JPS6332572A - Reversal developing and recording device - Google Patents

Abstract

PURPOSE:To prevent an unnecessary toner from sticking to a photosensitive body, and to prevent the increase of the consumption of a toner by providing a mechanism by which a developer in a developing tank is not brought to contact with a photosensitive body for a prescribed time when the photosensitive body starts to move. CONSTITUTION:When a recording start signal is inputted, a current is conducted to a solenoid 13, and a solenoid rod 13a is attracted. As a result, a developing tank 3 rotates in the direction D by using a rotary shaft 10 as a fulcrum, and separated from the surface of a photosensitive body 1. Accordingly, a developer (toner) 30 on a magnet sleeve 14 in the developing tank 3 does not contact the photosensitive body 1. Simultaneously, the photosensitive body 1 starts to rotate. After a prescribed time is elapsed, when the surface of the photosensitive body opposed to the developing tank 3 is electrified by a main electrification charger and becomes a prescribed electrification potential, an electric conduction to the solenoid 13 is stopped. The developing tank 3 rotates in the direction E centering around the rotary shaft 10 and returns to its regular position.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a reversal development recording device, and more specifically, a latent image is formed on the photoreceptor by shining light on the photoreceptor, and the image is visualized by being developed with toner. The present invention relates to an electrophotographic copying machine and printer in which the toner image is transferred to paper and then fixed.

2. Description of the Related Art In this type of electrophotographic copying machine, the surface of the original is irradiated, and the reflected light is guided to a photoreceptor by a lens and formed into an image, forming a latent image on the photoreceptor. At that time, strong reflected light from the white part of the original hits the photoreceptor,
That portion is neutralized and the potential applied by the main charger approaches zero level. On the other hand, there is almost no reflected light in black parts such as characters on the original, so the photoreceptor is not neutralized and maintains the potential given by the main charger. When the latent image formed in this manner passes through the developer tank, the toner adheres to a portion of the photoreceptor where the potential is maintained in accordance with the absolute value of the potential and is visualized. This toner is transferred onto copy paper by a transfer charger and then fixed to complete a copy of the original.

In an electrophotographic printer, a latent image is formed on a photoreceptor by irradiating the photoreceptor with light emitted from a recording head, similar to the copying machine described above. Unlike copying machines, there are two methods for making the latent image visible in printers. Method 2 is a method in which toner is attached to a portion where the potential is close to zero level.

Among these methods, the first method is called normal development, and the second method is called reversal development, and the present invention relates to the above-mentioned reversal development.

To explain a conventional reversal development recording device with reference to FIG. 5, in the figure, around the photoreceptor l rotating in the direction of the arrow, there are a main charger 2) a developer tank 3 separated from the exposure area B-C;
A transfer charger 4, a peeling charger 5, a cleaner 6, and a static elimination lamp 7 are installed, and a recording paper 8 is guided by a paper guide 9 and inserted between the transfer charger 4 and the photoreceptor l.

In the above apparatus, the photoreceptor 1 is a negatively charged organic photoreceptor, and the main charger 2 applies a negative charge to the photoreceptor 1, so that the photoreceptor 1 is uniformly negatively charged. This negatively charged photoreceptor 1 is exposed to light reflected from the light irradiating the document in the exposure area B-C, and the exposed portion is neutralized according to the amount of light.

In the next developer tank 3, a negative bias voltage is supplied to the mag roller, and the toner in the developer tank 4 is negatively charged due to friction with the carrier. Therefore, now,
Assuming that the charged potential of the photoreceptor is -600V, the bias voltage is -350V, and the potential of the neutralized portion is -100V, the negatively charged toner is attracted to and adheres to the neutralized portion. On the other hand, the unexposed part is -250
Negatively charged toner, which corresponds to the potential of V, does not adhere. In the next transfer charger 4, a positive charge is applied from the back side of the recording paper 8 to transfer the toner onto the recording paper 8. After the paper transfer, the toner not transferred by the transfer charger 4 is collected by the cleaner 6. After passing through the cleaner 7, the photoreceptor 1 is irradiated with long-wavelength light from the charge eliminating lamp 7 to uniformly eliminate the charge on the entire surface of the photoreceptor.

As mentioned above, the reversal development method is a development method in which toner is attached to a location where the potential is at a low level close to OV. Therefore, when the reversal development method is used, unnecessary toner will adhere unless the portion of the photoreceptor that is not the recording latent image area is always maintained at the main charging potential level. Therefore,
The main charger that applies the main charging potential must always be in an applied state while the photoreceptor is rotating. By adopting this method, it is possible to always stably maintain the photoreceptor potential at the main charging potential during recording, but a problem occurs when the photoreceptor starts rotating from a stopped state.

That is, as shown in the figure, the main charger 2 and the developer tank 3 are located apart from each other with an exposure area between them.

Therefore, even if the main charger 2 is applied and the photoreceptor l is charged at the same time that the photoreceptor l starts rotating in the direction of the arrow, the photoreceptor in the exposure area between the main charger 2) and the developer tank 3 It is not possible to charge parts B-C. The potential of this photoconductor portion B-C is approximately at the O■ level when the photoconductor 1 is stopped for a long time, but on the other hand, for example, when the next rotation starts immediately after the previous rotation for recording ends. etc., the potential level is close to the predetermined band N potential, and the area of the photoreceptor B-C is an area where the potential is unstable. When the potential of the area of the photoconductor B-c is at the OV level,
This photoconductor portion B-C is the developing area Fi! ! 3, toner adheres to the B-C portion of the photoreceptor 1. This adhered toner is not transferred to the recording paper 8 but is removed by the cleaner 7 and becomes waste toner, resulting in an increase in toner consumption.

Purpose of the Invention The present invention has been made in view of the above-mentioned drawbacks, and it is an object of the present invention to remove unnecessary toner by preventing toner from adhering to the photoreceptor for a certain period of time after the photoreceptor starts rotating. The purpose is to prevent adhesion and, therefore, to prevent an increase in toner costs.

Structure of the Invention In order to solve the above problems, the present invention charges a photoreceptor,
In an electrophotographic reversal development recording apparatus that forms a latent image by irradiating the photoreceptor with light, develops it with toner, transfers the toner image to paper, and then fixes it.1. A mechanism is provided to keep the developer in the developing tank away from the photoreceptor for a certain period of time when the photoreceptor starts moving, and specifically provides the following four mechanisms. That is, a) a device that is equipped with a mechanism that moves the entire developing tank away from the photoreceptor for a certain period of time when the photoreceptor starts moving, so that the developing agent does not come into contact with the photoreceptor, and b) a photoreceptor. A device in which a mechanism is provided in which a mag sleeve in a phenomenon tank moves F hyperactively in a direction away from a photoreceptor for a certain period of time when the body starts to move, and the movement prevents the developer from coming into contact with the photoreceptor, C. ) A device that is equipped with a mechanism that brings the doctor blade in the phenomenon tank closer to the mag sleeve for a certain period of time when the photoreceptor starts moving, thereby eliminating spikes of developer and preventing the developer from coming into contact with the photoreceptor; d) When the photoreceptor starts moving, the device is equipped with a mechanism that rotates the magnetic pole of the mag roll in the developing tank for a certain period of time, and moves the position of the spikes of developer to prevent the developer from coming into contact with the photoreceptor. This is what we provide.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below with reference to embodiments shown in the drawings.

FIG. 1 (A) (BXC) shows a first embodiment of the present invention,
Similarly to FIG. 5, in the figure, 1 is a photoreceptor, 3 is a developing tank, and other structures such as a main charger and a transfer charger are the same as in FIG. 5, and their explanation and illustration will be omitted.

A rotating shaft IO is fixed to the lower substrate 3a of the developer tank 3, and both sides of the rotating shaft 10 are rotatably supported by a base frame (not shown), and the center of the rotating shaft 10 is used as a fulcrum for development. The tank 3 is made rotatable in the direction shown by arrow DE.

One end of a rotating arm 11 is fixed to a portion of the rotating shaft lO that protrudes outward from the base frame, and one end of a connecting arm 12 is pivotally connected to the other end of the arm 11.
2 is connected to the solenoid rod +3a of the solenoid 13. Therefore, when the solenoid 13 is energized, the solenoid rod 13a is attracted into the solenoid body.
Accordingly, the rotating arm 11 is pulled to the right in the figure, the rotation mto rotates clockwise, and the developer tank 3 fixed to the rotating shaft 10 is configured to rotate in a direction away from the photoreceptor l. There is.

In the above reversal development recording apparatus, when a recording start signal is input, current is applied to the solenoid 13 and the solenoid rod 13a is attracted. Due to the operation of the solenoid rod 13a, the developer tank 3 is moved in a direction D with the center of the rotating shaft 10 as a fulcrum.
direction, and as shown in FIG. 2 (II[), the photoreceptor
move away from the surface. Therefore, the developing agent (toner) 30 on the mag sleeve 14 in the developer tank 3 does not come into contact with the photoreceptor 1.

As soon as the developer tank 3 completes its movement away from the photoreceptor l, the photoreceptor l starts rotating. After a certain period of time, developer tank 3
When the front part (the part that first faces the developer tank) of the photoreceptor l facing the surface is charged by the main charging charter 2 and reaches a predetermined charging potential, the energization to the solenoid 13 is stopped. The solenoid rod 13a pops out from the solenoid 13, and the developer tank 3 rotates in the direction E in the figure about the rotating shaft 10, and returns to its normal position.

Developer tank 3 by energizing/stopping the solenoid 13 described above
The rotational movement of is carried out not only when the rotation of the photoreceptor 1 is started by a recording start signal, but also when the rotation of the photoreceptor 1 is started in any situation, and the developer tank 3 is moved to a position away from the photoreceptor 1 for a certain period of time. ing.

As described above, when the photoreceptor l starts rotating, the developer tank 3 is moved to a position away from the photoreceptor l for a certain period of time during which the unstable potential region passes through the developer tank 3, and the developing tank 3 is moved to a position away from the photoreceptor l. agent 30
is prevented from coming into contact with the photoreceptor l. Therefore, toner does not adhere to unstable areas, and unnecessary increase in waste toner can be prevented.

In the first embodiment, the rotational movement is performed by a solenoid, but it goes without saying that other suitable driving means such as a motor may be used. Further, in the above embodiment, the mechanism is such that the developer tank 3 is moved by rotation, but it may be configured to slide the developer tank 3 linearly away from the photoreceptor 1.

FIG. 2 (AXBXC) shows a second embodiment of the present invention, in which a mag sleeve 14 inside the developer tank 3 is movable in a direction away from the photoreceptor l.

That is, one end of the rotation support arm I6 is fixed to the mag sleeve 14 via the support shaft 15, and the other end of the rotation support arm I6 is fixed to the rotation shaft 17 rotatably supported on the lower substrate 3a of the developer tank 3. The mag sleeve 14 is configured to rotate in accordance with the rotation of the rotating shaft 17. The rotating shaft 17
A worm wheel 18 is externally fitted and fixed on the outwardly projecting portion of the worm wheel 18 , and a worm 20 that is rotationally driven by a motor I9 is engaged with the worm wheel 18 . arrow F
When rotated in the direction, the rotation shaft 17 and the rotation support arm 16
The mag sleeve 14 is rotated in the direction of the arrow G through the mag sleeve 14 and moved to a position away from the photoreceptor l, so that the developer 30 around the mag sleeve 14 does not come into contact with the photoreceptor l.

The operation of the above device is similar to that of the first embodiment, and when a recording start signal is input manually, the motor 19 rotates and moves the mag sleeve 14 to a position away from the photoreceptor l, and at the same time the movement is completed, the photoreceptor The rotation of the body 1 starts, and the developer 30 in the developer tank 3 is applied to the surface of the photoreceptor 1, which has not reached a predetermined potential.
prevents contact. After the photoreceptor 1 starts rotating,
After a certain period of time has elapsed, when a portion that has been charged by the main belt electronic charger and has a predetermined charging potential is located at the front of the developer tank 3, the motor 19 is rotated in the reverse direction, and the mag sleeve 1 is rotated in the opposite direction.
4 is returned to its original position as shown in FIG. 3(A), and the developer 30 is brought into contact with the photoreceptor 1 to perform development. In this way, when the unstable charged potential region that occurs when the photoreceptor l starts rotating passes through the developer tank 3, the mag sleeve 14 is separated from the photoreceptor l to prevent the developer 30 from coming into contact with the photoreceptor l. , it is possible to prevent unnecessary toner from adhering to unstable areas, and to reduce the amount of waste toner.

FIG. 3 (AXBXC) shows a third embodiment of the present invention, in which a doctor blade 21 for regulating the formation of spikes of the developing agent 30 is provided so as to be movable in a direction away from the photoreceptor l. That is,
Support part 2 of doctor blade 21 inside developer tank 3
A rotating shaft 22 is fixed to 1a, and rotatably supported on the base frame of the developer tank 3. The ohm wheel 23 is fixed to the rotating shaft 22 in the same manner as in the second embodiment, and the ohm wheel 22 is engaged with the worm 25 rotated by the motor 24, so that the worm wheel 22 is rotated by the forward rotation of the motor 24. The doctor blade 21 is rotated in the direction of arrow H in the figure, and the doctor blade 21 is rotated in the direction of arrow 1 in conjunction with the blade part 21.
b to limit the spikes of the developer 3o, and the developer 30
is prevented from coming into contact with the photoreceptor l. On the other hand, when the motor 24 is rotated in the reverse direction, the doctor blade 21 moves as shown in FIG.
I am trying to return it to the original position shown in A).

The operation of the third embodiment is also similar to that of the first and second embodiments,
When a recording start signal is input, the motor 24 is rotated in the forward direction to rotate the doctor blade 21 in the direction of the arrow 1 and move in the direction of regulating the flow of the developer 30. Therefore, the spikes of the developer 30 are limited by the doctor plate 21 and become low, and contact with the photoreceptor 1 is avoided. doctor blade 21
The photoreceptor 1 starts rotating at the same time as the movement of the doctor blade 21 is completed, and after a certain period of time, the motor 24 is reversely rotated to rotate the doctor blade 21.
is returned to its original position and developed.

FIG. 4 (AXBXC) shows a fourth embodiment of the present invention, in which a mag roll 26 having two north poles and two south poles is fitted into the mag sleeve 14 in the developer tank 3. Further, a rotating shaft 27 is fixed to the center of the mag roll 26, and the rotating shaft 27 is rotatably supported on the base frame of the developer tank 3. As in the second and third embodiments, a ohm wheel 28 is fixed to a portion of the rotating shaft 27 that protrudes from the base frame, and the ohm wheel 28 is connected to the worm 3 rotated by a motor 29.
It meshes with 1. As shown in FIG. 4(A), the mag roll 26 normally has one NW pole located on a line connecting the center of the photoreceptor 1 and the center of the mag roll 26, and the developing material is placed on the N pole. A spike 30a of the developer 30 is formed, and the developer 30 is brought into contact with the surface of the photoreceptor 1 at this normal position. When the motor 29 is rotated forward, the worm 31. Worm wheel 28
, the rotating shaft 27 rotates, and the mag roll 26 is rotated as shown in FIG.
), and the spikes 30a of the developer 30 are moved away from the photoreceptor 1. On the other hand, when the motor 29 is reversely rotated, the mag roll 26 returns to the position (A).

In the above device, when a recording start signal is input, the motor 29
rotates, rotates the mag roll 26 in the direction of the arrow, and the photoreceptor 1
The N pole that was on the line connecting the center of Magroll 26 with (C
), it moves to the position J, and accordingly moves from the spike 30a of the phenomenon agent 30 formed on the N pole. Therefore, the spikes 30a of the developer 30 disappear on the line connecting the center of the photoreceptor l and the center of the mag roll 26, and the developer 30
The layer becomes thin, and the developer 30 and the photoreceptor l do not come into contact with each other.

After a certain period of time has elapsed, the motor 29 is reversely rotated to rotate the mag roll 2.
6 is rotated to return the spikes 30a of the developer 30 to the position 5 where they come into contact with the surface of the photoreceptor 1, and thereafter, development is performed.

In the above-mentioned 2) third and fourth embodiments, as in the first embodiment, the action of separating the developing agent 30 from the photoreceptor l is performed not only at the time when the rotation of the photoreceptor l is started by the recording start signal, but also at any time. This is done at the start of rotation of the photoreceptor 1 under certain conditions, and when a certain period of time has passed after the start of rotation and the portion that has a predetermined charged potential reaches the development Wj3, the developer 30 is applied to the surface of the photoreceptor l. Returned to contact position.

Further, in the 2nd) third and fourth embodiments, a rotational movement mechanism is used to move the developer 30 away from the photoreceptor l, but a linear sliding movement mechanism may also be used. It goes without saying that instead of the motor as the driving source for movement, an appropriate means such as a solenoid may be used.

Furthermore, in any of the above embodiments, when the recording start signal is issued, the developer 30 is first retracted from the surface of the photoreceptor 1 so as not to come into contact with the photoreceptor 1, and then the developer 30 is rotated. However, the retraction operation of the phenomenon agent 30 and the rotation of the photoreceptor I may be started simultaneously with the recording start signal.

Effects of the Invention As is clear from the above explanation, the reversal development recording device according to the present invention prevents the developing agent in the developer tank from coming into contact with the photoreceptor for a certain period of time when the photoreceptor starts rotating. Therefore, it is possible to prevent toner from adhering to an unstable potential area that occurs when the photoreceptor starts rotating. Therefore, unnecessary waste toner can be prevented, toner /r4 costs can be reduced, and the performance of the apparatus can be improved.

[Brief explanation of the drawing]

FIG. 1 (AXB) (C) shows the first embodiment of the present invention. A) is a cross-sectional view showing the state when the developer is attached to the photoreceptor, and (B) is a cross-sectional view when the developer is not attached. A cross-sectional view showing the condition,
(C) is a front view showing the drive mechanism, Figure 2 (AXBXC)
3(A), 3(B), and 3(C) show a third embodiment, and FIGS.
A drawing similar to the embodiment, FIG. 4 (AXBXC), shows a fourth embodiment, and a drawing similar to the first embodiment, FIG. 5, is a front view showing a conventional reversal development recording apparatus. ■・Photoreceptor 2...Main charger. 3.Developer tank 4.Transfer charger 6.Cleaner 7.Static charge removal lamp 8..Recording paper 1O117,2/2.27..Rotating shaft 13..Solenoid 19.24.29..Motor 30...Developer

Claims (5)

[Claims] (1) In an electrophotographic reversal development recording device that charges a photoreceptor, irradiates light onto the photoreceptor to form a latent image, develops it with toner, transfers the toner image to paper, and then fixes it. 1. A reversal development recording device comprising a mechanism that separates the developer in the developer tank from the photoreceptor for a certain period of time when the photoreceptor starts moving, and prevents the developer from coming into contact with the photoreceptor. (2) The apparatus according to claim (1), characterized in that the device includes a mechanism for moving the entire developer tank away from the photoreceptor for a certain period of time when the photoreceptor starts moving. Development recording device. (3) The apparatus according to claim (1) is characterized by having a mechanism for moving the mag sleeve in the developer tank in a direction away from the photoreceptor for a certain period of time when the photoreceptor starts moving. A reversal development recording device. (4) In the apparatus according to claim (1), a mechanism is provided that, when the photoreceptor begins to move, brings the doctor blade in the developer tank close to the mag sleeve for a certain period of time to limit the spikes of developer. A reversal development recording device characterized by comprising: (5) In the device according to claim (1), when the photoconductor starts moving, the magnetic pole of the mag roll fitted in the mag sleeve in the developer tank is moved for a certain period of time to remove the developer. A reversal development recording device characterized by being equipped with a mechanism for moving the spike from a photoreceptor contact area.