Automatic document feeder

Abstract: A main frame (10) is so mounted as to be pivoted with respect to a platen glass (8) provided on the housing of an image forming machine. A paper feeding unit (12) is provided at one end of the main frame (10) and a paper discharging unit (14) is provided at the other end. A conveyer belt mechanism (17) is disposed between the paper feeding unit (12) and the paper discharging unit (14). The document-placing table (16) is attached to a table support means (56) provided for the paper feeding unit (12), and is allowed to move in the back-and-forth direction of the image forming machine (4), so that its position can be adjusted.

Description: The present invention relates to an automatic document feeder that is employed for an image processing machine such as an electrostatic copying machine or an image reader. A platen glass is provided on the upper surface of a housing of an image processing machine such as an electrostatic copying machine. On the upper surface of the housing is further mounted an automatic document feeder (hereinafter simply referred to as ADF). In order to automatically process the documents, in recent years, there have been proposed and practically used ADFs of a variety of types by which the documents to be copied or read out are conveyed onto a predetermined position on the platen glass and are then carried away from the platen glass. Typical examples of the ADF have been disclosed in, for example, Japanese Laid-Open Patent Publication No. 229,744/1986 and Japanese Laid-Open Patent Publication No. 295,334/1988. The German Laid-Open Publication DE-A-32 20 140 discloses another document feeder comprising a main frame pivotally mounted on a copier housing of an image forming machine. A paper feeding tray and a paper discharging tray are arranged at either end of the feeder unit. Original documents are conveyed from the feeding tray to the discharging tray over a platen glass by means of a conveyor belt mechanism. The feeding tray and the discharging tray are integrally formed with the housing of the document feeder. In a typical ADF, a main frame is mounted on the housing of an electrostatic copying machine (hereinafter simply referred to as copying machine) to pivot on the pivot axis of the main frame between a closed position and an open position thereof. The pivot axis of the main frame is so positioned as to extend along an edge of the platen glass on the back side (rear side) of the copying machine. The main frame is usually a unit body of nearly a box-like shape whose upper surface and side surfaces are covered with a plastic covering and whose lower surface is open. The main frame covers the platen glass when it is brought to the closed position and exposes the upper surface of the platen glass when it is brought to the open position. The main frame is required to be opened and closed to place the document on the platen glass by hand. A paper feeding unit is provided at the one end of the main frame (on the left side of the copying machine) and a paper discharging unit is provided at the other end thereof (on the right side of the copying machine). The main frame is provided with a document-placing table and a document discharging tray. The document-placing table is provided for the paper feeding unit, and the document discharging tray is formed on the upper surface of the covering between the paper feeding unit and the paper discharging unit. The paper feeding unit includes a document introduction passage that leads from the document-placing table onto the platen glass, and the paper discharging unit includes a document delivery passage that leads from the platen glass to the document discharging tray. The document-placing table is mounted onto the paper feeding unit on the side of the inlet of the document introduction passage. The document discharging tray is formed on the upper surface of the covering between the paper feeding unit and the paper discharging unit. There is disposed a document conveying means which conveys the document via the document introduction passage, upper surface of the platen glass and the document delivery passage. The document conveying means includes a document introduction means which conveys the document through the document introduction passage, a conveyer belt mechanism which conveys the document along the upper surface of the platen glass, and a document delivery means which conveys the document through the document delivery passage. The conveyer belt mechanism is provided between the paper feeding unit and the paper discharging unit. More concretely speaking, the conveyer belt mechanism is positioned under the covering between the paper feeding unit and the paper discharging unit, i.e., positioned under the document discharging tray. When the main frame is brought to the closed position, the conveyer belt mechanism is positioned with face toward the platen glass. The conveyer belt mechanism includes a pair of support means disposed at a space apart in the back-and-forth direction, a driven roller and a follower roller which are supported at both ends thereof, and an endless belt (hereinafter simply referred to as belt) wrapped round these rollers. The paper feeding unit includes an open/close frame that is supported to pivot on the pivot axis of the open/close frame and that extends substantially perpendicularly to the pivot axis of the main frame. The main frame is provided with an upright front side plate and an upright rear side plate disposed spaced at a distance from each other in the direction of pivot axis of the open/close frame. Furthermore, the open/close frame is provided with a front wall plate and a rear wall plate disposed in the axial direction spaced at a distance smaller than the above distance. The front wall plate and the rear wall plate of the open/close frame are rotatably supported by the upright front side plate and the upright rear side plate via bearing means, and the open/close frame is thus supported to pivot with respect to the main frame. The main frame is provided with a first introduction passage defining means, and the open/close frame is provided with a second introduction passage defining means. The document introduction passage is partly defined by the first introduction passage defining means and the second introduction passage defining means. The above-mentioned part of the document introduction passage becomes open when the open/close frame is pivoted from the closed position to the open position. The document introduction means which conveyers the document through the document introduction passage includes introduction rollers located on the most upstream side of the document introduction passage, feed rollers located on the downstream side thereof, and separation rollers mounted on the open/close frame to come in contact with or separate away from the feed rollers. Discharge rollers are included in the document delivery means that discharges the document through the document delivery passage of the paper discharging unit. The documents from the discharge rollers are discharged onto the document discharging tray through the discharging port of the paper discharging unit and are stacked. The document-placing table provided for the paper feeding unit is positioned extending over the document discharging tray. However, the conventional ADF devices have the following problem related to adjusting the deviation between the optical axis of the copying machine (center line of the copying machine in the direction of width, i.e., in the back-and-forth direction) and the center line of the ADF in the back-and-forth direction. In assembling the ADF in the copying machine in the prior art, the position of the whole ADF is made adjustable in the back-and-forth direction relative to the copying machine so that the above deviation can be adjusted. In a large copying machine which is designed to deal with a document having a maximum size, e.g., A2 size stipulated under the JIS (Japanese Industrial Standards) however, the operator must bear a great burden for adjusting the optical axis by moving the whole ADF back and forth, causing the operation efficiency to be greatly impaired. On the other hand, it can further be contrived to adjust the optical axis by moving the paper feeding unit back and forth. When the paper feeding unit is moved, however, a problem arises in regard to fitness to the covering of the ADF, making it difficult to fully solve the above-mentioned problem. Summary of the Invention A first object of the present invention is to provide an improved ADF which makes it possible to very easily adjust the deviation between the optical axis of the image forming machine and the center line of the ADF in the back-and-forth direction without the need of moving the whole ADF. According to the present invention, an automatic document feeder is provided as defined in claim 1. Fig. 1 is a perspective view showing the state where a preferred embodiment of an automatic document feeder is mounted on an electrostatic copying machine; Fig. 2 is a sectional view which schematically illustrates the automatic document feeder of Fig. 1; Fig. 3 is a perspective view showing the automatic document feeder of Fig. 1; Fig. 4 is a perspective view showing, in a disassembled manner, part of the automatic document feeder of Fig. 3; Fig. 5 is a front view which partly shows a stay of Fig. 4; Fig. 6 is a left side view of Fig. 5; Fig. 7 is an upper view of a table support member of Fig. 4; Fig. 8 is a side view of when Fig. 7 is watched from the lower side; Fig. 9 is a view of when Fig. 7 is watched from the left side; Fig. 10 is a plan view showing major portions of the document-placing table of Fig. 4; Fig. 11 is a side view of when Fig. 10 is watched from the lower side; Fig. 12 is a diagram of when Fig. 10 is watched from the left side; Fig. 13 is a plan view showing a bottom plate of Fig. 4; Fig. 14 is a side view on an enlarged scale of when Fig. 13 is watched from the lower side; Fig. 15 is a view of when Fig.14 is watched from the direction of arrow A; Fig. 16 is a side view showing the state where the document-placing table is mounted on the paper feeding unit. The present invention will now be described in further detail with reference to the accompanying drawings that illustrate preferred embodiments of the ADF constituted according to the present invention. With reference to Figs. 1 to 3, the ADF which as a whole is designated at 2 is applied to a copying machine 4 in the illustrated embodiment. In this specification, the front side refers to the front side of the copying machine 4 shown in Fig. 1; the rear side, the back side of the copying machine 4; the right side, the right side of the copying machine 4; and the left side, the left side of the copying machine 4. The copying machine 4 has a housing 6 of nearly a rectangular parallelepiped shape, and a platen glass 8 (Fig. 2) is provided on the upper surface of the housing 6. A document to be copied is placed at a predetermined position on the platen glass 8. The copying machine 4 itself may be the one which is known per se., and is not described here. The ADF 2 has a main frame 10 that is so mounted as to be pivoted between a closed position and an open position with respect to the platen glass 8 provided on the housing. The pivot axis (not shown) of the main frame 10 is so positioned as to extend along one edge of the platen glass 8 on the rear side of the copying machine 4. The main frame 10 consists of a nearly box-shaped unit body with its upper and side surfaces covered with a plastic covering and with its lower surface open. The main frame 10 at its closed position covers the platen glass 8, and at its open position permits the upper surface of the platen glass 8 to be exposed. A paper feeding unit 12 is provided at the one end of the main frame 10 (on the left side of the copying machine) and a paper discharging unit 14 is provided at the other end (on the right side of the copying machine). The main frame 10 is further provided with a document-placing table 16 and a document discharging tray 18. The document-placing table 16 is attached to the paper feeding unit 12, and the document discharging tray 18 is formed on the upper surface of the covering between the paper feeding unit 12 and the paper discharging unit 14. The paper feeding unit 12 includes a document introduction passage 20 that leads from the document-placing table 16 onto the platen glass 8, and the paper discharging unit 14 includes a document delivery passage 22 that leads from the upper surface of the platen glass 8 to the document discharging tray 18. The document-placing table 16 is attached to the paper feeding unit 12 on the inlet side of the document introduction passage 20. A conveyer belt mechanism 17 is provided on the lower side of the covering, i.e., on the lower side of the document discharging tray 18 between the paper feeding unit 12 and the paper discharging unit 14. A document conveying means is arranged to convey documents through the document introduction passage 20, upper surface of the platen glass 8, and document delivery passage 22. The document conveying means includes a document introduction means which conveys the document through the document introduction passage 20, the conveyer belt mechanism 17 that conveys the document along the upper surface of the platen glass 8, and a document delivery means which conveys the document through the document delivery passage 22. The paper feeding unit 12 is provided with a guide plate 24 that defines the document introduction passage 20, and guide plates 26 and 28 that are disposed being opposed thereto. The document introduction means is provided for the paper feeding unit 12. The document introduction means includes an introduction roller 30 disposed along the document introduction passage 20, a pair of separation rollers 32, and a pair of resist rollers 34. An introduction port 21 (see Fig. 2) is formed at the most upstream position of the document introduction passage 20 in the paper feeding unit 12. The paper feeding unit 12 further includes an open/close frame 38 which is supported to pivot on the pivot axis 36 relative to the main frame 10. The pivot axis 36 is so positioned as to extend substantially perpendicularly to the above-mentioned pivot axis of the main frame 10. The open/close frame 38 is supported by bearing means disposed on the pivot axis 36 and turns relative to the main frame 10 as will be described later in detail. The guide plate 26 and one of the pair of separation rollers 32 are provided on the side of the open/close frame 38. When the open/close frame 38 is brought to the open position, the guide plate 26 is separated away from the opposing guide plate 24, one of the pair of separation rollers 32 is separated away from the other one, and many portions of the document introduction passage 20 are exposed in the paper feeding unit 12. The conveyer belt mechanism 17 which will be described later in detail includes a driven roller 40 and a follower roller 42 disposed spaced apart from each other in the conveying direction (right-and-left direction in Fig. 2), as well as an endless belt 44 wrapped round these rollers, and a plurality of pressing rollers 46. When the main frame 10 is brought to the closed position, the conveyer belt mechanism 17 is positioned with face toward the upper surface of the platen glass 8. The acting running portion, i.e., the lower running portion, of the endless belt 44 is pressed onto the upper surface of the platen glass 8 due to the action of the pressing rollers 46. As the endless belt 44 is rotated by a rotary drive source 72 that will be described later, the document is conveyed from the left toward the right along the upper surface of the platen glass 8. The paper discharging unit 14 includes a pair of guide plates 48 that define the document delivery passage 22. The document delivery means is provided for the paper discharging unit 14. The document delivery means includes a pair of delivery rollers 50 and a pair of discharge rollers 52, both of rollers 50 and 52 being disposed along the document delivery passage 22. A document discharge port 54 is formed on the downstream side of the pair of discharge rollers 52 in the paper discharging unit 14. The documents that are stacked on the document-placing table 16 are conveyed by the rollers 30, 32 and 34 in the paper feeding unit 12 piece by piece from the introduction port 21 toward the conveyer belt mechanism 17 through the document introduction passage 20. The document is located at a predetermined position on the upper surface of the platen glass 8 owing to the action of the conveyer belt mechanism 17. Then, predetermined steps of copying are carried out by the copying machine 4. After the steps of copying are finished, The document is conveyed by the conveyer belt mechanism 17 toward the paper discharging unit 14. The document is discharged onto the document discharging tray 18 from the discharge port 54 by the rollers 50 and 52 in the paper discharging unit 14 through the document delivery passage 22. The basis of constitution and action of the ADF2 have been disclosed in the specification of Japanese Laid-Open Patent Publication No. 88486/1993 filed on September 30, 1991 (European Laid-Open Patent Publication No. 0535648). The fundamental constitutions and functions of the paper feeding unit 12, paper discharging unit 14 and conveyer belt mechanism 17 may be those which have been known per se., and are not described in further detail here. Next, described below is a mechanism for mounting the document-placing table 16 on the paper feeding unit 12. With reference to Figs. 3 and 4, the paper feeding unit 12 is provided with a table support means, and the document placing table 16 is so mounted on the table support means that its position can be adjusted by being moved in the back-and-forth direction of the copying machine 4. With reference to Fig. 4, the table support means is constituted by a pair of table support members 56 that have substantially the same constitution. The table support members 56 are secured to a stay 58 that is provided for the paper feeding unit 12 in a manner to protrude from the paper feeding unit 12, spaced at a predetermined distance from each other in the back-and-forth direction of the copying machine 4. The stay 58 is secured to a lower portion of the introduction port 21 of the paper feeding unit 12. Referring to Figs. 4 to 6, the stay 58 is formed from a metal plate that is folded in nearly an L-shape as viewed from the side surface thereof. That is, the stay 58 has a horizontal portion 60, a tilted portion 62 that upwardly extends in a tilted manner from an end of the horizontal portion 60, and a mounting portion 64 that upwardly extends from an end of the tilted portion 62 being slightly tilted from the vertical direction toward the horizontal portion 60 side. The horizontal portion 60 and the mounting portion 64 are provided at their both ends with attaching flanges 66 and 68 for being attached to the paper feeding unit 12. The attaching flange 66 has two screw holes 66a and the attaching flange 68 has a screw hole 68a. The mounting portion 64 has substantially the same slits 70 formed nearly at its both ends thereof. Two screw holes 64a are formed under each of the slits 70. The stay 58 is inserted in an opening 23 (see Fig. 4) in a manner to shut it, the opening 23 being formed under and along the introduction port 21 of the paper feeding unit 12. By utilizing the attaching flanges 66 and 68, the stay 58 is secured to a pair of upright side plates 72 and 74 that are provided for the main frame on both sides of the paper feeding unit 12. The table support members 56 have substantially the same constitution, and only one of them will be described here. With reference to Figs. 7 to 9, the table support member 56 is formed by folding a metal plate and has a flat receiving surface 76 of substantially a rectangular shape formed in an upper portion thereof. At the central portion of the receiving surface 76 is formed by punching a mounting portion 78 that downwardly protrudes in a tilted manner. The mounting portion 78 has a mounting hole 78a. Downwardly extending flanges 80 and 82 are formed on both sides of the receiving surface 76, and at the ends of the flanges are formed attaching flanges 84 and 86 that are folded in directions to meet each other. In the attaching flanges 84 and 86 are formed a mounting hole 84a and 86a, respectively. The mounting hole 84a is of an oblong shape. An upwardly folded flange 88 for hooking is provided at an end of the receiving surface 76. To mount the table support member 56 on the stay 58, the flange 88 of the table support member 56 is inserted (hooked) in the slit 70 of the stay 58. Positions of the mounting holes 84a and 86a of attaching flanges 84 and 86 of the table support member 56 are brought into agreement with positions of the screw holes 64a of the stay 58, and they are secured together using screws that are not shown (see Fig. 16). As described above, the table support members 56 are mounted on the portions of the slits 70 of the stay 58. Described below is the document-placing table 16 mounted on the table support members 56. With reference to Figs. 10 to 12, the document-placing table 16 has a flange along the circumference thereof and is made of a synthetic resin member of substantially a box shape with its lower side open. When viewed on a plane, the document-placing table 16 has a rectangular shape, part of which being cut away, and has in the upper surface thereof two guide slits 90 and 92 that extend straight in the direction of width. Into the slits 90 and 92 are movably fitted width defining members 94 and 96 that are shown in Fig. 4 to define the width of the document. Two recessed portions 100 and 102 with their lower sides open are formed in a flange 98 that is formed at one end portion of the document-placing table 16. Referring to Fig. 16, a bottom plate 104 is attached to the lower side of the one end portion of the document-placing table 16 spaced at a predetermined distance apart. With reference to Figs. 13 to 15, the bottom plate 104 as viewed on a plane is constituted by a metal plate of substantially a rectangular shape, and has horizontal portions 106 and 108 as well as an inclined portion 110 located therebetween. Attaching holes 112 are formed in a number of two in the horizontal portion 106 and in a number of three in the horizontal portion 108. The attaching holes 112 are formed in the dish-like protruded portions that are formed directing upwards from the bottom plate 104. The bottom plate 104 has flanges 114 and 116 formed extending upwards at the one end and at the other end. In the inclined portion 110 are formed by punching two attaching portions 118 spaced from each other in the lengthwise direction thereof. The attaching portions 118 upwardly extend in a tilted manner and have an oblong attaching hole 118a, respectively. On the lower surface of the document-placing table 16 are formed five bosses 120 (see Figs. 10 and 16) protruding downwards. A threaded hole is formed in each of the bosses 120. Arrangement of these bosses is substantially the same as that of the attaching holes 112 formed in the bottom plate 104. The bottom plate 104 is fastened to the lower surface of the document-placing table 16 by using screws that are not shown under the condition where the attaching holes 112 of the bottom plate 104 are in match with the threaded holes of the bosses 120. With reference to Fig. 16 together with Figs. 11 and 12, the flange 114 of the bottom plate 104 is positioned under the flange 98 of the document-placing table 16 under the condition where the bottom plate 104 is mounted on the document-placing table 16. Therefore, openings 122 and 124 are formed between the flange 114 of the bottom plate 104 and the recessed portions 100 and 102 in the flange 98 of the document-placing table 16. The openings 122 and 124 have substantially the same constitution and have a substantially rectangular shape that can be fitted to the table support members 56. The openings 122 and 124 are wider than the table support members 56. In the lower portion of the document-placing table 16 on the inside of the openings 122 and 124 are formed placing portions 126 that come in contact with the receiving surfaces 76 of the table support members 56. The placing portions 126 are each constituted by the lower surfaces of two ribs that extend from the inside toward the rear side of the openings 122 and 124. With reference to Fig. 16, when the openings 122 and 124 of the document-placing table 16 are fitted to the table support members 56, the placing portions 126 of the document-placing table 16 are placed on the receiving surfaces 76 of the table support members 56. Furthermore, the attaching portions 118 provided on the bottom plate 104 of the document-placing table 16 come in contact with the mounting portions 78 of the table support members 56 to define the position of insertion thereof. Then, the oblong attaching holes 118a of the attaching portions 118 are brought into agreement with the mounting holes 78a of the mounting portions 78. The oblong attaching holes 118a are then moved in the direction of width relative to the mounting holes 78a (in the back-and-forth direction of the copying machine 4) to adjust the document-placing table 16 for its mounting position on the table support members 56, and is fastened by screws 119. Since the document-placing table 16 is supported by the paper feeding unit 12 in a manner as described above, deviation between the optical axis of the copying machine 4 and the center line of the ADF 2 in the back-and-forth (width) direction is adjusted by moving the document-placing table 16 in relation to the table support members 56 in the back-and-forth direction of the copying machine 4 perpendicular to the paper feed direction. As a result, the deviation can be adjusted very easily by moving neither the whole ADF 2 nor the paper feeding unit 12. Even in the case of a large ADF mounted on a large copying machine, the operator can bear a reduced burden contributing to greatly improving the operability. In the ADF constituted according to the present present invention, the deviation between the optical axis of the image forming machine and the center line of the ADF in the back-and-forth direction can be very easily adjusted by moving the document-placing table in the back-and-forth (width) direction without the need of moving the ADF as a whole or the paper feeding unit that is required in the prior art. In the case of a large ADF mounted on a large image forming machine, in particular, the operator can bear a reduced burden and the operation efficiency can be greatly improved.

Claims: An automatic document feeder comprising a main frame (10) mounted to be pivoted between a closed position and an open position with respect to a platen glass (8) provided on the housing (6) of an image forming machine (4), a paper feeding unit (12) provided at one end of said main frame (10), a paper discharging unit (14) provided at the other end, a conveyer belt mechanism (17) disposed between said paper feeding unit (12) and said paper discharging unit (14) to face toward said platen glass (8) in the closed position of said main frame (10) and a document-placing table (16) attached to said paper feeding unit (12) via a table support means (56, 58), characterized in that said document-placing table (16) is adapted to be mounted to said table support means (56, 58) such that its position in the width direction of said image forming machine (4) perpendicular to the paper feed direction can be adjusted without having to move the whole automatic document feeder. An automatic document feeder according to Claim 1, wherein said table support means comprises a pair of table support members (56) having substantially the same constitution, each of said table support members (56) is so secured to said paper feeding unit (12) as to protrude from said paper feeding unit (12) at a predetermined distance from each other and each has a receiving surface (76) formed at an upper portion thereof as well as a mounting portion (78) which downwardly protrudes with a mounting hole (78a) formed therein, said document-placing table (16) has, formed at one end thereof, openings (122, 124) of substantially the same constitution into which said table support members (56) are inserted, said openings (122, 124) have a width larger than the width of said table support members (56), the lower portion of said document-placing table (16) on the inside of said openings (122, 124) is provided with a placing portion (126) that comes in contact with said receiving surfaces (76) of said table support members (56), and is provided with an attaching portion (118) having an oblong attaching hole (118a) extending in said width direction, and wherein when the openings (122, 124) of said document-placing table (16) are fitted to said table support members (56), the placing portions (126) of said document-placing table (16) are placed on said receiving surfaces (76) of said table support members (56) and the attaching portions (118) of said document-placing table (16) come in contact with said mounting portions (78) of said table support members (56) to define the position of insertion, whereby said oblong attaching holes (118a) of said attaching portions (118) are brought in agreement with said mounting holes (78a) of said mounting portions (78), and said oblong attaching holes (118a) are moved in said width direction with respect to said mounting holes (78a) thereby to adjust the mounting position of said document-placing table (16) relative to said table support members (56), and said document-placing table (16) is secured using screws (119). An automatic document feeder according to Claim 2, wherein said document-placing table (16) has a flange (98) along the periphery thereof and is constituted by a synthetic resin member of substantially a box shape with its lower side open, said openings (122, 124) are formed in the flange (98) of said one end side of said document-placing table (16), a bottom plate (104) is mounted, on the lower side of said one end of said document-placing table (16), spaced at a predetermined distance from said placing portion (126), said bottom plate (104) defining the bottom of said openings (122, 124), and said attaching portions (118) are formed in said bottom plate (104).

Inventors: KAKUTA MASAYUKI, KIDA YASUHIKO, MATSUO TAKESHI, NAGAO TSUYOSHI, OTSUKA NOBUKAZU, YOSHIDA TAKESHI, KAKUTA, MASAYUKI, KIDA, YASUHIKO, MATSUO, TAKESHI, NAGAO, TSUYOSHI, OTSUKA, NOBUKAZU, YOSHIDA, TAKESHI, Kakuta, Masayuki, c/o Mita Industrial Co., Ltd., KIDA, YASUHIKO, C/O MITA INDUSTRIAL CO., LTD., Matsuo, Takeshi, c/o Mita Industrial Co., Ltd., NAGAO, TSUYOSHI, C/O MITA INDUSTRIAL CO., LTD., Otsuka, Nobukazu, c/o Mita Industrial Co., Ltd., Yoshida, Takeshi, c/o Mita Industrial Co., Ltd.
Applicants: MITA INDUSTRIAL CO LTD, MITA INDUSTRIAL CO., LTD.
Application year: 1993
Main classification: G03G15
IPC codes: G03G15