JPS6021382B2 - image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a short, small-focus imaging element array as an optical system for forming a desired optical image on an electrophotographic photoreceptor in order to form a static latent image on the photoreceptor. The present invention relates to an image forming apparatus.

Compared to image forming devices such as electrophotographic copying machines that use so-called monocular long-focal through lenses or mirror lenses, devices that use a compound-eye, trout-dot small imaging element array as the imaging optical system are smaller in size. On the other hand, since the output end face of the array and the photoreceptor surface, or the input end face and the surface of the original to be copied, are placed in close proximity, dust and dirt may adhere to the end faces, especially the output end face. Easy to do.

When dirt adheres to the end face of the small image forming element array, the effect on image formation is more significant than when dirt adheres to the surface of a normal large-diameter, monocular through lens, or mirror lens. In other words, since each of the imaging elements in the small imaging element array has a very small aperture, and because it has a compound eye configuration, only a part of the imaging element, not the entire array, is used to form a single rear point. is involved, the rate of light ray blocking for one image point due to dirt is large compared to when dirt of the same size adheres to the through lens and in-mirror lens, and the image point corresponding to the dirt part The decrease in illuminance becomes significant, and if the dirt distribution is uneven, the illuminance of the entire image will not decrease uniformly, but the illuminance distribution of the image will also become uneven. The main dust that contaminates the output end face of the short-focus small imaging element array is developer floating in the air near the surface of the electrophotographic photoreceptor. In the case of a one-component developer, the developer consists of a magnetic toner, and in the case of a two-component developer, it consists of a non-magnetic toner and a magnetic carrier. These developer components may mechanically adhere to the output end face of the array, or because the array is made of a material that easily charges, such as glass or synthetic resin, it may become charged due to friction with other members or other causes. In this case, the above-mentioned floating toner is electrostatically attracted to the output end face, which tends to cause dirt on the output end face of the array. The floating developer may also adhere to the incident end face of the array. Therefore, the main object of the present invention is to prevent the magnetic components of the developer from staining the end surfaces of the short focus small imaging element array.

Therefore, in the device of the present invention, the output end face of the array and
Alternatively, a dust-proofing magnet is arranged near the incident end face, and the magnetic field formed by this magnet near the end face prevents the magnetic component of the floating developer from being directed toward the array end face. Therefore, the present invention is particularly useful for devices in which toner is magnetic, which is a major cause of contamination, that is, devices using one-component developers. However, the present invention is not limited to an apparatus using a one-component developer, but can also be applied to a machine using a two-component developer. It has a high stain prevention effect because it can prevent the adhesion of dirt. In an apparatus using a two-component developer, if a dust-proof electrode for forming a dust-proof electric field is used in addition to the magnet, it is possible to prevent toner from adhering to the surface of the array machine, thereby further increasing the stain-preventing effect. (Conversely, the dust-proof magnet can prevent the carrier from adhering to the array surface, which cannot be prevented by the screen-proof electrode.) This dust-proof electrode can be used not only for direct use in bags using two-component developers, but also for one-component developers. It is also effective when applied to equipment that uses chemicals. In other words, gaseous ion particles generated due to charging of the surface of the photoreceptor or corona discharge used for transfer, etc., exist in the atmosphere inside the device, but these ion particles , combines with substances such as magnesium, and the compound mechanically and electrostatically adheres to the entrance and exit surfaces of the small imaging element array, resulting in stains.
- When the imaging element array is magnetized, ion particles are attracted to the small imaging element array by electrostatic attraction and enter the small imaging element array, accelerating the contamination of the output end face, and further contaminating various other dust particles in the air. This is the factor for the input of the array,
Dust mechanically and electrostatically adheres to the output end face as dirt, but especially when the small imaging element array is electrically charged and the blade dust is combined with ion particles, the dust is attracted by electrostatic attraction. - It is attracted to the imaging element array and adheres to the element end face, accelerating the contamination of the output end face. Irrespective of the composition of the developer used, charged floating bonito dust other than these toner particles can be prevented from adhering to the surface of the array machine by using a dust-proofing electrode in combination. Embodiments of the present invention will be described below with reference to the drawings. First, an outline of the short fishing point small imaging element array will be explained.

The one shown in FIG. 1A is a light-concentrating optical fiber-shaped light guide element 1, in which the refractive index decreases by 4.0 mm from the center toward the outer diameter in a parabolic curve. For example, Samurai Ko (Sho 47)
This lens is disclosed in Japanese Patent Publication No. 1280, etc., and has an imaging effect, and by making the length of the light beam, it forms an erect light image 1 of the same size as the object ○. The item shown in FIG.
In a bar lens system 2 as shown in Keitei Publication), a bar lens 2' forms an aerial image 1' of an object ○, and a bar lens 2^ refocuses an image 1 of an image r. When the lenses 2' and 2'' have the same focal length and are placed symmetrically with respect to the image point 1', an erect real image of the object can be formed at the same magnification.The element array used in the present invention is as follows. The elements 1 and 2 as described above are
As shown in Figure A, the light balls of each element are arranged in parallel and densely arranged in a straight line. In Figure 2 A, they are stacked in two tiers, but they may be stacked in three or more tiers, or only one tier. But that's fine. A suitable fixing frame 4 is fixed with iron around the outer periphery of the array 3. If such a short fish dot 4/imaging element array 3 is used, it will act as a compound eye imaging system, and in the case of iso-emotional formation, an object 0 of approximately the same size as the incident surface of the array will be erected at the same magnification. A light image 1 can be formed. This is shown in Figure 2-8. Next, the copying process of an electrostatographic copying apparatus to which the present invention is applied, which uses a short-focus small imaging element array as an imaging optical system, will be outlined with reference to FIG.

A photosensitive drum rotating in the direction of the arrow in the figure, that is, a photosensitive drum having a light guide fin 5 on a grounded conductive drum 5', is first uniformly charged on its surface by a corona magnetizer 6, and reaches the photosensitive part. . Here, a document table 8 illuminated by an illumination light source 7 (moved in the direction of the arrow at the same speed as the drum circumferential speed when forming a foundation image)
The image light of the upper original 9 is introduced onto the surface of the photoreceptor through the short-focus small imaging element array 3, which is an imaging optical system, and the original light image is exposed to the photoreceptor in a slit exposure manner. As a result, a static latent image corresponding to the original image is formed on the surface of the photoreceptor. This static fin latent image is visualized by a dry developing device 101 that applies magnetized toner to a photoreceptor, and then this toner image is transferred to a transfer paper 12 by a corona transfer charger 11. Thereafter, the surface of the photoreceptor is cleaned by an elastic blade 13 pressed against it, and the next copying process is started. The developing device 10' brings a one-component developer made of magnetic toner or a two-component developer made of magnetic carrier and toner into contact with the photoreceptor. Figure 3 shows an Atsuko photocopying machine that uses the so-called Carlson process, but a mother-child photocopying machine that uses a conductive base layer, a light guiding fin layer, and a transparent silk edge layer as a photoreceptor in this order, such as the Tokko Show 42-23
The processes described in Publication No. 91, Misaki No. 43-247, etc. can also be adopted.

In this case, the dotted point 4 and the output end surface side of the imaging element array are arranged in a corona discharger that attenuates the surface charge of the photoreceptor at the same time as the optical backlight. FIG. 4 is an explanatory diagram of a main part of an example in which the present invention is applied directly to the bag shown in FIG.

In FIG. 4a, 14 and 15 are magnets.

These magnets 16, 17 are non-magnetic supports 16, 17.
It is pasted on the bottom surface of. The supports 16 and 17 are integrally fixed to the array 3 on the output end surface 3' side of the array 3,
The lower end is projected toward the photoreceptor below the array output end face 3' within a range that does not eclipse the required imaging light emitted from the array 3, and the magnet 14.
15 is supported at a distance that does not eclipse the above-mentioned Koto,
It also prevents bonito dust from entering the end face 3' from the side.
The magnets 14 and 15 are opposed to each other, and in the figure, the pupils are arranged so that the opposing parts have opposite magnetic poles.
As a result, a magnetic field substantially perpendicular to the optical axis of each element of the array 3 is formed, and the supports 16, 17 and magnets 14, 15
covering the output end face 3' of the array 3 in cooperation with its own thickness;
Floating particles having magnetism such as magnetic toner or magnetic carrier are prevented from moving toward the surface 3'. That is, if magnetic dust tries to pass between the magnets 14 and 15, it will be attracted to one of the magnets. Unlike FIG. 4a, the opposing portions of the magnets 1, 4, and 15 may be rearranged so that they have the same magnetic polarity. In this case as well, magnetic dust floating near the magnet is attracted and prevented from being directed toward the array end face 3'. Next, in the embodiment shown in FIG. 4a, the supports 16 and 17 are made of a conductive material.

The conductive supports 16 and 17 are connected to the other pole of a DC power source E whose one pole is grounded as shown in the figure. As a result, an electric field approximately parallel to the optical axis of the elements of array 3 is formed between the photoconductor and the charged dust floating in or near this magnetic field, even if it is non-magnetic. a support 16 that acts as a photoreceptor side or a box pole depending on the electric field;
It is electrostatically attracted to the side of 17. The suction direction of this dust is determined by the charging polarity of the dust and the direction of the fin field, but in a diamond pupil using a two-component developer, assuming that the dust is non-magnetic toner, the surface of the photoreceptor is negatively charged. When the toner has a positive frictional force and a positive position is exposed to the electrode plates 16 and 17 as shown in the figure, the dusty toner is attracted to the photoconductor side by the above-mentioned dustproof field. Incidentally, as long as the dirt does not accumulate on the photoreceptor, the amount of dirt adhering to the photoreceptor is very small, so that its influence on image formation can be ignored.

Since the photoreceptor is cleaned every cycle of the image forming process, the dirt caused by the honey dust does not accumulate. The N potential applied to the fin poles 16 and 17 and its polarity are:
It is preferable that it is determined by the distribution of charge polarity of non-magnetic dust floating near the output end face of the array 3. In other words, if there is a lot of bonito dust with a positive polarity, the dust of that polarity will move in a direction that increases from the output end face 3' of the array 3. It is desirable to apply such a potential to the electrodes 16 and 17 as to move as much of the contaminating factors as possible toward the photoreceptor. When forming a dust-proof electric field using the supports 16 and 17 as dust-proof electrodes as described above, it is preferable that the magnets 16 and 17 are conductive in order to form a good dust-proof electric field.

In this case, the magnets 14 and 15 also act as part of the dust-proof electrode. Although the same DC voltage was applied to the electrodes 16 and 17 in FIG. You can let go.

Furthermore, it is also possible not to use the supports 16 and 17 as electrodes; in this case, the supports 16 and 17 may be made of an insulator such as synthetic resin, and the magnets 14 and 15 may also be made of ferrite. An insulating magnet may also be used.

Furthermore, unlike FIG. 4a, the electrodes 16, 17 and the magnets 14, 15 may be arranged separately. For example, the magnets 14 and 15 may be placed between the electrodes 16 and 17 and the photoreceptor, or on the sides of the electrodes 16 and 17. Additionally, the supports 16 and 17 may be made of magnetic material. In this case, the supports 16 and 17 also act as part of the dustproof magnet.

FIGS. 4b, c, d, and e show an embodiment in which the conductive magnets I8 and 19 are used also as dust-proof electrodes.

In the valley diagram, conductive magnets 18 and 19 are provided integrally with the array 3 on the output end face 3' side of the array 3, and each magnetic pole part does not obscure the desired imaging light output from the array 3'. It protrudes further toward the photoreceptor side from the array emitter surface 3' within the range. The protruding magnetic pole portions face each other, and the opposing portions have opposite magnetic polarities in each figure. As a result, as described above, a magnetic field is formed in a direction that almost perpendicularly traverses the optical path of the imaging light beam. But magnet 1
The opposing portions 8 and 19 may be arranged to have the same magnetic polarity. In any case, the magnets 18 and 19 attract magnetic dust and prevent it from being directed toward the output end face 3' of the array 3, as described above. Figure 4 b, c, d. In the embodiment e, the conductive magnets 18 and 19 are also used as dust-proof electrodes, as described above.

The same DC voltage is applied to the magnets 18 and 19 in FIG. 4B, the same AC voltage is applied in FIG. 4C, and the ground voltage is applied in FIG. 4C. When grounded, when charged dust comes close to a conductive magnet, a mirror image charge of opposite polarity is induced thereto, which attracts the dust. This can prevent the charged non-magnetic toner from adhering to the array end surface 3' as described with reference to FIG. 4a. Also, Figure 4 a. In cases b, c, and d, the two dust-proof electrodes were set at the same potential, but voltages of different polarities were applied to the magnets 18 and 19, which also served as dust-proof crab electrodes, respectively, as shown in Fig. 4 d, or one of them was grounded. , a positive or negative voltage may be applied to the other, or a low voltage of the same polarity as the other may be applied to one.

In any case, by doing this, an electric field is formed between the two housing poles 18 and 19, which crosses the output light base of the array 3 almost perpendicularly, so that the output end face 3' of the array 3 is connected to the magnet and electrodes 18 and 19. It is completely shielded from bonito dust by the lower part of the protrusion, the magnetic field, and the electric field. That is, the magnet and electrode 18
, 19 and try to reach the array end face 3', magnetic dust and charged dust are attracted to either the magnet/electrode 18 or 19. Figures 5a and 5b show the present invention
2-23910, 43-24748, etc., which employs a fin photographic process using an electrophotographic photoreceptor having an insulating layer on its surface, and uses a small short-shaped imaging element array. This shows the main part of the applied example.

That is, the output end face 3' of the array 3 has a corona release wire connected to an AC or DC fin pressure source, and the release end face 3' of the array 3.
and a grounded conductive shield 22 surrounding the corona discharger. This corona discharger has an array 3 on an electrophotographic photoreceptor having a transparent insulating layer 5^ on its surface.
Corona discharge is applied simultaneously with the optical image irradiation of the original 9 by
This is to remove charges that have been accumulated on the surface before exposure in the bright area of the photoimage. After this simultaneous exposure and static elimination process, the entire surface of the photoreceptor is uniformly exposed to light to form a high-contrast static image. As shown in FIG. 5a, in this embodiment as well, conductive magnets 18 and 19 are provided integrally with the array 3 on the emitter surface 3' side of the array 3, as shown in FIGS. 4b to 4c. .

The lower end portions of the magnets 18 and 19 are further projected toward the photoconductor side than the output end surface 3'' of the magnetic pole array 3, and the projecting portions are opposed to each other.The polarities of the opposing portions may be opposite or the same. conductive magnet 1 to attract magnetic dust and prevent dirt on the end surface 3'.
Voltages as shown in FIG. 4b, c, d, and e are applied to the plates 18 and 19, so that they serve as dustproof magnets and dustproof electrodes, but in FIG. , 19 are applied with equal positive voltage. In this case, plate 18
, 19 and the photoreceptor, and between the shield member 22, a dust-proof electric field is formed. Even if the charged dust is non-magnetic, it moves in this fin field depending on its charging polarity, and is electrostatically attracted to the electrodes 18 and 19, the shield member 22 side, and the photoreceptor side.
In addition, the conductive magnets 18, 19 are arranged so that spark discharge does not occur between the discharge wire 20 and the conductive magnets 18, 19.
19 is coated with a coating 21 of an insulating material, for example a synthetic resin. FIG. 5b shows a diamond plate using Umako photoreceptor having insulating properties on the surface, with the supports 16 and 17 shown in FIG. This is applied to the direct array 3.

In this case, no discharge occurs between the discharge wire 20 and the fifth
The insulating coating as shown in Figure a is unwritten. The above is an example of preventing dirt on the output end face 3' of the short-focus small imaging element array 3, but in order to prevent dirt on the input end face 3r, the steps shown in FIGS. 6a and 6b may be used, for example.

In FIGS. 6A and 6D, light-guiding magnets 23 and 24 are provided integrally with the short-focus small imaging element array 3 on the side of the incident surface 3^ of the array 3. The upper end sides of the conductive magnets 23 and 24 are projected further toward the document 9 side than the incident end surface 3' within a range that does not eclipse the light from the document incident on the array 3, and the respective protruding surfaces are opposed to each other. There is. These opposing parts may have the same magnetic polarity or opposite magnetic polarity. In any case, a dust-prevention magnetic field is formed to attract magnetic floating particles that try to pass between the two magnets and reach the incident end surface 3r of the array 3, thereby preventing the surface 3' from becoming contaminated. Further, in FIG. 6a, a conductive magnet 23 is placed close to the lower surface of the document table 8.
, 24, each having a guiding fin plate 25
, 26 are arranged. The plates 25 and 26 are also used to form optical slits that limit the document facing area of the array 3. In FIG. 6a, the plates 25 and 26 forming this slit are grounded, while the plates 23 and 24 attached to the array 3 are connected to the other pole of the grounded DC power source E on one pole side. has been done. In this way, the magnets 23 and 24 also serve as electrodes, and the electrodes 23 and 2
5 and between the electrodes 24 and 26, an electric field approximately parallel to the optical axis of each element of the array 3 is formed. This electric field acts as a dust prevention electric field as described above, and even if the charged floating dust is non-magnetic, it is attracted to the electrodes 23, 25 or 24, 26 depending on the polarity of the charge. Further, in FIG. 6b, the conductive magnet 23 is grounded, and a positive voltage is applied to the conductive magnet 24.

Thus, the magnets 23 and 24 also act as electrodes,
An electric field substantially perpendicular to the optical axis of each imaging element of the array 3 is formed between the opposing surfaces together with a magnetic field, and magnets 23 and 2 that also serve as electrodes are formed.
Even if the charged particles trying to pass through between the electrodes 23 and 4 are non-magnetic, they are prevented from directing toward the array entrance end surface 3 by this tortoise field, and depending on the sacrifice of the dust band, the electrode-cum-magnets 23,
24. The means shown in FIGS. 6a, b are used in FIGS. 4a, b, c, d, e, and 5a. It may be combined with the embodiment b. o In each of the above embodiments, the dustproof magnets 14, 15, 18, 19, 23, 2
4 and supports 16 and 17 are plate-shaped and have a length equal to or longer than the length of the output end face and/or the input end face of the short-focus small imaging element array 3, as shown in FIG. Needless to say, it is desirable to cover the following.

Furthermore, in the above-mentioned embodiment, the dustproof magnet was provided integrally with the array 3, but it is also possible to arrange it separately.
As can be seen from the above, according to the present invention, a dust-proof magnetic field is formed near the exit and/or input plane of the short-focus small imaging element array to prevent dirt on the end face, so the structure is simple and compact. Therefore, the objective of miniaturizing the device using the short-focus small imaging element array is not impaired, and it has various useful effects, such as being highly effective in preventing stains on the end face of the array and being able to stably form high-quality images. It is something that plays.

[Brief explanation of the drawing]

Figures 1A and B, Figures 2A and B show a short focus small imaging element array, Figure 3 shows an example of an electrophotographic copying bag to which the present invention can be applied, and Figures 4a, b, c, and d. , e, Figs. 5a and 5b, Figs. 6a and b, and Fig. 7 are diagrams for explaining embodiments of the present invention, respectively. 3 is a short focus 4/imaging element array, 14, 15, 18, 1
9, 23, and 24 are anti-housing magnets. Chrysanthemum/Zu Tsutomu 2 Figure 3 Urawa Figure 4 Figure 5 Figure 6

Claims (1)

[Scope of Claims] 1. In an image forming apparatus that uses a short focus small imaging element array as an optical system for forming a desired optical image on an electrophotographic photoreceptor in order to form an electrostatic latent image on the photoreceptor, An image forming apparatus characterized in that a dustproof magnet and a dustproof electrode are disposed near at least one of an entrance end face and an exit end face of the short focus small imaging element array. 2. The image forming apparatus according to claim 1, wherein the dustproof magnet is conductive and also serves as the dustproof electrode.