JPS59176718A - Image recording device - Google Patents

Abstract

PURPOSE:To increase resolving power and the amount of exposure by providing an image-forming optical system which consists of a fine lens array and has unmagnified refracting power in main scanning directions and reduction refracting power in subscanning directions. CONSTITUTION:The image-forming optical system 5 consists of a master lens system 6 for unmagnified image formation and a displacement lens system 7 which has the reduction refracting power only in the subscanning directions Y. The master lens system 6 consists of a multiple plastic lens array of four lens strips having plural fine lenses in optical-axis directions. The variable power lens system 7 has the reduction refracting power in subscanning directions Y, so the image-forming optical system 5 may use elements having wider area than usual as shown by dotted lines as long as an image reduced in the subscanning directions Y as shown by solid lines in the figure is of the same size as before, thereby increasing the amount of exposure. Further, the length is increased in the subscanning directions Y without varying the element area to increase the resolving power correspondingly.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an image recording device, more specifically, to obtain a copy of an image from a digital signal such as a computer output or a facsimile output. The present invention relates to an apparatus that forms a one-line image on a photoreceptor by controlling light shielding, and records the image by sequentially repeating this process.

Prior Art Conventionally, in this tumor image recording apparatus, recording light from a recording array is projected onto a photoreceptor surface via an imaging optical system. However, since the imaging optical system is set to the same magnification, there is a limit to the increase in resolution, and the same applies to increasing the exposure amount. In particular, in order to increase the amount of exposure, it is necessary to increase the amount of light from the light emitting elements and the light source itself, but there is a limit to the amount of light from the light emitting elements, and increasing the amount of light from the light source itself requires additional cooling means. Becoming,
The problem is that the life of the light source is shortened.

Purpose of the Invention The present invention has been made in view of the above-mentioned drawbacks, and its purpose is to improve the resolution of images by increasing the exposure amount without increasing the light amount of the light emitting element or light source itself. The purpose is to provide a recording device.

In order to achieve the object beyond the gist of the invention, an image recording device according to the present invention is composed of a microlens array, and has a refractive power of equal magnification in the main scanning direction (the direction in which the light emitting elements or light shielding elements are arranged), and a refractive power of 1x in the sub scanning direction. It is characterized by comprising an imaging optical system having a refractive power for reduction in direction C (direction perpendicular to the main scanning direction).

That is, if the light-emitting element or the light-shielding element is made longer in the sub-scanning direction than in the past, the exposure amount will be increased by 2' even with the same illumination light as in the past, and if the element area is not changed and the element is made longer in the sub-scanning direction, the resolution will be increased. becomes.

Embodiment FIGS. 1 to 4 show the @1 practical efficiency of the image recording apparatus according to the present invention. In this first embodiment, an image is recorded by a well-known electrophotographic method, and a charger (1) is located at the arrow in FIG. 2), a predetermined charge is applied to f, and the recording light from the light emitting element array (3) is focused and projected through the imaging optical system (5) 2 to form an electrostatic latent image. The latent image is transferred to a developer (
8), the toner image is transferred to a copy paper (not shown) using a transfer charger (9). The copy paper is fed from the left side in the figure, and the transfer in step 111j is performed while it is in close contact with the lower part of the photoreceptor drum (1).The copy paper is further conveyed to the right side in the figure, and the toner image is transferred to the fixing device not shown in the figure. After it has been fixed, it is discharged from the machine.

Meanwhile, the photoreceptor drum (1) continues to rotate, and the cleaner (1)
At step 0), the residual toner is removed and the charge is erased at the eraser lamp (11) in preparation for the next copying.

As shown in FIG. 2, the light emitting element play (3) is, for example, light emitting diodes (4) arranged in a line in the main scanning direction (X), and receives digital signals such as computer output or facsimile output. Its blinking is controlled.

As shown in FIG. 3, the imaging optical system (5) includes a master lens system (6) with equal magnification and a variable magnification lens system (7) having refractive power for reduction only in the sub-scanning direction (Y). It consists of The master lens system (6) consists of a 4-lens strip structure with a plurality of 1-year-old small lenses in the optical axis direction.The master lens system (6) consists of a multi-lens array made of L tough plastic with a conjugate distance of 70 and a lens effective diameter of 26 m. Tosa h is there. The variable magnification lens system (7) consists of a plastic cylindrical lens, and has a refractive index (magnification) uo in the sub-scanning direction α), 7
It is said to be 14.

Here, the surface radius of each lens is 9 intervals and the refractive index.

The Atsube numbers are shown in Table 1. In Table 1, the numerical values are listed in order from the light emitting element surface (3a) side to the photosensitive drum (1) side, as shown in FIG.

In the following, the imaging optical system (5) is indicated by a solid line as shown in FIG. If the image of the element reduced in the sub-scanning direction (Yl) is the same size as the conventional one, an element with a wider area than the conventional one, shown by the dotted line, can be used, and the exposure amount will increase.

In addition, the element area is unchanged from the conventional one, and the sub-scanning direction (Y
), the resolution will increase by the same amount.

Note that the master lens system (6) may use a convergent transmitter array in which fibers and fibers having a gradient of refractive index are arranged.

In this way, the same-magnification master lens system (61,1!:
The advantage of combining the lens system (7) with a variable magnification lens system (7) that reduces only the scanning direction (2) is that it is easy to manufacture. That is, the converging light transmitting element cannot change its refractive power in the main and sub-scanning directions (X), m. In addition, although it is possible to change the refractive power of the multi-lens array in the main and sub-scanning directions IXJ and m, it is possible to change the refractive power in the main and sub-scanning directions of individual microlenses.
The radius of curvature must be changed, making manufacturing difficult.

On the other hand, if the main magnifying lens system (7) is manufactured separately and combined as in the Kinotsu case, manufacturing is easy because this is a cylindrical 1-dimensional lens. Therefore, the master lens system (
6) may be the same size as the conventional one.

Figure 5 shows a second example of an actual cannon, which differs from the first case in that a glass cemented cylindrical 1-dimensional lens is used as the variable magnification lens system (7) of the imaging optical system (5). It is in the point that
The refractive index (magnification) in the sub-scanning direction (Y'l) is 0.707.

The radius of curvature of each lens in this second actual case.

The spacing, bending rate, and number of attachments are shown in Table 2. However, in this Table 2, only the parts that differ from those in the above-mentioned Table 1 are listed.

In addition, in the first example and the second example described in 11J, the variable magnification lens system (71u) was provided on the photosensitive drum (1) side, but it may be provided on the light emitting element and child surface (3a) side. In this case, a cylindrical lens with a concave surface is used.

FIG. 6 shows a third practical example, in which a light shielding element Aluminum (13) is used as a recording array, in which, for example, liquid crystals are arranged in a line in the main scanning direction.

This light shielding element play (13) is connected to the above-mentioned imaging optical system (5).
is opposed to the photoreceptor drum (1) via a condenser lens (14), and directly above it is a reflecting mirror (
A lamp (15) with a lamp (16) is installed. Like the light emitting element array 3), the operation of the light shielding element array (13) is controlled by digital signals such as computer output or facsimile output, and appropriately blocks the illumination light of the lamp (15). 1) Form an electrostatic latent image thereon.

This third biological sister example is also the same as the first biological sister example.

As with the second example, it is possible to increase the resolution by increasing the exposure meter's resolution, but in particular, the exposure amount can be increased without increasing the light amount of the lamp (15).
By increasing the amount of light, the conventional problems of increasing the size of the cooling f-stage and shortening the life of the lamp (15) can be eliminated.

It should be noted that the image recording apparatus according to the present invention does not make one assumption for each of the 11th real ellipse examples, and can be variously modified within the scope of the gist. For example, a fluorescent tube or the like may be used as the light emitting element, and a magneto-optic effect element or the like may be used as the light shielding element.

As is clear from the explanation in ``Effects of the Invention'', the present invention includes an imaging optical system that is composed of a microlens array and has a refractive power of equal magnification in the main scanning direction and a reduced refractive power in the sub-scanning direction. Because of this, the recording light from the recording array, which was conventionally projected at the same magnification onto the photoreceptor surface, can now be projected at a reduced size in the sub-scanning direction, effectively increasing resolution and exposure amount. .

In particular, as shown in the actual case, the imaging optical system (5) is a combination of a master lens system (61) with equal magnification and a variable magnification lens system (7) having a refractive power for reduction in the sub-scanning direction. This makes it easy to manufacture the imaging optical system (5).

[Brief explanation of the drawing]

1 to 4 show a first actual example of the image recording apparatus according to the present invention, in which FIG. 1 is a schematic diagram of the overall configuration (see 1), FIG. 2 is an explanatory diagram of a light emitting element play, and FIG. , Fig. 4 is an explanatory diagram of the imaging optical system. Fig. 5 is an explanatory diagram of the imaging optical system in the second real example, and Fig. 6 is an explanatory diagram of the main part of the third real example. In the figure, 5 (1) photosensitive drum, (3) light emitting element array, (5) optical system, (6) master lens system, (7) variable magnification lens system, (13) - Ji optical element array, (15)...Illumination lamp. Patent applicant Minolta Camera Co., Ltd. Agent BuT
Physician Aoyama Hajime and 2 others

Claims (1)

[Claims] 1. In an image recording apparatus that projects recording light from a recording play having light emitting elements or light shielding elements arranged in a line onto a photoreceptor surface via an imaging optical system, the imaging optical system is a microlens array. B. An image recording device characterized by having a refractive power of equal magnification in the main scanning direction and a refractive power of reduction in the sub-scanning direction.