JP3570840B2 - Image reading device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image reading apparatus, and more particularly to a configuration of a moving unit of a fixed original reading apparatus used for a facsimile apparatus or the like.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in this type of fixed-document type reading apparatus, reflected light from a document placed on a document table (a glass plate or the like) is received, and contents (characters, symbols, images, etc.) drawn on the document are received. While the reading unit for reading moves in the sub-scanning direction at a constant speed, irradiation light from a light source mounted inside the reading unit irradiates the document surface.
[0003]
In this case, the reading unit that moves at a constant speed keeps the distance to the document constant. Therefore, as long as the original can be placed on the platen, even a thick original or a book can directly read the drawn contents, which is a feature of this point.
[0004]
As shown in FIG. 5, in the above-mentioned fixed document reading apparatus, a reading unit 11, a document table 12 on which a document 13 is placed, and carriages 31a and 31b (which hold both ends of the reading unit 11, respectively) are provided. The carriage 31b is not shown), pulling wires 8a and 8b for pulling the carriages 31a and 31b (the pulling wires 8b are not shown), and a drive pulley that pulls the pulling wires 8a and 8b in the moving direction of the reading unit 11. 9a to 9d (the drive pulleys 9c and 9d are not shown), guide rails 33a and 33b for guiding the reading unit 11 (the guide rail 33b is not shown), and the reading unit 11 is smoothly moved on the guide rails 33a and 33b. And high sliding members 32a to 32d (the high sliding members 32c and 32d are not shown).
[0005]
The platen 12 is made of a transparent material such as glass for transmitting irradiation light from a light source (not shown) built in the reading unit 11. In the reading unit 11, the pulling wires 8a, 8b are pulled in the moving direction by the rotation of the driving pulleys 9a to 9d, and the carriages 31a, 31b move smoothly on the guide rails 33a, 33b by the high sliding members 32a to 32d. As a result, it moves in the sub-scanning direction (the direction of arrow X).
[0006]
At the same time as the reading unit 11 moves in the sub-scanning direction, irradiation light is emitted from the light source 11b to the document 13 as shown in FIG. The main scanning direction of the reading element 11a of the reading unit 11 is a direction perpendicular to the reading surface of the document 13 (axial direction of the reading line d). While the reading unit 11 is moving, the original 13 is scanned in the sub-scanning direction while sequentially reading the signal from the reading element 11a, that is, the signal obtained by converting the reflected light reflected by the original 13 into an electric signal. Is read out from the entire surface.
[0007]
As shown in FIG. 6, another document fixed type reading device includes a reading unit 11, a document table 12 for placing a document 13, a carriage 41 holding the reading unit 11, and a carriage 41. A pulling wire 8a for pulling, drive pulleys 9a and 9b for pulling the pulling wire 8a in the moving direction of the reading unit 11, a guide rail 42 for guiding the reading unit 11, and guiding the reading unit 11 along the guide rail 42. And a slide bearing 43 for performing the operation.
[0008]
In this case, a slide carriage 45 is attached to the slide bearing 43. The slide carriage 45 supports one end of the carriage 41 at a fulcrum 46, and guides a guide roller 47 provided at the other end of the carriage 41 by a spring 44. The base 12 is in contact with the back side. With this configuration, the optical path length between the reading unit 11 and the document 13 is kept constant. This configuration is disclosed in Japanese Patent Application Laid-Open No. Sho 62-69771.
[0009]
[Problems to be solved by the invention]
In the above-described conventional fixed document reading apparatus, when the original is a thick original or a book, the original plate bends with the weight of the original, or vibration occurs from the driving system or vibration occurs during movement of the reading unit. Occasionally, they may cause blurred reading. When the reading line is blurred, the resolution of the image read from the document is reduced, and wow and flutter (the accuracy of the reading point in the sub-scanning direction) is deteriorated.
[0010]
On the other hand, in a configuration in which one end of a carriage that holds a reading unit is pivotally supported, and a guide roller provided at the other end of the carriage is abutted against the back side of the document table by a spring, the optical path length between the reading unit and the document is reduced. Since the document can be kept constant, even if the document is a thick document or a book, it can cope with the case where the document table is bent by the weight of the document.
[0011]
However, since the fulcrum supporting one end of the carriage is located away from the reading line, when the reading unit moves to the end face side of the platen, the reading line is not perpendicular to the document, resulting in a deterioration in resolution. I do.
[0012]
Also, in this configuration, the vibration from the driving pulley is transmitted to the fulcrum, so that the wow and flutter cannot be improved.In addition, the fulcrum and the document table must always be kept parallel. Precision must be high.
[0013]
SUMMARY OF THE INVENTION It is an object of the present invention to provide an image reading apparatus which can solve the above-mentioned problems and can prevent a decrease in resolution and a deterioration in wow and flutter due to vibration without increasing the assembling accuracy.
[0014]
[Means for Solving the Problems]
An image reading apparatus according to the present invention includes a document table on which a sheet to be read is placed and which is made of a transparent member, and receives light reflected from the sheet while moving in parallel with the document table. A reading unit for reading the content drawn on the paper sheet in a housing, wherein the holding unit holds the reading unit, and a reading unit is provided at a bottom of the housing; and A guide rail for guiding the movement of the reading unit, a moving member for moving the reading unit along the guide rail, a connecting member for rotatably connecting the holding member to the moving member, and a moving member. A moving groove provided to allow the connecting member to be movable in a direction substantially perpendicular to a mounting surface of the sheet on the document table; and a moving groove set in advance at positions before and after the moving direction of the reading unit. Given The first and second contact members disposed on the holding member so as to be spaced from each other and abutting on the document table, and have a predetermined interval that is set in advance at positions before and after in the moving direction of the reading unit. Third and fourth abutting members disposed on the moving member and abutting against one of the bottom surface of the housing and the guide rail; pressing the first abutting member against the platen; A first urging member that presses the third contact member against one of the bottom surface of the housing and the guide rail; and a fourth urging member that presses the second contact member against the document table. And a second urging member for pressing the contact member of the second embodiment against one of the bottom surface of the housing and the guide rail.
[0015]
Another image reading apparatus according to the present invention, in addition to the above configuration, further includes a pulling wire for pulling the moving member, and a drive for moving the moving member by pulling the pulling wire in a moving direction of the reading unit. Means.
[0016]
Another image reading apparatus according to the present invention has a document table on which a sheet to be read is placed and which is made of a transparent member, and which moves parallel to the document table and reflects light reflected from the sheet. What is claimed is: 1. An image reading apparatus, comprising: a reading unit that receives light and reads contents drawn on a sheet; and a first and second holding members that respectively hold both ends of the reading unit. And first and second guide rails arranged in parallel with each other on the bottom of the housing and for guiding the movement of the reading unit; and First and second moving members for moving the reading unit along first and second guide rails, and the first and second holding members are rotatable with respect to the first and second moving members, respectively. First and second connecting members connected to the The first and second moving members are disposed on the first and second moving members, respectively, and the first and second connecting members are movable in a direction substantially perpendicular to a mounting surface of the sheet on the document table. A first moving member and a first and a second moving groove, which are disposed on the first holding member so as to be at a predetermined distance from each other at positions before and after the reading unit in the moving direction, and are in contact with the document table; A third contact member and a third and a fourth contact members which are disposed on the second holding member so as to be at a predetermined distance from each other at positions before and after the reading unit in the movement direction of the reading unit and contact the document table. And the contact member and the first moving member are disposed on the first moving member so as to have a predetermined interval set before and after the reading unit at the front and rear positions in the moving direction of the reading unit. Fifth and sixth contact members contacting one side Are arranged on the second moving member so as to be at a predetermined distance from each other at positions before and after the moving direction of the reading unit, and contact the same contact surface as the fifth and sixth contact members. Contacting the seventh and eighth contact members, the first and third contact members against the platen, and the fifth and seventh contact members against the bottom surface of the housing and the guide rail A first and a second urging member for pressing one of the first and second contact members, and a second for pressing the second and fourth contact members against the platen and the sixth and eighth contact members for the housing. And third and fourth urging members that press against one of the bottom surface and one of the guide rails.
[0017]
Still another image reading apparatus according to the present invention includes first and second pulling wires for pulling the first and second moving members, and moving the first and second pulling wires by moving the reading unit. First and second drive means for moving the first and second moving members by pulling in the directions.
[0018]
That is, in the image reading apparatus of the present invention, the carriage that holds and moves the reading unit is divided into an upper carriage and a lower carriage, and each of the upper and lower carriages has two contact points at a predetermined interval. That is, a contact is provided for contacting the platen and the bottom surface of the housing or the guide rail, respectively. Two contact points of the upper carriage press the document table and two contact points of the lower carriage are connected to the bottom surface of the housing or the guide rail. Is pressed by a pressing spring so as to press. In this case, the pulling wire is attached only to the lower carriage, and the reading unit is moved by pulling the pulling wire with the driving pulley.
[0019]
Therefore, in the image reading apparatus of the present invention, when performing the reading operation of the document, the contact point of the upper carriage always moves while being in contact with the document table when being moved in the sub-scanning direction by the pulling wire connected to the lower carriage. Will be done. At this time, the reading line of the reading unit is always kept perpendicular to the document surface, and the focal length is hardly fluctuated because the focal length is affected only by the accuracy of the thickness of the document table.
[0020]
As a result, the focal length of the reading line of the reading unit and the perpendicularity with respect to the document are always kept constant, and vibration from the drive system is not transmitted to the reading unit. It is possible to prevent wow and flutter from being deteriorated due to vibration.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of one embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, and FIG. 3 is a perspective view of an image reading apparatus according to one embodiment of the present invention. It is.
[0022]
In these figures, a reading unit 11 of an image reading apparatus according to an embodiment of the present invention is housed in a housing 10, is disposed in the housing 10, and has a lower side of a document table 12 on which a document 13 is placed. Are located in Here, the document table 12 is formed of a transparent material such as a glass plate.
[0023]
Further, the reading unit 11 is held by carriages 14a and 14b composed of upper carriages 1a and 1b (the upper carriage 1b is not shown) and lower carriages 3a and 3b (the lower carriage 3b is not shown) and in the sub-scanning direction (arrows). X direction).
[0024]
That is, the reading unit 11 is held by the upper carriages 1a and 1b, and is moved in the sub-scanning direction by the lower carriages 3a and 3b connected to the upper carriages 1a and 1b. Connecting members 2a, 2b (the connecting member 2b is not shown) are attached to the upper carriages 1a, 1b, and the connecting members 2a, 2b are provided in U-shaped grooves 4a, 4b (U) provided in the lower carriages 3a, 3b. The upper carriages 1a, 1b are connected to the lower carriages 3a, 3b so as to be rotatable and movable in the vertical direction (the direction of arrow Z) by fitting into the groove 4b (not shown). The movement of the upper carriages 1a, 1b in the direction of arrow Y is restricted by the connecting members 2a, 2b.
[0025]
The upper carriages 1a, 1b and the lower carriages 3a, 3b are arranged so as to be at predetermined intervals at positions before and after in the moving direction of the reading unit 11, that is, each of the upper carriages 1a, 1b and the lower carriages 3a, 3b. High sliding members 5a to 5h (high sliding members 5e to 5h are not shown) are attached to both ends of the reading unit 11 along the moving direction.
[0026]
The high sliding members 5a, 5b, 5e, and 5f are respectively in contact with the back surface of the document table 12, and the high sliding members 5c, 5d, 5g, and 5h are in contact with the bottom surface of the housing 10, respectively. 11 to smoothly move the document 11 between the document table 12 and the bottom surface of the housing 10. These high sliding members 5a to 5h are urged toward the original table 12 and the bottom surface of the housing 10 by pressing springs 6a to 6d (the pressing springs 6c and 6d are not shown).
[0027]
Towing wires 8a, 8b are attached to the lower carriages 3a, 3b. One end of each of the pulling wires 8a and 8b is fixed to one end of the lower carriages 3a and 3b, and the other ends are driven pulleys 9a to 9d (the drive pulley 9d is not shown) and tension adjusting springs 7a and 7b (the tension adjusting spring 7b is It is fixed to the other ends of the lower carriages 3a, 3b via a not shown). That is, the pulling wires 8a and 8b are stretched between the drive pulleys 9a to 9d with a constant tension by the tension adjusting springs 7a and 7b.
[0028]
The drive pulleys 9a and 9c are attached to a drive shaft 16, and the drive shaft 16 is driven to rotate by a drive unit 17. Therefore, when the drive unit 17 rotates the drive shaft 16, the drive pulleys 9a and 9c rotate to pull the pulling wires 8a and 8b, and pull the lower carriages 3a and 3b, that is, the reading unit 11, to pull the pulling wires 8a and 8b. Move in the direction. At this time, the lower carriages 3a, 3b are guided by guide rails 15a, 15b provided in the housing 10. Incidentally, the high sliding members 5c, 5d, 5g, 5h of the lower carriages 3a, 3b may be brought into contact with the guide rails 15a, 15b, respectively.
[0029]
In the image reading apparatus configured as described above, when the reading unit 11 performs the reading operation of the original 13, when the driving unit 17 drives the driving shaft 16 to rotate, the driving pulleys 9 a and 9 c rotate to pull the pulling wires 8 a and 9 a. Since the lower carriage 3a, 3b is pulled, the lower carriages 3a, 3b move in the direction in which the pulling wires 8a, 8b are pulled (the direction of arrow X). At this time, even if the accuracy of the lower portion of the housing 10 or between the guide rails 15a and 15b and the document table 12 (the interval of B) varies, the upper carriages 1a and 1b are always moved by the pressing springs 6a to 6d. As a result, the focal length of the reading line a and the verticality of the reading unit 11 with respect to the document 13 are always kept constant.
[0030]
Further, since the pressing springs 6a to 6d are arranged between the upper carriages 1a and 1b and the lower carriages 3a and 3b, vibration transmitted from the housing 10 to the lower carriages 3a and 3b and deflection of the document table 12 are also reduced. The pressure can be absorbed by the pressing springs 6a to 6d. Therefore, the reading line a is hardly blurred due to factors other than the speed unevenness of the driving unit 17, and the image quality of the reading unit 11 can be improved.
[0031]
As a result, the focal length of the reading line a of the reading unit 11 and the verticality with respect to the document 13 are always kept constant, and the vibration from the driving unit 17 is not transmitted to the reading unit 11, so that the assembling accuracy is not increased. In addition, it is possible to prevent the wow and flutter from deteriorating due to a decrease in resolution or vibration.
[0032]
FIG. 4 is a sectional view of another embodiment of the present invention. In the figure, an image reading apparatus according to another embodiment of the present invention has the same configuration as that of the embodiment of the present invention except that the reading element 18 of the reading unit is fixed in the housing 10 without being mounted on the carriage. ing.
[0033]
That is, the configuration of the carriage including the upper carriage 1a and the lower carriage 3a on which the light source 20 and the reflection mirrors 21 and 22 of the reading unit are mounted is the same as that of the embodiment of the present invention. In this case, the irradiation light emitted from the light source 20 is reflected by the document 13 placed on the document table 12, and the reflected light is respectively reflected by the reflection mirrors 21 to 23 and is incident on the reading element 18 through the lens 19. .
[0034]
Therefore, the focal length of the reading line a with respect to the document 13 and the verticality with respect to the document 13 are always kept constant, and the vibration from the driving unit 17 is not transmitted to the light source 20 and the reflection mirrors 21 and 22, so that the assembling accuracy is improved. Without this, it is possible to prevent the wow and flutter from deteriorating due to the reduction in resolution and vibration.
[0035]
As described above, the carriages 14a and 14b which hold and move the reading unit 11 are divided into the upper carriages 1a and 1b and the lower carriages 3a and 3b, and the upper carriages 1a and 1b and the lower carriages 3a and 3b are respectively fixed to each other. Two high sliding members 5a to 5h are provided at intervals so that the high sliding members 5a, 5b, 5e and 5f of the upper carriages 1a and 1b press the document table 12 and the lower carriages 3a and 3b. The high sliding members 5c, 5d, 5g, 5h are urged by the pressing springs 6a to 6d so as to press the bottom surface of the housing 10 or the guide rails 15a, 15b, and the pulling wires 8a, only to the lower carriages 3a, 3b. 8b, and pulling the pulling wires 8a, 8b by the drive pulleys 9a to 9d, the drive shaft 16, and the drive unit 17 When the original 13 is read, the contacts of the upper carriages 1a and 1b are always in contact with the original table 12 when the originals 13 are moved by being pulled in the sub-scanning direction by the pulling wires 8a and 8b connected to the lower carriages 3a and 3b. Will move.
[0036]
At this time, the reading line a of the reading unit 11 is always kept perpendicular to the document 13, and the focal length is hardly fluctuated because the focal length is affected only by the accuracy of the thickness of the document table 12. Accordingly, the focal length of the reading line a of the reading unit 11 and the verticality with respect to the document 13 are always kept constant, and the vibration from the driving unit 17 is not transmitted to the reading unit 11, so that the assembling accuracy is not increased. It is possible to prevent the wow and flutter from deteriorating due to a decrease in resolution and vibration.
[0037]
【The invention's effect】
As described above, according to the present invention, a document table on which a sheet to be read is placed and which is made of a transparent member, and which moves parallel to the document table and receives reflected light from the sheet. And a reading unit for reading the content drawn on the paper sheet in the housing, a holding member for holding the reading unit, and a reading unit provided at the bottom of the housing and having the reading unit. A guide rail for guiding the movement, a moving member for moving the reading unit along the guide rail, a connecting member for rotatably connecting the holding member to the moving member, and a document table provided on the moving member and connecting the connecting member to the document table. A moving groove that is movable in a direction substantially perpendicular to the paper sheet mounting surface, and a holding member that is arranged at a predetermined interval between each other at positions before and after in the moving direction of the reading unit; and Abuts the platen The first and second abutting members are disposed on the moving member so as to be at a predetermined distance from each other at positions before and after the reading unit in the moving direction, and one of the bottom surface of the housing and the guide rail A first and a second contact member that presses the first contact member against the platen and presses the third contact member against one of the bottom surface of the housing and the guide rail. And a second urging member that presses the second contact member against the platen and presses the fourth contact member against one of the bottom surface of the housing and one of the guide rails. Accordingly, there is an effect that it is possible to prevent a decrease in resolution and a deterioration in wow and flutter due to vibration without increasing the assembly accuracy.
[Brief description of the drawings]
FIG. 1 is a sectional view of one embodiment of the present invention.
FIG. 2 is a sectional view taken along the line AA in FIG.
FIG. 3 is a perspective view of an image reading apparatus according to an embodiment of the present invention.
FIG. 4 is a sectional view of another embodiment of the present invention.
FIG. 5 is a sectional view of a conventional example.
FIG. 6 is a sectional view of a conventional example.
FIG. 7 is a diagram showing a configuration of a reading unit.
[Explanation of symbols]
1a Upper carriage 2a Connecting member 3a Lower carriage 4a U-shaped grooves 5a to 5d High sliding members 6a, 6b Pressing spring 7a Tension adjusting springs 8a, 8b Pulling wires 9a to 9c Driving pulley 10 Housing 11 Reading unit 12 Document table 14a, 14b Carriage 15a, 15b Guide rail 16 Drive shaft 17 Drive unit

Claims (6)

A document table on which a sheet to be read is placed and which is formed of a transparent member, is moved in parallel with the document table, receives reflected light from the sheet, and is drawn on the sheet. An image reading apparatus comprising a reading unit for reading the read contents in a housing, a holding member for holding the reading unit, and a reading unit disposed at the bottom of the housing for guiding the movement of the reading unit. A guide rail, a moving member that moves the reading unit along the guide rail, a connecting member that rotatably connects the holding member to the moving member, and a connecting member that is provided on the moving member and includes the connecting member. A movement groove that is movable in a direction substantially perpendicular to the paper sheet mounting surface of the document table, and the holding groove so as to be at a predetermined interval set before and after at positions before and after in the movement direction of the reading unit. To the member A first and a second abutting member that is provided and abuts on the platen; and the moving member is disposed on the moving member so as to be at a predetermined distance from each other at positions before and after in a moving direction of the reading unit; Third and fourth contact members that contact one of the bottom surface of the housing and the guide rail, the first contact member is pressed against the document table, and the third contact member is A first urging member that presses one of the bottom surface of the housing and the guide rail; a second urging member that presses the second abutting member against the platen; and a fourth abutting member that presses the fourth abutting member of the housing. An image reading apparatus comprising: a second urging member that presses one of the bottom surface and the guide rail. 2. The image reading apparatus according to claim 1, further comprising: a pulling wire for pulling the moving member; and a driving unit that moves the moving member by pulling the pulling wire in a moving direction of the reading unit. . The first and second contact members have high slidability so as to smoothly move the contact surface of the platen,
The said 3rd and 4th contact member is provided with the high sliding property so that one contact surface of the bottom surface of the said housing | casing and the said guide rail may move smoothly. The image reading device according to claim 1. A document table on which a sheet to be read is placed and which is formed of a transparent member, is moved in parallel with the document table, receives reflected light from the sheet, and is drawn on the sheet. A reading unit for reading the contents read in a housing, wherein the first and second holding members respectively hold both ends of the reading unit, and a reading unit parallel to a bottom of the housing. And first and second guide rails that guide the movement of the reading unit, and are disposed corresponding to both ends of the reading unit and along the first and second guide rails. First and second moving members for moving the reading unit, and first and second connections for rotatably connecting the first and second holding members to the first and second moving members, respectively. A member and each of the first and second moving members A first and a second moving groove provided to allow the first and second connecting members to be movable in a direction substantially perpendicular to a mounting surface of the sheet on the document table; First and second contact members that are disposed on the first holding member and are in contact with the platen so as to be at a predetermined interval that is set in advance at positions before and after the moving direction, and movement of the reading unit. Third and fourth abutting members disposed on the second holding member and abutting on the platen so as to be spaced from each other at predetermined positions before and after the direction, and a moving direction of the reading unit Fifth and sixth abutments which are disposed on the first moving member at a predetermined interval set before and after each other and abut on one of the bottom surface of the housing and the guide rail. Member and direction of movement of the reading unit Seventh and eighth abutments arranged on the second moving member so as to be at predetermined intervals at front and rear positions and abutting on the same abutment surface as the fifth and sixth abutment members. A contact member that presses the first and third contact members against the platen and presses the fifth and seventh contact members against one of the bottom surface of the housing and the guide rail; First and second urging members, the second and fourth contact members are pressed against the platen, and the sixth and eighth contact members are pressed between the bottom surface of the housing and the guide rail. An image reading apparatus comprising: third and fourth urging members that press against one of the first and second biasing members. First and second pulling wires for pulling the first and second moving members; and the first and second pulling wires by pulling the first and second pulling wires in the direction of movement of the reading unit. 5. The image reading apparatus according to claim 4, further comprising first and second driving means for moving said moving member. The first to fourth contact members have high slidability so as to smoothly move the contact surface of the platen,
The said 5th-8th contact member is provided with the high sliding property so that one contact surface of the bottom surface of the said housing | casing and the said guide rail may move smoothly. The image reading device according to claim 4 or 5.

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