Medium Conveyance Device

This is a continuation application of U.S. National Phase patent application Ser. No. 18/568,746, filed Dec. 8, 2023, which claims priority to and the benefit of International Application Number PCT/JP2021/022726, filed on Jun. 15, 2021, the entire content of which is incorporated herein by reference.

The present disclosure relates to a medium conveying apparatus and particularly relates to a medium conveying apparatus including a feed roller and a separation roller, a control method, and a control program.

In recent years, it is preferred that a medium conveying apparatus to convey and image a plurality of media while separating the media, such as a scanner, convey not only common plain paper copier (PPC) paper but also various types of media, such as thin paper, an envelope, and bound carbon paper. Thin paper is likely to include a wrinkle or a tear and further is soft, and therefore when thin paper is conveyed as a medium, jamming of the medium due to occurrence of buckling of the medium is likely to occur. When a medium composed of a plurality of sheets of paper, such as an envelope or carbon paper, is conveyed, jamming of the medium may occur due to exertion of a separating force on the medium. A medium conveying apparatus generally has a separation mode of separating and feeding a medium and a non-separation mode of feeding a medium without separation as a feed mode. For example, by setting the feed mode of the medium conveying apparatus to the non-separation mode, occurrence of jamming of a medium is prevented; however, a user feels troublesomeness of having to change the feed mode for each medium type, which impairs user convenience. Further, when a plurality of types of media are collectively set in a loading tray and are sequentially conveyed, it is difficult to change the feed mode for each medium type.

A paper feeding apparatus including a paper feeding means for separating and feeding paper one sheet, assuming that the paper has a convexly curled state is disclosed (see PTL 1). The paper feeding apparatus includes a turn guide to reverse separated and fed paper in a convex direction and a guiding member provided between the turn guide and the paper feeding means, to guide paper reversed in the convex direction while adjusting the paper to a curled state in a direction opposite to the convex direction.

A paper feeding-conveyance apparatus including a paper feeding means, a conveyance roller pair to convey paper fed from the paper feeding means, and a lower paper feeding guide installed between the paper feeding means and the conveyance roller pair is disclosed (see PTL 2). The lower paper feeding guide includes a part where paper guide surfaces on both ends are higher than a guide surface in the central part.

It is preferred that a medium conveying apparatus suitably feed a plurality of types of media.

An object of a medium conveying apparatus is to enable suitable feeding of a plurality of types of media.

According to some embodiments, a medium conveying apparatus includes a guide member including an opening or a notch and configured to form a conveyance surface of a medium, a feed roller located inside the opening or the notch and configured to feed the medium, a separation roller located to face the feed roller, and protruding parts located on left and right sides of the separation roller relative to a medium conveying direction. The guide member includes recessed parts positioned on left and right sides of the feed roller relative to the medium conveying direction. The protruding parts are located at positions facing the opening or the notch, or the recessed parts in such a way that the medium is conveyed between the protruding parts and the recessed parts. A tip of each of the protruding parts is positioned on the feed roller side of a nip part of the feed roller and the separation roller.

The medium conveying apparatus according to the present embodiment can suitably feed a plurality of types of media.

The object and advantages of the invention will be realized and attained by means of the elements and combinations, in particular, described in the claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory, and are not restrictive of the invention as claimed.

Hereinafter, a medium conveying apparatus, a control method and a control program according to an embodiment, will be described with reference to the drawings. However, it should be noted that the technical scope of the invention is not limited to these embodiments, and extends to the inventions described in the claims and their equivalents.

is a perspective view illustrating an example of a medium conveying apparatus configured as an image scanner. The medium conveying apparatusconveys and images a medium being a document. For example, a medium is paper, thin paper, thick paper, a card, carbon paper, or an envelope. Carbon paper is a medium acquired by binding a plurality of sheets of thin paper, such as non-carbon paper. The medium conveying apparatusmay be a facsimile, a copying machine, a multifunctional peripheral (MFP), etc. A conveyed medium may be an object being printed on, etc., instead of a document, and the medium conveying apparatusmay be a printer, etc.

The medium conveying apparatusincludes a lower housing, an upper housing, a loading tray, an ejection tray, an operation device, a display device, etc.

The upper housingis located at a position covering the top surface of the medium conveying apparatusand is engaged with the lower housingby a hinge in such a way as to be openable when, for example, a medium is stuck or cleaning of the inside of the medium conveying apparatusis performed.

The loading trayis engaged with the lower housingand places a medium to be fed and conveyed. The ejection trayis engaged with the upper housingand places an ejected medium. The ejection traymay be engaged with the lower housing.

The operation deviceincludes an input device such as a button, and an interface circuit acquiring a signal from the input device, accepts an input operation by a user, and outputs an operation signal based on the input operation by the user. The display deviceincludes a display including a liquid crystal, an organic electro-luminescence (EL), etc., and an interface circuit outputting image data to the display, and displays the image data on the display.

is a diagram for illustrating a conveyance path inside the medium conveying apparatus.

The conveyance path inside the medium conveying apparatusincludes a medium sensor, a feed roller, a separation roller, a first conveyance roller, a second conveyance roller, an imaging device, a first ejection roller, a second ejection roller, etc.

Each of the numbers of the feed roller, the separation roller, the first conveyance roller, the second conveyance roller, the first ejection roller, and/or the second ejection rolleris not limited to one and may be more than one. In that case, a plurality of feed rollers, separation rollers, first conveyance rollers, second conveyance rollers, first ejection rollers, and/or second ejection rollersare respectively spaced in the width direction Aperpendicular to a medium conveying direction.

The top surface of the lower housingforms a lower guideof the conveyance path of a medium, and the bottom surface of the upper housingforms an upper guideof the conveyance path of a medium. An arrow Ainindicates a medium conveying direction. Hereinafter, an upper stream refers to an upper stream in the medium conveying direction A, and a lower stream refers to a lower stream in the medium conveying direction A.

The medium sensoris located on the upstream side of the feed rollerand the separation roller. The medium sensorincludes a contact detection sensor and detects whether a medium is placed in the loading tray. The medium sensorgenerates and outputs a first medium signal the signal value of which varies between a state in which a medium is placed in the loading trayand a state in which a medium is not placed. The medium sensoris not limited to a contact detection sensor and any other sensor that can detect existence of a medium, such as a light detection sensor, may be used as the medium sensor.

The feed rolleris provided in the lower housing, sequentially separates media placed in the loading trayfrom the lower side, and feeds the media. The separation rolleris a so-called brake roller or retard roller, is provided in the upper housingto face the feed roller, and rotates in a direction opposite to the medium feeding direction. The feed rollermay be provided in the upper housing, the separation rollermay be provided in the lower housing, and the feed rollermay sequentially separates media placed in the loading trayfrom the upper side.

The first conveyance rollerand the second conveyance rollerare located on the downstream side of the feed rollerto face each other and convey a medium fed by the feed rollerand the separation rollerto the imaging device. The first conveyance rolleris provided in the lower housing, and the second conveyance rolleris provided in the upper housingand above the first conveyance roller.

The imaging deviceis located on the downstream side of the first conveyance rollerand images a medium conveyed by the first conveyance roller. The imaging deviceincludes a first imaging deviceand a second imaging devicethat are located to face each other with the medium conveyance path in between. The first imaging deviceincludes a line sensor based on a unity-magnification optical system type contact image sensor (CIS) including complementary metal oxide semiconductor- (CMOS-) based imaging elements linearly arranged in a main scanning direction. The first imaging devicefurther includes lenses each forming an image on an imaging element, and an A/D converter amplifying and analog-digital (A/D) converting an electric signal output from the imaging element. The first imaging devicegenerates an input image by imaging the front side of a conveyed medium in accordance with control from a processing circuit to be described later and outputs the generated image.

Similarly, the second imaging deviceincludes a line sensor based on a unity-magnification optical system type CIS including CMOS-based imaging elements linearly arranged in the main scanning direction. The second imaging devicefurther includes lenses each forming an image on an imaging element, and an A/D converter amplifying and analog-digital (A/D) converting an electric signal output from the imaging element. The second imaging devicegenerates an input image by imaging the back side of a conveyed medium in accordance with control from the processing circuit to be described later and outputs the generated image.

Only one of the first imaging deviceand the second imaging devicemay be located and only one side of a medium may be read in the medium conveying apparatus. Further, a line sensor based on a unity-magnification optical system type CIS including charge coupled device- (CCD-) based imaging elements may be used in place of the line sensor based on a unity-magnification optical system type CIS including CMOS-based imaging elements. Further, a reduction optical system type line sensor including CMOS-based or CCD-based imaging elements may be used.

The first ejection rollerand the second ejection rollerare located on the downstream side of the imaging deviceto face each other and eject a medium conveyed by the first conveyance rollerand the second conveyance rollerand imaged by the imaging deviceinto the ejection tray. The first ejection rolleris provided in the lower housing, and the second ejection rolleris provided in the upper housingand above the first ejection roller.

A medium placed in the loading trayis conveyed between the lower guideand the upper guidetoward the medium conveying direction Aby the feed rollerrotating in a direction of an arrow Ain, i.e., the medium feeding direction. As a feed mode, the medium conveying apparatushas a separation mode of separating and feeding a medium and a non-separation mode of feeding a medium without separation. The feed mode is set by a user by using the operation deviceor an information processing apparatus connected to the medium conveying apparatusby communication. When the feed mode is set to the separation mode, the separation rollerrotates in a direction of an arrow A, i.e., a direction opposite to the medium feeding direction at the time of medium feeding. When a plurality of media are placed in the loading tray, only a medium in contact with the feed rollerout of the medium placed in the loading trayis separated by working of the feed rollerand the separation roller. Consequently, conveyance of a medium other than the separated medium is restricted (prevention of multi feed). On the other hand, when the feed mode is set to the non-separation mode, the separation rollerrotates in a direction opposite to the arrow A, i.e., the medium feeding direction.

A medium is fed between the first conveyance rollerand the second conveyance rollerwhile being guided by the lower guideand the upper guide. The medium is fed between the first imaging deviceand the second imaging deviceby the first conveyance rollerand the second conveyance rollerrotating in directions of an arrow Aand an arrow A, respectively. The medium read by the imaging deviceis ejected into the ejection trayby the first ejection rollerand the second ejection rollerrotating in directions of an arrow Aand an arrow A, respectively.

is a schematic diagram for illustrating an example of a feeding mechanism in the medium conveying apparatus.

As illustrated in, the medium conveying apparatusincludes a guide memberand a feed armin addition to the feed rollerand the separation rolleras the feeding mechanism. In the example illustrated in, the medium conveying apparatusincludes two each of the feed rollersand the separation rollers.

The guide memberis a plate-shaped member, is provided on the top surface of the lower housingto form a conveyance surfaceof a medium and forms part of the lower guide. The guide memberhas an openingin the central part in the width direction Aperpendicular to the medium conveying direction, and the feed rolleris located in the opening

The conveyance surfaceof the guide memberincludes recessed partspositioned on the left and right sides of the feed rollerrelative to the medium conveying direction A. In the example illustrated in, the guide memberincludes two recessed parts. The recessed partis formed in such a way that the downstream side of the recessed partis inclined downward relative to a regionin the conveyance surfaceon the upstream side of the recessed part

The feed armis provided in the upper housingand is located on the upstream side of the separation rollerand in the neighborhood of the separation roller. The feed armincludes protruding partsextending from the upper housingside to the lower housingside, i.e., from the separation rollerside to the feed rollerside. The protruding partsare located on the left and right sides of the separation rollerrelative to the medium conveying direction A. In particular, the protruding partsare located at positions facing the openingof the guide member. In the example illustrated in, the feed armincludes two protruding parts

is a schematic diagram of the feeding mechanism viewed from above.

As illustrated in, the recessed partis provided in a region Rbeing in the central part and being outside the openingin the width direction A. Further, the recessed partis provided in a region Rincluding a nip part of the feed rollerand the separation rollerin the medium conveying direction A. While the upstream edge Pof the recessed partis positioned on the downstream side of the upstream edge of the feed rollerin the example illustrated in, the recessed partmay be provided in a region including the entire feed rollerand the entire separation rollerin the medium conveying direction A.

is a schematic diagram of the feeding mechanism viewed from the downstream side. In, display of parts other than the protruding partof the feed armis omitted for enhanced visual recognizability.

As illustrated in, a tip (lower end) of the protruding partis positioned on the feed rollerside of (below) the nip part of the feed rollerand the separation roller. A medium Mfed by the feed rollerand the separation rolleris conveyed between the protruding partof the feed armand the recessed partof the guide member.

The protruding partpushes down a region of the fed medium Mfacing the recessed partin the width direction Abelow than an inner region in contact with the feed rollerand the separation roller, and a region outside the recessed part. Consequently, the fed medium Mis wavily bent in the width direction A, and therefore the medium conveying apparatuscan stiffen the medium and can improve stiffness of the medium moving forward in the medium conveying direction A. Accordingly, even when soft thin paper is conveyed as a medium, the medium conveying apparatuscan suppress occurrence of buckling of the medium and suppress occurrence of jamming of the medium. Further, even when a medium composed of a plurality of sheets of paper, such as an envelope or carbon paper, is conveyed, the medium is provided with stiffness that can resist a separating force by the separation roller; and therefore the medium conveying apparatuscan suppress occurrence of jamming of the medium.

The protruding partpushes down the region in the medium Mfacing the recessed partin the width direction Abelow than the inner region in contact with the feed rollerand the separation roller. Consequently, the position in a height direction perpendicular to the conveyance surfacevaries between the inner region in contact with the feed rollerand the separation roller, and a region outside the inner region in the medium M. Therefore, when a plurality of media are collectively set in the loading trayand are fed, the frictional force between the medium placed between the feed rollerand the separation rolleris less likely to propagate outward in the width direction A. Accordingly, the medium conveying apparatuscan suppress occurrence of jamming of a special medium, such as thin paper, an envelope, or carbon paper, while improving separation performance for normal paper, such as PPC paper.

A region outside the recessed partin the width direction Ain the conveyance surfaceof the guide memberis positioned on the feed rollerside of (below) the nip part of the feed rollerand the separation roller. Assuming that the conveyance surfaceis located above the nip part, a medium is less likely to come in contact with the feed roller, and the medium conveyance force is reduced. By the conveyance surfacelocated below the nip part, the medium conveying apparatuscan satisfactorily stiffen a medium while suppressing reduction in medium conveyance force.

A gap is provided between the tip of the protruding partand the recessed partin the height direction perpendicular to the conveyance surface. Consequently, the medium is satisfactorily fed between the protruding partand the recessed partwithout being hampered by the protruding partand the recessed part

The distance W [mm] from the outer edge of the feed rollerto the outer edge of the recessed partis preferably set to satisfy Equation (1) below.

Wc denotes the length [mm] in the width direction Abetween both ends of the recessed parts, and Wr denotes the length [mm] in the width direction Abetween both ends of the feed rollers. The length Wr in the width direction Abetween both ends of the feed rollersis set to a length less than or equal to the minimum medium size width supported by the medium conveying apparatus(such as the length of the Asize in the widthwise direction).

The length Wc in the width direction Abetween both ends of the recessed partsis preferably set to satisfy Equation (2) below.

Wm denotes the minimum medium size width of a mainly fed medium and, for example, is set to 148 [mm] being the length of the Asize in the widthwise direction (the length of the Asize in the lengthwise direction). Consequently, both ends of the fed medium are placed outside the recessed partsin the width direction A, and the outer region of the medium is positioned above a region facing the recessed parts; and therefore the medium conveying apparatuscan satisfactorily bend the medium.