JPS61177475A - Lighting device - Google Patents

Abstract

PURPOSE:To eliminate deterioration and deficiency of picture quality and, at the same time, to prevent useless consumption of toner, by providing a slit member which forms a clearance having parallel linear side edges between lens members and an image carrier. CONSTITUTION:Luminous fluxes radiated from LEDs 12 are shaped to rectangular luminous fluxes by means of light intercepting members 13 and narrowed their spread angles theta by means of lens members 14, and then, become parallel band-like luminous fluxes having linear side edges after passing through a slit member 23. The band-like luminous fluxes are irradiated upon an image carrier 6 in the shape of a rectangle with high intensity of illumination and no other luminous flux does reach the image carrier 6. Therefore, the light quantity distribution on the surface of the image carrier 6 becomes such that no light is leaked to an image area A and only an no-image area A can be illuminated sharply with high intensity of illumination. Moreover, since even the light quantity at the trough part in the light quantity distribution is higher than the level required for removing electricity from the image carrier 6, the electricity can be removed uniformly from the no-image area B. Accordingly, deterioration and deficiency of picture quality and useless consumption of toner can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image forming apparatus using an electrostatic photographic process such as an electrophotographic copying machine or a printer, particularly a variable magnification type image forming apparatus and an editing function. The present invention relates to a lighting device suitable for use in an image forming apparatus having the present invention.

(Prior Art) In a well-known image forming apparatus that transfers a transferable toner image formed on the surface of an image carrier onto a transfer material and fixes it, it is possible to obtain copy images of various sizes from the same original. Variable magnification types like this are becoming widely used. Recently, there has also been an increasing demand for image forming apparatuses having an editing function for erasing any part of a document and inserting another document.

In variable magnification type image forming apparatuses, the size of the image carrier that forms the image of the document is a certain size that can receive an image at the maximum magnification, so it is particularly difficult to use when reducing the magnification. Naturally, a portion unnecessary for image formation (non-image area) is generated on a part of the image carrier.

Since the non-image area on the image bearing member is not exposed during image exposure, the charge is conserved, so that the developing process is carried out in the subsequent printing process (K), and toner also adheres to the non-image area. This not only wastes toner but also puts a burden on the cleaner and causes contamination within the device. Therefore, in order to prevent this, it is common to irradiate the non-image area of the image carrier with light to eliminate the charge in the non-image area.

In addition, in an image forming apparatus having an editing function, it is necessary to erase any part of the electromagnetic film normally formed on the image carrier. Light is irradiated to eliminate static electricity in this area.

Conventionally, as a lighting device for eliminating unnecessary charges on the image carrier, an appropriate number of light emitting elements such as LEDs 32 are arranged so as to face the surface of the image carrier 31, as shown in FIG. Then, turn on these lights as necessary to set the first
As shown in FIG. 2, there is a method for eliminating static in a non-image area Y. The LED 32 as a light emitting element includes, for example, a transparent cylindrical portion 33 and a convex lens-shaped condensing portion 34 at the tip on the irradiation side.

(Problems to be Solved by the Invention) However, in such conventional technology, although the light irradiated from the condensing part 34 of the LED 32 effectively eliminates static electricity, the light irradiated from the cylindrical part 33 A part of the luminous flux (particularly the luminous flux 35 in the illustrated case) enters the image area
If the boundary between Y and the non-image area Y is made vague, the image near the boundary becomes unclear, and the image quality deteriorates, resulting in K.

That is, as shown in FIG. 12, a part of the light beam irradiated from the LED 32 enters the boundary part 36 along the rotational direction on the image carrier 31, thereby deteriorating the image quality of this part. . Furthermore, since the light beam from the LED 32 illuminates a circular area on the image carrier 31, at the boundary portion 37 in the axial direction of the image carrier 31, the non-image area Y and the image area
The boundary between the two ends up becoming blurred and wavy. Note that if you try to edit with such a configuration, the same thing as above will occur at the boundary of the static-eliminating portion 2 in the image area There are problems in that the image quality deteriorates near the boundary between the area or the area where the image should be erased and the image area, and sharp edges of the image portion cannot be formed.

In order to reduce the influence of such harmful light, it may be possible to reduce the distance between the LED and the image carrier, but in this case, the rotation of the image carrier and the accompanying microvibrations, etc. flows, and as a result, floating toner, dust, etc. are induced between the LED and the surface of the image carrier.
There was a risk that the BDK would adhere to the surface, making it impossible to obtain an effective amount of light and reducing the static elimination effect.

The present invention has been made in order to solve the problems of the above-mentioned conventional example, and its purpose is to remove static electricity at the boundary between the image area and the non-IIIGR area or the part where the image is to be erased. It is an object of the present invention to provide a special illumination device which can sharply cut a luminous flux, eliminate deterioration and defects in image quality near the boundary, and prevent wasteful consumption of toner.

(Means for Solving the Problems) Therefore, in order to achieve the above object, the present invention is arranged so as to face the surface of an image carrier, and by illuminating the image carrier, the image carrier is A lighting device for eliminating unnecessary charges on a body includes a light emitting element and a light shielding member that blocks part of the light so that the light emitted from the light emitting element illuminates an image carrier in a rectangular shape. , a lens member disposed closer to the image carrier than the light shielding member; and a slit member disposed between the lens member and the image carrier and forming a gap having parallel linear edges. It is configured to be equipped.゛(Example) The present invention will be explained below based on the illustrated example. 1st
FIG. 1 shows an image forming apparatus 2 to which an illumination device 1 according to the present invention is applied.The configuration thereof will be explained below. 3 is a document; 4 is a document lamp for illuminating the document 3;
Reference numeral 5 denotes an imaging optical system consisting of a plurality of mirrors, lenses, and the like.

Reference numeral 6 denotes an image carrier formed in a cylindrical shape, which is indicated by the arrow a in FIG.
The image bearing member 6 is pivoted so as to be rotatable in the direction K11'', the periphery K11'' of the image carrier 6, the electric charger 7, the developer 8, and the transfer charger 9.
, cleaner 10 are provided.

The illumination device 1 according to the present invention is disposed around the image carrier 6 and between the electronic device 7 and the developing device 8 . Further, a fixing device and the like are arranged around the image carrier 6, but
This has been omitted for convenience of explanation. In the figure, 11 is a transfer material.

This image forming apparatus 2 forms an image of the original 3 via the imaging optical system 5 on the surface of the image carrier 6 that is uniformly charged by the electronic device 7, thereby forming an electrostatic latent image. . Then, this electrostatic latent image is visualized by a developing device 8, and the visible image on the image carrier 6 is transferred to a transfer material 11 by a transfer charger 9.
The image is fixed in a fixing device.

Further, the image forming apparatus 2 is a so-called variable magnification type image forming apparatus that can obtain copies of different sizes from an original 3 of the same size by adjusting the position of the lens of the imaging optical system 5. It has become. Note that the scaling may be performed stepwise or continuously.

In this case, as shown in FIG. 1(a), depending on the copying magnification, the image area A in the illustrated case becomes the image area with respect to the effective image area Il@ of the image carrier 6. The area B at the side edge adjacent to is a non-image area.

The illumination devices 1 are arranged in large numbers across the entire width in the axial direction so as to face the surface of the image carrier 6, and illuminate the image carrier 6 before the electrostatic latent image is developed. This is to remove charges in the non-image area B. This lighting device 1 is
As shown in FIGS. 1 to 3, the light emitting element 12 consists of a light emitting element 12, a light shielding member 13, a lens member 14, and a slit member 23. An LED embedded in the mold 16 is used.

In the illustrated embodiment, the LEDs 12 are linearly arranged at regular intervals to form an LED array (not shown), and correspondingly, the light shielding member 13 and the lens member 14 are also arranged in a straight line at regular intervals.
A light shielding member array 18 and a lens array 19 are arranged in one-to-one correspondence with D12.

The light shielding member array 18 is formed of a synthetic resin or the like in a black shape to block light, and the light shielding members 13 are integrally arranged in a linear manner. Each light shielding member 13 consists of a side wall portion 20 and an inward 7 flange portion 21. A rectangular opening 22 is formed at the tip of the light shielding member. Note that the inward 7 flange portion is not necessarily necessary here; Figure 1 (c
) may be used as long as a rectangular opening is formed. The light-shielding member array 18 accommodates the LEDs 12 at predetermined positions within each light-shielding member 13 and is fixed to a substrate (not shown) K of the LBD array in this state.

Further, the lens array 19 is formed by integrally forming lens members 14, which are convex lenses made of synthetic resin such as acrylic, glass, or the like, arranged in a straight line as shown in FIG. This lens array 19 includes each lens member 1
The light shielding member array 18 is disposed in front of the light shielding member array 18 so that the optical axis C of the light shielding member 13 passes through the center of the opening 22 of the light shielding member 13. At that time, of course, LED 120 light emitting chip 5
is located on the optical axis C. The lens member 14 is used to reduce the spread angle θ of the light beam irradiated from the opening 22 of the light shielding member 13 and to irradiate the image carrier 6 onto the image carrier 6. In addition to increasing the illuminance of the light, the distance between the lens member 14 and the image carrier 6 (XJIt-) is increased so that toner and the like floating around the image carrier 6 can be removed from the lens member 1.
This prevents the amount of light from decreasing due to adhesion to the surface of the surface.

The slit member 23, as shown in FIG. 1(b),
A first pair of plate members 24 and 24 are arranged parallel to the image carrier 6 on the image carrier 6 side of the lens array 19.

The surfaces of the plates 24.24 are painted black or the like to prevent reflection of light. Between these plates 24.24, there is a gap 25 having linear edges parallel to each other.
It is formed in a band shape along the arrangement direction. This slit member 23 is blocked by the light blocking member 13 in a rectangular shape,
By further passing the irradiated light focused through the lens member 14 through the gap 25, even when a large number of LEDs 12 are arranged in a straight line, a band-shaped irradiation having a straight edge along the arrangement direction is achieved. It is for getting light.

That is, when a large number of IDs 12 are arranged in a straight line, as shown in FIG. 4, if there is variation in the position of each LED 12 in the direction perpendicular to the arrangement direction, as shown in FIG.
The areas D and E irradiated by each LED 12 are shifted in a direction perpendicular to the arrangement direction, and the edges of the portions that are neutralized by the irradiation light are not straight, but uneven.

Therefore, by providing the slit member 23, the variation in the irradiation light in the direction perpendicular to the arrangement direction can be reduced by using the plate material 24.24.
This is for irradiating irradiation light having linear edges parallel to each other along the arrangement direction of the IDs 12 from the gap 25. This effect is greater when the slit member 23 is disposed near the image carrier 6.

Note that the size of the opening 22 of the light shielding member 13, lID12
The dimensions of each part, such as the optical path length from to the lens member 14, must be set so that the image carrier 6 is irradiated under predetermined conditions. Incidentally, when an ID 12 with a wavelength of 610 nm is used and acrylic with a refractive index of about 1.5 is used as the material of the lens member 14, an example of the dimensions of each part is shown in FIGS. 7 and 8. 11il between each lID12
Lt = 2.5■, optical path length from LED 120 light emitting chip 15 to lens member 14 = 2.0ms+, part of mold 16 L3''++1.5sm, air portion L4 = 1.0■, opening 22 Size length Ls=1.
6 cabinets, horizontal L @ 1, 4 cabinets, radius of curvature R of lens member 14
= 2.3 mm, thickness T = 1.4 mm, distance between lens member 14 and image carrier 6: [,, = 2.0 to 3.0 ms,
The clearance of the threading member 23 is +1.8 .

In the above configuration, in the illumination device according to the present invention, the surface of the image carrier is illuminated Il# in the following manner. That is, the light beam emitted from the light emitting chip 15 of the ID 12 is blocked by the light shielding member 13 and is irradiated only from the opening 22 in a rectangular shape.
The spread angle θ is narrowed down by the slit member 23, and the ji! It becomes the irradiation light having 111k,
The image carrier 6 is irradiated with a rectangular shape. In addition, ID12
and ID12. Since the 1III wall 20 of the light shielding member 13 exists between the
The light does not enter the lens member 14 corresponding to No. 2.

In this way, the light beam radiated from the ID 12 is shaped into a rectangular light beam by the light shielding member 13, and then spread by the lens member 14, narrowed down to a small angle θ, and further shaped into parallel beams by the slit member 23. The light beam forms a band having linear edges and is irradiated onto the image carrier 6 in a rectangular shape with high illuminance, and no other light beams reach the image carrier 6. Therefore, the surface of the image carrier 6 is exposed to the opening 2 of the light shielding member 13.
A rectangular shape similar to 2 is illuminated, and other parts are not illuminated at all. Therefore, the area illuminated by each length 12, E, is the 915th! The position and shape of each LED 12, light shielding member 13, and lens member 14 should be set so that they are adjacent to each other without any gaps as shown in FIG. , no light leaks into the image area A, and only the non-image area B can be sharply illuminated with high illuminance, and even the light amount in the valley part of the light amount distribution is not necessary to neutralize the image carrier 6. ), the non-image area B is uniformly neutralized. Note that the areas illuminated by adjacent IDs 12 may overlap each other.

In the illustrated embodiment, the light from IIDI・2 is blocked by the light shielding member 1.
The light shielding member 13 may block the light from the ID 12 only in a band shape having edges parallel to each other in a direction perpendicular to the arrangement of the LBb 12. In such a case, lID12t
- When a large number of light shielding members 13 are arranged in a straight line, the side wall portions 2 degrees of the light shielding members 13 are mutually Kll! arranged so that

In the illustrated embodiment, a case will be explained in which the non-image area B exists on only one side of the large image area on the image carrier 6. Of course, even if an image area exists, the glaze angle can be applied.

In addition, since the illumination device of the s-hole s example provides illumination in a rectangular shape, the light emitting elements are arranged along the entire length of the image carrier in the axial direction, and the image carrier corresponding to the front end and rear end beyond the image area is It can also be used to erase charges by irradiating the body surface with light.

Furthermore, in the illustrated embodiment, a case has been described in which a main*jima/corner illumination device is used to eliminate static electricity in a non-image area caused by a reduction magnification, but the present invention is not limited to this. The illumination device may be used in an image forming apparatus having an editing function. In this case, a plurality of the illumination devices of this embodiment are arranged in the axial direction of the image carrier, and by changing the light emission timing of the LEDs, the illumination device can be used on the image carrier. The charge may be removed from any part of the image, such as an area where the image should be erased.

(Effects of the Invention) The present invention has the above-described configuration and operation, and the light emitted from the light emitting element is blocked by the light shielding member so as to become a band-shaped emitted light, and the lens member reduces the aperture, further reduces the aperture, and further reduces the aperture.
The above-mentioned band-shaped irradiation light is irradiated from the gap between the slit members having mutually parallel linear ends perpendicular to the slit members in the shape of a carrier, so that a large number of light emitting elements and lens members are arranged in a linear manner. In this case, if there is variation in the position of the light emitting elements or lens members in the direction perpendicular to the arrangement direction, the light from the light emitting elements is blocked in a band shape in the direction perpendicular to the arrangement direction using a light shielding member, and this band shape is In order to further irradiate the irradiation light onto the image carrier from the gap between the merit members along the direction perpendicular to this, that is, the arrangement direction, a "band-shaped strip" having linear edges parallel to each other is spread over the image carrier. can be illuminated sharply.Therefore,
It is possible to reliably prevent the light beam for charge removal from entering the image area, and also to trap and remove unnecessary charges on the image carrier, thereby preventing deterioration of image quality and wasteful consumption of toner. This is particularly effective when eliminating static electricity in a strip along the axial direction. Further, since the irradiation light can be focused by providing the lens member, there is no need to place the light emitting element close to the image carrier, and there are some advantages such as being able to prevent loss of light amount due to attraction of toner or the like.

[Brief explanation of drawings]

FIG. 1(a) is a vertical cross-sectional view showing the usage state of the lighting device according to the present invention, and FIG. Figure 1(e) is a sectional view showing the other side of the light shielding member, Figure 2 is a plan view showing the lighting device with the lens member removed, Figure 3 is a perspective view showing the lens array, and Figure 3 is a perspective view showing the lens array. FIG. 4 is a plan view showing the LED arrangement a, FIG. 5 is a perspective view showing the light irradiation area in the state shown in FIG. 4, and FIG.
The figure is a cross-sectional view showing the action of the slit member, Figure 7 is a cross-section showing the dimensions of each part of the lighting device, Figure 8 is a plan view of the same, and Figure 9 is a cross-sectional view showing the function of the slit member.
FIG. 10 is a graph showing the light intensity distribution characteristics of the lighting device; FIG. 11 is a schematic diagram showing an image forming apparatus to which the lighting device according to the present invention is applied; FIG. 12 is a schematic diagram showing how a conventional lighting device is used. Explanation of symbols

Claims (1)

[Claims] An illumination device that is disposed to face the surface of an image carrier and that eliminates unnecessary charges on the image carrier by illuminating the image carrier includes a light emitting element and a light emitting element that emits light from the light emitting element. a light shielding member that blocks part of the light so that the light illuminates the image carrier in a rectangular shape; a lens member disposed at least closer to the image carrier than the light shielding member; and a lens member and the image carrier. 1. A lighting device comprising: a slit member disposed between the slit members and forming a gap having parallel linear edges.