JPH01277875A - Separating device for transfer material - Google Patents

Abstract

PURPOSE:To ensure the separation of the transfer material from a photosensitive body and also prevent the transfer material from having transfer deviation by providing a control means which limits the irradiation time of a light irradiating means to a constant time from the head end of the transfer material superposed on the photosensitive body to before the tail end. CONSTITUTION:The irradiation time control means 9 turns on the light irradiating means 8 in or after the transfer process of a copying machine, and the surface of the photosensitive body 1 is irradiated by the light only in the constant area from the head end of the transfer material 6 before the tail end with light through the transfer material 6 from the rear surface of the transfer material 6. Then residual charges at the surface part of the photosensitive body 1 are reduced as to the part which is superposed upon the transfer material 6 and further superposed upon said constant area. Further, the irradiation time of the light irradiating means 9 is limited to only the constant time from the head end of the transfer material 6 superposed on the photosensitive body 1 before to the tail end to limit a decrease in attracting force between the transfer material 6 and photosensitive body 1 which is harmful to a transfer process to a necessary area. Consequently, the separation of the transfer material 1 from the photosensitive body 1 is secured and the transfer material 6 is prevented from having transfer deviation.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image forming apparatus such as an electrophotographic device, a recording machine, etc. using a reversal development method, and more specifically, the present invention relates to an image forming apparatus such as an electrophotographic device or a recording machine using a reversal development method. The present invention relates to a transfer material separation device that reduces transfer deviation due to a decrease in conveying force during separation while separating the transfer material.

[Conventional technology] Inversion 31! In image-based image forming apparatuses, a self-separation method is mainly used to separate the transfer material from the surface of the photoreceptor after transfer, using the rigidity and weight of the transfer material itself. As a separation assisting means for small ii1 paper, etc., a method of irradiating light from the back side of the transfer material after transfer (for example, Japanese Patent Laid-Open No. 62-47081) has been proposed.

An image forming apparatus using this method, as shown in FIG.
A photoreceptor 1 rotating in the direction of the arrow, a charger 2 arranged around it, and an exposure device 3. developing device 4, timing roller 5,
It includes a transfer device 7, a light irradiation device 14, a cleaner 10, an eraser 11, and the like.

This image forming apparatus charges the surface of a photoreceptor 1 rotating in the direction of the arrow with a charger 2, and exposes it with light according to image information using an exposure device 3 to form an electrostatic latent image. A toner image is formed by developing with a developing device 4.

Then, the transfer material 6 is transported in the direction of the arrow by the timing roller 5, and is transferred by a transfer device '117, and after the transfer, light is irradiated from the back side of the transfer material 6 by the light illumination FI4 device 14.
By removing the surface charge of the photoreceptor 1, the transfer material 6 is separated properly by the rigidity and weight of the transfer material itself, and is sent to the fixing roller 13 via the conveyance guide plate 12 to obtain a recorded image. ing.

[Problems to be Solved by the Invention] However, in the conventional method described above, when light is irradiated from the back side of the transfer material as a separation assisting means, the irradiation light tends to go around to the transfer area. Therefore, the adhesion force between the transfer material and the photoreceptor decreases, and transfer misalignment occurs due to external disturbances such as shocks and vibrations applied to the transfer material during conveyance.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a transfer H separation device that can both ensure separation of the transfer material from the photoreceptor and prevent transfer misalignment of the transfer material.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the transfer material separation device of the present invention has a method for distributing a photoreceptor on the surface of a photoreceptor, which is provided at the position of the means for transferring onto the transfer material or on the downstream side thereof. a light irradiation means for transmitting light through the transfer material from the back side of the transfer material, which is straight, and irradiating the surface of the photoreceptor; This is achieved by providing a II control means for irradiating light only for a certain period of time.

[Function] In the transfer material separation device of the present invention 13, the light irradiation means is turned on by the irradiation time control means during or after the transfer f process of the copying machine, and the light irradiation means is turned on by the irradiation time control means, and the light irradiation means is turned on only in a certain area from the front end to the rear end of the transfer material. The surface of the photoreceptor is irradiated with light that passes through the transfer material from the back side of the transfer material, and the portion of the photoreceptor surface that overlaps with a certain area from the leading edge to the rear end of the transfer material out of the area that extends beyond the transfer material is removed. The electric charge decreases, and the Coulomb force that attracts the transfer material to the photoreceptor in that area decreases or disappears. Therefore, the transfer material can be easily separated from the photoreceptor from its leading edge. Further, by means of a control means that limits the irradiation time of the light irradiation means to only a certain period of time from the leading edge to the trailing edge of the transfer material superimposed on the photoreceptor, the transfer material and the photoreceptor are harmful to the transfer process. Limits the decrease in suction force to the necessary area. It is possible to both ensure the separation of the transfer material from the photoconductor and prevent transfer misalignment of the transfer material, and furthermore, it is possible to prevent the life of the photoconductor from being shortened due to unnecessary exposure time.

[Example] The present invention will be explained in detail below.

FIG. 1 shows a schematic configuration of an image forming apparatus using a reversal development method according to an embodiment of the present invention. This image forming apparatus includes a drum-shaped photoreceptor 1, a charger 2, an exposure device 3, a developer 4, a timing low 55, and a charger 2 arranged around the photoreceptor 1.
Transfer device 7, separation light emitter 8, cleaner 10, eraser 1
1. The apparatus further includes an irradiation time control means 9, a conveyance guide plate 12, and a fixing roller 13. Note that the separated light emitting device 8 has a plurality of light emitting diodes (LEDs) arranged in parallel rows in the axial direction of the photoreceptor 1, so its length is approximately the width of the drum of the photoreceptor 1. This image forming apparatus charges the surface of the photoreceptor 1 rotating in the direction of the arrow with a charger 2, and exposes the surface of the photoreceptor 1 with light according to image information using an exposure device 3, so that an electrostatic latent image is formed on the surface of the photoreceptor 1. The electrostatic latent image is developed by a developer 4 to form a toner image. On the other hand, the timing roller 5 transports the transfer material 6 in synchronization with the rotation of the photoreceptor 1 in the direction of the arrow, and the transfer device l! 7. After the transfer, the transfer material 6 is irradiated for an irradiation time υ1 by the separation light emitting device 8 controlled by the means 9 as shown in the timing chart shown in FIG.
The photoreceptor 1 is irradiated with light from the back side of its tip portion for a certain period of time to remove the charge on a part of the surface of the photoreceptor 1.

As a result, the transfer material 6 adsorbed to the photoreceptor 1 has a lower adhesion force to the photoreceptor 1 at its leading end, and is separated from the photoreceptor 1 due to the rigidity and weight of the transfer material 6 itself, and the conveyance guide plate 12 The toner is guided along the transfer material 6 and further sent to the fixing roller 13, where the toner is heated and melted, adheres to the transfer material 6, and is fixed. Since the part of the transfer material 6 following the leading edge is subject to the weight of the part separated from the photoreceptor 1, it naturally separates from the photoreceptor 1 even if the charge on the photoreceptor 1 has not been removed, and continues to the leading edge. transport guide plate 12
, the image is sent to the fixing roller 13 and fixed.

The irradiation time υJIB means 9 of the separation device of this embodiment is the second
As shown in the timing chart in the figure, the timing roller 5 is made! At the same time as time t1 of [1] (ON), the separation light emitting device 8 is turned on (ON). At this time, the transfer material 6 has not yet reached the opposing portion of the separated light emitter 8. Then, at time t2, the leading edge of the transfer material 6 reaches the opposing portion of the separation light emitter 8, with the photoreceptor 1 being attracted. After this, the separated light emitter 8 is turned off (OFF) at time t3. Photoconductor 1 is at time t1
Until time t3, light is irradiated by the separated light emitter 8, and the charge on the irradiated portion is removed or reduced.

Thereafter, the rear end of the transfer material 6 passes the timing roller 5, and the timing roller 5 is stopped <OFF> at time t4. Then, at time t5, the rear end of the transfer material 6 is connected to the separated light emitter 8.
to the opposite part.

In this example, the transfer material: 64a/m2 paper, the drum diameter of the photoreceptor: φ3Q1m, and the transfer output crab aluminum tube current is 30μ△
The light irradiation time to the transfer material was set to 0.48 under the following conditions: process speed: 50+m/s, transfer section position: horizontal sheet feeding, environmental temperature: 25°C, humidity 71%. Note that the light irradiation time required to separate the transfer material varies depending on the scale of the transfer material, the drum diameter of the photoreceptor, the transfer output, the position of the transfer section, the environment, and the like. Zunawara,
The thinner the transfer material is, the larger the drum diameter of the photoreceptor, the more
The higher the transfer output, the higher the humidity (the higher the moisture content of the transfer material) 8i! , the irradiation time of the separate light emitter 8 becomes longer.

Furthermore, the faster the process speed is, the longer the length of the transfer material 6 from the tip required for separation becomes.

After the time t3 when the light emitter 8 finishes irradiating light, the adhesion force between the transfer material 6 and the photoreceptor 1 can maintain the same strength as before the irradiation, which is effective in preventing transfer misalignment. By controlling the light irradiation time of the separated light emitter 8 in this way,
It is necessary to reduce the adsorption force between the transfer material and the photoreceptor, which is harmful to the transfer process!
! ! Limited to the area, transfer the transfer material from the photoconductor to 1lllt.
It is possible to achieve both +lW & maintenance and prevention of transfer deviation of the transfer material, and furthermore, it is possible to prevent the life of the photoreceptor from being shortened due to unnecessary exposure time.

In the above-described embodiment, the irradiation start time of the separation light emitting device 8 is set to be the same as the time t1 when the timing roller 5 is activated (ON'), but it is not particularly necessary to limit it to the same time as the time t1, and the transfer material 6 If the time is before the time t2 when the leading edge of the minute 111ff light emitter 8 passes over the opposing portion of the minute 111ff light emitter 8, it is also possible to set the time before or after the tense t1.

Control can also be performed according to the following timing chart depending on the length of the rotation '7446. FIG. 3 is a timing chart when the transfer material 6 is relatively long (the transfer material 6 straddles the fixing roller 13 and the timing roller 5). In this case, in order to reduce transfer deviation due to the impact (A) when the leading edge of the transfer material 6 enters the fixing roller 13, the irradiation of the separation light emitter 8 is finished before time A. In addition, in FIG. 4, the transfer material 6 is relatively short (after the rear end of the transfer material 6 comes off the timing roller 5, the leading edge of the transfer material 6 touches the fixing roller 13).
This is a timing chart for the case where the in this case,
When the rear end of the transfer material 6 comes off the timing row 55 (B
), the irradiation of the separation light emitter 8 is finished before time B in order to reduce the shift η caused by the impact.

Furthermore, it is clear that the means for irradiating the surface of the photoreceptor with light passing through the transfer material from the back side of the transfer material is not limited to the separate light emitting device illustrated in FIG. Further, the arrangement location is not limited to the downstream side of the transfer means, but it is also possible to arrange it 2F behind the transfer means as shown in FIG.

Furthermore, as for the irradiation time control means for irradiating the light irradiation means only on a certain area from the leading edge of the transfer material placed on the photoreceptor to the pre-positioning end, the irradiation time control means may be controlled by a microcomputer using υ110, or by using a microphone [1 switch]. Regardless of the method, the illumination QJ time of the light irradiation means is determined by the above conditions.
It is clear that any controllable υ1 length stage can be used.

[Effects of the Invention] As is clear from the above description, the present invention provides a method in which, after the transfer step, the light irradiation means passes through the transfer material from the back side of the transfer material and irradiates the surface of the photoreceptor with light, so that the photoreceptor surface is overlapped with the transfer material. Reduces residual charge on the photoreceptor surface. Therefore, the Coulomb force that attracts the transfer material to the photoreceptor is reduced or eliminated, making it easier to separate the photoreceptor and the transfer material. Furthermore, the irradiation time of the light irradiation means is limited to a certain period of time from the front end to the rear end of the transfer material superimposed on the photoreceptor.
jJ 111 steps [).

As described above, the present invention limits the decrease in adsorption force between the transfer material and the photoreceptor, which is harmful to the transfer process, to a necessary area, and achieves both the separation of the transfer material from the photoreceptor and the prevention of transfer misalignment of the transfer material. This has the effect of preventing the life of the photoreceptor from being shortened due to unnecessary exposure time.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a reversal development type image forming apparatus equipped with a transfer material separation device according to an embodiment of the present invention, and FIG. 2 is a timing diagram of a control means for controlling the irradiation time of the light irradiation means of the present invention. Chart diagram, Figure 3 is the second chart when the transfer material is long.
FIG. 4 is a timing chart similar to FIG. 2 when the rolled material is short, FIG. 5 is an explanatory diagram of main parts in another embodiment of the present invention, and FIG. 1 is a schematic configuration diagram of a reversal development type image forming apparatus equipped with a conventional transfer material separation device. 1... Photoreceptor, 2... Charger, 3... Exposure device, 4
Developing device, 5 Timing roller, 6 Transfer material, 7 Transfer device, 8 Separation light emitter (light irradiation means), 9 Irradiation time control means, 10 ...Cleaner, 11
...Eraser, 12...Transportation guide plate, 13...
・Constant volume roller, 14...Light irradiation device patent applicant
Minolta Camera Co., Ltd. Agent Patent Attorney Okawa
Hiroshi

Claims (1)

[Claims] (1) An image forming apparatus using a reversal development method, which is provided at or downstream of a means for transferring a toner image on a photoconductor to a transfer material superimposed thereon, from the back side of the transfer material. A light irradiation unit that irradiates the surface of the photoconductor with light through the transfer material, and an irradiation time that causes the light irradiation unit to irradiate only a certain area from the front end to the rear end of the transfer material superimposed on the photoconductor. A transfer material separation device comprising: a control means;