JPH01101509A - image recording device - Google Patents

Abstract

PURPOSE:To miniaturize a picture recorder by arranging a rotating scanner on the inside of a photosensitive body and radiating an optical beam from the inside of the photosensitive body. CONSTITUTION:The rotating scanner 20 is arranged on the inside of the hollow photosensitive drum 15, the inner surface of the drum 15 is constituted of a transparent member and a laser beam reflected on a reflecting face 21 of the scanner 20 is radiated from the inside of the drum 15 to form an electrostatic latent image. For instance, the reflecting face 21 is formed by forming the scanner 20, spirally forming an Al layer on the surface of the scanner 20 by evaporation method or the like and working the Al layer like a mirror. Since the drum 15 is not opposed to the scanner 20, the device can be miniaturized.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an image recording device that irradiates a photosensitive member with a beam of light modulated by image data and prints an image recorded on the photosensitive member onto paper. be.

[Traditional technique]

As an image recording device, for example, a beam light emitted from a laser light source is modulated according to image data such as characters and figures output from an external information processing device such as a computer, and this modulated beam light is applied to a photoreceptor drum. A laser printer is known that prints a recorded image (electrostatic latent image) recorded on a photoreceptor drum on paper according to a known electrophotographic process.

FIG. 6 is a schematic diagram of a conventional laser printer.

This laser printer 1 includes a laser diode 2, a light modulator 3, a polygon mirror 4, an fθ lens 5, a beam detector 6, a cylindrical lens 7, a photosensitive drum 8, and electrophotographic process members such as a developing device and a transfer device (not shown). It is made up of. A laser beam oscillated from a laser diode 2 at a predetermined frequency is modulated by an optical modulator 3 into an intermittent laser beam according to image data to be recorded, and is irradiated onto a polygon mirror 4 . polygon mirror 4
is rotating at a predetermined number of rotations in the direction of the arrow, and the laser beam irradiated onto the polygon mirror 4
The light is reflected by the fθ lens 5 and enters the fθ lens 5. The fθ lens 5 is provided to correct the beam spot reflected by the polygon mirror 4 so that it moves at a constant speed on the photoreceptor drum 8. A beam detector 6 controls the output timing of the light beam that is output from the light modulator 3 to the photoreceptor drum 8 by detecting the light beam incident through the polygon mirror 4 and the fθ lens 5. Thereafter, as the polygon mirror 4 rotates, the modulated beam reflected on the polygon mirror surface passes through the fθ lens 5 and the cylindrical lens 7, and is scanned and irradiated Cn light onto the circumferential surface (photosensitive surface) of the photoreceptor drum 8 in the direction of the arrow. ) to be done. In this way, an electrostatic latent image is formed on the surface of the photoreceptor drum 8 in accordance with the image data, and thereafter, a developing device (not shown) converts the electrostatic latent image into a toner image, and a transfer device (not shown) transfers the toner image onto paper. Transfer and print the image onto paper.

A laser printer 9 having the configuration shown in FIG. 7 does not use the expensive fθ lens 5 compared to the laser printer 1 described above.
has also been devised. In this laser printer 9, a spiral reflecting mirror 11 is provided on the circumferential surface of a rotating cylinder 10 in order to sequentially irradiate (expose) the circumferential surface of the photosensitive drum 8' with laser light in the direction of the arrow. That is, the rotating cylinder 10 is rotated by the morph 12 at a predetermined speed in the direction of the arrow, and the optical modulator 3
The laser beam from the laser diode 2' that enters the reflecting mirror 11 through the mirror 11 is reflected in the right angle direction, and
The peripheral surface of the photoreceptor drum 8', which is disposed facing the
exposure). Further, the initial position of the laser beam is controlled by rotating the rotary cylinder 10, causing the laser beam to pass through a slit portion 13 in which the reflecting mirror 11 is not provided, and to enter the beam detector 6'.

[Problems with conventional technology]

The laser printer configured as described above has the following problems.

(B) First, the laser printer 1 having the configuration shown in FIG. 6 must use an expensive fθ lens 5 that corrects the beam spot light reflected by the polygon mirror 4 so that it moves at a constant speed on the surface of the photoreceptor drum 8. .

In addition, in order to expose a predetermined position on the circumferential surface of the photoreceptor drum 8 with laser light, a predetermined optical distance is required from the polygon mirror 4 to the circumferential surface of the photoreceptor drum 8, which causes problems such as increasing the size of the laser printer. It has its drawbacks.

(b) On the other hand, the laser printer 9 having the configuration shown in FIG. 7 that uses the rotating cylinder 10 does not require a long optical distance from the reflecting mirror 11 to the circumferential surface of the photosensitive drum 8', so it can be made smaller. It seems to me.

However, the scanning length of the laser beam on the surface of the photoreceptor drum 8' is
Then, the diameter of the rotating cylinder 10 is 7 if the set angle of the spiral reflecting mirror 11 with respect to the incident laser beam is 45°. For example, if the scanning length of the laser beam is set to 210 mm to correspond to A4 size paper, the diameter is 67 *s.
A rotating cylinder is required. In the case of the configuration shown in FIG. 7, it is necessary to provide a rotating cylinder 10 having a diameter that is approximately the same as or larger than that of the photosensitive drum 8'. Therefore (a)
Similarly, the problem of increasing the size of laser printers is unavoidable.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional drawbacks, it is an object of the present invention to provide an image recording device that can be miniaturized and is inexpensive.

[Key points of the invention]

In order to achieve the above object, the present invention provides a rotating scanning body in which a spiral reflective surface is formed on the outer periphery, and a beam of light directed toward the reflective surface from a direction parallel to the rotation axis of the rotating scanning body. It has a light source that emits light, and a photosensitive member that is provided on the side of the rotating scanning body and is irradiated with the beam light reflected by the reflecting surface, and the photosensitive member emits the beam light that is modulated based on image data. The light is reflected by a surface and irradiated onto the photosensitive member to record an image on the photosensitive member.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a perspective view of the main components of a laser printer 14 as an embodiment of an image recording apparatus according to the present invention, and FIG. 2 is a sectional view of the central part of FIG. 1.

In FIG. 2, a charger 16, a developer 17, a transfer device 18, and a cleaner 19 are sequentially arranged near the circumferential surface of the photoreceptor drum 15 along the rotational direction a of the photoreceptor drum 15 (however, In FIG. 1, the charger 16, developer 17, transfer device 18, and cleaner 19 disposed near the photoreceptor drum 15 are not shown to make the drawing complicated). Further, the photoreceptor drum 15 has a hollow structure, and a rotating scanning member 20 is disposed inside the photoreceptor drum 15 . A reflecting mirror 21, which will be described later, is provided on the circumferential surface of the rotary scanning body 20, and reflects a laser beam, which will be described later, and the photosensitive drum 15 is exposed from the inside by this reflected light.

As shown in the sectional view of FIG. 3, this photosensitive drum 15 is constructed by sequentially laminating a transparent cylinder 15a, a transparent conductive film 15b, a carrier generation layer 15c, and a carrier transport layer 15d from the inside. The transparent cylindrical body 15a serves as the base of the photosensitive drum 15, and is made of a material with a certain degree of structural strength, such as transparent glass or acrylic so that laser light can pass through from the inside. The transparent conductive layer 15b is made of a transparent conductive material, such as Nesa glass, and is grounded as described later. When the carrier generation layer 15c is irradiated with laser light, the charge applied to the carrier transport layer 15d flows through that portion to the above-mentioned transparent conductive layer 15b. The carrier transport layer 15d is provided with a uniform charge on its upper surface by the above-mentioned charger 16, and causes the charge in the portion irradiated with the above-mentioned laser beam to flow to the carrier generation layer 15c.

The charger 16 applies a -like charge to the carrier transport layer 15d on the circumferential surface of the photoreceptor drum 15, and the developer 17 applies an electrostatic latent image formed on the carrier transport layer 15d by the above-mentioned exposure. For example, visualized with toner (toner image)
It is something that becomes.

Further, the transfer device 18 is used to transfer a toner image onto a sheet of paper P that is sent by a paper transport mechanism (not shown). Furthermore, the cleaner 19 removes toner that is not transferred to the paper P by the transfer device 18 and remains on the photosensitive drum 15.

As shown in FIG. 1, the photoreceptor drum 15 is positioned by supporting rolls 22a to 22c provided at a position where one end is in pressure contact with the outer peripheral surface of the photoreceptor drum 15, and the other end is supported by a shaft 23. There is. Also, a gear 24 is attached to the shaft 23, and a gear 26 attached to the rotating shaft 25a of the motor 25 meshes with the gear 24, so that the photoreceptor drum 15 is rotated as the motor 25 rotates. Rotate in the direction of arrow a mentioned above.

On the other hand, a reflective surface 21 is formed in a spiral shape on the circumferential surface of the rotating scanning body 20. The reflective surface 21 is formed by forming aluminum (AJ) into a spiral shape using a vapor deposition method or the like after creating the rotating scanning body 20, and then mirror-finishing the aluminum (AJ). Further, this rotating scanning body 20 is pivotally attached to a rotating shaft 27a of a motor 27, and the rotating shaft 27a
A bearing 28 provided at 7a is rotatably supported by a casing (not shown), so that it is stably rotated.

Further, the laser diode 29, the optical modulator 330°, and the beam detector 31 are provided on the same optical axis as indicated by the dashed line in FIG. 1, and each is fixed to the housing by a mounting not shown.

Further, the above-mentioned reflecting surface 21 is located on this front axis, and the laser beam is reflected by the reflecting surface 21, or when the laser beam passes through the gap 21' where the reflecting surface 21 does not exist, the beam detector 31 is configured to be detected.

As described above, the rotating scanning body 2 is placed inside the photoreceptor drum 15.
The operation of the laser printer 14 of this embodiment provided with 0 will be described below.

First, the motors 25 and 27 are rotated to rotate the photosensitive drum 15 and the rotating scanning body 2o.

Then, the laser diode 29 oscillates a laser beam of, for example, 400 Hz, and irradiates it onto the light changer 813G.

The optical modulation rMB 30 modulates the incident laser beam based on the image data to be recorded output from a computer or the like (not shown).For example, in the case of image data to be printed in dots, the incident laser beam is modulated based on the image data to be recorded. If the image data corresponds to a non-printed dot, the incident laser light is blocked, and a laser light sound 5 in which the emitted light is intermittent is generated for the laser light 40011z. The laser beam modulated by the optical modulator 30 in this manner is incident on the reflective surface 21 of the rotating scanning body 20 that is rotationally driven.

Thereafter, in order to synchronize the timing of scanning one line to the photoreceptor drum 15, the above-mentioned laser light passes through the gap 21' on the rotating scanning body 20 where the reflective surface 21 is not present, and the beam detector 31 detects this laser light. When detected, a control circuit (not shown) performs control to set the start point of scanning one line to the photosensitive drum 15. After that, the rotating scanning body 2
As the laser beam rotates, the laser beam is incident on the reflective surface 21, and the reflected light is irradiated from the inside of the photosensitive drum 15.

FIG. 4 is a diagram showing the relationship between input and output of the laser beam at the reflecting surface 21 at this time. However, this figure is an expanded view of the rotary scanning body 20. Since the rotary scanning body 20 is rotating in the b direction shown in FIGS. 1 and 2, it sequentially moves in the opposite direction to the sub-scanning direction (rotation direction of the photosensitive drum 15) as shown in FIG. Therefore, the laser light incident on the reflective surface 21 sequentially moves in the main scanning direction. For this reason, the reflective surface 21
The laser beam reflected by the photosensitive drum 15 enters the photosensitive drum 15 while sequentially moving in the main scanning direction, and when the rotating scanning body 20 rotates once, the main scanning of one line on the photosensitive drum 15 is completed.

For example, if the paper P used is A4 size, the length (L+) of one line scanned at this time is 210 1.

Furthermore, since the incident/output angle at the reflecting surface 21 is 90°, the circumferential length (Lo) of the rotating scanning body 20 is 210 m5.
+cx (a is the width of the gap 21').

The laser beam reflected by the reflective surface 21 in this way is transmitted to the transparent cylinder 15a inside the photoreceptor drum 15-"the transparent conductive layer 1".
5b and enters the carrier generation layer 15c. At this time, as shown in the equivalent circuit of FIG. 5(a), the photosensitive drum 15 is uniformly charged (+charge) by the charger 16 in the same way as when a bias voltage is applied by the DC power supply 32, for example. It is applied to the carrier transport layer 15d. after that,
The carrier generation layer 15C1 and the carrier transport layer 15d into which light has entered through the transparent cylinder 15a and the transparent conductive film 15b become conductive, and the ten charges on the corresponding carrier transport layer 15d flow to the ground through the transparent conductive layer 15b. , the charge distribution state is as shown in FIG.

In this way, an electrostatic latent image is formed on the carrier transport JW 15d, and this electrostatic latent image is created one line in the main scanning direction of the photoreceptor drum 15 every time the above-mentioned rotating scanning body 20 rotates once. . After the photoreceptor drum 15 has been moved by one dot in the b direction (sub-scanning), the laser beam reflected on the reflective surface 21 is sequentially exposed from the inside of the photoreceptor drum 15 each time the rotating scanning member 20 rotates. An electrostatic latent image based on the image data is formed on the surface of the photoreceptor drum.

The electrostatic latent image formed in this way is transferred to the photoreceptor drum 1.
With the rotation of 5, present@! The toner image is developed (turned into a toner image) by W17, the toner image is transferred to the paper P by the transfer rjr1B, the toner image is thermally fixed to the paper by a fixing device (not shown), and the image is printed onto the paper P.

As described above, in this embodiment, the rotary scanning body 20 is provided inside the hollow photosensitive drum 15, and the inner surface of the photosensitive drum 15 is made of a transparent member.
The laser beam reflected by the reflective surface 21 of 0 is irradiated from the inside of the photoreceptor drum 15 to form an electrostatic latent image. Since the device does not need to be installed in parallel with the device, the device can be significantly downsized.

In this example, the photoreceptor on which the laser beam is irradiated and the electrostatic latent image is formed is formed of a drum-shaped photoreceptor, but it is also possible to carry out the same process using an endless belt-shaped photoreceptor. . Further, in this embodiment, a laser diode is used to generate laser light, but the laser diode is not limited to the laser diode, and a gas laser, a solid laser, or the like may be used.

In addition, although a laser printer was described in this embodiment,
Of course, the present invention is not limited to laser printers, and can be similarly implemented with any image recording apparatus that uses a light beam.

〔Effect of the invention〕

As described above in detail, according to the present invention, since the rotating scanning member is provided inside the photoreceptor and the beam light is irradiated from inside the photoreceptor, the image recording apparatus can be downsized.

In addition, the image recording apparatus of the present invention has a spiral reflecting surface on the rotating scanning body, and by rotating the rotating scanning body, the beam reflected by the reflecting surface is irradiated onto the photosensitive surface, so an expensive f-theta lens is required. There is no need to use the above, and costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the main configuration of the laser printer of this embodiment, FIG. 2 is a sectional view of the laser printer of this embodiment, and FIG. 3 is a sectional view of the photosensitive drum used in the laser printer of this embodiment. FIG. 4 is a configuration diagram explaining the state of reflection of laser light on a reflective surface, FIG. 6 and 7 are perspective views of conventional laser printers. 14... Laser printer, 15... Photosensitive drum, 15a... Transparent cylinder, 15b... Transparent conductive layer, 15c ...Carrier generation layer, 15d...Carrier transport layer, 20...Rotating scanning body, 21...Reflection surface, 29...Laser diode, 30...Photometer, 31...Beam Detector. Patent applicant Casio Electronics Industries Co., Ltd. Same as above.
Casio Computer Co., Ltd. Fig. 3 Main direction of erosion Fig. 4 (b) Fig. 5 Fig. 6

Claims (1)

[Claims] a rotating scanning body with a spiral reflective surface formed on its outer periphery;
a light source that emits a beam of light toward the reflective surface from a direction parallel to the rotation axis of the rotary scanning body; and a photosensitive member that is provided outside the rotary scanning body and is irradiated with the beam of light reflected by the reflective surface. An image recording apparatus comprising: a beam light modulated based on image data is reflected by the reflecting surface and irradiated onto the photosensitive member to record an image on the photosensitive member.