying becomes possible in the state in which the image forming apparatus is attached, and the image forming process will be explained for the sixth [R1].

First, the surface of the photoreceptor drum (2) is connected to the charger (3).
), the surface of the photosensitive drum (2) is exposed to light irradiated onto the negative image by the optical system, forming a negative electrostatic latent image.

At this time, the potential of image 1 is dropped to -110cm. On the other hand, the potential of the non-image area remains at -500.

Next, negative polarity toner is supplied from the second developing unit (5b) and adheres to the image area.

At this time, since the potential (-500V) of the non-image area is lower than the potential (-450V) of the developing sleeve (52), negative toner does not adhere to the non-image area.

After that, the negative toner adhering to the image area becomes a positive polarity due to the positive discharge of the transfer charger (7). uQ'
It is transferred to the sort that is jt.

In this way, a positive image is obtained from a negative original N-f))
'I copy is executed.

As is clear from the above explanation, the first phenomenon unit (5a
) can be used to perform P-P copying, and by installing Uniso 1 (5b), N-1 copying can be performed.

[According to 7, if the user uses only P-P copying, he only needs to have the first phenomenon unit (5a).

And N-P? When SJ copying is required, it is sufficient to prepare a second developing unit (5b) for N-I copying.

Note that in the above description, only the developing unit (5) is used in the copying machine (
1), but the invention is not limited to this, and by replacing two process units in which the first developing unit (5a) or the second developing unit (5b) is attached to the photo drum (2). , it may be possible to perform both functions of bond-positive copying and negative-bond copying.

(Effects of the Invention) As is clear from the following explanation, the image forming unit according to the present invention is removable from the image forming device, and is capable of applying a voltage of a polarity different from that of the toner contained therein. By installing a power transformer that applies voltage to the transfer charger, storing toner of different polarity, and selectively mounting one of the two image forming units to the image forming device.
The front/positive copy maf2 is capable of performing negative/positive copying (9 copies).

Therefore, only one transformer for the π charger and one transformer for the transfer charger is required, and there is no need for a high-voltage relay to switch the high-voltage power supply internally, so it is possible to reduce the manufacturing cost of the image forming device. Not only that, but it also eliminates the need to permanently install two developing devices, making the overall size smaller and more compact.

In addition, for users who only use positive/positive copying, they only need to manually handle the image format unit for positive/bond copying, and only have to manually handle the image forming unit for negative/positive when needed, which reduces waste. It is economical as it does not require major investment.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing the general structure of the copying machine, Fig. 2 is a perspective view of the developing unit, and Figs. 3 and 4 show the electrical connections between the first and second phenomenon units and the main body of the copying machine. 5 and 6 are diagrams showing the image forming process. 1... Copying machine, 2... Photosensitive drum, 3... Charger, 4... Optical system, 5... Developing unit,
5a... First developing unit, 5b... Second phenomenon unit, 7... Transfer charter, 20... Copying machine main body,
21... Main unit side connector, 22... Control unit, 52...
Developing sleeve, 55 Transformer, 56 Transformer, 57 Rectifier, 58 Unit side connector. Patent applicant Minolta Camera Co., Ltd. Agent
Patent attorney Maeda Ao and 2 others 57 Zero S]

Claims (1)

[Claims] (1) An electrostatic latent image carrier, a developing device that supplies charged toner to the electrostatic latent image formed on the surface of the electrostatic latent image carrier to form a toner image, and a sheet being fed. a transfer device that transfers the toner image onto a sheet by imparting an electric charge to the image forming device, wherein at least the developing device is configured as an image forming unit and is removably attached to the image forming device; When installed in the image forming device, the transfer device receives electric power from the main body of the image forming device, transforms it, and applies a voltage having a polarity different from that of the toner contained therein to the transfer device. An image forming unit characterized by being provided with power supply means.