JPH0452745Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an exposure apparatus using a convergent light transmission body used in an image forming apparatus or the like.

[Prior art]

In general, a self-focusing optical transmitter (trade name) lens array (hereinafter abbreviated as SLA) can shorten the optical path length compared to conventional lens systems, and can also produce an erect, same-magnification image on the imaging plane. You can get it, but
To do this, the distance between the lens center and the object side must be set equal to the distance between the lens center and the image side.

A conventional example will be described below with reference to the accompanying drawings.

FIG. 6a is a sectional view showing the main parts of a conventional exposure apparatus. In the figure, in order to accurately fix the center of the lens of SLA1 at the center of the original glass 2 and photosensitive surface 3 (the center of the lens of SLA1 is at the center of the height Z of SLA1), the center of the lens of SLA1 is fixed at the center of the height Z of SLA1. A support piece 4 provided with a stepped portion 4a is arranged in the middle.

The upper surface of the stepped portion 4a is separated by l _i from the photosensitive surface 3, and the end of the SLA 1 having a height Z is connected to the stepped portion 4.
a and fix the spring 5 with screws from above.

At this time, the distance between the upper surface of the SLA 1 and the original glass 2 is l _p . In the exposure apparatus having the above configuration, the supporting piece 4 and the stepped portion 4 are arranged so that l _i =l _p .
Set the position of a.

As another conventional example, as shown in FIG. 6b, a gripping piece 6 is provided between the photosensitive surface 3 and the original glass 2, which are separated by a gap T, and a spring 6a and a lever 6b are rotated around a fulcrum 6d. The spring 6a and the lever 6 can be freely installed.
There was one that sandwiched SLA1 with b and then fixed it with screw 6c.

In the above configuration, by adjusting the tightness of the screw 6c, the distance l _p between the original glass 2 and the SLA1 and the distance l _i between the SLA1 and the photosensitive surface 3 are adjusted to be equal.

[Problems with conventional technology]

The conventional exposure apparatus shown in FIG. 6A having the above-mentioned structure does not have a focus position adjustment mechanism, and therefore cannot cope with the need for focus position adjustment when it becomes necessary. In addition, in the device shown in FIG. 6b, the number of parts increases, resulting in high cost.
Confirming the focus by visually adjusting the screws has disadvantages in that it causes variations in product quality and is time consuming.

Furthermore, it took time to adjust the left and right balance of the SLA, making the assembly process difficult.

[Purpose of invention]

In view of the above-mentioned conventional drawbacks, the present invention aims to provide an exposure apparatus that has a simple configuration and does not require focus adjustment.

[Key points of the idea]

In order to achieve the above object, the present invention provides an exposure apparatus in which a converging light transmitting body is disposed between an object plane and an image plane. An elastic body having the same elastic modulus and the same length is interposed between the object plane side end surfaces and between the image plane side reference plane and the image plane side end surface outside the imaging area of the focusing light transmitting body. It is characterized in that the center of the lens of the optical transmitter is always maintained at the center of the object plane and the image plane.

[Example of idea]

An embodiment of the present invention will be described in detail below with reference to the drawings. Note that the same parts as in the conventional example are given the same reference numerals to avoid redundant explanation.

1 and 2 are main part configuration diagrams showing a case where the exposure apparatus of the present invention is applied to a printer head.

FIG. 1 is a support state diagram of one side end of the exposure device of the present invention before it is assembled into the printer main body. Second
The figure is a support state diagram of one side end showing a state where it is incorporated into the printer main body.

The printer head 10 includes an SLA 1 which is a convergent light transmission body that forms a same-size erect image, elastic bodies 11 and 12 made of the same material disposed on the stepped portions 1a of the support portions at both ends of the SLA 1, and It is composed of a claw 13 that supports the end portion when assembled, an object surface 14, etc.

Note that the stepped portions 1a, 1a of the above SLA1 are
The center of the distance 1a is set to be the center of the lens.

In the pre-assembly state shown in FIG.
1 and 12 represent free lengths in an unloaded state,
Dimensions between step portions 1a and 1a of SLA1 and both elastic bodies 11,
The total dimension Tφ with 12 is the conjugate length T _c of the SLA1
is set larger.

FIG. 1 shows one end of the printer head 10, and the other end (not shown) is also provided with members having a similar structure.

FIG. 2 shows a state in which the printer head 10 configured as described above is assembled into a printer main body.

Reference numeral 15 denotes an equivalent object surface optically equivalent to the object surface 14 formed at the abutting portion of the elastic body 11, and reference numeral 16 denotes an equivalent image optically equivalent to the image plane of the photoreceptor 17 of the printer main body. It is a surface.

Dimensions between step parts 1a and 1a of SLA1 and both elastic bodies 1
The total dimension Tφ of 1 and 12 is the conjugate length T _c of SLA1
When the printer head 10 is assembled into the main body, the SLA 1 is sandwiched between the equivalent object plane 15 and the equivalent image plane 16 via the elastic bodies 11 and 12.

At this time, if the printer head 10 is fixed so that the distance between the object plane 14 and the image, that is, the distance between the objects and images, T, is equal to the conjugate length T _c of SLA 1, then T = T _c <
A relationship Tφ occurs, and both elastic bodies 11 and 12 contract by ΔTφ (=Tφ−T _c ) in total.

Here, since the elastic bodies 11 and 12 are made of the same material and have the same elastic modulus, the contraction amount ΔTφ is divided by 1/2ΔTφ between the elastic bodies 11 and 12.

Therefore, SLA 1 sandwiched between elastic bodies 11 and 12
is always located between the object plane and the image plane.

In other words, even if the distance between the object plane and the image plane changes under some conditions, the SLA1 is always located between the two, so that deterioration in the imaging characteristics of the SLA1 can be minimized.

Generally, it is known that the rate of decline in the imaging characteristics of SLA is minimum when the image side distance l _i =object side distance (l _p ).

Furthermore, since the distance between the equivalent object surface 15 and the claw 13 is larger than the sum of the thicknesses between the elastic body 11 and the stepped portions 1a, 1a of the SLA, when the printer head 10 is incorporated into the printer body, , S.L.A.
is separated from the grip of the claw 13 and is supported only by the elastic bodies 11 and 12.

On the other hand, FIG. 3 is a diagram illustrating the main part configuration when the present invention is used in an optical system of an electrophotographic copying machine.

In the figure, the SLA 1 includes an elastic body 11 between the original glass 18 on which the original is placed and the photoreceptor 17.
It is pressed and supported by an equivalent object plane 15 and an equivalent image plane 16 via 12 .

Even in this configuration, the image side distance (l _i ) and the object side distance (l _p ) are equally distributed.

Incidentally, when SLA is used in a printer or an electrophotographic copying machine, since toner is used, there is a drawback that the toner inevitably adheres to the surface of the SLA. This contamination of the SLA surface by toner has an adverse effect on the optical transmission characteristics of the SLA, so a prevention device as shown in FIG. 4 has been proposed.

In the prevention device, a shielding plate 20 is fixed on the side surface of the printer head 19 on the upstream side in the rotational direction of the photoreceptor 17.

The shielding plate 20 is curved, and the wind flowing toward the printer head 19 is diffused in the directions shown by arrows in FIG.

Therefore, the air containing toner does not accumulate in one place, and the printer head 19 can be prevented from becoming dirty.

[Effect of idea]

As described in detail above, according to the exposure apparatus of the present invention, the distance between the lens center and the object plane side is automatically made equal to the distance between the lens center and the image plane side, so there is no need for focus adjustment. Moreover, it is possible to absorb the deviation of the device due to vibrations, etc., and always maintain the same distance between the object plane side and the image plane side, thereby minimizing image deterioration.

Furthermore, the structure is simple and the number of parts can be reduced.

[Brief explanation of the drawing]

1 and 2 are main part configuration diagrams when the exposure apparatus of the present invention is applied to a printer head, FIG. 3 is a main part configuration diagram showing another embodiment of the present invention, and FIG.
5 is an explanatory diagram showing the flow of wind, and FIGS. 6a and 6b are diagrams showing the main parts of a conventional exposure apparatus. DESCRIPTION OF SYMBOLS 1...SLA (focusing light transmitter), 2... Original glass, 3... Photosensitive surface, 4a... Step part, 4... Support piece, 5... Spring, 6... Gripping piece, 10... Printer head, 11, 12...elastic body, 13...claw,
14...Object surface, 15...Equivalent object surface, 16...
Equivalent image plane, 17...photoreceptor, 18...original glass, 19...printer head, 20...shielding plate.

Claims (1)

[Scope of utility model registration request] In an exposure apparatus in which a convergent light transmission body is disposed between an object plane and an image plane, the distance between the object plane side reference plane and the end face of the object plane side outside the imaging area of the convergence light transmission body and the image plane side reference plane is An elastic body having the same elastic modulus and the same length is interposed between the surface and the image plane side end surface outside the imaging area of the converging light transmitting body, so that the center of the lens of the converging light transmitting body is always the object plane. and said image plane.