JP3858891B2 - Paper size detection device - Google Patents

Description

  The present invention relates to a paper mount for feeding and feeding originals and recording paper one by one toward a reading unit and a recording unit in an image forming apparatus such as a facsimile machine, a copying machine, and a printer (including these multifunction machines). The present invention relates to a paper size detection device in a placement unit.

In general, an electrophotographic copying machine or a facsimile apparatus includes an automatic document feeder (ADF) that separates documents set on a document tray one by one and continuously supplies them to a reading unit. In the case of the above-described apparatus and printer, a cassette type paper feed unit and a manual feed tray are provided so that recording sheets are separated one by one and continuously supplied to the recording unit. In the ADF apparatus and the paper feed apparatus using the manual feed tray as described above, a sheet width detecting unit for determining the size of the fed sheet is provided in the sheet placing unit and the sheet conveying path. Based on the detection information, the reading unit and the recording unit are controlled. As an example of a sheet feeding device provided with such a sheet width detecting means, the one disclosed in Patent Document 1 or Patent Document 2 can be cited.
Japanese Patent Laid-Open No. 08-133551 Japanese Patent Laid-Open No. 10-194469

  In the sheet (paper) conveyance device disclosed in Patent Document 1, for example, in the case of a standard specification device that uses A3 paper as a maximum size, at least A4 (vertical), B4 (vertical), and A3 (vertical) paper are used. The three sensors that are turned on by the respective actions are arranged side by side at appropriate intervals in the direction orthogonal to the paper feeding direction to constitute the paper width detecting means. As described above, in the standard specification apparatus in which the A3 sheet is the maximum size, at least three sensors are required as the sheet width detecting means, which is a factor in increasing the cost. In addition, it is necessary to secure the installation space in a limited space, and design restrictions cannot be ignored. Here, (vertical) means that the long side of the paper is facing the paper feeding direction.

  Patent Document 2 discloses an apparatus for determining the size of a document in the width direction by detecting a separation distance between a pair of side guides on a document placement tray by a sensor. To detect the separation distance of the side guide in this device, a variable lever is attached to the rack linked to one side guide, and the separation distance is determined by the change in the resistance value based on the amount of movement of the variable lever with respect to the sliding volume resistor. It is something to be done. In addition, Patent Document 2 describes that a rotary type volume resistor, a piezoelectric position detecting unit, a moving distance detecting unit using an optical encoder, or the like can be employed. However, it is expected that these paper width detection means are both large-scale and costly, and the control sequence is complicated.

  The present invention has been made in view of the above circumstances, and can be used for paper feeding that can reduce the number of sensors with a simple structure, reduce costs, and reduce design constraints. A paper size detection apparatus is provided.

The present invention provides a sheet feeding guide member that includes a width-shifting guide member for shifting the placed paper, and is attached to the transporting device main body for transporting the paper so that it can swing up and down with a hinge as a fulcrum. The present invention relates to a paper size detection device in a paper placement unit.
According to a first aspect of the present invention, a sheet width detection unit including a plurality of sensors spaced along the width direction is provided on one side portion in the width direction below the sheet placement portion, and the margin guide member includes An action piece having a length that can turn on the plurality of sensors at the same time as the slide operation is suspended from the back surface of the paper placement portion so as to be slidable along the width direction. It is formed in a cylindrical shape, and lead wires of the plurality of sensors are inserted through the cylinder of the hinge portion, and are connected to a control unit in the main body of the transfer device.
Size detection device.

According to a second aspect of the present invention, a paper presence / absence sensor is disposed on the upstream side of the paper width detection means at the other side portion of the paper placement section, and the sensor constituting the paper width detection means is a paper placement sensor. Arranged at a position within 1/2 of the maximum paper length from the front end position of the paper placed on the placement section,
On the other hand, the sheet presence / absence sensor is arranged at a position upstream from a position of ½ of the maximum sheet length from the front end portion of the sheet placing portion.
According to a third aspect of the present invention, a guide serving as a reference for a set position of a paper sheet placed on one side edge part of a plurality of side edge parts substantially parallel to the paper feeding direction of the paper paper loading part. A wall is formed so as to be raised, and an instruction unit for indicating a set position is provided in the vicinity of the guide wall.

  According to the paper size detecting device of the present invention, when the marginal guide member is slid along the side of the sheet placed on the sheet placing portion, the action piece suspended from the back surface of the marginal guide member. However, when a plurality of paper width detection sensors are simultaneously turned on according to the paper width size, when any one of the sensors is turned on alone or in combination, or when not all the sensors are turned on, etc. A plurality of on / off patterns appear, and the paper width size can be determined by the plurality of on / off patterns. Therefore, it is not necessary to install a number of sensors according to the types of paper of different sizes that can be fed, and a variety of commercially available sensors such as photo sensors and limit switches can be used, making the structure simple and low cost. Can be configured. When combined with the detection information from the sheet presence / absence sensor according to claim 2, it is possible to determine various sheet sizes including the difference between the horizontally placed sheets and the vertically placed sheets.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a main part of an automatic document feeder (ADF) 1 in a facsimile machine, a copying machine, or a so-called multi-function machine having both functions of facsimile and copying. The ADF 1 shown in the figure is configured as an automatic document feeder for reading images on both sides of a sheet of document D one by one and outputting them as digital signals.

  The document tray 2 is detachably attached to the document supply port 2A of the ADF 1 so that the document tray 2 is inclined downward toward the document supply port 2A. The document placement unit is configured by the document supply port 2A and the document tray 2. A (paper placing portion) 2B is configured. A pickup roller 3 is provided on the document supply port 2A to feed out the document (paper) D deposited on the document placement portion 2B from the upper layer portion. A document separating means 4 for separating and feeding the sheets one by one is provided. The document separating means 4 includes a separation roller 4a and a separation pad 4b urged so as to elastically contact the peripheral body of the separation roller 4a. The document fed out by the pickup roller 3 is introduced between the separation roller 4a and the separation pad 4b, and is separated one by one due to the difference in friction coefficient with respect to the two papers as the separation roller 4a rotates, and is fed downstream. Sent. The compression spring 4c is for elastically contacting the separation pad 4b with the peripheral body of the separation roller 4a.

  The originals separated one by one by the original separation means 4 are registered by a registration roller 6, a first conveyance roller 7 and a second conveyance roller 8 which are sequentially arranged along a document conveyance path 5 formed in a U-turn shape. The resist is conveyed to the first reading point (reading unit) P1, and further fed to the second reading point P2 by the third conveying roller 9, and discharged to the discharge tray 11 by the discharge roller 10. A platen 12 is disposed at the first reading point P1, and when the document passes over the platen 12, the image information on the surface of the document is sequentially read by the reading and scanning device 13 waiting under the platen 12. As a digital signal.

  The reading scanning device 13 includes a light source 13a formed of a fluorescent lamp or a cold cathode tube, a plurality of mirrors 13b..., A condensing lens 13c, and a CCD (charge coupled device) 13d. It is mounted on 13e. Irradiation light from the light source 13a is reflected by the original passing through the reading point P1 on the platen 12, and then repeatedly reflected by the four mirrors 13b, is condensed by the condenser lens 13c, and enters the CCD 13d ( (Refer to the light path of the one-dot chain line). In the CCD 13d, image information drawn on the surface of the document is converted into an electric signal and output as a digital signal.

  The reading scanning device 13 in the figure is configured to be used also as a flat bed scanner (FBS). That is, although a part of the illustration is omitted, the FBS part 14 is coupled to the right side of the broken part in FIG. Although the carriage 13e is stationary at the reading position of the ADF document in the illustrated example, when the FBS document is read, the carriage 13e moves into the FBS unit 14 and reciprocates in the FBS unit 14 along the lower surface of the platen glass 15. The image information of the document placed on the platen glass 15 is read by the reading scanning device 13 in the same manner as described above. The ADF 1, the document tray 2, and the discharge tray 11 are integrated to form a platen cover, and can be opened and closed up and down with the back side of the paper surface as a hinge portion (not shown). Accordingly, when the FBS unit 14 reads a document, the platen cover is opened and the document is placed on the exposed platen glass 15.

  As described above, the original whose surface image has been read at the first reading point P1 is further conveyed by the third conveying roller 9 to the second reading point P2, and this second reading point P2 is The contact point between the contact image sensor 16 disposed on the back side of the transported document and the platen roller 17 disposed in contact therewith. That is, the document introduced between the contact image sensor 16 and the platen roller 17 is fed while sliding the reading surface of the contact image sensor 16 by the rotation of the platen roller 17. The image is read by the mold image sensor 16, converted into an electrical signal, and output as a digital signal.

  The separation roller 4a, the registration roller 6, the first to third transport rollers 7 to 9, the platen roller 17 and the discharge roller 10 use a single motor (not shown) as a drive source and appropriately transmit gears or belts. Drive transmission is made through (same as above), and ON / OFF control is performed individually by an electromagnetic clutch (same as appropriate).

  The pickup roller 3 is configured to be driven and transmitted from the drive shaft 4d of the separation roller 4a. Briefly, a frame 3a is attached to the drive shaft 4d via a torque limiter (not shown) so as to be swingable up and down, and a support shaft 3b is supported on the front side of the frame 3a so as to be rotatable. ing. A belt 3d is stretched between a pulley 4e attached to the drive shaft 4d and a pulley 3c attached to the support shaft 3b, and the rotation of the drive shaft 4d passes through the pulley 4e, the belt 3d and the pulley 3c. The rotation of the support shaft 3b is transmitted to the pickup roller 3 via a one-way clutch (not shown).

  The pickup roller 3 configured as described above is positioned above the frame 3a in the standby state, and when the drive shaft 4d rotates in the forward direction (A direction), the frame 3a acts on the drive shaft 4d as a fulcrum by the action of the torque limiter. Swings downward. This swinging is stopped when the pickup roller 3 is pressed against the uppermost layer portion of the document D deposited on the document placing portion 2, but the transmission system (pulley 4e, belt) is driven by the continued rotation of the drive shaft 4d. The pickup roller 3 rotates via 3d and the pulley 3c). In this way, while the drive shaft 4d is rotating forward, the pickup roller 3 rotates while being pressed against the uppermost layer portion of the stacked originals D, so that the original document D is sequentially fed out from the uppermost layer portion. When the drive shaft 4d is temporarily stopped and reversely rotated (counter A direction), the frame 3a swings upward by the action of the torque limiter, and is held stationary in a standby state by the subsequent stop of the drive shaft 4d.

  The separation roller 4a is driven and transmitted from the drive shaft 4d via a not-shown one-way clutch. Accordingly, the document D is fed out from the pickup roller 3 as described above by the forward rotation of the drive shaft 4d, and the fed document is introduced between the separation roller 4a and the separation pad 4b, one by one as described above. Separated and fed downstream. The document D fed from the separation roller 4a is registered by the registration roller 6 and conveyed further downstream. The peripheral speeds of the rollers 7, 8, 9, 17, and 10 after the registration roller 6 are as follows. The peripheral speed of the separation roller 4 a and the pickup roller 3 is set to be larger than the peripheral speed of the separation roller 4 a and the registration roller 6. Accordingly, when the leading edge of the document D fed from the separation roller 4a reaches the registration roller 6, a transport load (tensile force) is applied to the document due to the difference in peripheral speed. However, the separation roller 4a and the pickup roller 3 are not described above. Thus, a one-way clutch (not shown) is incorporated, whereby both rollers 4a and 3 are idly rotated, and the conveying load is alleviated.

  Pressure rollers 6a, 7a, 8a, 9a and 10a are respectively provided on the registration roller 6, the first to third conveying rollers 7, 8, 9 and the discharge roller 10, and the original is nipped and conveyed by these rollers. The The separation roller 4a and the pickup roller 3 and pressure rollers 6a and 7a associated with the separation roller 4a are attached to the inside of a jam access cover 18 pivotally attached to the hinge pin 18a so as to be opened and closed vertically. Accordingly, when a document jam occurs in the document conveyance path 5 up to the second conveyance roller 8, the jam access cover 18 is opened to connect the separation pad 4b, the registration roller 6, and the first conveyance roller 7. Can be easily removed.

  The second conveying roller 8, the third conveying roller 9, the pressure rollers 8a, 9a, the platen roller 17 and the discharge roller 10 which are paired with the second conveying roller 8, the machine frame 19 forming the machine frame of the platen cover including the ADF 1, and the same. It is attached to a cylindrical intermediate inner guide frame 20 fixed to the frame. Further, the contact image sensor 16 and the pressure roller 10a are attached to an intermediate frame 21 pivotally attached to the drive shaft 6b of the registration roller 6 so that the drive shaft 6b can be opened and closed vertically. When the jam occurs at the third conveyance roller 9 or later, if the intermediate frame 21 is opened after the jam access cover 18 is opened, the contact between the contact image sensor 16 and the platen roller 17, and the discharge roller 10 and the pressure roller 10a Since the nip relationship is released, the jammed document can be easily taken out at this portion.

  A document (paper) width detecting means (sensor) 22 and a document (paper) presence / absence sensor 23 are provided on the document tray 2 of the document placement unit 2B, and a lead sensor 24 is provided in the vicinity of the upstream side of the second conveying roller 8. , Respectively. In addition, although not shown, a registration sensor or the like is appropriately disposed in the vicinity of the upstream side of the registration roller 6. The read sensor 24 outputs a signal for controlling the operation of the second transport roller 8 and the reading / scanning device 13. When the read sensor 24 detects the leading edge of the fed document, the control means (not shown) Based on the detection signal, the second conveying roller 8 is operated to control the original to be conveyed to the reading point P, and the operation of the reading scanning device 13 is controlled in synchronization with the feeding of the original. The registration sensor also controls the operation of the registration roller 6 using the control means based on the detection signal.

  Next, details of the document tray 2 will be described. 2 is a perspective view of the document tray 2, FIG. 3 is a plan view thereof, FIG. 4 is a sectional view taken along line XX of FIG. 3, and FIG. 5 is a sectional view taken along line YY of FIG. The document tray 2 in the figure is configured by combining a plurality of synthetic resin molded product parts. Parts 2c and 2d of the bottom plate 2a and the top plate 2b are made of transparent resin so that the discharged original on the discharge tray 11 (see FIG. 1) can be seen through from above. The document tray 2 is attached to the machine frame 19 so as to be able to swing up and down with the hinges 2e and 2e at both ends on the front side as fulcrums, to take out the read document on the discharge tray 11 and to jam on the conveyance path 5. It is made convenient for taking out the manuscript. The hinge portion 2e is formed in a cylindrical shape, and lead wires 25 of sensors 22a, 22b, 23 described later installed within the thickness of the document tray 2 are inserted and led out, and connected to a control unit (not shown) in the apparatus. It is made so that.

  A fixed guide wall 2 f is formed on the upper surface of the document tray 2 so as to protrude from the right end when viewed in the document feeding direction (the Z direction in FIG. 3). D is set on the basis of the guide wall 2f with a so-called right reference. A mark 2g engraved on the top plate 2b indicates to the operator the setting position of the document. A marginal guide member 26 is installed on the upper left side (one side) of the document tray 2 so as to be slidable in the width direction (direction perpendicular to the Z direction). A guide groove 2h in the width direction is formed in the top plate 2b, and a guide protrusion piece 26a projecting from the lower surface of the offset guide member 26 is slidable in the guide groove 2h along the longitudinal direction. It is inserted so that it cannot be put out. As a result, the marginal guide member 26 can slide within a predetermined range in the width direction on the document tray 2.

  Two sensors 22a and 22b are provided along the width direction on the left side of the document tray 2 below the sliding area of the offset guide member 26, and the two sensors 22a and 22b are used to separate the document. A width detecting means 22 is configured. The top plate 2b is provided with a narrow groove 2i extending along a line connecting the two sensors 22a and 22b and parallel to the guide groove 2h. A shaped action piece 26b is loosely inserted into the narrow groove 2i. Each of the sensors 22a and 22b is a concave photosensor in which a light emitting portion and a light receiving portion are arranged to face each other, and the action piece 26b passes through a concave portion between the light emitting portion and the light receiving portion as the sliding guide member 26 slides. It is made to do. The sensors 22a and 22b are configured to output an ON signal when shielded by the action piece 26b, and the length of the action piece 26b in the sliding direction is set to a length that can straddle both the sensors 22a and 22b.

  The distance between the sensors 22a and 22b constituting the document width detecting means 22, the positional relationship along the width direction of the document tray 2, and the length along the sliding direction of the action piece 26b are set as follows. Note that the maximum document size that can be handled by the ADF 1 of this embodiment is A3 portrait, and the minimum document size is A5 landscape, where the portrait refers to the state in which the longitudinal direction of the document is along the Z direction, This means a state orthogonal to the Z direction.

That is, the distance between the sensors 22a and 22b, the positional relationship along the width direction of the document tray 2, and the length along the sliding direction of the action piece 26b are set so that all of the following patterns are satisfied.
(A) When the right side portion of the A3 vertical document or A4 horizontal document is set on the document tray 2 along the guide wall 2f, and the marginal guide member 26 is shifted to the left side portion of the document, the action piece 26b is detected by the sensor 26b. Only 22a is turned on (state shown in FIG. 4).
(B) When the right side portion of the B4 vertical document or B5 horizontal document is set on the document tray 2 along the guide wall 2f, and the offset guide member 26 is shifted to the left side portion of the document, both the action pieces 26b are The sensors 22a and 22b are turned on.
(C) When the right side portion of the A4 vertical document or the A5 horizontal document is set on the document tray 2 along the guide wall 2f, and the marginal guide member 26 is shifted to the left side portion of the document, the action piece 26b is detected by the sensor 26b. Only 22b is turned on.
(D) When the right side portion of the B5 vertical document or A5 vertical document is set on the document tray 2 along the guide wall 2f, and the offset guide member 26 is shifted to the left side portion of the document, the action piece 26b is The sensors 22a and 22b are not turned on.

  The positions of the sensors 22a and 22b along the Z direction are positions that are ½ of the maximum document length from the front end D1 of the document D placed on the document placement unit 2B, as shown in FIG. It is set to be within D2 (position of 210 mm when the maximum document is A3).

  A document presence / absence sensor is located upstream of the position D2 on the document tray 2 near the guide wall 2f (on the other side) and turned on for B5 portrait, A4 portrait, B4 portrait, and A3 portrait documents. 23 is installed. Accordingly, the document size cannot be determined only by the document width detection sensors 22a and 22b, but as shown in FIG. 6, the on / off state by the action piece 26b of the two document width detection sensors 22a and 22b and the document presence / absence sensor. According to the 23 on / off combination patterns, eight types of document sizes from A5 horizontal to A3 vertical can be determined.

  That is, in the case of (a), when the document presence sensor 23 is on, it is an A3 portrait document, and when the document presence sensor 23 is off, it is an A4 landscape document. In the case of (b), when the document presence sensor 23 is on, it is a B4 portrait document, and when the document presence sensor 23 is off, it is a B5 landscape document. Further, in the case of (c), when the document presence / absence sensor 23 is on, it is an A4 portrait document, and when the document presence / absence sensor 23 is off, it is an A5 landscape document. In the case of (d), when the document presence sensor 23 is on, it is a B5 portrait document, and when the document presence sensor 23 is off, it is an A5 portrait document. As described above, although the number of sensors is small, it is possible to determine the sizes of many types of documents, and it is possible to employ commercially available simple sensors. This greatly contributes to the reduction of the control sequence and the simplification of the control sequence.

  In FIG. 1, a sheet leading edge aligning shutter 27 that can be projected and retracted is provided on a document placing portion 2B between a pickup roller 3 and a separation roller 4a. The shutter 27 protrudes on the document placing portion 2 B in the standby state, and functions to align the front end of the document D set on the document tray 2 with the position of the D 1. A link mechanism (not shown) 28 that swings up and down in conjunction with the rotation of the link mechanism 28 is configured to appear and disappear on the document placement portion 2B when the link mechanism 28 swings up and down. Since the shutter 27 is mechanically interlocked with the registration roller 6 in this manner so that the shutter 27 appears and disappears on the document placing portion 2B, the operation mechanism of the shutter 27 can be provided without using expensive electrical components such as solenoids. It can be configured simply.

  In the above-described embodiment, an example in which the original is set on the original tray 2 with the so-called right reference is shown, but the left reference or the center reference may be used. In the case of the center reference, the other side portion with respect to the installation position of the document presence / absence sensor 23 means the position on the other side when viewed from the margin guide member 26. It may be in the vicinity of a center not included. In addition, although an example in ADF has been shown, it goes without saying that the present invention can also be applied to a manual paper feed tray in an image forming apparatus including a printer. Furthermore, although an example for double-sided reading has been shown as an ADF, it goes without saying that the present invention can also be applied to an ADF for single-sided reading. In addition, although the example which employ | adopted the photo sensor as a sensor was shown, the sensor which show | plays the same function like other limit switches etc. is employable.

It is a longitudinal cross-sectional view which shows the principal part of ADF and a scanning device. It is a perspective view of a document tray. It is the same top view. It is the XX sectional view taken on the line of FIG. It is the YY sectional view taken on the line of FIG. It is a figure which shows the relationship between a document size and the ON / OFF pattern of a sensor.

Explanation of symbols

1 ADF
2B Document placement section (paper placement section)
22 Document (paper) width detection sensor 23 Document (paper) presence / absence detection sensor 26 Wide margin guide member 26b Working piece D Document (paper)
D1 Front end position of document (paper) D2 Position of half of maximum document (paper) length from front end position

Claims (3)

A paper loading section for feeding paper, which includes a width-shifting guide member for narrowing the loaded paper, and is attached to the transport apparatus main body for transporting the paper so as to swing up and down with a hinge as a fulcrum. A paper size detection device in
A sheet width detecting means including a plurality of sensors spaced along the width direction is provided on one side portion in the width direction below the sheet placing portion, and the offset guide member has a width on the upper surface of the sheet placing portion. An operation piece having a length that can turn on the plurality of sensors simultaneously with the sliding operation is suspended from the back surface of the hinge portion, and the hinge portion is formed in a cylindrical shape. A sheet size detecting device, wherein lead wires of a plurality of sensors are inserted through a cylinder of the hinge portion and connected to a control portion in the main body of the conveying device.   A sheet presence / absence sensor is disposed upstream of the sheet width detecting means at the other side portion of the sheet placing section, and the sensors constituting the sheet width detecting means are placed on the sheet placing section. The sheet presence sensor is disposed at a position within ½ of the maximum sheet length from the front end position of the sheet, while the sheet presence sensor is located upstream from the position of ½ of the maximum sheet length from the front end of the sheet stacking unit. The paper size detection apparatus according to claim 1, wherein the paper size detection apparatus is disposed at a position of   A guide wall that serves as a reference for the setting position of the loaded paper is formed on one side edge of the plurality of side edges that are substantially parallel to the paper feeding direction of the paper loading section. 3. A paper size detection apparatus according to claim 1, further comprising an instruction section for instructing a set position in the vicinity of the guide wall.

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