JPS6250775A - Exposing device - Google Patents

Abstract

PURPOSE:To prevent a light source from becoming short in life by lighting a liquid crystal shutter array by a light source for exposure through an optical fiber. CONSTITUTION:When a copy is taken by the liquid crystal shutter array 1010, an original platen is moved to align the array 1010 with a lens array 1002 and also matches the through hole of a light source box 2008 with a photodetection part 2006. Then when a halogen lamp 2009 is turned on, direct light from the lamp 2009 and reflected light from a reflector umbrella 2010 are made incident on the photodetection part 2006 through the through hole of the box 2008 and a heat absorbing filter 2007. The incident light is projected from one end surface of the optical fiber 2002 through the optical fiber 2002 to illuminate the array 1010. Then, when a copy start button is pressed, an image signal is sent to the array 1010 to form a latent image on a photosensitive drum with the image light transmitted through the array 1010. Thus, the lamp 2009 is not provided to a moving original platen, but fitted to a copying machine body 1, so the lamp 2009 is prevented from deteriorating in life owing to a shock.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention is applicable to, for example, an electrophotographic copying apparatus.

The present invention relates to an exposure device used to form a latent image on a latent image carrier such as a photosensitive drum.

[Background of the invention]

In recent years, electrophotographic copying machines (hereinafter referred to as hybrid copying machines) are equipped with two exposure devices, for example, a first exposure device consisting of a platen glass and a document illumination device, and a second exposure device using a Radhe optical system. However, it was difficult to miniaturize the main body of the copying machine and the price was high in the case of an exposure device using a radar optical system.

However, recently, line-type exposure devices using liquid crystal shutters, shutter arrays, etc. have been developed, making it possible to downsize and lower the cost of copying machines. Controlling the shutter array to transmit or not transmit light from light sources arranged in a shape on the back side,
A latent image carrier such as a photosensitive drum is exposed to light.

FIG. 6 shows a high-lid copying machine using a liquid crystal shutter array. This copying machine is of a movable original platen type (by incorporating a column exposure device consisting of a light source liquid crystal micro-shutter array into a part of the movable original platen, it is possible to replace the original platen of a conventional copying machine with a movable platen platen). It has the advantage that it can easily function as an inexpensive, small-sized hybrid copying machine by simply changing the machine.

FIG. 6(2) shows the case where the copying machine is used as a normal copying machine. 1009° is a document, 1008 is a movable document table, and 1012 is a light Ij10 attached to a part of the document table.
11 and a liquid crystal microphone four-shutter array 1010 (hereinafter referred to as an optical printer head).

A document 1009 is irradiated by a document irradiation light source 1003, and the reflected light is uniformly charged on its surface by a convergent lens array 1002. The image is formed on the drum 1001 to form a latent image on the photosensitive drum 1001. The latent image is developed into a visible image with the toner of 1005, and the toner image is transferred to the transfer paper fed in the direction of the arrow of the dotted line (I) 1006. Furthermore, the toner image is fixed on the transfer paper in fixing step 1007 to complete the copying.

FIG. 6 ω) shows the original printer head in use.

First, the manuscript table 1008t-1 bundle fiber play 10
02 and the liquid crystal micro-shutter array 1010 and its light source 1011 are moved to coincide with each other.

In this case, unlike the normal copying machine mode, the original platen 1008
does not move in this mode, and the document illumination light source 1003
does not light up.

The other devices other than those described above perform normal copying operations, including the liquid crystal microshape, the tar array 1010, and the light source 101.
A latent image is formed on a photosensitive drum 1001 rotating in the direction of the arrow 1 using an optical printer head 1012 consisting of 1 and a convergent lens array 1002 which is used in the copying mode, and the image is transferred onto transfer paper through a development-transfer constant process. make a copy.

By the way, the light transmittance of a liquid crystal micro-shutter array is generally around 20%, and the response of the liquid crystal is l m5.
Since the light source is about EC, a high-intensity light source is required. In this case, the brightness of the convergent lens play that is the light transmission system also becomes a problem. This convergent lens play is called a SELFOC lens array (trade name), and its brightness varies greatly depending on its conjugate length, and the longer the conjugate length, the darker it becomes.

According to the experiments of the present invention, when a surface emitting source with the same brightness is imaged using a lens array, the brightness at the imaging potential of the lens array with a conjugate length of 54 points is that of a conjugate length of 15 cm. In comparison, it was about 171 O.

The conjugate length of the lens array used in a copying machine as shown in Figure 5 is 43 points or 54 m, and a lens array with a short conjugate length is expensive, has a shallow depth of focus, and suffers from chromatic aberration. Since the distance between the lens surface of the lens array and the photoreceptor drum is particularly short, it is necessary to pay attention to things such as toner adhesion, so a lens array with a long conjugate length as described above is generally used. .

Therefore, when forming a latent image on a photoreceptor drum using a SELFOC lens array in a printer head based on a liquid crystal micro-shutter array, a light source of very high brightness is required.

An example of such a high-brightness light source is a rod-shaped halogen ring, but this rung generates extremely high heat and has a large effect on the liquid crystal microshutter. According to experiments, ordinary liquid crystals stopped working when the ambient temperature exceeded +80°C.

In the normal copying mode, this halogen rung is placed on the document table, so it is always subject to impact from the movement of the document table, which has the disadvantage that the life of the halogen rung is shortened by this impact. Ta.

[Purpose of the invention]

An object of the present invention is to be able to irradiate a liquid crystal display, a tar array, etc. without imparting heat from a light source for illumination to a means for transmitting or non-transmitting light, such as a liquid crystal display, a tar array, etc., and to reduce the lifespan of the light source. It is an object of the present invention to provide an exposure apparatus that can prevent this.

[Summary of the invention]

The exposure apparatus of the present invention is characterized in that the means for selectively transmitting or not transmitting light to the latent image carrier is configured to be illuminated by an exposure light source via a light transmitting means. It is.

[Embodiments of the invention]

The present invention will be described in detail below based on embodiments shown in the drawings.

Figure Wc1 is a schematic diagram showing an example of an electrophotographic copying apparatus to which the present BA is applied, and Figure 2 is a sectional view thereof.

Note that for the same parts between the structure in this embodiment and the structure shown in the conventional example, the reference numerals cited in the conventional example will be attached to the structure in this embodiment, and a description of the structure will be omitted.

In the figure, reference numeral 1 denotes the copying machine main body, and a liquid crystal shutter array 1010 and an illumination unit 2003 according to the present invention that illuminates the liquid crystal shutter array 1010t are installed in a case 2004 at one end of the movable document table 1008. Being/being. As shown in FIG. 3, this illumination unit 2003 has a support frame 2005 facing the liquid crystal shutter array 1010, and one end side of a large number of original plastic fibers 2002 is arranged in multiple rows along the length direction of the support frame 2005. The other ends gIUf of the plurality of original fibers 2002 are further bundled together into a cylindrical shape to form a light receiving section 2006, and a heat ray absorption filter 2007 is provided in front of this light receiving section 2006. The back wall surface 20 of the case 2004
It is installed on 041.

Reference numeral 2008 denotes a light source box attached to the rear side of the upper surface of the copying machine main body l corresponding to the length direction of the lens array 1002, and a halogen rung 2009 and a reflector shade 20!0 are housed therein. A through hole 2011 is formed at 2008&, so that the light receiving section 2006 of the illumination section 2003 is aligned with this through hole 2011 when the document table 1008t is moved to the left end in the figure. In 2012, the light source is a cooling fan attached to the side wall 2008b of the box 200B, which sends outside air into the light source & into the box.
The air in the oven heated by the halogen lamp 2009 and the halogen lamp 2009 are then cooled down. The halogen rung 2009 and the fan 2012 are turned on when the document table 1008t is moved to the left end.

The above is the structure of this embodiment.
【explain.

In the case of normal copying, an original is placed on the original platen 1008 as in the conventional case, and by pressing a bee start button (not shown), the original platen 1008 is moved in the direction indicated by the arrow, and normal copying is performed.

When using a copy tube using a liquid crystal shutter array 1010, move the document table 1008 to the left end in FIG. 20
11 and the light receiving section 2006 of the irradiating section 2003 are aligned.

When the document table 1008 moves to the left end, the halogen lamp 2009 is turned on, and the light source is emitted from the halogen lamp 2009 through the hole in the glass 2008 and from the reflective shade 20.
The light reflected by 10 passes through the heat absorption filter 2007t and enters the light receiving section 2006 of the illumination section 2003. The light incident on this light receiving section 2006 is transmitted to each party's fiber 20.
The light is emitted from one end face of the optical fiber 2002 through 02, and illuminates the liquid crystal shutter array 1010.

When a button is pressed to start copying, an image signal is sent to the liquid crystal shutter array 1010, and the photosensitive drum is exposed to the image light transmitted through the liquid crystal shutter array 1010, forming a latent image.

As described above, according to this embodiment, the liquid crystal lamp array 1010 is irradiated with the source from the halogen lamp 2009 through the source fiber bundle, so that the liquid crystal is heated by the heat from the halogen lamp 2009. The effect is that the liquid crystal display and tar array can always operate normally without any problems.

In addition, the halogen lamp 2009 is moved to the document table 1008.
Since the halogen rung is attached to the main body of the copying machine instead of being provided on the main body of the copying machine, it is possible to prevent the life of the halogen rung from deteriorating due to impact.

Furthermore, using a 0.755 mφ glass fiber, a liquid crystal shutter array with a pixel density of 10 dots was created using a 24 V, 150 W halogen □ lamp through an optical fiber bundle stacked in two layers at the output end. As a result of measuring the amount of light on the photoconductor drum rotating at a process speed of 40 m/s@e, which is often used in small copying machines, it was found that the photoconductor has a high original energy of 3 to 5 lux・se@. It turns out that it can be obtained on the surface.

4 and 5 show other embodiments of the invention, respectively.

In the embodiment shown in FIG. 4, the light receiving section 2006 of the illumination section 2003 is made to protrude outward from the back wall surface 2004a of the case 2004.

Further, in the embodiment shown in FIG.
The light receiving portion 2006 of No. 3 is bent at a right angle toward the other end of the document table 1008, and the light receiving portion 2006 and the light source
As shown in FIG. 5@), the transparent light 2011 of No. 08 is fitted in a fitting manner to prevent original leakage.

In each of the above-mentioned embodiments, the liquid crystal shutter array 1010 and the illumination unit 2 are installed on the document table of a moving document table copying machine.
003, and this illumination section 2 is installed in the copying machine main body l.
Although the Halodan rung 2009'i is provided to illuminate the liquid crystal shutter array 1010 through the light receiving section 2003, the present invention may be applied to a copying machine with a fixed manuscript table. A light source may be provided.

Furthermore, although glass fibers are used as optical fibers in the illumination section, the present invention is not limited thereto, and glass fibers may also be used.

Further, although the liquid crystal shutter array is attached to the glass of the document table, it may be provided to the document pressure plate of the document table.

〔Effect of the invention〕

As described above, according to the present invention, the exposure light source includes means for selectively transmitting or not transmitting the original through the light transmission means;
For example, since the liquid crystal display and the main array are illuminated, it is possible to place the exposure light source at any position free from vibrations, shocks, etc., and to prevent shortening of the life of the exposure light source due to vibrations, etc. The effect that can be obtained is obtained.

In addition, since the exposure light source is separated from, for example, the liquid crystal shutter and tar array, the heat of the light source is not transferred to the liquid crystal, and the effect that the liquid crystal shutter and tar array can operate normally can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic view showing a first embodiment of an electrophotographic copying machine to which the present invention is applied, FIG. 2 is a cross-sectional view thereof, and FIG. 3 is a perspective view showing an embodiment of the main part of an exposure apparatus according to the present invention. 4 is a schematic plan view showing the second embodiment, FIG. 5 (4) is a schematic plan view showing the third embodiment, and FIG. 5 (B) is a sectional view of the main part thereof.
FIGS. 6(4) and 6(B) show schematic diagrams of a conventional electrophotographic copying machine. l: copying machine main body, 1001: photosensitive drum, 10
02: Lens array, 1003: Light source, 1004: Charging unit, 1oo5: Developing unit, 1006: Transfer unit, 1007: Fixing unit, 1008: Original table,
1009: Manuscript, 1010: Liquid A microshaft, array, 1011: Light source, 1012: Exposure device, 2002: Original fiber, (grid) 2003: Illumination section, 2004: Case, 2005
: Support frame, 2006: Light receiving part, 2007: Filter, 2008: Light source, box, 2009: Halogen lamp, 2010: Reflective shade, 2011: Through hole, 201
2nian. Figure 1 Figure 2 Figure 3 3o02 Figure 4 Figure 5 cA) IOo8 Figure 6 (A)

Claims (1)

[Claims] An exposure apparatus characterized in that a means for selectively transmitting or not transmitting light to a latent image carrier is configured to be illuminated by an exposure light source via a light transmitting means.