JPS63195667A - Image forming device - Google Patents

Abstract

PURPOSE:To eliminate the labor of mounting a transfer material on a paper feed part temporarily and feeding it again and to shorten an image formation time by performing the both-sides image formation and multiple image formation of the transfer material continuously. CONSTITUTION:This device is equipped with a 1st image forming means A which forms an image on a 1st surface of the transfer material P and a 2nd image forming means B which forms an image on the 1st or 2nd surface of the transfer material P. Then a conveyance path 12 for the multiple image formation wherein images are formed on the 1st surface of the transfer material P by 1 2nd image forming means after the image formation of the 1st image formation A and a conveyance path 13 for the both-surface image formation wherein an image is formed on the 2nd surface of the transfer material P are switched by a switching means to form the images continuously on the 1st or 2nd surface of the transfer material P which has a specific image formed on the 1st surface. Consequently, the conveyance path for the transfer material P is shortened to perform the both-sides and multiple image formation in a short period.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image forming apparatus that performs double-sided and multiple transfer of a transfer material in, for example, an electrophotographic copying machine or a laser beam printer.

(Prior Art) Conventionally, image forming apparatuses capable of forming images on both sides of a transfer material or performing multiple image formation on the same surface are widely known, regardless of whether they are analog systems or digital systems.

Conventionally, as this type of device, there are the following types. That is, as shown in FIG.
After the toner image formed on the photoreceptor drum 52 is transferred to the first surface of the transfer material fed by the transfer unit in the transfer section, this transfer material is separated from the photoreceptor drum 52 and fixed in the fixing device 53. Then, it is temporarily stored in an intermediate tray 54 provided within the apparatus. Next, the transfer material is again fed from the intermediate tray 54 through the loop-shaped conveyance path, and a second surface of the transfer material formed on the photoreceptor drum 52 is superimposed on the second surface or the first surface of the transfer material. After the image is transferred by the transfer unit, it is fixed by the fixing device 53 and discharged to the outside.

(Problems to be Solved by the Invention) However, the above conventional example has the following problems. That is, when copying images on both sides of a transfer material or in multiple layers, a predetermined image is first transferred and fixed on the first side of the transfer material, and then the transfer material is temporarily stored in the intermediate tray 54, and this transfer material is conveyed to the transfer section again. Then, the image is transferred and fixed onto the second side or the first side. As a result, time is required to copy the image on both sides or one side of the transfer material, and even if the model is capable of performing normal one-sided copying at high speed, it takes less time to copy the image on one side or multiple copies. Both methods require twice as much time, and there is a problem in that the time required for copying becomes longer.

Furthermore, since there is a limit to the number of transfer materials that can be placed on the intermediate tray 54, when copying a large amount of transfer materials,
There was a problem in that the copying had to be done several times, which increased the time required for copying.

Furthermore, since the transfer material on which a predetermined image has been formed on the first side is conveyed to the transfer section again via the conveyance path including the intermediate tray 54, jams are likely to occur, and once a jam occurs, the conveyance path is Since the transfer material is long, there is a problem in that it is extremely troublesome to remove the transfer material.

Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and its purpose is to shorten the conveyance path of the transfer material so that double-sided and multiple image formation can be performed in a short time. The objective is to provide an image forming apparatus that can.

(Means for Solving the Problems) In order to solve the problems of the prior art described above, the present invention provides a first image forming means for forming an image on the first surface of a transfer material; and a second image forming means for forming an image on either the first surface or the second surface of the transfer material, and after the image formation by the first image forming means, the transfer material is transferred to the second image forming means. A switching means is configured to switch between a conveyance path for multiple image formation in which multiple images are formed on the first side and a conveyance path for double-sided image formation in which images are formed on the second side of the transfer material.

(Function) In the present invention having the above configuration, after a predetermined image is formed on the first surface of the transfer material by the first image forming means, multiple images are formed when the transfer material is conveyed to the second image forming means. The conveyance path for image formation and the conveyance path for double-sided image formation are switched by a switching means, and an image is continuously conveyed on the first side or the second side of the transfer material on which a predetermined image has been formed. It was designed so that it could be formed.

(Example) The present invention will be explained below based on illustrated embodiments.

FIG. 1 shows an image forming apparatus according to an embodiment of the present invention, in which A is a first
The image forming means is a Carlson type electrophotographic process. First, a laser beam emitted from a laser scanning optical system l based on an image signal formed on a light receiving element (not shown) such as a COD or a signal created by a computer (not shown) is transmitted to a mirror 2. and reaches the photosensitive drum 4, which is uniformly charged by a corotron type primary charger 3.

The first photoreceptor drum 4 is rotating in the direction of the arrow, and the latent image formed on the surface of the photoreceptor drum 4 by the laser beam is developed into a toner image by the developing device 5, and further developed by the paper feed roller 6. Then, the image is transferred by the transfer charger 9 onto the transfer paper P which is conveyed from the transfer paper storage section 8 at a timing by the registration rollers 7 . After this transfer step, the toner remaining on the surface of the photosensitive drum 4 is removed by a cleaner 10, and the remaining latent image is erased by an exposure lamp 11 provided at a predetermined position.

Reference numeral 12 denotes a first conveyance unit that suctions and conveys the transfer paper P for double-sided image formation to form an image on the second side of the transfer paper P;
Reference numeral 13 denotes a second conveyance unit that suctions and conveys the transfer paper P for multiple image formation. Reference numeral 14 denotes a flapper as a switching means, which is attached to the first conveying section 12 and is swung by an electromagnetic solenoid or the like (not shown) to move the transfer paper P with a predetermined image formed on its first surface. Sort to the first or second transport section 12.13.

Reference numeral B denotes a second image forming means, which has a first-order configuration. That is, 15 is a second photosensitive drum that can rotate clockwise and counterclockwise, that is, forward and reverse, and the laser beam emitted from the laser scanning optical system l passes through mirrors 16 and 17 to the surface of the drum 15. Further, a laser beam emitted from a second laser scanning optical system 18 provided on the first surface side of the transfer paper P exposes the surface of the drum 15 via a mirror 19.

A charger 20 functions as a primary charger that uniformly charges the surface of the second photoreceptor drum 15 by controlling the voltage and polarity, and also serves as a charger that is formed on the surface of the photoreceptor drum 15 on the transfer paper P. It has a function of transferring the toner image and a function of separating the transfer paper P from the photoreceptor drum 15. A charger 21 has the same function as the charger 20, and is controlled as a pair with the charger 20 so that double-sided or multiple copying can be performed.

22 is a developing device, which, as shown in FIG. 2, includes a developing sleeve 22a that can be rotated clockwise and counterclockwise, and releasable doctor blades 22b that are provided on the upstream and downstream sides of the developing sleeve 22a in the rotational direction. , 22c, a screw 22d for conveying toner, and a roller 22e for replenishing a small amount of toner.

A cleaner 23 serves as a cleaning means for removing toner remaining on the photosensitive drum 15, and as shown in FIG. Ta,
A leaning blade 23b that can freely come into contact with and separate from the second photoreceptor drum 15.

23c, and a screw 23d for conveying the toner. Therefore, the cleaner 23 is configured to be able to remove toner when the photosensitive drum 15 rotates in both directions. Further, 24 and 25 are exposure lamps for erasing the latent image remaining on the photoreceptor drum 15.

As described above, in this embodiment, in order to make the configuration of the image forming apparatus compact, the second photosensitive drum 15, charger 20,
21, a developing device 22, and a cleaner 23 are commonly used.

In the above configuration, in the image forming apparatus according to this embodiment, images are formed on both sides or in multiple layers of the transfer paper P in a primary manner. That is, first, the transfer paper P is fed from the transfer paper storage section 8 according to the paper feed signal, and is fed at a predetermined timing by the paper feed roller 6 and the registration roller 7.
Next, on the first surface of the transfer paper P, a predetermined image formed by the laser scanning optical system l on the first photosensitive drum 4 which rotates clockwise and is uniformly charged by the primary charger is transferred. The transfer paper P on which the 0 image has been formed is transferred by the charger 9a and is separated from the first photoreceptor drum 4 by the one-separation charger 9b and guided to the first conveyance section 12.

When forming images on both sides of the transfer paper P, the following steps are performed. First, the flapper 1 is
4 to be connected to the second conveyance section 13,
As a result, the transfer paper P is smoothly transferred to the second conveyance section 1.
3, and is sucked and conveyed to image forming means B at S2.

In this case, the second photoreceptor drum 15 is rotating counterclockwise, that is, in the opposite direction to the first photoreceptor drum 4 at the same speed, and the second photoreceptor drum 15 is uniformly charged by the charger 20. On the surface of drum 15.

A light image on the second surface of the transfer paper P is formed as a latent image by the laser scanning optical system 18.

This latent image is transferred together with the second photosensitive drum 15, and a toner image is formed on the drum surface by the developing device 22.

That is, in the developing device 22, as shown in FIG. 2, after a certain amount of toner is coated by a doctor blade 22b, a latent image is visualized by a developing sleeve 22a to become a toner image. In this case, Doctor Blade 2
2c is in the release position and is not activated.

This toner image is transferred onto the second surface of the transfer paper by a charger 21 having a transfer and separation function, separated from the second photosensitive drum 15, and sent to an air conveying section 26.

After that, the remaining toner on the photoreceptor drum 15 is removed by a cleaner 2.
Cleaned by 3. In this case, as shown in FIG. 3, cleaning is performed by a cleaning blade 23c that is provided so as to be able to come into contact with and separate from the photoreceptor drum 15, while the cleaning blade 23b is in the release position and is not operating. , second photosensitive drum 15
The upper latent image is erased by being illuminated by the exposure lamp 25.

The transfer paper P, on which images have been transferred on both sides in this manner, is sent to the fixing device 28 by an air conveyance unit 26 that blows air in the direction of travel so as not to deteriorate the image quality on the second side, and images are fixed at the same time. Note that the surface of this fixing device 28 is cleaned by a cleaner 27. Thereafter, the transfer paper P is discharged to the outside of the apparatus by the discharge roller 29 and placed on the tray T1.

Next, a case where multiple images are formed on the transfer paper P will be described.

The transfer paper P, on which a predetermined image has been formed on the first side by the above-described process, is transferred to the first conveyance section 12 by switching the flapper 14.
By storing it inside, the image forming apparatus is suctioned and conveyed by the first conveying section 12 and guided to the second image forming means B.

R's Jin^埴2's Aruhankan V → 1. IF + 1 ÷ - 15 In other words, the photosensitive drum 15 rotates in the same direction and at the same speed as the first photosensitive drum 4 and is uniformly charged by a charger 21 having a primary charging function by switching a switch. The surface is exposed by a laser scanning optical system 1 with a light image to be formed superimposed on the first surface, and is formed as an Hs image.

This latent image is transferred together with the photoreceptor drum 15, and the developing device 2
2, a toner image is formed. That is, developing device 2
2, as shown in FIG. 2, after a certain amount of toner is coated by a doctor blade 22c, the latent image is visualized by a developing sleeve 22a to become a toner image. In this case, the doctor blade 22b is in the released position and is not operating.

Does this toner image have a transfer separation function? Electric appliances 20
The toner image is superimposed on the first surface of the transfer paper P, separated from the second photoreceptor drum 15, and sent to the third conveyance section 30.

After that, the remaining toner on the photoreceptor drum 15 is removed by a cleaner 2.
Cleaned by 3. In this case, as shown in FIG. 3, cleaning is performed by a cleaning blade 23b that is provided so as to be able to come into contact with and separate from the photoreceptor drum 15, while the cleaning blade 23c is in the release position and is not operating. The latent image on the photosensitive drum 15 is erased by being illuminated by the exposure lamp 24.

The transfer paper P on which multiple images have been formed on the first surface is suction-conveyed by the conveyance section 30 of the uS3, but in this case, the transfer paper P is moved to near the end of the third conveyance section 30. The first surface is fixed by the fixing device 28, and then the discharge roller 3
1 and is discharged to the outside of the apparatus and placed on tray T2 provided below tray Tl.

Furthermore, in this multiple copying process, if the developing units 5 and 22 are made replaceable, images of two different colors can be formed multiple times. Incidentally, when making a normal one-sided copy, the conveyance path in the multiple copying process described above is used, and the electronic image formation is performed by the second image forming means B.

In this embodiment having the above-described configuration and operation, since double-sided image formation and multiple image formation on the transfer paper P are performed continuously by the first and second image forming means A and H, the transfer paper P
This eliminates the need to temporarily place the transfer paper P on a paper feed section such as an intermediate tray and then refeed the paper, and the time required to form images on both sides or in multiple layers of the transfer paper P can be greatly shortened.

Further, since there is no need to provide a loop-shaped conveyance path for refeeding the transfer paper P, jams are less likely to occur, and even if a jam occurs, it can be easily handled.

Although three laser scanning optical systems are used in this embodiment, a laser scanning optical system having a configuration as shown in FIG. 4 may also be used. 41, whereas the laser 42. Two sets of collimator lenses 43 and tilt correction optical systems 44, 45, and 46 are provided.

It is configured to emit beams in two directions. As a result,
Compared to the case where two sets of scanning optical systems are provided, the optical system can be formed more compactly and power consumption can be kept low. In this case, it is also possible to use other scanning means, such as an LED array or an LCD (liquid crystal display), depending on the scanning speed and the type of image.

Further, the second image forming means B shares the chargers 20 and 21, the developing device 22, and the cleaner 23 in order to make the configuration compact, and rotates the photosensitive drum 15 in two directions, that is, double-sided copying or multiplexing. Although the configuration is adapted to accommodate copying, each may be arranged individually if space permits.

Further, in this embodiment, one fixing device is provided to fix the toner image on the surface of the second photosensitive drum 15, and the image is fixed after completing the transfer process on both sides of the transfer paper P or multiple times. , yet another fixing device may be provided near the first image forming means A, and a predetermined image on the transfer paper P may be fixed first. In this case, it is possible to reduce the difficulty of handling transfer paper with unfixed images. Further, in this embodiment, the fixing device 28 is moved to fix the air conveying section 26 or the third WI screw 30), respectively. The air conveyance section 26 and the third conveyance section may be configured to merge. In this case, there is no need to move the fixing device 28, and there is only one discharge port for the transfer paper P. Easy to handle.

As described above, the developing device 22 used in this embodiment has a configuration that can handle the rotation of the photoreceptor drum 15 in both directions. Even if there is, by changing the number of rotations, bias, etc., development can be performed without problems at low copying speeds, and it can be applied to small machines.

Furthermore, the cleaner 23 is not limited to the blade type described above, and may have, for example, a fur brush equipped with a dusting mechanism for removing toner, so as to correspond to the rotation of the second photoreceptor drum 15 in both directions. It may be arranged.

In conclusion, the present invention is not limited to the electrophotographic copying device according to the above-mentioned embodiment, but can be applied to any device capable of copying images from electrical signals, for example, a magnetic recording device. Furthermore, the image carrier is not limited to the photosensitive drum, but a belt, a magnetic drum, etc. may also be used.

(Effects of the Invention) In the present invention having the above configuration and operation, since double-sided image formation and multiple image formation on the transfer material are performed continuously by the first and second image forming means, the transfer material is This eliminates the need to once place the paper on a paper feed unit such as a tray and then refeed the paper, and the time required to form images on both sides of the transfer material or in multiple layers can be greatly shortened.

Further, since there is no need to provide a long loop-shaped conveyance path for refeeding the transfer material, jams are less likely to occur, and even if a jam occurs, it can be easily handled.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of an image forming apparatus according to the present invention, and FIG. 2 is an enlarged cross-sectional view showing a developing device of the same embodiment.
FIG. 3 is an enlarged sectional view showing the cleaner of the same embodiment, FIG. 4 is a schematic configuration diagram showing one embodiment of the laser scanning optical system, and FIG.
The figure is a configuration diagram showing a conventional image forming apparatus. Explanation of symbols A: First image forming means B: Second image forming means 14: Flapper (switching means) Fig. 2 Fig. 3 Fig. 4

Claims (7)

[Claims] (1) A first image forming means that forms an image on a first surface of a transfer material, and a second image forming means that forms an image on either the first surface or the second surface of the transfer material. , a conveyance path for multiple image formation for forming multiple images on the first surface of the transfer material in the second image forming means after the image formation by the first image forming means; An image forming apparatus characterized in that a switching means switches between a conveyance path for forming an image on a surface and a conveyance path for double-sided image formation. (2) The second image forming means includes a set of chargers that have a primary charging function and a transfer separation function and can mutually switch both functions, and an image carrier in the second image forming means. Claim 1, characterized in that the image carrier is provided with one developing device capable of developing when the image bearing member moves in different directions, and one cleaning means capable of cleaning when the image bearing member moves in different directions. The image forming apparatus according to item 1. (3) The charger has at least two shielded charging parts each having a U-shape, and the charging parts have variable charging voltage and polarity. The image forming apparatus according to item 2. (4) The developing device includes a developing sleeve that can freely rotate in forward and reverse directions, and a set of doctor blades that are provided on the upstream and downstream sides of the developing sleeve in the rotational direction and can freely approach and separate from the image carrier. An image forming apparatus according to claim 2, characterized in that: (5) The image forming apparatus according to claim 4, wherein the doctor blade is selectively operated in accordance with the moving direction of the image carrier. (6) The cleaning means includes at least one set of cleaning blades that are provided upstream and downstream in the direction of movement of the image carrier and selectively operate in accordance with the direction of movement of the image carrier. An image forming apparatus according to claim 2, characterized in that: (7) The cleaning means includes at least one fur brush rotatable in forward and reverse directions corresponding to the moving direction of the second image carrier, and the cleaning means includes at least one fur brush rotatable in forward and reverse directions corresponding to the moving direction of the second image carrier, and 3. The image forming apparatus according to claim 2, further comprising a removing mechanism for removing at least one toner.