JP7793966B2 - Image reading device and image forming device - Google Patents

Description

The present invention relates to an image reading device and an image forming device.

Image reading devices are included in image forming devices such as facsimiles, copiers, and multifunction devices that combine printer and scanner functions, as well as in standalone image reading devices. Such image reading devices include those that read by moving a document relative to a fixed reading optical system, and those that scan by using a moving optical system to read a document placed on a table. A known configuration of the latter type is one in which a carriage equipped with a reading element arranged in the main scanning direction moves in the sub-scanning direction within the housing of the reading device that houses it.

A known configuration uses a flexible flat cable (FFC) (hereinafter referred to as "flexible cable") as a medium for transmitting carriage read signals and carriage drive power to and from the device main body. One end of the flexible cable is fixed to the carriage side, and the other end is fixed to the main body side. One known device is configured so that the flexible cable is curved and moved between the contact glass (document placement area) and the main body as scanning occurs (see, for example, Patent Document 1).

In image reading devices that are designed to be more compact in height, the flexible cable is configured to come into contact with the contact glass. In this configuration, as the carriage moves back and forth in the sub-scanning direction, the flexible cable repeatedly comes into contact with and separates from the contact glass. This repeated movement can cause damage to the flexible cable, and static electricity generated by friction can cause the flexible cable to adhere to the bottom of the contact glass, which can then become entangled in the moving optical scanning unit. Furthermore, dirt and dust from the flexible cable can adhere to the contact glass, causing problems with reading. If the surface of the contact glass becomes dirty, noise will be introduced into the reading signal, significantly reducing image quality.

In response to this, Patent Document 1 discloses a configuration that includes a spacing means to prevent the curved portion of the flexible cable from coming into contact with the contact glass.

Patent Document 1 discloses two types of separation means for separating the flexible cable from the contact glass: one with a shaft fixed to multiple points on the flexible cable and rollers attached to both ends of the shaft, and another with two rollers arranged opposite each other with the flexible cable in between, a connecting member for the rollers, and a guide. However, both separation means have complex configurations, which leads to increased costs.

On the other hand, in order to prevent contact between the flexible cable and the contact glass, it is necessary to ensure a separation distance between the two, which leads to an increase in the size of the image reading device.
In contrast, if the contact area and contact time can be reduced and the generation of static electricity can be reduced without completely separating the flexible cable from the contact glass, it is believed that the problems described above, particularly the flexible cable becoming entangled in the optical scanning unit, can be prevented.

The present invention aims to provide an image reading device that can prevent the flexible cable from becoming entangled in the optical scanning unit without increasing the size of the device.

In order to solve the above problem, the image reading device of the present invention is an image reading device comprising: a contact glass which is the reading surface of a document placed on it; an optical scanning unit having an image sensor which moves across the reading area of the contact glass to read the document; and a carriage which holds the image sensor so that it can move in the sub-scanning direction; and a flexible cable which has one end connected to the optical scanning unit and the other end connected to a fixed part on the inside bottom surface of a housing which houses the optical scanning unit, and which has a cross-sectional shape which is curved between the contact glass and the inside bottom surface of the housing, wherein the carriage has a holding part which holds the flexible cable on a surface which is the leading side of the outward path in the sub-scanning direction, and the flexible cable has a load member which bends the flexible cable to form a recess at a position which is the center of the horizontal distance from the holding part to the fixed part at the home position of the optical scanning unit, and the surface of the flexible cable is made of a material which contains polyester, and the load member is made of a material which contains any of polyester, polycarbonate, ABS resin, polystyrene, urethane resin, polypropylene, vinyl chloride resin, and silicone resin .

This invention provides an image reading device that can prevent the flexible cable from becoming entangled in the optical scanning unit without increasing the size of the device.

1 is a schematic external view illustrating an example of an image forming apparatus according to an embodiment of the present invention. 2 is a schematic diagram of a scanning and reading unit constituting the image forming apparatus of FIG. 1, which is an example of an image reading apparatus according to an embodiment of the present invention. 3 is a cross-sectional view of the scanning and reading unit of FIG. 2 taken along line XX. FIG. 4 is a partial enlarged view of FIG. 3 . 10A and 10B are schematic diagrams showing an example of an adjusting means for adjusting the length of a flexible cable.

The image reading device and image forming device of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the embodiments shown below, and other modifications, additions, corrections, deletions, and other changes may be made within the scope of what one skilled in the art could conceive. Any aspect that achieves the functions and effects of the present invention is within the scope of the present invention.

Figure 1 is a schematic diagram showing the exterior of an embodiment of an image forming apparatus equipped with an image reading device according to the present invention. Note that the image reading device, described below, may be an image scanner, and the image forming apparatus may be a copying machine or facsimile machine with an image scanner, or even a multifunction machine with both copying and facsimile functions.

In FIG. 1, the image forming apparatus of this embodiment includes an image forming unit 101, a scanning and reading unit 102 as an image reading device according to the present invention, and an automatic document feeder (hereinafter also referred to as "ADF") 103.
The ADF 103 is attached to the scanning and reading unit 102 via an opening and closing mechanism such as a hinge so as to be able to open and close freely.

The image forming unit 101 constitutes the image forming means and includes an exposure device (not shown), multiple photosensitive drums, developing devices containing toner of different colors (cyan (C), yellow (Y), magenta (M), black (Bk)) installed around each photosensitive drum, a transfer belt, and a fixing device.

Based on the image information read by the scanning and reading unit 102 and separated by color, an image is formed on multiple photosensitive drums in different colors. The toner on the photosensitive drums is then superimposed and transferred onto recording paper supplied from the paper feed unit. After that, the toner of the toner image transferred to the recording paper is melted by a fixing device, fixing the color image to the recording paper.

FIG. 2 is an example of an image reading apparatus according to an embodiment of the present invention, and is a schematic diagram of the scanning and reading unit 102 that constitutes the image forming apparatus of FIG.
As shown in FIG. 2, the image reading device (scanning unit) 102 of this embodiment includes a contact glass 7 which is the reading surface of a document placed thereon, and an optical scanning unit 16 in a housing 4 .

The optical scanning unit 16 has an image sensor that reads the document by moving over the reading area W of the contact glass 7, and a carriage that holds the image sensor so that it can move in the sub-scanning direction (the direction of the arrow B in the figure). The main scanning direction of the image sensor is the longitudinal direction (the direction of the arrow A in the figure).
Specifically, the optical scanning unit 16 holds an image sensor, a CCD (charge-coupled device), a light source, a lens, and a mirror, and is moved in the sub-scanning direction (direction B) by a driving means (not shown) to read a two-dimensional color image of a document placed on the contact glass 7.

The electrical signal representing the read information is sent via a cable from a board containing a CCD attached to the optical scanning unit 16 to a main body board located on the inside bottom side of the housing 4. A flexible cable is used as the cable, which is ideal for saving space.

The ADF 103 shown in FIG. 1 includes, for example, a document tray and a paper feed section consisting of various rollers that separate documents one by one from a stack of documents placed on the document tray and transport them toward the contact glass 7. The ADF 103 also includes a paper discharge section consisting of various rollers, and documents on the contact glass 7 are read by the optical scanning unit 16 of the scanning/reading section 102 and then discharged to the paper discharge tray.

The ADF 103 also functions as a document pressing section that presses and fixes the document against the contact glass 7 when the optical scanning unit 16 moves in the sub-scanning direction (direction B) to read the document placed on the contact glass 7.
The contact glass 7 is provided on the upper part of the housing 4 of the scanning and reading unit 102 and forms the top surface of the housing 4 .

FIG. 3 is a schematic cross-sectional view of the scanning and reading unit 102 taken along line XX in FIG. 2, and FIG. 4 is a partially enlarged view of FIG.
The optical scanning unit 16 reads the document by moving in the sub-scanning direction from a predetermined home position (standby position) shown in FIGS.

As shown in FIGS. 3 and 4, a flexible cable 30 for power supply or signal transmission/reception is connected to the optical scanning unit 16 .
One end of the flexible cable 30 is connected to the substrate 17 of the optical scanning unit 16, and the other end is connected to a fixed portion 21 on the inner bottom surface of the housing 4 that houses the optical scanning unit 16, and has a curved cross-sectional shape between the contact glass 7 and the inner bottom surface of the housing 4. The fixed portion 21 is electrically connected to the main body side substrate provided in the housing 4.

The carriage of the optical scanning unit 16 has a holding portion 22 for holding a flexible cable 30 on the surface at the leading end in the outward movement in the sub-scanning direction.
The flexible cable 30 has a load member 24 that bends the flexible cable 30 to form a recess 33 at a position 23 that is approximately the center of the horizontal distance L2 from the holding portion 22 to the fixed portion 21 when the optical scanning unit 16 is in the home position (in the figure, L3 = L2/2).

By including the load member 24, the flexible cable 30 can bend without being affected by the stiffness of the rising portion 31 rising from the fixed portion 21, and can form the recess 33. If the load member 24 is not provided, the area of the flexible cable 30 facing the contact glass 7 will be convex as a whole, and will come into contact with the contact glass 7 over a wide area.
In contrast, in this embodiment, a recess 33 is formed in approximately the center of the convex portion, and there are two or more convex portions including convex portions (32, 34) formed on both sides of the recess 33, thereby reducing the contact area between the flexible cable 30 and the contact glass 7.

It is preferable that the flexible cable 30 be positioned in a location that is not visible or difficult to see from the user, etc., from an external perspective. This can reduce the impact of the flexible cable 30 coming into contact with the contact glass 7 when the optical scanning unit 16 moves back and forth in the sub-scanning direction B.

The load member 24 is made of a material that is close in position in the triboelectric series to the material that forms the surface of the flexible cable 30. This makes it possible to reduce or prevent the generation of static electricity.
Since the surface of the flexible cable 30 is generally covered with a material containing polyester, it is preferable that the material of the load member 24 be made of a material containing, for example, any of polyester, polycarbonate, ABS resin, polystyrene, urethane resin, polypropylene, vinyl chloride resin, and silicone resin.

In the examples of Figures 3 and 4, the load member 24 is provided on the upper surface of the flexible cable 30 (the surface facing the contact glass 7), but this is not limited to this and the load member 24 may be provided on any surface of the flexible cable 30 as long as the flexible cable 30 can be bent in a direction away from the contact glass 7 to form a recess 33.
The load member 24 may be provided detachably with respect to the flexible cable 30, or may be adhesively fixed thereto with an adhesive or the like.

This configuration prevents the flexible cable 30 from becoming entangled in the moving optical scanning unit 16.

It is preferable that the fixed portion 21 be disposed at a position that is approximately the center of the scanning range L in the sub-scanning direction B of the optical scanning unit 16. In this case, L2 = L/2 in Figures 3 and 4.

It is preferable that the load member 24 and the recess 33 of the flexible cable 30 formed by the load member 24 displace as the optical scanning unit 16 moves in the sub-scanning direction B without coming into contact with the contact glass 7 and the inner bottom surface of the housing 4.
If the recess 33 comes into contact with the inner bottom surface of the housing 4, the flexible cable 30 may become entangled under the moving optical scanning unit 16. To prevent this, it is preferable to adjust the weight of the load member 24 and/or the length of the flexible cable 30.
In order to adjust the length of the flexible cable 30, for example, as shown in Figures 3 and 4, the carriage of the optical scanning unit 16 can be provided with an adjustment means 26 for adjusting the length between the holding portion 22 and the fixed portion 21 of the flexible cable 30.

Figure 5 shows an example of an adjustment means for adjusting the length of the flexible cable 30. Figure 5(A) is a perspective view of an example screw member (length adjustment screw) 26, and Figure 5(B) is a perspective view showing an example of the state in which the flexible cable 30 is wound around the screw member.

In this embodiment, the adjustment means is a screw member 26 that can be rotated to wind up the flexible cable 30 .
The screw member 26 has a threaded portion 29 that rotatably engages with a screw hole (not shown) provided in the carriage, a shaft portion 28 for winding up the flexible cable 30, and a hook portion 27.
3 and 4, Fig. 5(B) shows a state in which the flexible cable 30 is inserted into the screw member 26. By rotating the screw member 26 in this state, the flexible cable 30 can be wound or unwound, and the length of the flexible cable 30 can be adjusted as needed.

The image reading device of this embodiment does not require an increase in size to separate the flexible cable 30 from the contact glass 7, and a simple configuration can prevent the flexible cable 30 from becoming entangled in the optical scanning unit 16.

4 Housing 7 Contact glass 16 Optical scanning unit 21 Connection fixing portion 22 Holding portion 23 Load member 26 Screw member (length adjustment screw)
27 Hook portion 28 Shaft portion 29 Screw portion 30 Flexible flat cable (FFC)
101 Image forming unit 102 Scanning and reading unit (image reading device)
103 Automatic document feeder (ADF)

Japanese Patent Application Publication No. 5-34838

Claims (7)

a contact glass that is the reading surface for the document to be placed on;
an optical scanning unit having an image sensor that reads an original by moving over a reading area of the contact glass, and a carriage that holds the image sensor so as to be movable in a sub-scanning direction;
an image reading device comprising: a flexible cable having one end connected to the optical scanning unit and the other end connected to a fixing portion on an inner bottom surface of a housing that houses the optical scanning unit, the flexible cable having a curved cross-sectional shape between the contact glass and the inner bottom surface of the housing,
the carriage has a holding portion for holding the flexible cable on a surface that is a leading side in the outward movement in the sub-scanning direction,
the flexible cable has a load member that bends the flexible cable to form a recess at a position that is the center of a horizontal distance from the holding portion to the fixed portion when the optical scanning unit is in a home position,
the surface of the flexible cable is made of a material containing polyester,
10. An image reading device, wherein the load member is made of a material containing any one of polyester, polycarbonate, ABS resin, polystyrene, urethane resin, polypropylene, vinyl chloride resin, and silicone resin . The image reading device described in claim 1, characterized in that the flexible cable has two or more convex portions, including two on either side of the concave portion formed by the load member. 2. The image reading device according to claim 1, wherein the fixed portion is disposed at a position that is the center of a scanning range in the sub-scanning direction of the optical scanning unit. An image reading device according to any one of claims 1 to 3, characterized in that the load member and the recess in the flexible cable formed by the load member are displaced in accordance with movement of the optical scanning unit in the sub-scanning direction without contacting the contact glass or the inner bottom surface of the housing. An image reading device according to any one of claims 1 to 4, characterized in that the carriage is provided with an adjustment means for adjusting the length between the holding portion and the fixed portion of the flexible cable. An image reading device as described in claim 5, wherein the adjustment means is a screw member that can be rotated to wind up the flexible cable. An image forming apparatus comprising the image reading device according to any one of claims 1 to 6 .