JP2003076093A - Image recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the degrading in image quality by shutting off disturbance light and reflected light in the image recording section of an image recording device which is provided with a slit at a casing for housing a photoreceptor drum, inserts an LED head into this slit and forms an electrostatic latent image by using this LED head. SOLUTION: A shielding piece 8a and a shielding rib 8b are vertically installed from an intermediate cover 8 to cover both front and rear sides of the LED head 30. The shielding piece 8a and the shielding rib 8b are disposed across the right and left of the intermediate cover 8 and is extended near to the top surface of the casing 36 of the photoreceptor unit 15. The shielding piece 8a and the shielding rib 8b are molded integrally with the intermediate cover 8 to curtail the number of parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image recording apparatus.

[0002]

2. Description of the Related Art Conventionally, an image recording apparatus such as a facsimile machine comprises an image reading section and an image recording section, and the image recording section is doubly covered by an intermediate cover and an outer cover. An LED head, which is an optical writing unit, is arranged in the width direction of the paper on the intermediate cover above the image recording unit. The LED head includes an LED array having a large number of light emitting units arranged in a line, the surface of the photoconductor drum is charged by a charger, and an electrostatic latent image is written on the surface of the photoconductor drum by the LED head. To superimpose toner on the electrostatic latent image to form a visible image, convey the paper between the photoconductor drum and a transfer roller provided opposite to the photoconductor drum, and transfer the paper to the transfer roller with a polarity opposite to that of the toner. Give a potential of. Then, in the uniform electric field formed between the photoconductor drum and the transfer roller, the toner is transferred from the photoconductor drum to the sheet to perform the transfer. The transferred sheet is conveyed to a fixing device, where the toner is fixed on the sheet by heat and pressure, and then the sheet is discharged.

[0003]

However, the frame supporting the image recording portion has a gap such as a ventilation hole,
Even though both the intermediate cover and the exterior cover are closed, ambient light may enter the photoconductor drum. On the other hand, it is difficult to close all the gaps between the ventilation holes and the joints with the exterior cover to release the heat generated by the fixing device. As described above, the light other than the direct light from the LED head is incident on the photoconductor drum, so that the electrostatic latent image formed on the photoconductor drum is disturbed, and as a result, the image quality recorded on the sheet is improved. In addition, there arises a problem that the image quality is deteriorated due to the disturbance such as the attachment of fine dots. In addition to the ambient light, LE
It is conceivable that the light emitted from the D head may be reflected by the intermediate cover or the like and enter the photoconductor drum. Therefore, an object of the present invention is to prevent the disturbance light from entering the photoconductor drum to prevent the disturbance of the electrostatic latent image and prevent the deterioration of the image quality.

[0004]

The problems to be solved by the present invention are as described above. Next, the means for solving the problems will be described. That is, as described in claim 1, a box having a photosensitive drum housed therein and having a slit formed therein, and an optical writing means inserted into the slit for forming an electrostatic latent image on the photosensitive drum. In the image recording apparatus including the image recording unit including the above, the image recording unit is provided with a shielding member that shields external light incident on the gap between the slit and the optical writing unit.

Specifically, as described in claim 2, the shielding member is integrally provided on the lid body on which the image recording portion is covered.

[0006]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will now be described with reference to a facsimile machine 1. In the following description, it is assumed that the direction of arrow A shown in FIG. 1 is the front (front side) of the facsimile apparatus 1 and the front-rear and left-right positions of each structure are described.

FIG. 1 is an overall perspective view of the facsimile machine 1. As shown in FIG. 1, the main body of the facsimile machine 1 is placed and fixed on a paper feeding device 5, and the image reading device 3 is installed in the main body. The image recording device 4 is arranged vertically. In this embodiment, a laser printer is adopted as the image recording device 4, and details thereof will be described later.

An automatic document feeder (hereinafter referred to as "ADF") 6 is attached above the image reading device 3, and an exterior cover 7 is provided in front of the ADF 6 so as to be openable and closable with respect to the main body of the facsimile device 1. Has been. The upper surface of the exterior cover 7 is used as a document discharge tray 10.
The paper feed tray 9 is provided on the top of the paper tray 0. Then, the originals set in the paper feed tray 9 are separated one by one and AD
The image is taken into the inside of F6 and the image is displayed on the C of the image reading device 3.
It is read by a CD (photoelectric conversion device) and discharged to the discharge tray 10.

Then, the read image is converted into a digital signal (image information) and transmitted to the other party via a telephone line. Further, the image information received from the other party is processed by the image recording device 4 and transferred to the paper taken in from the paper feeding device 5. Alternatively, the image read by the image reading device 3 can be directly transferred to a sheet by the image recording device 4 without being transmitted (a so-called copy function).

Further, FIG. 2 shows a state in which the outer cover 7 of the facsimile apparatus 1 is opened. As shown in FIG. 2, an intermediate cover 8 is provided therein to cover the image recording apparatus 4. There is. The rotation fulcrum shaft of the exterior cover 7 and the rotation fulcrum shaft 11 of the intermediate cover 8 are arranged in directions orthogonal to each other, and the exterior cover 32 opens and closes in the left-right direction, whereas the intermediate cover 8 It is configured to open and close in the front-back direction. Therefore, even if the exterior cover 7 is accidentally closed while the exterior cover 7 and the intermediate cover 8 are both open, the intermediate cover 8 is not pushed and closed by the exterior cover 7.

3 and 4 are side cross-sectional views of the image recording apparatus 4, showing a state in which the intermediate cover 8 is closed and a state in which the intermediate cover 8 is open. As shown in both figures, a process unit 13 is arranged below the intermediate cover 8,
The process unit 13 is configured by combining the developing unit 14 and the photoconductor unit 15.

The photoconductor unit 15 includes a photoconductor drum 16 that contacts a sheet and transfers toner, a box 36 that houses the photoconductor drum 16, and a surface of the photoconductor drum 16 that is charged to a positive potential. The charging device 18 is provided. Further, a slit 36a is opened in the left and right direction on the upper surface of the box body 36, and an optical writing means described later is inserted therein.

The developing unit 14 comprises a toner chamber 19 for containing toner, a developing roller 20 for supplying the toner to the photosensitive drum 16, and a supply roller 21 for supplying the toner to the developing roller 20.

A fixing unit 22 is provided behind the process unit 13 (downstream side in the sheet feeding direction), and the fixing unit 22 includes a heat roller 23 and a heat roller 23.
And a press roller 24 arranged to face the heat roller 23.

LED head 30 as the optical writing means
Is laterally provided at a portion of the intermediate cover 8 located above the photoconductor unit 15. The LED head 30
Is an LED array 31 having a large number of light emitting portions arranged in a line in the width direction of the sheet, and a SELFOC lens 3 for condensing light from the LED array 31 onto the photosensitive drum 16.
2 and are screwed from below by screws 33. When the intermediate cover 8 shown in FIG. 3 is closed, the SELFOC lens 32 of the LED head 30 is inserted into the slit 36a of the box 36 of the photoconductor unit 15 and projects downward (to the photoconductor drum 16 side). The LED head 30 is based on the image information read by the image reading device 3 (when the copy function is used) or the received image information (when the facsimile function is used).
The LEDs on the D array 31 are made to emit light. The SELFOC lens 32 forms an image of the light emitting point of the LED on the photoconductor drum 16, and an electrostatic latent image is formed on the photoconductor drum 16. In addition to the LED head 30, a laser scanner or the like may be used as the optical writing means.

Then, toner is adhered to the electrostatic latent image on the photosensitive drum 16 to form a toner image, and the toner image is formed on the paper fed from the paper feeding device 5 to the image recording device 4. It is designed to be transferred sequentially. In the fixing unit 22, the sheet to be fed is pressed against the heat roller 23 by the press roller 24, and the toner transferred onto the sheet is heated and fused by the heat roller 23 to be fixed. After this, the paper is
The discharge rollers 25 and 26 disposed on the downstream side (rear side) of the heat roller 23 discharge the image from the image recording apparatus 4.

By the way, conventionally, as shown in FIG. 1, although the intermediate cover 8 and the outer cover 7 are closed, ambient light is incident on the photosensitive drum 16 through the gap between the main bodies of the apparatus. It was In addition to this disturbance light, LED
The light emitted by the head 30 may be reflected by the inner frame of the intermediate cover 8 and the reflected light may enter the photoconductor drum 16.

When the light other than the direct light from the LED head 30 is incident on the photosensitive drum 16 in this way, the electrostatic latent image formed on the surface of the photosensitive drum 16 is disturbed, and as a result, it is recorded on the paper. The image quality will be degraded.

Therefore, in the present invention, the shield piece 8a and the shield rib 8b are vertically provided from the intermediate cover 8 to cover the front and rear sides of the LED head 30. The shield piece 8a and the shield rib 8b are formed to have a length substantially equal to the length of the LED head 30, and are provided over the entire width of the intermediate cover 8 at the lower end up to the vicinity of the upper surface of the box body 36 of the photoconductor unit 15. It has been extended. Further, the shielding piece 8a and the shielding rib 8b are formed integrally with the intermediate cover 8,
We are trying to reduce the number of parts.

By the shielding piece 8a and the shielding rib 8b formed as described above, from the gap between the slit 36a of the box 36 and the LED head 30, the photosensitive drum 16 is removed.
The ambient light does not enter.

Further, a rib 37 is provided on the upper surface of the box body 36 of the photoconductor unit 15 and a sponge 38, which is an elastic body, is attached to the lower surface of the shielding piece 8a. They are arranged so as to face each other. The rib 37 and the sponge 38 are formed to have a length substantially equal to the left-right length of the LED head 30, and when the intermediate cover 8 is closed, the sponge 38 is pressed against the rib 37 and the periphery of the fixing unit 22. The space and the space above the photoconductor unit 15 are divided and separated from each other, which also allows the photoconductor drum 16 to be separated.
The ambient light does not enter.

Further, the inner cover 8 including the shield piece 8a and the shield rib 8b is processed so that it is difficult to reflect light. For example, the inner cover 8 is formed of a black resin, preferably a matte black resin. By this, L
The light emitted by the ED head 30 is suppressed from being reflected by the inner frame of the intermediate cover 8. With such a configuration, LE
Light other than the direct light from the D head 30 is applied to the photosensitive drum 16
In this way, the electrostatic latent image is accurately formed by preventing the incident light on the sheet, and the deterioration of the image quality recorded on the sheet is prevented.

As described above, the embodiment according to the present invention is not particularly limited to this constitution, but an opaque film is hung from the intermediate cover 8 and preferably a matte black film is hung. The lower end of the LED head 30 is lightly contacted with the upper surface of the box 36 of the photoconductor unit 15.
The front and rear sides may be covered to block ambient light. Further, if the front and rear sides of the LED head 30 are covered with the shielding pieces 8a and the shielding ribs 8b and the right and left sides are covered with the film, the disturbance can be blocked more effectively. Of course, the front, rear, left and right sides of the LED head 30 may be covered only with the film, and according to this, the LED head 3 can be covered.
It is possible to prevent disturbance light from entering in all directions, such as front, rear, left and right, which enters toward 0.

Although the shielding member is provided on the lid side in the above, the shielding member may be provided on the box body 36 side. FIG. 5 is a side cross-sectional view of the photosensitive unit 15 and the LED head 30, and as shown in the figure, a recess 36b is formed around a slit 36a formed in a box 36 that houses the photosensitive drum 16.
By providing an elastic body such as sponges 39 and 39 in the recess 36b and closing the central cover 8, the LED head 30 as an optical writing means comes into contact with the sponges 39 and 39. Invasion of external light may be prevented.

[0025]

Since the present invention is configured as described above, it has the following effects. That is, as in claim 1, a box body accommodating the photoconductor drum and having a slit formed therein, and an optical writing means inserted into the slit for forming an electrostatic latent image on the photoconductor drum, In the image recording apparatus including the image recording unit including the above, by providing the image recording unit with a shielding member that shields external light incident on the gap between the slit and the optical writing unit, the disturbance light Is blocked by the blocking member, an electrostatic latent image can be formed without disturbance, and deterioration of the image quality recorded on the sheet can be prevented.

Further, as in claim 2, since the shielding member is provided integrally with the lid body on which the image recording portion is covered, in addition to the effect obtained by claim 1, It can be molded with the number of parts, which can contribute to reduction of manufacturing cost and man-hours.

[Brief description of drawings]

FIG. 1 is an overall perspective view showing a facsimile device 1.

FIG. 2 is a perspective view of the facsimile apparatus 1 with an outer cover 7 opened.

FIG. 3 is a side sectional view of the image recording device 4.

FIG. 4 is an image recording device 4 with an intermediate cover 8 opened.
FIG.

FIG. 5 is a side sectional view of the photosensitive unit 15 and the LED head 30.

[Explanation of symbols]

1 Facsimile machine 7 Exterior cover 8 Intermediate cover 8a Shield piece 8b Shielding rib 13 process units 15 Photoconductor unit 16 photoconductor drum 30 LED head 31 LED array 32 Selfoc lens 36 Box 36a slit 38 Sponge 39 Sponge

Claims (2)

[Claims] 1. A box body for accommodating a photosensitive drum and having a slit formed therein, and an optical writing means inserted into the slit for forming an electrostatic latent image on the photosensitive drum,
In an image recording apparatus including an image recording unit including
An image recording apparatus, wherein a shielding member for shielding external light incident on a gap between the slit and the optical writing unit is provided in the image recording unit. 2. The image recording apparatus according to claim 1, wherein the shielding member is integrally provided on a lid body that covers the image recording unit.