JP3602351B2 - Document feeder - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a document feeder in an image forming apparatus such as a copying machine, a facsimile, a printer, and the like.
[0002]
[Prior art]
Conventionally, as a technique for detecting the size of a document set in a document feeder that sends a document such as a sheet or a sheet to the main body of an image forming apparatus, the size of the document is determined by the amount of movement of a guide plate that guides the direction of document transport. There is known a technique for detecting the occupancy. This is achieved by providing a printed circuit board having Ni (nickel) plating or the like on its surface, providing a conductive plate spring that slides on the surface of the printed circuit board on a guide plate, and determining the contact position of the plate spring with the printed circuit board. This is a technique for detecting the size of a document.
[0003]
[Problems to be solved by the invention]
However, in the above-described technology, there is a problem that the apparatus body is easily damaged by, for example, peeling of the Ni plating of the printed board due to the plate spring directly sliding on the surface of the printed board. Particularly, in a frequently used apparatus such as an automatic document feeder (ADF), the apparatus main body is easily damaged.
[0004]
Therefore, an object of the present invention is to provide a document feeder that can prevent damage to the apparatus main body.
[0005]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a guide member which is slidable perpendicularly to a sheet material conveying direction, abuts on a side edge of the sheet material to guide the sheet material in the conveying direction, and a plurality of guide members are provided on the guide member. A conductive member having a branch portion that branches into a plurality of rails, a plurality of rail portions provided on a track of each branch portion on the substrate, and sliding the conductive member by contacting each branch portion one-on-one; Control means for determining the size of the sheet material based on a contact signal between the section and the branch section, wherein each rail section is configured by arranging metal members in parallel, and the metal member is a rail. Each branch is configured to have a different length, and each branch has a thickness that does not make contact with the substrate, and is divided in the track direction of the branch. Misplaced It is characterized in.
[0006]
According to the first aspect of the present invention, the conductive member (each branch) moves while contacting each rail with the movement of the guide member. Since each rail section has a different length, the number of contacts (contact signal) between each branch section and each rail section differs depending on the stop position of the conductive member. The control means determines the size of the sheet based on the contact signal between the branch portion and the rail portion.
[0007]
Since the metal member is interposed between the conductive member and the substrate, unlike the related art, the conductive member does not directly slide on the surface of the substrate, so that damage to the main body can be prevented. In addition, since the metal members are arranged in parallel, the branch portion can move stably, and the branch portion is prevented from derailing from the metal member.
[0009]
Further, since the metal member is divided, the length per one metal member is shortened, so that the metal member is hardly bent.
[0011]
Further, since the dividing positions of the adjacent metal members are different from each other, there is no break at the branch portion between the branch portion and the rail portion, so that the guide plate can be moved smoothly. Further, since there is no break, a non-contact portion between the branch portion and the rail portion can be eliminated, and the size of the sheet can be accurately detected.
[0012]
According to a second aspect of the present invention, in the first aspect of the present invention, each of the branch portions is formed with a groove portion with which a rail portion is engaged.
[0013]
According to the second aspect of the present invention, since the groove for engaging the rail is formed in the branch, the branch is further prevented from derailing from the rail.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment will be described based on the attached drawings. FIG. 1 schematically shows a sheet-through type automatic document feeder (hereinafter simply referred to as “ADF”) 1 to which the present invention is applied. The ADF 1 is attached to an image forming apparatus such as a copying machine and a facsimile, and conveys the original 5 to the image forming apparatus.
[0015]
The ADF 1 is provided with a document table 3 on which a document 5 as a sheet material is set. The document 5 set on the document table 3 is conveyed in the direction of arrow A by a roller (not shown) provided on the ADF 1 or the like. A pair of guide members 7 and 9 slidable in the direction of arrow B are arranged on the document table 3, and the pair of guide members 7 and 9 abut on both side edges of the document 5 to move the document 5 in the conveying direction. invite.
[0016]
FIG. 2 is a plan view showing the pair of guide members 7 and 9. As shown in FIG. 2, a first rack 11 is provided integrally with one guide member 7 via a guide groove 3a (see FIG. 1) provided in the document table 3, and similarly, the other guide member is provided. 9, the second rack 13 is also provided integrally via the guide groove 3a. Each of the first and second racks 11 and 13 meshes with a pinion 15 that is supported by a rotation shaft 16 provided on the document table 3. Due to the meshing between the first and second racks 11, 13 and the pinion 15, the pair of guide members 7, 9 move along the guide grooves 3a in a direction approaching or away from each other (see an arrow B in FIG. 1). You can slide.
[0017]
The first rack 11 is provided with a metal leaf spring (conductive member) 17, and the leaf spring 17 moves together with the one guide member 7 (along with the first rack 11). The leaf spring 17 includes a base 17a fixed to the first rack 11, a first branch 17b extending from the base 17a toward a substrate 19 described later, a second branch 17c, and a third branch 17d. It is composed of
[0018]
3 is a cross-sectional view showing the vicinity of one guide member 7, FIG. 4 is a perspective view showing the substrate 19 viewed from the direction of arrow C in FIG. 3, and FIG. It is a side view showing the state where each rail part has contacted. As shown in FIG. 3, a substrate 19 such as a printed circuit board is fixed to the back surface of the document table 3, and the leaf spring 17 moves while contacting the substrate 19 with the movement of the one guide member 7. (This will be described later).
[0019]
As shown in FIG. 4, the substrate 19 includes a first rail portion 21 on the track of the first branch portion 17b of the leaf spring 17, a second rail portion 23 on the track of the second branch portion 17c, and a third branch portion 17d. The third rail portions 25 are provided on the respective tracks. The first to third branch portions 17b, 17c, 17d are in contact with the first to third rail portions 21, 23, 25, respectively. As is clear from the figure, the first rail portion 21, the second rail portion 23, and the third rail portion 25 each have a length in the moving direction of the leaf spring 17 (the longitudinal direction of the substrate 19). Is different. That is, each of the rails 21, 23, 25 is provided such that the second rail 23 is longer than the third rail 25 and the first rail 21 is longer than the second rail 23. ing.
[0020]
The first rail portion 21 is configured by arranging two wires (metal members) 27 in parallel with each other. As shown in FIG. The portion 17b slides (moves while making contact). Since the wires 27, 27 are arranged in parallel, the first branch portion 17b can move stably, and the first branch portion 17b is prevented from derailing from the rail portion 21.
[0021]
Further, the wire 27 is divided in the longitudinal direction of the substrate 19, and the adjacent wires 27, 27 are provided so that their division positions are different. Since the wire 27 is divided, the length of one wire 27 is shortened, so that the wire 27 is hardly bent. Further, since the divided positions of the adjacent wires 27 are different from each other, there is no break in the contact portion between the first branch portion 17b and the first third rail portion 21, so that the pair of guide members 7, 9 is provided. Can be smoothed (the rugged feeling when the guide member is moved can be eliminated).
[0022]
Note that the configuration of the second and third rail portions 23 and 25 is substantially the same as that of the above-described first rail portion 21, and a description thereof will be omitted.
[0023]
The printed circuit board 21 is provided with a control means 29, and the control means 29 makes contact between the first to third rail portions 21, 23, 25 and the first to third branch portions 17b, 17c, 17d. The size of the original 5 is determined based on the signal. The control means 29 includes first to third rail portions 21, 23, 25 (hereinafter sometimes simply referred to as “each rail portion”) and first to third branch portions 17 b, 17 c, 17 d (hereinafter simply referred to as “each rail portion”). A document size corresponding to the number of contacts with each of the "branches" is input in advance. In this embodiment, the document size of A3 vertical size when the number of contacts is three, and the document size of A4 vertical size when the number of contacts is two is input to the control means 29 in advance.
[0024]
That is, in FIG. 4, when the leaf spring 17 is located at the position D (the position indicated by the solid line), the first to third rails 21, 23, 25 have the first to third branch portions 17 b, 17 c, 17 d. Are in contact with each other, and the number of contacts is three. At this time, the control unit 29 determines that the size of the document 5 set on the document table 3 is the A3 vertical size.
[0025]
On the other hand, when the leaf spring 17 is located at a position E (a position indicated by a two-dot chain line) in FIG. 4, the first and second rail portions 21 and 23 and the first and second branch portions 17b and 17c Are in contact, and the number of contacts is two. At this time, the control unit 29 determines that the size of the document 5 set on the document table 3 is the A4 portrait size.
[0026]
The document size determined by the control unit 29 is not limited to the above-described size, and various sizes can be determined based on the document size input to the control unit 29 in advance. Further, if the number of rails is increased, it is possible to determine the size of the original document more finely.
[0027]
Next, the operation of the first embodiment will be described based on the above-described configuration. When sending the original 5 to the image forming apparatus, first, the original 5 is set on the original platen 3. Next, the pair of guide members 7 and 9 are slid to bring the pair of guide members 7 and 9 into contact with both side edges of the document 5. With the movement of the one guide member 7, the first to third branch portions 17b, 17c, and 17d move while contacting the first to third rail portions 21, 23, and 25, respectively. It stops when it comes into contact with the side edge of the document 5.
[0028]
Since the first to third rail portions 21, 23, and 25 have different lengths, the number of contacts between each rail portion and each branch portion differs depending on the stop position of the leaf spring 17. The control unit 29 determines the size of the document 5 based on the number of contacts (contact signal). That is, as described above, for example, when the leaf spring 17 is located at the position E in FIG. 4, the size of the document 5 is determined to be the A4 vertical size.
[0029]
With the movement of one guide member 7, each branch portion is configured to move while being in contact with each rail portion, that is, wires 27, 27. Wire 27 is interposed between substrate 19 and each branch portion. Therefore, unlike the related art, the leaf spring 17 does not directly slide on the surface of the substrate 19, thereby preventing the apparatus main body from being damaged. In addition, since the wires 27 of each rail portion have no break because the divided positions of the adjacent wires 27 are different from each other, a non-contact portion between each branch portion and each rail portion can be eliminated. 5 can be accurately detected.
[0030]
Next, other embodiments will be described in sequence, but portions having the same functions and effects as those described above will be denoted by the same reference numerals and description thereof will be omitted.
[0031]
FIG. 6 is a perspective view showing a substrate 19 according to the second embodiment. In the second embodiment, the first to third rail portions 17b, 17c, 17d are provided separately in the orbit direction (moving direction) of the leaf spring 17, and the divided positions of the adjacent wires 27, 27 of each rail portion are provided. Were made to match.
[0032]
FIG. 7 is a perspective view showing a substrate 19 according to the third embodiment. In the third embodiment, the first to third rail portions 21, 23, 25 are provided without being divided in the track direction of the leaf spring 17, in other words, the wires 27, 27 of each rail portion are divided. Instead, each was composed of one wire.
[0033]
FIG. 8 is an enlarged perspective view showing a leaf spring 17 according to the fourth embodiment. In the third embodiment, the groove portions 17e, 17e, 17e with which the respective rail portions engage are formed in the first to third branch portions 17b, 17c, 17d of the leaf spring 17, respectively. And different. With this configuration, it is possible to further prevent the first to third branch portions 17b, 17c, and 17d from derailing from the respective rail portions.
[0034]
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the present embodiment, two wires 27 are provided. However, the present invention is not limited to this, and a plurality of wires such as three or four wires may be provided. Further, although the wire 27 is used as the metal member, the present invention is not limited to this. For example, a sheet metal or the like may be used. Further, in the present embodiment, the leaf spring 17 is used as the conductive member, but a conductive member such as a conductive brush may be used.
[0035]
Further, in the present embodiment, the leaf spring 17 is provided on the first rack 11, but the leaf spring 17 may be provided on the other rack 13. Further, a wall portion on which one side edge of the document 5 abuts on the document table 3 and a guide member on which the other side edge of the document 5 abuts are provided. The document 5 may be guided by the wall and the guide member. With such a configuration, only one guide member is required, so that the number of parts can be reduced.
[0036]
Although the present invention is applied to the ADF, the same operation and effect can be obtained by applying the present invention to a document feeder of an image forming apparatus such as a copying machine and a facsimile.
[0037]
【The invention's effect】
According to the first aspect of the present invention, since the metal member is interposed between the conductive member and the substrate, the main body can be prevented from being damaged. Further, since the metal members are arranged in parallel, the conductive member can move stably, and the contact body is prevented from derailing from the metal member.
[0038]
Further, since the metal member is divided, the length per one metal member is shortened, so that the metal member is hardly bent.
[0039]
Further, since the dividing positions of the adjacent metal members are different from each other, the movement of the guide plate can be made smooth, and the non-contact portion between the conductive member and the rail portion can be eliminated. Size can be accurately detected.
[0040]
According to the second aspect of the present invention, since the groove to which the rail is engaged is formed in the branch, the branch is further prevented from derailing from the rail.
[Brief description of the drawings]
FIG. 1 is a perspective view schematically showing an automatic document feeder according to the present invention.
FIG. 2 is a plan view showing a pair of guide members.
FIG. 3 is a sectional view showing the vicinity of one guide member.
FIG. 4 is a perspective view showing the substrate as viewed from the direction of arrow C in FIG. 3;
FIG. 5 is a side view showing a state in which each branch portion and each rail portion are in contact with each other.
FIG. 6 is a perspective view showing a substrate according to a second embodiment.
FIG. 7 is a perspective view showing a substrate according to a third embodiment.
FIG. 8 is an enlarged perspective view showing a leaf spring according to a fourth embodiment.
[Explanation of symbols]
5. Manuscript (sheet material)
7 One guide member 9 The other guide member 17 Leaf spring (conductive member)
17b First branch 17c Second branch 17d Third branch 17e Groove 19 Substrate 21 First rail 23 Second rail 25 Third rail 27 Wire (metal member)
29 control means

Claims (2)

A guide member that is slidable perpendicularly to the sheet material conveyance direction, and guides the conveyance direction by contacting a side edge of the sheet material;
A conductive member provided on the guide member, and having a branch portion that branches into a plurality,
A plurality of rail portions provided on the track of each branch portion on the substrate, and sliding the conductive member in one-to-one contact with each branch portion;
Control means for determining the size of the sheet material based on a contact signal between the rail portion and the branch portion, and a document feeder,
Each rail section is configured by arranging metal members in parallel,
The metal member is configured to have a different length for each rail, and has a thickness such that each branch does not contact the substrate, and is divided in the track direction of the branch,
A document feeder according to claim 1, wherein adjacent metal members in each rail section have different division positions . 2. The document feeder according to claim 1 , wherein a groove is formed in each of the branch portions so as to be engaged with the rail.

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