JPH01253774A - Optical device in image forming device - Google Patents

Abstract

PURPOSE:To eliminate the vibration of an image due to the jump of a carriage in spite of moment arising when exposure and scanning start and to improve image quality by providing a leaf spring pinching one end of an optical carriage in the position, in which the optical device of an image forming device starts exposing and scanning, together with a guide. CONSTITUTION:When the exposing lamp of the optical device lights up to start copying, a photosensitive body 23 is rotated and simultaneously a 1st optical carriage 33 is drived and advanced in the exposing and scanning direction (t) of an original 22. At this time, a 1st bearing 33 is pinched between a 1st guide rail 36 and the leaf spring 38 and advanced without the carriage 33 jumping. At the end of exposing and scanning the original 22, the carriage 33 is returned opposite to the direction (t) by a driving belt 35 faster than on the ongoing route. In the beginning of the action, moment in a direction (v) arises in the forward direction (t), and leads the carriages to return to the position in which it is pinched with the guide rail 36 and the flat spring 38.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Field of Application) The present invention relates to image formation in which an optical carriage supporting an optical member is scanned in an electrophotographic apparatus or the like to form an image of a document onto an image recording medium. The present invention relates to an optical device in an apparatus.

(Conventional Apparatus) In an image forming apparatus such as a copying machine, an apparatus as shown in FIG. 7 has been conventionally used in which an optical device is reciprocated by an opening device for scanning a document. That is, in this device, the support parts (16) on both sides of the optical carriage (14)
The blocks (], 7a) and (17b) made of plastic with a low friction coefficient are attached to the guide rail (18).
), and a drive device (not shown) drives the block (1
7a) and (17b) on the guide rail (18) to reciprocate the optical carriage (14).

However, in such a device, when the optical carriage (14) starts scanning forward or backward, a moment is generated around the tip of the optical carriage (14) in the moving direction. Since the optical carriage (14) is only placed on the guide rail (18) by its own weight via the blocks (17a) and (17b), it tends to jump up when the reciprocating movement starts. Moreover, as the copy speed increases, the vibration caused by the bounce increases, and even when the exposure scan enters the image area, the vibration does not subside, resulting in one image blur, making it impossible to apply to high-speed models. I have a problem.

(Problems to be Solved by the Invention) Conventionally, an optical carriage is vibrated due to the moment at the start of reciprocating motion, which causes image blurring and deteriorates image quality.

Therefore, the present invention solves the above problems, and by preventing the vibration of the optical carriage at the start of scanning and preventing image blurring, it is possible to obtain good images, and it is also possible to apply it to high-speed models. The purpose is to provide an optical device for an image forming apparatus.

[Structure of the invention]

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a plate spring that clamps one end of the optical carriage together with a guide at the exposure scanning start position.

(Function) By the above-mentioned means, the present invention prevents the optical carriage from jumping up and vibrating and causing image blurring, regardless of the moment that occurs at the start of exposure scanning, and improves image quality.
Furthermore, it is intended to be applied to high-speed models.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. The original (22) on the original platen (21) of the copying machine main body (20) and the photoreceptor (23) which is one image recording member.
In between, an original image is focused on a photoreceptor (23), a first scanning section (24a), a second scanning section (24b), a fixed lens unit (26), and a fourth mirror (27a). ), an optical section consisting of a fifth mirror (27b), and a sixth mirror (27c)! (28) is provided. Here, the first scanning section (24a) includes an exposure lamp (30) with an optical member.
), a reflector (31), a first mirror (32), a first optical carriage (33) on which these are mounted, and a first attachment of a first drive belt (35) which is a heeling device. It is equipped with a fitting part (34). Further, (36) is a first guide rail that supports both sides of the first optical carriage (33) when it reciprocates during scanning. The first optical carriage (33) has bearing mounting plates (34) on both sides of the first support (33a), and the first and second optical carriages reciprocate on the first guide rail (36). It has bearings (37a) and (37b). Furthermore (38)
is a leaf spring, which holds the first bearing (37a) together with the first guide rail (36).

- The scanning unit (24b) of the power cylinder 2 includes optical members such as a second mirror (40), a third mirror (41), a second optical carriage (42) on which these are mounted, and an active device. The second attachment portion (44) of the second drive belt (43) is
). and a second optical carriage (42
) has blocks (46a) and (46b) made of plastic with a low coefficient of friction and are supported by the second support member (48) on the bottom surfaces of both sides of the second support body (42a). ), (46b) are placed on the second guide rail (47).

Next, we will discuss the effect. When a copy button (not shown) is turned on to start copying, the exposure lamp (30) is turned on, the photoreceptor (23) is rotated in the direction of arrow S, and the first optical carriage (33) is not shown. By driving the motor, the document (22) is moved through the first drive belt (35).
) is moved forward in the direction of the arrow, which is the exposure scanning direction. At the start of this forward movement, a moment acts in the direction of arrow U at the rear of the first optical carriage (33) in the exposure scanning direction, but at this time, the first bearing (37a) is still
Since the first optical carriage (33) is held between the first guide rail (3G) and the leaf spring (38), the first optical carriage (33) is moved forward in the direction of the arrow U without upward vibration. As a result, the first bearing (37a) is removed from between the first guide rail (36) and the leaf spring (38), and exposure scanning of the original (22) is started. After this, the exposure lamp (
30), the first optical carriage (33) moves to the first drive belt (35).
), the optical carriage (3
3) A moment in the direction of arrow V is generated in the forward direction of the arrow. Since the first optical carriage (33) is faster when moving backward than when moving forward, the moment in the direction of arrow V is greater than the moment in the direction of arrow U. As a result, the first optical carriage (33) is raised and vibrated in the direction of arrow V, and the first bearing (37a) is at the start end of the exposure scan, and the first bearing (37a) is attached to the first guide. Rail (3
6) and the leaf spring (38). Meanwhile, during this time, the second optical carriage (42)
The optical carriage (33) is reciprocated together with the first optical carriage (33) at half the moving speed of the first optical carriage (33).

However, although the second optical carriage (42) does not have a leaf spring to prevent it from springing up at the exposure scan start end, its moving speed is 1/2 that of the first optical carriage (33). and slow, and the second mirror (4
0) and the third mirror (41), and because it is heavy, it is almost affected by the moment generated in the second optical carriage (42) at the start of reciprocating movement. Nothing happens and there is no vibration. In this way, a head-to-head electrostatic latent image is formed on the photoreceptor (23) while the first optical carriage (33) and the second optical carriage (42) move forward in the direction of the arrow. This will result in

If planted in this way, during forward movement to perform exposure scanning of the original (22), although a moment is generated in the first optical carriage (33) at the beginning of the forward movement, the first bearing (37a ) is held between the leaf spring (38) and the first guide rail (36), and the first optical carriage (33) does not spring up, and even in high-speed models, the photoreceptor (23) A good copy image can be obtained without blurring of the electrostatic latent image formed thereon, and it can also be applied to high-speed models. Furthermore, at the start of the backward movement, the rear end of the first optical carriage (33) in the backward movement direction is allowed to swing without being restricted by the leaf spring, and the first optical carriage (33) The swinging absorbs and alleviates the impact that occurs when switching from the forward motion to the backward motion, thereby preventing damage to the striking belt, etc.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be modified in various ways. For example, as in the modified example shown in FIG. 6, the optical carriage (48) is not a bearing but a block made of plastic with a low coefficient of friction. (50a), (50
b) may be configured to reciprocate on the guide rail (51); in this case, the upper surface of the end (48b) of the support (48a) 4 is pressed by the leaf spring (52), and the support The end portion (48b) may be held between the leaf spring (52) and the guide rail (51) to prevent the optical carriage (48) from springing up at the start of exposure scanning. Further, in the embodiment, the second optical carriage is not provided with a leaf spring to prevent it from springing up at the start of exposure scanning, but the second optical carriage is also provided with a leaf spring to prevent it from springing up. This makes it possible to reliably prevent vibrations occurring in the second optical carriage at the start of exposure scanning, especially in high-speed models, thereby making it possible to further increase the speed of the apparatus.

〔Effect of the invention〕

As explained above, according to the present invention, even in high-speed models, the end of the optical carriage does not spring up when exposure scanning of a document starts, and the vibration caused by the lifting extends to the image area, causing image blurring. Therefore, it is possible to obtain a good image, and the speed of the apparatus can be further increased.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, FIG. 1 is a schematic explanatory diagram thereof, and FIG. 2 is a schematic explanation showing the state in which the first optical carriage is attached to the first guide rail. Fig. 3 is a partially omitted sectional view of Fig. 2, and Fig. 4 is a partially omitted sectional view of Fig. 2.
5 is a partially omitted sectional view taken along the line A-A' in FIG. 4, and FIG. 6 is another modified example. Schematic explanatory diagram showing the attachment state of the optical carriage to the guide rail, No. 7
The figures show the attachment state of the conventional optical carriage to the guide rail, (A) is a schematic explanatory diagram thereof, and (B) is its B-
It is a partially omitted sectional view taken along line B'. 20... Copying machine main body, 21... Original table, 22... Original, 23... Photoreceptor, 24a... First scanning section, 24b...
- Second scanning unit, 28... optical device,
30... Exposure lamp, 33... First optical carriage, 33a... First support body, 36... First guide rail, 37a... First bearing. 38... Leaf spring. Agent: Patent Attorney Nori Ogo Figure 1, Figure 2, Figure 3, Figure 3-S, Figure 5, Figure 8

Claims (1)

[Claims] An optical member that receives image light from a document is mounted on an optical carriage, and a driving device scans the optical carriage along a guide, wherein the optical member is provided at an exposure scanning start position of the optical carriage so as to face the guide. An optical device for an image forming apparatus, comprising a leaf spring that clamps a rear end portion of the optical carriage in the exposure scanning direction together with the guide.