JP2003262925A - Image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make improvable the stability of a carriage, to be provided to a reader, with respect to an elastic body by constituting a slider which is made to slide on a guide rail with low friction, as the one of which the area of slide surface is large. <P>SOLUTION: A member which slides on the guide rail 30 of a frame 23a of the carriage is composed of a nearly cylindrical resin-made slider 33 and guided by sliding to the elastic body 31 made of fluorocarbon resin provided on a guide surface of the guide rail 30. The slider 33 is made of a resin material like low-friction nylon with wear resistance and the slide surface which comes into contact with the guide rail is formed having large plane area to decrease a pressing force per unit area to the elastic body 31 to a small value, thereby preventing the elastic body 31 from being dented. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus for reading an image of a document set on a platen, and more particularly to an image reading apparatus provided with a sliding member capable of stably sliding a guide rail of a carriage. Regarding

[0002]

2. Description of the Related Art A manuscript is set on a platen glass,
An image reading device (flat bed scanner ... FBS) of a type that reads an image by a scanning device that is moved along the lower surface of the platen is generally used, and the FBS is an image of an original of a sheet original or a book. Is used to read. In the FBS, a scanning device is arranged on the lower surface of the platen glass, and a pressing member such as a platen cover is openably and closably provided on the platen glass. When the image of the original is read using the FBS, the read image surface is set toward the platen glass, and then the pressing member is pressed from above so that the image surface of the original is not separated from the glass. To hold. In the general FBS type image reading apparatus, a lamp and one mirror are arranged, and a full rate carriage that is moved at a constant speed in the sub-scanning direction and a half distance by following the full rate carriage. A half rate carriage that moves at half speed is arranged. Then, an optical path toward a photoelectric conversion device (CCD) arranged at a fixed position is formed through a mirror provided on the half rate carriage, and an image is formed on the CCD through a lens arranged immediately in front thereof. I am trying.

The two carriages arranged in the image reading device are arranged below the platen glass so as to guide both ends of the carriage, so that the ends of the carriage can slide with respect to the guide rails. I have to.
However, in the scanner used in the image reading apparatus, the lamp and the mirror are mounted on the two carriages, and since the weight including the equipment is relatively large, the carriage is guided. It has a large sliding resistance when sliding on the guide rail. Therefore, in order to guide the carriage along the guide rail, a low-friction member such as a fluororesin tape is provided on the surface of the guide rail, and a hemispherical shape of an oil-impregnated alloy is provided on the portion sliding on the carriage rail. Is provided so that the carriage can be moved under a slight resistance.

[0004]

However, when the soft member is arranged on the surface of the guide rail to slide the hemispherical sliding member, the carriage is fixed to the guide rail during transportation. Since the sliding member is in point contact with the guide rail, a recess may be formed on the rail surface pressed by the sliding member.
Then, if the carriage is stopped for a long time, the recess may not be able to be naturally recovered, and the guide surface of the guide rail may have irregularities. There is a problem that the information of the image is affected by the vibration and an inconvenience occurs when the information of the read image is reproduced as a recording sheet. Such an inconvenience did not occur particularly when both the guide rail and the sliding member were made of a hard material such as metal, but each member constituting the sliding portion was made of a resin material. It occurs when configuring.

The present invention is intended to solve the problem of the guide portion of the carriage, and a sliding member provided on the carriage is configured to be in surface contact with a guide rail, thereby locally exerting a large pressing action. The purpose is to provide a device that does not perform.

[0006]

According to the present invention, a carriage is guided by a guide rail arranged along a platen glass of an apparatus main body, and an image of an original is read by a reading device provided on the carriage. Image reading apparatus. According to a first aspect of the present invention, each of the guide surface of the rail of the guide rail for guiding the carriage and the sliding member in contact with the guide rail of the carriage are made of a resin material having a small friction coefficient. Characterize. Therefore, when the carriage moves, a smooth guiding action can be performed, and the carriage does not vibrate, so that the read image information does not have a defect.

According to a second aspect of the present invention, the elastic body provided on the rail surface of the guide rail is made of a soft resin sheet having a small friction coefficient, and the sliding member of the carriage that slides on the rail surface is It is characterized in that it is made of a resin material harder than the resin sheet. Further, since there is little friction between the sliding member and the guide surface, it is possible to endure long-term use.

According to a third aspect of the present invention, the sliding member in contact with the guide rail of the carriage is formed as a cylindrical member, and a flat surface of the cylindrical member is slid on the guide rail. To do. Further, since the area of the sliding member pressed against the resin guide surface is large, no local pressing force is applied, the flatness of the guide surface can be maintained, and the guide function of the carriage is good. It becomes possible to do it.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The configuration of the apparatus of the present invention will be described with reference to the illustrated example. The example shown in FIG. 1 shows a schematic structure of an apparatus that is configured by combining an image reading apparatus and a recording unit as a general image forming apparatus. The image forming apparatus can be configured as an electrophotographic copying machine, a facsimile machine, or a multifunction machine that combines the two functions of the electrophotographic copying machine, the facsimile machine, and the image reading apparatus 10 disposed on the upper part of the apparatus.
It is combined with a recording unit 2 that creates recording paper based on a read signal. A paper feeding unit (not shown) is arranged below the recording unit 2, and the paper fed from a paper feeding means such as a paper feeding tray is conveyed through the paper conveying path 3 to the photosensitive drum. The formed toner image is transferred onto a sheet, fixed, and discharged as a recording sheet.

The recording section 2 is provided with a conveying means for conveying the sheet in the sheet conveying path 3 by the conveying roller device 4, as in the case of an image forming apparatus using a general electrophotographic system. A memory removing unit, a charging unit, a writing unit, and a developing device 6, which are not shown, are arranged for the photosensitive drum 5 arranged in the recording section, and the surface of the photosensitive drum 5 is arranged. After being charged to a uniform potential by the charging means, light of an image is irradiated from the writing means to form an electrostatic latent image, and the developing roller 6a of the developing device 6 is applied to the electrostatic latent image.
The toner is supplied from the above to form a visible toner image.
Then, the toner image formed on the photosensitive drum is transferred to the paper by applying a predetermined potential from the back side of the paper by the transfer roller 7, and the fixing device 8 applies heat and pressure to fix the toner image. Then, the discharging roller device 9 discharges it to the outside of the machine.

In the image reading apparatus 10 arranged above the recording unit 2, the document handling unit 11 is provided above the reading unit 20 and the ADF is used for handling the sheet document.
An (automatic document feeder) 12 and an FBS (flatbed scanner) for reading a document of a sheet or book set on a platen 22 are used. The ADF1
When scanning a sheet original using
A document set on a document tray 13 is fed to a document feeding path 15 for feeding the document in F12, a sheet feeding roller 16 arranged at an entrance, a sheet separating device 17 and a feeding roller device 18 for sorting and feeding the document. Is provided. Then, the conveyance roller device 18 that conveys the document at a constant speed causes the small platen 21 disposed below the document conveyance path 15 to handle the reading, and the document that has been read is discharged by the discharge roller device 19 to the discharge tray 14 To discharge.

When reading using the FBS function, the image surface of the original is positioned on the large platen 22 and the platen cover integrally provided with the discharge tray 14 of the ADF 12 is pressed to perform the reading operation. To do.
The reading unit 20 provided with the two large and small platens 21 and 22 is provided with a scanning device movable along the lower surface of the platen. The scanning device is a lamp 2
Full rate carriage 2 with 4 and one mirror m1
3 and a half rate carriage 25 provided with two mirrors m2 and m3. Then, the image surface of the original is irradiated with the light of the lamp 24, the reflected light is reflected by the three mirrors m1 to m3, and is imaged on the photoelectric conversion element 27 by the lens 26.
By converting the optical signal into a digital signal at 7, the optical signal is transmitted to the image information processing unit.

The two carriages are respectively connected to drive transmission members 29 and 29a such as wires or belts, and are synchronously driven by drive pulleys 28 and 28a.
The full-rate carriage 23 is attached to the large platen 22.
The half-rate carriage 25 is moved at a constant speed in the length direction of the original set on the table, and the half-rate carriage 25 is moved at a half speed thereof so that the light is reflected by the mirror and is incident on the lens and the photoelectric conversion element 27. Image. The image signal obtained by reading the original document can be used as a signal to be written on the photosensitive drum 5 by the recording unit 2, and can also be transmitted to another facsimile apparatus by using the function of the facsimile apparatus. Further, when the sheet original is read using the small platen 21 corresponding to the ADF 12, as shown by the phantom line in the figure, the two carriages 23 and 25 are used.
Is stopped at the position of the small platen 21, and the ADF12
An image of a document conveyed in the document conveyance path 15 at a constant speed is read by the scanning device stopped at the fixed position.

In the image reading device 10, of the two carriages arranged in the scanning device, the full rate carriage 23 will be explained as an example. As shown in FIGS. 2 and 3, the scanning device is provided on both sides of the frame of the scanning device. Guide rail 3
The slider 33 provided on the lower portion of the carriage frame 23a is guided with respect to 0 in a state of sliding. On the carriage frame 23a of the carriage 23, a lamp 24 and one mirror m1 are arranged in a state as shown in the figure, and the light of the lamp 24 is reflected by a curved reflection mirror R.
1 and R2 are used to focus and irradiate the screen of the document set on the large platen 22. The reflected light emitted to the document is transmitted by the mirror m1 toward the mirror m2 of the half rate carriage 25, thereby forming the light transmission system as shown in FIG.

As shown in the figure, sliders 33 are arranged at predetermined positions below the carriage frame 23a of the full rate carriage 23, and the lower surface of the slider 33 is guided along the upper surface of the guide rail 30. To be done. A sheet-like elastic body 31 is attached to the upper surface of the guide rail 30 in order to smoothly slide the slider 33 of the carriage. In the present embodiment, the resin layer provided on the upper surface of the guide rail 30 is made of a fluororesin sheet, and the low frictional property of the fluororesin is utilized so that the guiding action for the carriage can be favorably performed. ing. Further, a slider 33 as a sliding member of the carriage frame 23a
Is made of a resin material such as nylon resin that has abrasion resistance and is easy to mold.

As shown in FIG. 4, the slider 33 can be constructed as a cylindrical shape, and the upper and lower surfaces 34, 34a are molded as parallel flat surfaces. And the upper surface 34a of the slider 33
Is attached and fixed to the lower surface of the carriage frame 23a, and the lower surface 34 is slid on the elastic body 31. As described above, since the lower surface (contact surface) of the slider 33 that slides on the elastic body 31 is a flat surface and is in surface contact with the guide rail 30, the area of the sliding surface of the slider 33 is large and the elastic body 31 The pressing force per unit area against is a very small value. Therefore, even if the carriage is stopped and held for a long time without using the image reading device,
The flatness of the guide surface of the guide rail can be maintained without applying a deforming action such as denting the elastic body of the portion pressed by the slider.

On the other hand, in the spherical projection provided on the sliding portion of the conventional carriage, since the spherical tip portion locally contacts the guide rail 30, the load on the carriage is very small. It was configured to be concentrated on the protrusion of the area. Therefore, when the elastic body 31 is provided on the upper surface of the guide rail 30, the elastic body 3
In the part where the sliding member (slider) of 1 was stopped,
A dent may be formed, and an unrecoverable dent may be formed in the elastic body between the time when the device is shipped and the time when the device is delivered to the customer, and the condition where the device is not used for a long time. there were. Since the guide surface of the elastic body provided on the guide surface of the guide rail is not in a flat state, vibration or the like occurs when the carriage is moved, which causes a problem in read image quality.

As described above, the sliding surface 34 of the slider 33 is formed as a flat surface, and the area pressed against the guide surface of the guide rail 30 is increased.
There is no need to apply a local pressing force to the elastic body 31. Further, the slider 33 can be made of any other low friction resin material other than the resin material such as nylon, and the sliding surface of the slider 33 with respect to the guide rail 30 is a flat surface. However, the whole shape is not limited to a cylinder, and can be configured as an arbitrary shape such as a truncated cone shape. Then, for example, if the area of the upper surface attached to the carriage frame 23a is large, the action of connection (adhesion or the like) to the carriage frame 23a can be made easier. Further, the elastic body 31 provided on the guide surface of the guide rail 30 may be made of a fluororesin tape, and may be made of any other low friction and abrasion resistant resin material. Therefore, it can be formed to have an arbitrary thickness within a range in which the guiding action with respect to the carriage can be excellently performed.

The carriage provided with the sliding member and the guide means can be applied to the half rate carriage 25 as well as the full rate carriage 23. Then, in each of the carriages, a wire 29 as a driving means is connected to a predetermined position of the carriage frame 23a, and the wire is driven,
When the carriage is moved at a predetermined speed, the sliding guide action by the slider 33 on the guide rail 30 can be performed in a good state. When the carriage is moved, the slider 3 with respect to the elastic body 31 is moved.
Since the sliding of 3 is performed smoothly, it is possible to prevent the inconvenience that the carriage frame jumps up and down, and the mirror and the like provided on the carriage do not shake, so that the carriage can move stably. In addition, the quality of the read image information can be kept good.

[0020]

Since the apparatus of the present invention is constructed as described above, the rail surface of the guide rail for guiding the carriage and the sliding member in contact with the guide rail of the carriage are each made of an elastic body. With this configuration, when the carriage is moved, a smooth guiding action can be performed, and since vibration or the like does not occur in the carriage, a defect does not occur in the read image information. Also, since the elastic body is a sheet of soft resin such as fluororesin, and the sliding member is made of hard resin such as nylon, there is less friction between the sliding member and the guide surface. It is possible to withstand long-term use. Further, the sliding member is configured as a cylindrical member, and the flat surface of the cylindrical member is slid on the guide rail, so that the sliding member pressed against the resin guide surface is Since the area is large, no local pressing force is applied, the flatness of the guide surface can be maintained, and the carriage guiding action can be favorably performed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a reading device to which a mechanism of the present invention can be applied.

FIG. 2 is a side view of a full rate carriage arranged in the reading device.

3 is a front view of the device of FIG. 2. FIG.

FIG. 4 is an explanatory diagram of a slider structure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 image forming apparatus, 2 recording unit, 3 paper transport path, 4 transport roller device, 5 photosensitive drum,
6 developing device, 7 transfer roller, 8 fixing device, 9 discharge roller device, 10 image reading device,
11 manuscript handling section, 12 ADF, 13
Document tray, 14 Document discharge tray, 15 Document transport path, 16 Paper feed roller, 17 Paper separating device, 18 Transport roller device, 19 Discharge roller device, 20 Reading unit, 21 Small platen, 22
Large platen, 23 full rate carriage, 2
4 lamps, 25 half rate carriages, 2
6 lens, 27 CCD, 29 pulley,
29 wires, 30 guide rails, 31 elastic bodies, 33 sliders, 34 sliding surfaces.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H108 AA01 CB01 FB22 FB91                 5C072 AA01 BA13 CA02 DA02 DA04                       EA04 MA04

Claims (3)

[Claims] 1. An image reading apparatus configured to move and guide a carriage by a guide rail arranged along a platen glass of a main body of the apparatus, and to read an image of an original by a reading apparatus provided on the carriage, An image reading apparatus characterized in that each of a guide surface of the rail for guiding the carriage of the rail and a sliding member in contact with the guide rail of the carriage is made of a resin material having a small friction coefficient. 2. The elastic body provided on the rail surface of the guide rail is made of a soft resin sheet having a small friction coefficient, and the sliding member of the carriage sliding on the rail surface is more than the resin sheet. The image reading device according to claim 1, wherein the image reading device is made of a hard resin material. 3. The sliding member in contact with the guide rail of the carriage is configured as a cylindrical member, and a flat surface of the cylindrical member is slid on the guide rail. 2. The image reading device described in 2.