US20240174472A1

US20240174472A1 - Paper feeder and image forming apparatus

Info

Publication number: US20240174472A1
Application number: US18/385,194
Authority: US
Inventors: Hironori Ogasawara
Original assignee: Sharp Corp
Current assignee: Sharp Corp
Priority date: 2022-11-24
Filing date: 2023-10-30
Publication date: 2024-05-30
Also published as: CN118062622A; JP2024075829A

Abstract

A paper feeder includes a tray; a delivery roller; a paper feed roller; a guide member that guides the delivered sheet from the tray toward the paper feed roller; a lifting/lowering mechanism capable of changing a height of the tray; and a controller that executes paper feed processing, wherein the controller has: a setting device that accepts job settings including settings related to plural types of sheets, the plural types of sheets including a first sheet and a second sheet that is thicker than the first sheet; and a lifting/lowering controller that controls the lifting/lowering mechanism such that, in the case where the second sheet is set, before initiation of the paper feed processing, a height of the tray with respect to the guide member becomes higher by a first predetermined magnitude than that in the case where the first sheet is set.

Description

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Application JP2022-187013, the content of which is hereby incorporated by reference into this application.

BACKGROUND OF THE INVENTION

Field of the Invention

The present disclosure relates to a paper feeder and an image forming apparatus.

Description of the Background Art

Conventionally, an image forming apparatus such as a copier or a printer is provided with a paper feeder that feeds a sheet to an image forming device, an image reader, or the like. The paper feeder includes, for example: a tray in which the sheets are placed; a lifting/lowering mechanism that lifts/lowers the tray; and a paper feed unit that separates and feeds the sheets placed in the tray one by one.
For example, a printer that includes a paper feed roller as the paper feed unit is disclosed. In the conventional printer, the paper feed roller rotates in a state where the tray is lifted and recording sheets are pressed against the paper feed roller. In this way, the recording sheets are separated and fed one by one.
The conventional printer is also provided with, as trays; a first paper tray that can accommodate the recording sheet including thick paper such as a postcard; and a second paper tray that can accommodate the recording sheet including thinner paper, such as copy paper, than the postcard.
In addition to the above-described paper feed unit, the paper feed unit may include, for example: a delivery roller that delivers an uppermost sheet placed in the tray; a paper feed roller that feeds the delivered sheet to a conveyance path; and a guide member that guides the sheet delivered by the delivery roller toward the paper feed roller. In general, the guide member is formed of a rubber material having a high friction coefficient. In this way, the guide member acts as resistance against the sheet to be delivered, and thus a sheet separation error (double feed) can be suppressed.
However, in the case where the above-described paper feeder is configured to feed plural types of sheets, the number of the trays that corresponds to the number of the types of sheets is required, which enlarges an apparatus. In addition, in the case where the above-described paper feeder is configured to feed the different types of sheets from the same tray, the following problems occur. For example, in the case where the type of the sheet is plain paper, the guide member acts as resistance against the plain paper to be delivered. Thus, it is possible to deliver the plain paper toward the paper feed roller while suppressing the sheet separation error (double feed). However, in the case where the type of the sheet is stiff paper such as the thick paper, the guide member acts as the large resistance against the thick paper to be delivered. Thus, a slippage of the delivery roller is increased, which may cause a pickup error.
In view of the above, an object of an aspect of the present disclosure is to provide a paper feeder and an image forming apparatus capable of reducing paper feed failures such as a sheet separation error (double feed) and a sheet pickup error even in the case where different types of sheets are fed from the same tray, for example.

SUMMARY OF THE INVENTION

A paper feeder according to an aspect of the present disclosure includes: a tray in which a sheet can be placed; a delivery roller that delivers the sheet placed in the tray; a paper feed roller that feeds the delivered sheet to a conveyance path; a guide member that guides the delivered sheet from the tray toward the paper feed roller and is provided to be inclined upward toward the paper feed roller; a lifting/lowering mechanism capable of changing a height of the tray; and a controller that executes paper feed processing to feed the delivered sheet from the tray to the conveyance path by causing the paper feed roller to rotate. The controller has: a setting device that accepts job settings including settings related to plural types of sheets, the plural types of sheets including a first sheet and a second sheet that is thicker than the first sheet; and a lifting/lowering controller that controls the lifting/lowering mechanism such that, in the case where the second sheet is set, before initiation of the paper feed processing, a height of the tray with respect to the guide member becomes higher by a first predetermined magnitude than that in the case where the first sheet is set.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view illustrating an image forming apparatus;

FIG. 2 is a perspective view illustrating a document conveyor;

FIG. 3 is a cross-sectional view illustrating the document conveyor;

FIG. 4 is a cross-sectional view of the document conveyor illustrating a lifting/lowering mechanism;

FIG. 5 is a perspective view illustrating a paper feed unit;

FIG. 6A is a schematic side view of the paper feed unit in a state where an upper limit sensor does not detect a detection piece;

FIG. 6B is a schematic side view of the paper feed unit in a state where the upper limit sensor detects the detection piece;

FIG. 7 is a block diagram illustrating a hardware configuration of the image forming apparatus;

FIG. 8 is an acceptance screen for an operation input related to plural types of sheets displayed on an operation panel;

FIG. 9A is a cross-sectional view of the document conveyor illustrating an initial position of a left tray;

FIG. 9B is a cross-sectional view of the document conveyor illustrating a height position of the left tray in a plain paper mode;

FIG. 9C is a cross-sectional view of the document conveyor illustrating a height position of the left tray in a thick paper mode;

FIG. 10 is a schematic side view of the document conveyor in which the height position of the left tray in the plain paper mode is compared to the height position of the left tray in the thick paper mode;

FIG. 11 illustrates an example of a flow related to lifting/lowering control before initiation of paper feed processing by a controller;

FIG. 12 illustrates an example of a flow related to lifting/lowering correction control during the paper feed processing by the controller;

FIG. 13 illustrates an example of a flow related to the lifting/lowering correction control by the controller at the time when a pickup error is determined; and

FIG. 14 illustrates an example of a flow related to a first modification example of the lifting/lowering correction control during the paper feed processing by the controller.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description will hereinafter be made on an embodiment of the present disclosure with reference to the drawings. For the drawings, the same or equivalent elements will be denoted by the same reference sign, and an overlapping description thereon will not be made.
A description will hereinafter be made on an image forming apparatus 1 according to an embodiment of the present disclosure with reference to FIG. 1 . FIG. 1 is a schematic cross-sectional view illustrating the image forming apparatus 1. In the following description, a printer 10 (a paper feeder 110) side is defined as a lower side, a document conveyor 30 side is defined as an upper side, a discharge tray 360 side of the document conveyor 30 is defined as a right side, and a conveyance path 330 side of the document conveyor 30 is defined as a left side.
The image forming apparatus 1 is a multifunction peripheral having a copy function, a printer function, a scanner function, a facsimile function, and the like, for example. The image forming apparatus 1 transmits image data, which is read by an image reader 20, to the outside, and forms an image of the image data of a read document or the image data received from the outside on a sheet of paper in a single color or multiple colors.
The image forming apparatus 1 includes the printer 10, the image reader 20, the document conveyor 30, and an operation panel 40 (see FIG. 7 ). The printer 10 forms the image on a recording medium such as a sheet. The image reader 20 is arranged above the printer 10 and reads the document. The document conveyor 30 is arranged on the upper side of the image reader 20 and sequentially transports the document placed in a tray onto a document placement table of the image reader 20.
A description will hereinafter be made on the printer 10 with reference to FIG. 1 .
The printer 10 includes the paper feeder 110, a conveyance roller pair 120, a resist roller pair 130, an image forming device 140, a discharge roller pair 150, and a discharge tray 160. In the image forming apparatus 1, a conveyance path R1 is formed to convey the sheet, which is fed from the paper feeder 110, to the discharge tray 160 through the conveyance roller pair 120, the resist roller pair 130, the image forming device 140, and the discharge roller pair 150.
The paper feeder 110 includes: a cassette 111 that is arranged below the image forming device 140; a paper feed tray 112 in which the sheets are stacked; a pickup roller 113 that is provided on the upper side of an end of the paper feed tray 112; a paper feed roller 114 that is arranged on a downstream side of the pickup roller 113 in a sheet conveyance direction; and a separation roller 115 that is pressed against the paper feed roller 114.
In the paper feeder 110, the sheet is delivered from the paper feed tray 112 to the paper feed roller 114 by the pickup roller 113, the sheet is separated one by one through a position between the paper feed roller 114 and the separation roller 115, and then the sheet is conveyed to the conveyance path R1 by the conveyance roller pair 120.
The resist roller pair 130 feeds the sheet at timing of toner image formation. The resist roller pair 130 temporarily stops the sheet to align a leading edge of the sheet, and thereafter conveys the sheet at timing to transfer a toner image in a nip area between an intermediate transfer belt 146 a and a transfer roller 147, both of which will be described below.
The image forming device 140 includes a photoreceptor drum 141, an electrifier 142, an exposure unit 143, a developing unit 144, a cleaner unit 145, an intermediate transfer belt unit 146, a transfer roller 147, a fusing unit 148, and the like.
The image data that is handled by the image forming device 140 corresponds to a color image in four colors that are black (K), cyan (C), magenta (M), and yellow (Y). Accordingly, four each of the photoreceptor drums 141, the electrifiers 142, the developing units 144, and the cleaner units 145 are provided to form four types of latent images corresponding to four respective colors, and thereby constitute four image forming stations. Four toner cartridges are provided such that toner corresponding to the respective image forming stations can be supplied.
The photoreceptor drum 141 is an electrostatic latent image carrier in which a photosensitive layer is formed on a surface of a cylindrical base body having conductivity. The electrifier 142 charges a surface of the photoreceptor drum 141 to a predetermined potential. The exposure unit 143 is a laser scanning unit that includes a laser emitter, a reflecting mirror, and the like. The exposure unit 143 exposes the charged surface of the photoreceptor drum 141 to light, and thereby forms an electrostatic latent image, which corresponds to the image data, on the surface of the photoreceptor drum 141. The developing unit 144 visualizes the electrostatic latent image, which is formed on the surface of the photoreceptor drum 141, with the four colors of the toner. The cleaner unit 145 removes and collects the residual toner on the surface of the photoreceptor drum 141 after the development and the image transfer.
The intermediate transfer belt unit 146 includes the intermediate transfer belt 146 a, a drive roller 146 b, a driven roller 146 c, four intermediate transfer rollers 146 d, and the like. The intermediate transfer belt unit 146 arranged above the photoreceptor drum 141. The intermediate transfer belt 146 a is provided to contact each of the photoreceptor drums 141. Each of the intermediate transfer rollers 146 d is used to sequentially superpose and transfer the toner image in the respective color, which is formed on the corresponding photoreceptor drum 141, on the intermediate transfer belt 146 a. In this way, the toner image is formed on the intermediate transfer belt 146 a.
The transfer roller 147 is arranged near the drive roller 146 b in the conveyance path R1. When the sheet passes through the nip area between the transfer roller 147 and the intermediate transfer belt 146 a, the toner image, which is formed on the intermediate transfer belt 146 a, is transferred onto the sheet.
The fusing unit 148 includes a heat roller 148 a and a pressure roller 148 b. The fusing unit 148 is arranged above the transfer roller 147, in other words, on the downstream side in the sheet conveyance direction in the conveyance path R1. When the sheet passes through the nip area between the heat roller 148 a and the pressure roller 148 b, the toner image, which has been transferred onto the sheet, is melted, mixed, and pressed, and thereby the toner image is thermally fused to the sheet. The sheet to which the toner image is fused is conveyed to the discharge tray 160 by the discharge roller pair 150.
In the case where the image is formed not only on a front side of the sheet but also on a back side of the sheet, the sheet is conveyed in a reverse direction to a reversing path R2 from the discharge roller pair 150. In the reversing path R2, the front and back sides of the sheet are reversed through a reversing roller pair 170, and the sheet is guided again to the resist roller pair 130. Thereafter, the sheet, whose back side is also formed with the image in the same manner as on the front side, is conveyed to the discharge tray 160.
Next, a description will be made on the image reader 20 with reference to FIG. 1 .
The image reader 20 reads the image formed on the sheet and generates the image data. Feed reading contact glass 21 in the form of a transparent plate is provided to a left portion of an upper surface of the image reader 20. Placement reading contact glass 22 in the form of the transparent plate is provided in a portion of the upper surface of the image reader 20, and the portion is located on the right side of the feed reading contact glass 21. The document conveyor 30 is attached in a freely openable/closable manner above the image reader 20 the document placing table 16 via a hinge or the like. When the document conveyor 30 is opened via the hinge or the like, the upper surface of the image reader 20 is exposed, and thus the document can be placed on the placement reading contact glass 22 by hand. The operation panel 40 is provided on the left side of the upper surface of the image reader 20. The operation panel 40 includes a display panel, a touch panel, hard keys, and the like.
The image reader 20 further includes a light source, plural mirrors, an imaging lens, a line sensor, and so on. The image reader 20 exposes the surface of the sheet to the light from the light source and guides reflected light from the surface of the sheet to the imaging lens by the plural mirrors. Then, the reflected light is imaged on a light receiving element of the line sensor by the imaging lens. The line sensor detects luminance and chromaticity of the reflected light that is imaged on the light receiving element, and the image data, which is based on an image on the surface of the sheet, is generated. A CCD, a CIS, or the like is used as the line sensor.
Next, a description will be made on the document conveyor 30 with reference to FIG. 1 to FIG. 3 . FIG. 2 is a perspective view illustrating the document conveyor 30. FIG. 3 is a cross-sectional view illustrating the document conveyor 30. The document conveyor 30 conveys the document placed in a paper feed tray 310, which will be described below, toward the feed reading contact glass 21. The document conveyor 30 functions as a cover that holds the document from above.
As illustrated in FIG. 2 and FIG. 3 , the document conveyor 30 includes a main body 31 having various structures. The main body 31 includes: the paper feed tray 310 in which the sheet can be placed; a paper feed unit 320 that feeds the sheet on the paper feed tray 310; the conveyance path 330 that conveys the fed sheet; plural conveyance roller pairs 340, each of which conveys the sheet to the conveyance path 330; a discharge roller pair 350; the discharge tray 360; and a lifting/lowering mechanism 370 (see FIG. 4 ) that lifts/lowers the paper feed tray 310.
The paper feed tray 310 has a shape in which plural sheets of the document can be stacked and placed. The sheets of the document placed in the paper feed tray 310 are fed one by one to the conveyance path 330 by the paper feed unit 320.
The paper feed tray 310 is aligned with the discharge tray 360 in a height direction. More specifically, the paper feed tray 310 is arranged in an upper stage, and the discharge tray 360 is arranged in a lower stage.
The paper feed tray 310 includes a left tray 311 and a right tray 312. The left tray 311 and the right tray 312 are aligned in a right-left direction. The left tray 311 can be lifted/lowered by the lifting/lowering mechanism 370. The left tray 311 can rotate in an up-down direction about a rotation fulcrum F that is located at a right end. A specific configuration of the lifting/lowering mechanism 370 will be described below.
The right tray 312 is fixed to the main body 31. The right tray 312 is inclined to be lowered from the right side toward the left side. That is, the right tray 312 is inclined such that, when the document is placed in the right tray 312, the document slides and moves toward the left tray 311 side by own weight. Only the left tray 311 in the paper feed tray 310 can be lifted/lowered. However, the paper feed tray 310 is not limited thereto, and the left tray 311 and the right tray 312 may be lifted/lowered as a whole.
The left tray 311 includes two document guides 311 a for aligning side edges of the document in a width direction (a front-rear direction). The two document guides 311 a are provided to oppose each other in the width direction in a manner to be movable in the width direction on the left tray 311. In this way, when the document is held between the two document guides 311 a, and the two document guides 311 a are moved to positions at which the document guides 311 a contact the side edges of the document in the width direction, the document can be positioned in the width direction.
As illustrated in FIG. 3 , the main body 31 is provided to oppose a left end (a tip) of the left tray 311 and is provided with a wall surface 31 a that is raised upward. The wall surface 31 a has a curved shape along a rotation locus of the left tray 311. When the leading edge of the document abuts the wall surface 31 a, a document conveyance direction can be positioned.
An upper surface of the main body 31 is provided with a cover 31 b that is attached in the freely openable/closable manner to the main body 31. The cover 31 b is provided with a grip 31 c for opening/closing the cover 31 b with respect to the main body 31. When a user grips the grip 31 c, a locked state between the main body 31 and the cover 31 b is canceled, and the cover 31 b can be moved in an opening direction.
An accommodating portion 31 d that accommodates various drive sources and power transmission members is provided to a rear portion of the inside of the main body 31. For example, a paper feed motor 322 b (see FIG. 7 ), which will be described below, a lifting/lowering motor 371 (see FIG. 7 ) constituting the lifting/lowering mechanism 370, which will be described below, and the like are accommodated as the drive sources in the accommodating portion 31 d. A gear constituting the lifting/lowering mechanism 370, which will be described below, and the like are accommodated as the power transmission members in the accommodating portion 31 d.
A description will be made on the lifting/lowering mechanism 370 that lifts/lowers the left tray 311 with reference to FIG. 4 . FIG. 4 is a cross-sectional view of the document conveyor 30 illustrating the lifting/lowering mechanism 370. In FIG. 4 , members other than the lifting/lowering mechanism 370, the paper feed tray 310, and the paper feed unit 320 are not illustrated.
The lifting/lowering mechanism 370 includes: the lifting/lowering motor 371; a first gear 372 that meshes with an output shaft of the lifting/lowering motor 371; a second gear 373 that meshes with the first gear 372; a third gear 374 that meshes with the second gear 373; a sector gear 375 that meshes with the third gear 374; a rotary shaft 376 that is fixed to a rotation center of the sector gear 375 and extends along the front-rear direction; and a pair of arms 377 that extends to the left from the rotary shaft 376 and supports a left portion of the left tray 311 from below.
In the configuration described so far, when the lifting/lowering motor 371 is driven, drive power of the lifting/lowering motor 371 is transmitted to the sector gear 375 via the first gear 372, the second gear 373, and the third gear 374, and causes the sector gear 375 to rotate. Along with the rotation of the sector gear 375, the pair of arms 377 rotates in the up-down direction together with the rotary shaft 376. For example, when left ends of the paired arms 377 rotate upward, the left end of the left tray 311 rotates upward about the rotation fulcrum F, and the left tray 311 is then lifted. Meanwhile, when the left ends of the paired arms 377 rotate downward, the left end of the left tray 311 rotates downward about the rotation fulcrum F, and the left tray 311 is then lowered.
A description will be made on the paper feed unit 320 with reference to FIG. 5 , FIG. 6A, and FIG. 6B. FIG. 5 is a perspective view illustrating the paper feed unit 320. In FIG. 5 , some of the members of the paper feed unit 320 are not illustrated. FIG. 6A is a schematic side view of the paper feed unit 320 in a state where an upper limit sensor 32, which will be described below, does not detect a detection piece 325 d. FIG. 6B is a schematic side view of the paper feed unit 320 in a state where the upper limit sensor 32, which will be described below, detects the detection piece 325 d.
As illustrated in FIG. 5 , FIG. 6A, and FIG. 6B, the paper feed unit 320 mainly includes: a pickup roller 321; a paper feed roller 322; a cover member 323 that integrally covers the pickup roller 321 and the paper feed roller 322; a separation roller 324; a pressing arm 325 that presses the cover member 323 from above; and a guide member 326 that guides the sheet delivered from the pickup roller 321 toward the paper feed roller 322.
The pickup roller 321 delivers the sheet in the left tray 311. The pickup roller 321 is provided with a rotary shaft 321 a that extends in the front-rear direction. The rotary shaft 321 a is rotatably supported by the cover member 323.
The paper feed roller 322 feeds the sheet, which has been delivered by the pickup roller 321, to the conveyance path 330. The paper feed roller 322 is arranged on the downstream side (the left side) of the pickup roller 321 in the conveyance direction. The paper feed roller 322 is provided with a rotary shaft 322 a that extends in the front-rear direction. The rotary shaft 322 a penetrates the cover member 323 and is rotatably supported by the main body 31. The paper feed motor 322 b (see FIG. 7 ) is connected to one end of the rotary shaft 322 a. The rotary shaft 322 a and the paper feed roller 322 are connected via a paper feed clutch 322 c (see FIG. 7 ). Even when the paper feed roller 322 rotates while the paper feed motor 322 b is not driven, the rotary shaft 322 a does not rotate.
The cover member 323 covers the pickup roller 321 and the paper feed roller 322 from above. A lower portion of the cover member 323 is opened, and a lower portion of the pickup roller 321 and a lower portion of the paper feed roller 322 are exposed. In the cover member 323, the pickup roller 321 and the paper feed roller 322 are coupled to each other via a belt. When the paper feed motor 322 b is driven, the pickup roller 321 rotates together with the paper feed roller 322. Thus, the uppermost sheet in the left tray 311 can be delivered in the conveyance direction.
A right portion (the pickup roller 321 side) of the cover member 323 is swingable in the up-down direction with the rotary shaft 322 a of the paper feed roller 322 being a fulcrum. An upper limit and a lower limit of a swing range of the cover member 323 are defined by various restriction members provided to the main body 31.
The separation roller 324 is provided to oppose the paper feed roller 322 and is pressed against the paper feed roller 322. The separation roller 324 applies a conveyance force to the sheet in a reverse direction from the paper feed roller 322.
The pressing arm 325 presses a swinging end (a right end) of the cover member 323 from above. That is, the pressing arm 325 presses the pickup roller 321 from above via the cover member 323. The pressing arm 325 has: a pair of extending portions 325 a opposing each other in the front-rear direction; a pressing portion 325 b that connects right ends of the paired extending portions 325 a; and an urging member 325 c (see FIG. 6A) that urges the pressing portion 325 b downward.
The pair of extending portions 325 a is provided to the main body 31 in a manner to hold the pickup roller 321 therebetween. Right portions of the paired extending portions 325 a are swingable in the up-down direction with left ends thereof being fulcrums. The pressing portion 325 b is located on an upper side of the swinging end (the right end) of the cover member 323. The urging member 325 c is provided to one extending portion 325 a of the paired extending portions 325 a and urges the right end of the extending portion 325 a downward. That is, the urging member 325 c urges the pressing portion 325 b downward.
The main body 31 is provided with the upper limit sensor 32 that detects an upper limit position of the left tray 311 at the time of lifting the left tray 311. The upper limit sensor 32 is an optical sensor, for example, emits light from a light emitter 32 a toward a light receiver 32 b, and detects an object depending on whether the light has reached the light receiver 32 b. The upper limit sensor 32 detects the upper limit position of the left tray 311 by detecting the detection piece 325 d provided to the pressing arm 325, which will be described below. Here, the upper limit position is the upper limit position of the left tray 311 in the case where a first sheet (plain paper), which will be described below, having a reference thickness is used.
In the pressing arm 325, the detection piece 325 d is provided to the other extending portion 325 a of the paired extending portions 325 a. The detection piece 325 d is provided to be projected outward in the front-rear direction from the other extending portion 325 a.
A description will hereinafter be made on detection of the detection piece 325 d by the upper limit sensor 32 with reference to FIG. 6A and FIG. 6B.
In the state illustrated in 6A, the left tray 311 does not abut the pickup roller 321, and the pressing arm 325 presses the pickup roller 321 from above by an urging force of the urging member 325 c. In this state, the detection piece 325 d of the pressing arm 325 is located below the upper limit sensor 32. That is, the upper limit sensor 32 is in a state of not detecting the detection piece 325 d. When the left tray 311 is lifted from the state illustrated in FIG. 6A, the uppermost sheet of a sheet bundle M in the left tray 311 abuts the pickup roller 321, and presses the pressing arm 325 and the pickup roller 321 upward against the urging force of the urging member 325 c. As a result, the detection piece 325 d moves upward, and, as illustrated in FIG. 6B, the upper limit sensor 32 detects the detection piece 325 d. In the case where the first sheet (the plain paper), which will be described below, is used, and the upper limit sensor 32 has detected the detection piece 325 d, the left tray 311 stops lifted, and paper feed processing, which will be described below, is initiated.
As illustrated in FIG. 6 , the guide member 326 guides the sheet, which is delivered from the left tray 311, toward the paper feed roller 322. The guide member 326 is provided between the pickup roller 321 and the paper feed roller 322. More specifically, the guide member 326 is provided at an upper end of the wall surface 31 a in the main body 31, for example, and is provided to be inclined upward toward the paper feed roller 322. A left end of the guide member 326 is inclined upward toward a nip area between the paper feed roller 322 and the separation roller 324.
The guide member 326 is a plate-shaped member, for example. A guide surface 326 a that is inclined upward is provided on an upper surface of the guide member 326. The guide member 326 is formed of an elastic member that is made of a rubber material, such as silicone or urethane, with a high friction coefficient (for example, 1.2 to 1.7).
In the configuration described so far, when the uppermost sheet in the left tray 311 is delivered by the pickup roller 321, the leading edge of the uppermost sheet abuts the guide surface 326 a of the guide member 326 and is guided to the paper feed roller 322 along the guide surface 326 a. In addition, since the guide member 326 is formed of the rubber material having the high friction coefficient, the guide member 326 serves as a resistance against the sheet that is delivered toward the paper feed roller 322, and it is thus possible to effectively suppress a sheet separation error (double feed).
The main body 31 is provided with a lower limit sensor 33 (see FIG. 3 ) that detects a lower limit position at the time when the left tray 311 is lowered. The lower limit sensor 33 is an optical sensor, for example. Since the lower limit sensor 33 has the same configuration as the upper limit sensor 32, a description thereon will not be made. In addition, the lower limit sensor 33 detects the lower limit position of the left tray 311 by detecting the detection piece (not illustrated) that is provided to the left tray 311. The lower limit position herein is an initial position P1 of the left tray 311, which will be described below.
The main body 31 is provided with a document detection sensor 34 (see FIG. 3 ) that detects placement of the document in the left tray 311. The document detection sensor 34 is an optical sensor that includes a light emitter and a light receiver, for example. The document detection sensor 34 is provided in an upper portion of the main body 31, more specifically, a portion opposing a front end of the left tray 311. For example, when the document is not placed in the left tray 311, light from the light emitter to the light receiver in the document detection sensor 34 is blocked.
The main body 31 is provided with a paper passing sensor 35 (see FIG. 3 ) that detects the sheet fed by the paper feed unit 320. The paper passing sensor 35 is an optical sensor that includes a light emitter and a light receiver, for example. The paper passing sensor 35 is arranged on a downstream side of the paper feed unit 320 in the conveyance direction. The paper passing sensor 35 detects the leading edge of the sheet that is conveyed to the conveyance path 330 via the paper feed unit 320, and thereby detects that the sheet has been fed to the conveyance path 330 by the paper feed unit 320.
In the configuration described so far, when the left tray 311 is lifted by the lifting/lowering mechanism 370, the uppermost sheet that is placed in the left tray 311 abuts the pickup roller 321. Then, when the paper feed motor 322 b is driven in a state where the uppermost sheet placed in the left tray 311 abuts the pickup roller 321, the uppermost sheet on the left tray 311 is delivered in the left direction by the pickup roller 321. The leading edge of the sheet that is delivered leftward by the pickup roller 321 is delivered to the paper feed roller 322 through the guide member 326. The sheet that is delivered to the paper feed roller 322 via the guide member 326 is fed to the conveyance path 330 through the nip area between the paper feed roller 322 and the separation roller 324. The sheet that is conveyed to the conveyance path 330 passes through the feed reading contact glass 21 of the image reader 20 by the plural conveyance roller pairs 340, and is then discharged to the discharge tray 360 by the discharge roller pair 350.
A description will be made on a hardware configuration of the image forming apparatus 1 with reference to FIG. 7 . FIG. 7 is a block diagram illustrating the hardware configuration of the image forming apparatus 1.
The image forming apparatus 1 includes a controller 200, a storage 210, a communicator 220, the printer 10, the image reader 20, the document conveyor 30, the operation panel 40, and the like.
The controller 200 controls the image forming apparatus 1. The controller 200 implements various functions by reading and executing various programs that are stored in the storage 210. The controller 200 includes one or plural central processing units (CPUs) and the like, for example.
The storage 210 stores the various programs, which are necessary for operation of the image forming apparatus 1, and various types of data. The storage 210 is a storage device such as a solid state drive (SSD) as semiconductor memory or a hard disk drive (HDD).
The communicator 220 controls wireless communication of the various types of the data with an external terminal such as a computer. The communicator 220 is not limited to one that controls the wireless communication, and may be one that controls wired communication.
The controller 200 is connected to the storage 210, the communicator 220, the printer 10, the image reader 20, the paper feed motor 322 b constituting the document conveyor 30, the paper feed clutch 322 c, the lifting/lowering motor 371, the upper limit sensor 32, the lower limit sensor 33, the document detection sensor 34, the paper passing sensor 35, and the like.
The controller 200 controls the paper feed motor 322 b to rotate the pickup roller 321 and the paper feed roller 322, and can thereby execute the paper feed processing to feed the sheet, which is delivered from the left tray 311, to the conveyance path 330.
The controller 200 includes a setting device 201, a lifting/lowering controller 202, a determination device 203, and a counter 204.
The setting device 201 makes settings related to various jobs according to an operation input that is accepted on the operation panel 40. The various jobs include a print job, an image reading job, and the like. For example, the setting device 201 can make settings related to plural types of sheets for an image reading job. The setting device 201 can set, as the plural types of sheets, the first sheet (the plain paper), a second sheet (thick paper), a third sheet (thin paper), and a fourth sheet (thick paper for a business card), for example.
The first sheet is the plain paper having the reference thickness. The second sheet is the thick paper that is thicker than the plain paper. The third sheet is the thin paper that is thinner than the plain paper. The fourth sheet is the thick paper for the business card that is thicker than the plain paper and is smaller in size than the plain paper.
The setting device 201 makes the settings related to the plural types of sheets for the image reading job. However, the setting device 201 is not limited thereto, and may make settings related to the plural types of sheets for the print job.
A description will be made on an acceptance screen for an operation input related to the plural types of sheets with reference to FIG. 8 . FIG. 8 illustrates the acceptance screen for the operation input related to plural types of sheets that is displayed on the operation panel 40.
As illustrated in FIG. 8 , on the acceptance screen, in addition to a sentence “PLEASE SELECT DOCUMENT TYPE”, a button 41 corresponding to “PLAIN PAPER”, a button 42 corresponding to “THICK PAPER”, a button 43 corresponding to “THIN PAPER”, and a button 44 corresponding to “BUSINESS CARD” are displayed. When the user touches a desired button, the setting device 201 sets the sheet type corresponding to the button.
For example, when the button 41 corresponding to “PLAIN PAPER” is touched, the setting device 201 sets a plain paper mode. When the button 42 corresponding to “THICK PAPER” is touched, the setting device 201 sets a thick paper mode. When the button 43 corresponding to “THIN PAPER” is touched, the setting device 201 sets a thin paper mode. When the button 44 corresponding to “BUSINESS CARD” is touched, the setting device 201 sets a business card mode.
The lifting/lowering controller 202 controls the lifting/lowering motor 371 on the basis of detection results of the various sensors. A description will hereinafter be made on lifting/lowering control for the left tray 311 executed before initiation of the paper feed processing by the lifting/lowering controller 202.
A description will be made on the lifting/lowering control for the left tray 311 executed before the initiation of the paper feed processing with reference to FIG. 9A, FIG. 9B, FIG. 9C, and FIG. 10 . FIG. 9A is a cross-sectional view of the document conveyor 30 illustrating the initial position P1 of the left tray 311. FIG. 9B is a cross-sectional view of the document conveyor 30 illustrating a height position P2 of the left tray 311 in the plain paper mode. FIG. 9C is a cross-sectional view of the document conveyor 30 illustrating a height position P3 of the left tray 311 in the thick paper mode. FIG. 10 is a schematic side view of the document conveyor 30 in which the height position P2 of the left tray 311 in the plain paper mode is compared to the height position P3 of the left tray 311 in the thick paper mode. In FIG. 9A, FIG. 9B, FIG. 9C, and FIG. 10 , members other than the paper feed tray 310 and the paper feed unit 320 of the document conveyor 30 are not illustrated.
As illustrated in FIG. 9A, the left tray 311 is located at the initial position P1 before the initiation of the paper feed processing.
First, a description will be made on the lifting/lowering control for the left tray 311 in the plain paper mode with reference to FIG. 9B and FIG. 10 . As illustrated in FIG. 9B, in the plain paper mode, the lifting/lowering controller 202 controls the lifting/lowering motor 371 in a manner to lift the left tray 311 from the initial position P1 to the height position P2 at which the upper limit sensor 32 detects the detection piece 325 d.
The height position P2 at which the upper limit sensor 32 detects the detection piece 325 d is a height position that is set on the basis of the first sheet (the plain paper) having the reference thickness. The height position P2 is such a height position that, when the paper feed processing is initiated, and the uppermost sheet is delivered by the pickup roller 321 from the sheet bundle M placed in the left tray 311, the leading edge of the sheet abuts a portion on a lower side of a center of the guide surface 326 a in the guide member 326. In this way, it is possible to secure a sufficient distance for the delivered uppermost sheet to move up on the guide surface 326 a. Thus, it is possible to guide the sheet toward the paper feed roller 322 while suppressing the double feed by the guide member 326. The height position P2 is the height position at which the leading edge of the delivered uppermost sheet abuts the portion on the lower side of the center of the guide surface 326 a. However, the height position P2 is not limited thereto, and only needs to be a height position with which it is possible to secure the sufficient distance for the leading edge of the uppermost sheet to move up on the guide surface 326 a. The height position P2 may be a height position at which the leading edge of the delivered uppermost sheet abuts a portion near the center of the guide surface 326 a or a height position at which the leading edge of the delivered uppermost sheet abuts a portion on an upper side of the center of the guide surface 326 a.
Next, a description will be made on the lifting/lowering control for the left tray 311 in the thick paper mode with reference to FIG. 9C and FIG. 10 . As illustrated in FIG. 9C and FIG. 10 , the lifting/lowering controller 202 controls the lifting/lowering motor 371 such that the left tray 311 becomes higher by a first predetermined magnitude A1 than that in the plain paper mode. More specifically, the lifting/lowering controller 202 controls the lifting/lowering motor 371 in a manner to lift the left tray 311 from the initial position P1 to the height position P3 that is higher by the first predetermined magnitude A1 than the height position P2, at which the upper limit sensor 32 detects the detection piece 325 d.
The first predetermined magnitude A1 is set within a range where the leading edge of the sheet can abut the guide surface 326 a of the guide member 326 when the uppermost sheet is delivered by the pickup roller 321 from the sheet bundle M placed in the left tray 311. In the present example, the first predetermined magnitude A1 is 3 mm, for example. In the present example, the height position P3 is such a height position that, when the paper feed processing is initiated, and the uppermost sheet is delivered by the pickup roller 321, the leading edge of the sheet abuts the portion on the upper side of the center of the guide surface 326 a in the guide member 326, for example. The height position P3 is the height position at which the leading edge of the delivered uppermost sheet abuts the portion on the upper side of the center of the guide surface 326 a. However, the height position P3 is not limited thereto, and only needs to be higher than the height position P2. The height position P3 may be a height position at which the leading edge of the delivered uppermost sheet abuts the portion near the center of the guide surface 326 a or the height position at which the leading edge of the delivered uppermost sheet abuts the portion on the lower side of the center of the guide surface 326 a.
Since the second sheet (the thick paper) is thicker than the first sheet (the plain paper), the second sheet has the higher resistance than the first sheet when being applied with a bending force. Accordingly, in the case where the distance for the delivered uppermost sheet to move up on the guide surface 326 a is the same as that for the first sheet (the plain paper), a pickup error is likely to occur due to an increase in a slippage of the pickup roller 321.
In view of the above, in the thick paper mode, the lifting/lowering controller 202 controls the lifting/lowering motor 371 such that the left tray 311 becomes higher by the first predetermined magnitude A1 than that in the plain paper mode. In this way, it is possible to reduce the distance for the uppermost sheet, which is delivered by the pickup roller 321, to move up on the guide surface 326 a. Thus, it is possible to guide the sheet toward the paper feed roller 322 while suppressing the pickup error. Since the second sheet (the thick paper) is thicker than the first sheet (the plain paper) and the second sheets are easily separated from each other, the double feed is less likely to occur. Thus, in the thick paper mode, even in the case where the distance for the uppermost sheet to move up on the guide surface 326 a is reduced, the double feed can be suppressed.
A description will hereinafter be made on lifting/lowering control for the left tray 311 executed before the initiation of the paper feed processing in the thin paper mode and the business card mode.
In the thin paper mode, the lifting/lowering controller 202 controls the lifting/lowering motor 371 such that the left tray 311 becomes higher by a second predetermined magnitude A2 than that in the plain paper mode. More specifically, the lifting/lowering controller 202 controls the lifting/lowering motor 371 in a manner to lift the left tray 311 from the initial position P1 to a height position that is higher by the second predetermined magnitude A2 than the height position P2, at which the upper limit sensor 32 detects the detection piece 325 d.
The second predetermined magnitude A2 is a value that is smaller than the first predetermined magnitude A1. That is, in the thin paper mode, the left tray 311 is lifted to the position that is higher than that in the plain paper mode and lower than that in the thick paper mode.
Since the third sheet (the thin paper) is thinner than the first sheet (the plain paper), the third sheet has the lower resistance than the first sheet when being applied with the bending force. Accordingly, in the case where the distance for the delivered uppermost sheet to move up on the guide surface 326 a is the same as that for the first sheet (the plain paper), the resistance is applied to the third sheet (the thin paper), and such damage that the leading edge of the sheet is bent possibly occurs.
In view of the above, in the thin paper mode, the lifting/lowering controller 202 controls the lifting/lowering motor 371 such that the left tray 311 becomes higher than that in the plain paper mode by the second predetermined magnitude A2 that is smaller than the first predetermined magnitude A1. In this way, it is possible to reduce the distance for the uppermost sheet, which is delivered by the pickup roller 321, to move up on the guide surface 326 a while securing the distance to some extent. Thus, it is possible to guide the sheet toward the paper feed roller 322 while suppressing the damage and the like of the sheet and the double feed.
In the business card mode, the lifting/lowering controller 202 controls the lifting/lowering motor 371 such that the left tray 311 becomes higher by a third predetermined magnitude A3 than that in the plain paper mode. More specifically, the lifting/lowering controller 202 controls the lifting/lowering motor 371 in a manner to lift the left tray 311 from the initial position P1 to a height position that is higher by the third predetermined magnitude A3 than the height position P2, at which the upper limit sensor 32 detects the detection piece 325 d.
The third predetermined magnitude A3 is a value that is larger than the first predetermined magnitude A1. That is, in the business card mode, the left tray 311 is lifted to the position that is higher than that in the thick paper mode.
Since the fourth sheet (the thick paper for the business card) is thicker and smaller in size than the first sheet (the plain paper), the fourth sheet has the higher resistance than the first sheet when being applied with the bending force. Accordingly, in the case where the distance for the delivered uppermost sheet to move up on the guide surface 326 a is the same as that for the first sheet (the plain paper), the pickup error is likely to occur due to the increase in the slippage of the pickup roller 321.
In view of the above, in the business card mode, the lifting/lowering controller 202 controls the lifting/lowering motor 371 such that the left tray 311 becomes higher than that in the plain paper mode by the third predetermined magnitude A3 that is larger than the first predetermined magnitude A1. In this way, it is possible to reduce the distance for the uppermost sheet, which is delivered by the pickup roller 321, to move up on the guide surface 326 a. Thus, it is possible to guide the sheet toward the paper feed roller 322 while suppressing the pickup error. Since the fourth sheet (the thick paper for the business card) is thicker than the first sheet (the plain paper) and the fourth sheets are easily separated from each other, the double feed is less likely to occur. Thus, in the business card mode, even in the case where the distance for the uppermost sheet to move up on the guide surface 326 a is reduced, the double feed can be suppressed.
In addition, as illustrated in FIG. 10 , in the thick paper mode, the lifting/lowering controller 202 controls the lifting/lowering mechanism 370 such that an angle of a placement surface, on which the sheet is placed, in the left tray 311 with respect to the guide surface 326 a becomes smaller than that in the plain paper mode. An angle a2 of the placement surface with respect to the guide surface 326 a in the thick paper mode is smaller than an angle a1 of the placement surface with respect to the guide surface 326 a in the plain paper mode, so as for the placement surface to be close to the guide surface 326 a. In addition, as illustrated in FIG. 10 , the rotation fulcrum F is provided at an upstream end (the right end) in the conveyance direction of the left tray 311. The left tray 311 can rotate in the up-down direction about the rotation fulcrum F that is located at the right end. For example, when the left end of the left tray 311 rotate upward about the rotation fulcrum F, the left tray 311 is lifted. Meanwhile, when the left end of the left tray 311 rotate downward about the rotation fulcrum F, the left tray 311 is lowered.
As it has been described so far, in the thick paper mode, the left tray 311 is lifted such that the inclination thereof causes the left tray 311 to be closer to the guide surface 326 a than in the plain paper mode. Thus, since it is possible to reduce the resistance at the time when the leading edge of the sheet on the left tray 311 abuts the guide surface 326 a, it is possible to suppress the occurrence of the pickup error.
Here, the inclination of the left tray 311 is configured that the left tray 311 comes closer to the guide surface 326 a as the left tray 311 is lifted. Thus, since the inclination of the left tray 311 causes the left tray 311 to be closer to the guide surface 326 a in any of the thick paper mode, the thin paper mode, and the business card mode than in the plain paper mode, it is possible to suppress the occurrence of the pickup error.
As it has been described so far, it is possible to reduce paper feed failures, which possibly occur depending on the sheet type, during the paper feed processing by changing the height of the left tray 311 according to the sheet type.
In addition, in regard to the magnitude by which the left tray 311 is lifted after the upper limit sensor 32 in the lifting/lowering controller 202 detects the detection piece 325 d, the rotation angle at which the lifting/lowering motor 371 is stored for each sheet type in the storage 210 in advance.
Furthermore, in the thick paper mode, the lifting/lowering controller 202 may lift the left tray 311 stepwise from the initial position P1 to the height position P3, or may lift the left tray 311 continuously from the initial position P1 to the height position P3.
First, a description will be made on a case where the left tray 311 is lifted stepwise from the initial position P1 to the height position P3. In the case where the document detection sensor 34 detects that the document is placed in the left tray 311 and any operation input (a touch operation input) is accepted via the operation panel 40, the lifting/lowering controller 202 lifts the left tray 311 from the initial position P1 to the height position P2 and then stops the left tray 311. In this way, the left tray 311 can be lifted to the height position P2 in advance before a job setting is initiated by the operation panel 40. Then, for example, when an instruction to start the job, which is set in the thick paper mode, is accepted via the operation panel 40, the lifting/lowering controller 202 lifts the left tray 311 from the height position P2 to the height position P3.
Next, a description will be made on a case where the left tray 311 is lifted continuously from the initial position P1 to the height position P3. For example, in the case where the document detection sensor 34 detects that the document is placed in the left tray 311 and the instruction to start the job, which is set in the thick paper mode, is accepted via the operation panel 40, the lifting/lowering controller 202 lifts the left tray 311 continuously from the initial position P1 to the height position P3.
As it has been described so far, in the thick paper mode, the left tray 311 may be lifted stepwise, or the left tray 311 may be lifted continuously. Not only in the thick paper mode, but also in the thin paper mode or the business card mode, the left tray 311 may be lifted stepwise or continuously.
A description will be made on a flow related to the lifting/lowering control for the left tray 311 before the initiation of the paper feed processing with reference to FIG. 11 . FIG. 11 illustrates an example of the flow related to the lifting/lowering control before the initiation of the paper feed processing by the controller 200. In the flow illustrated in FIG. 11 , it is assumed that the plain paper mode or the thick paper mode can be set as the sheet type.
In S11, the document detection sensor 34 detects that the document is placed in the left tray 311, and the processing proceeds to S12. In S12, it is determined whether any (input operation) touch operation has been accepted via an operation acceptor. If the touch operation has been accepted in S12, that is, if it is determined Yes in S12, the processing proceeds to S13. If the touch operation has not been accepted in S12, that is, if it is determined No in S12, the processing returns to S12.
In S13, the left tray 311 is lifted, and the processing proceeds to S14. In S14, it is determined whether the upper limit sensor 32 detects the detection piece 325 d. If it is determined in S14 that the upper limit sensor 32 detects the detection piece 325 d, that is, if it is determined Yes in S14, the processing proceeds to S15. If it is determined in S14 that the upper limit sensor 32 does not detect the detection piece 325 d, that is, if it is determined No in S14, the processing returns to S14. In S15, the left tray 311 is stopped, and the processing proceeds to S16.
In S16, it is determined whether a job start instruction has been accepted. If it is determined in S16 that the job start instruction has been accepted, that is, if it is determined Yes in S16, the processing proceeds to S17. If it is determined in S16 that the job start instruction has not been accepted, that is, if it is determined No in S16, the processing returns to S16. In S17, it is determined whether the thick paper mode is set. If it is determined in S17 that the thick paper mode is set, that is, if it is determined Yes in S17, the processing proceeds to S18. If it is determined in S17 that the thick paper mode is not set, that is, the plain paper mode is set, that is, if it is determined No in S17, the processing is terminated. In S18, the left tray 311 is lifted by the first predetermined magnitude A1, and then the processing is terminated.
Next, a description will be made on lifting/lowering correction control for the left tray 311 executed during the paper feed processing. In the paper feed processing, the paper feed motor 322 b is driven to cause the pickup roller 321 and the paper feed roller 322 to rotate, and the sheets are thereby delivered one by one from the sheet bundle M in the left tray 311 to the conveyance path 330. Then, when the number of the sheets in the sheet bundle M in the left tray 311 is gradually reduced, and the height of the uppermost sheet, which is stacked in the left tray 311, is then reduced, the pickup roller 321 is pressed by the pressing portion 325 b and is gradually lowered. As a result of the detection piece 325 d being lowered in conjunction therewith, the upper limit sensor 32 no longer detects the detection piece 325 d. Consequently, the leading edge of the sheet may not abut the desired position of the guide member 326, and thus the sheet may not be guided to the paper feed roller 322 appropriately.
Accordingly, in the plain paper mode, the lifting/lowering controller 202 controls the lifting/lowering motor 371 such that, in the case where the upper limit sensor 32 no longer detects the detection piece 325 d during the paper feed processing, the left tray 311 is further lifted from the height position P2 before the initiation of the paper feed processing to the height position at which the upper limit sensor 32 detects the detection piece 325 d.
In the thick paper mode, the lifting/lowering controller 202 controls the lifting/lowering motor 371 such that, in the case where the upper limit sensor 32 no longer detects the detection piece 325 d during the paper feed processing, the left tray 311 becomes higher by the first predetermined magnitude A1 than that in the plain paper mode. Similarly, in the thin paper mode, the lifting/lowering controller 202 controls the lifting/lowering motor 371 such that the left tray 311 becomes higher by the second predetermined magnitude A2 than that in the plain paper mode. In the business card mode, the lifting/lowering controller 202 controls the lifting/lowering motor 371 such that the left tray 311 becomes higher by the third predetermined magnitude A3 than that in the plain paper mode.
In this way, even in the case where the number of the sheets in the sheet bundle M in the left tray 311 is reduced during the paper feed processing, and the position at which the leading edge of the sheet abuts the guide surface 326 a is lowered, the position at which the leading edge of the sheet abuts the guide surface 326 a can be raised by lifting the left tray 311. Thus, it is possible to deliver the sheet to the paper feed roller 322 while suppressing the paper feed failure.
A description will be made on a flow related to the lifting/lowering correction control for the left tray 311 during the paper feed processing with reference to FIG. 12 . FIG. 12 illustrates an example of the flow related to the lifting/lowering correction control during the paper feed processing by the controller 200. In the flow illustrated in FIG. 12 , it is assumed that the plain paper mode or the thick paper mode can be set as the sheet type. In the flow illustrated in FIG. 12 , it is assumed that the paper feed processing by the controller 200 is initiated.
In S21, it is determined whether the upper limit sensor 32 no longer detects the detection piece 325 d. If it is determined in S21 that the upper limit sensor 32 no longer detects the detection piece 325 d, that is, if it is determined Yes in S21, the processing proceeds to S22. If it is determined in S22 that the upper limit sensor 32 detects the detection piece 325 d, that is, if it is determined No in S21, the processing returns to S21. In S22, it is determined whether the thick paper mode is set. If it is determined in S22 that the thick paper mode is set, that is, if it is determined Yes in S22, the processing proceeds to S23. If it is determined in S22 that the thick paper mode is not set, that is, the plain paper mode is set, that is, if it is determined No in S22, the processing proceeds to S26.
In S23, the left tray 311 is lifted, and the processing proceeds to S24. In S24, it is determined whether the upper limit sensor 32 detects the detection piece 325 d. If it is determined in S24 that the upper limit sensor 32 detects the detection piece 325 d, that is, if it is determined Yes in S24, the processing proceeds to S25. If it is determined in S24 that the upper limit sensor 32 does not detect the detection piece 325 d, that is, if it is determined No in S24, the processing returns to S24. In S25, the left tray 311 is further lifted by the first predetermined magnitude A1, and then the processing returns to S21.
In S26, the left tray 311 is lifted, and the processing proceeds to S27. In S27, it is determined whether the upper limit sensor 32 detects the detection piece 325 d. If it is determined in S27 that the upper limit sensor 32 detects the detection piece 325 d, that is, if it is determined Yes in S27, the processing proceeds to S28. If it is determined in S27 that the upper limit sensor 32 does not detect the detection piece 325 d, that is, if it is determined No in S27, the processing returns to S27. In S28, the left tray 311 is stopped, and the processing proceeds to S21.
Next, a description will be made on the lifting/lowering correction control by the lifting/lowering controller 202 at the time when the pickup error is determined. In the thick paper mode, the height position of the left tray 311 is higher than that in the plain paper mode. That is, in the thick paper mode, the left tray 311 is located at the higher position than the height position at which the upper limit sensor 32 detects the detection piece 325 d. Accordingly, the position at which the leading edge of the uppermost sheet abuts the guide member 326 is likely to be changed significantly by the time the upper limit sensor 32 no longer detects the detection piece 325 d due to the reduction in the number of the sheets in the sheet bundle M. Thus, the slippage of the pickup roller 321 is increased despite a fact that the upper limit sensor 32 detects the detection piece 325 d. As a result, the pickup error is likely to occur.
In the case where it is determined that the pickup error has occurred, the controller 200 can execute retry processing to temporarily stop driving the paper feed motor 322 b and then drive the paper feed motor 322 b again.
The controller 200 has the determination device 203 that determines whether the pick error has occurred during the paper feed processing. The determination device 203 determines that the pickup error has occurred in the case where the paper passing sensor 35 does not detect feeding of the sheet to the conveyance path 330 within a predetermined time after the paper feed motor 322 b is driven to cause the paper feed roller 322 to rotate. The determination device 203 determines that the pickup error has not occurred in the case where the paper passing sensor 35 detects feeding of the sheet to the conveyance path 330 within the predetermined time after the paper feed motor 322 b is driven to cause the paper feed roller 322 to rotate.
In the configuration described so far, in the thick paper mode, in the case where it is determined that the pick error has occurred during the paper feed processing, the lifting/lowering controller 202 lifts the left tray 311 by a predetermined magnitude. The predetermined magnitude is a magnitude by which the height of the left tray 311 reaches a predetermined height position that is higher by the first predetermined magnitude A1 than the height position at which the upper limit sensor 32 detects the detection piece 325 d. Timing at which the lifting/lowering controller 202 lifts the left tray 311 by the predetermined magnitude is timing at which the controller 200 executes the retry processing, that is, timing after driving of the paper feed motor 322 b is temporarily stopped and before the paper feed motor 322 b is driven again.
As it has been described so far, in the thick paper mode, when the pickup error occurs, it is possible to raise the height, at which the leading edge of the sheet abuts the guide surface 326 a, by lifting the left tray 311 by the predetermined magnitude. Thus, it is possible to deliver the sheet to the paper feed roller 322 while suppressing the paper feed failure.
Meanwhile, when the pick error occurs in the plain paper mode, unlike the thick paper mode, the retry processing is executed without lifting the left tray 311. In the plain paper mode, the left tray 311 is located at the lower position than that in the thick paper mode. Accordingly, the position at which the leading edge of the uppermost sheet abuts the guide member 326 is not changed significantly by the time the upper limit sensor 32 no longer detects the detection piece 325 d due to the reduction in the number of the sheets in the sheet bundle M. Accordingly, in the case where the left tray 311 is lifted when the pickup error occurs in the plain paper mode, there is a possibility that the distance for the delivered uppermost sheet to move up on the guide surface 326 a is not secured sufficiently. For this reason, in the plain paper mode, the retry processing is executed without lifting the left tray 311. In this way, it is possible to deliver the sheet to the paper feed roller 322 while securing the distance for the delivered uppermost sheet to move up on the guide surface 326 a.
In the thick paper mode, the left tray 311 is lifted by the predetermined magnitude when the pickup error occurs in the thick paper mode. However, the present disclosure is not limited thereto. Also, in the business card mode, the left tray 311 may similarly be lifted by the predetermined magnitude when the pickup error occurs. In this case, the predetermined magnitude is such a magnitude by which the height of the left tray 311 reaches a predetermined position that is higher by the third predetermined magnitude A3 than the height position at which the upper limit sensor 32 detects the detection piece 325 d.
A description will be made on a flow related to the lifting/lowering correction control for the left tray 311 at the time when the pickup error is determined with reference to FIG. 13 . FIG. 13 illustrates an example of the flow related to the lifting/lowering correction control by the controller 200 at the time when the pickup error is determined. In the flow illustrated in FIG. 13 , it is assumed that the plain paper mode or the thick paper mode can be set as the sheet type. In the flow illustrated in FIG. 13 , it is assumed that the paper feed processing by the controller 200 is initiated.
In S31, it is determined whether the upper limit sensor 32 detects the detection piece 325 d. If it is determined in S31 that the upper limit sensor 32 detects the detection piece 325 d, that is, if it is determined Yes in S31, the processing proceeds to S32. If it is determined in S32 that the upper limit sensor 32 does not detect the detection piece 325 d, that is, if it is determined No in S31, the processing returns to S31. In S32, it is determined whether the pickup error has occurred. If it is determined in S32 that the pickup error has occurred, that is, if it is determined Yes in S32, the processing proceeds to S33. If it is determined in S32 that the pickup error has not occurred, that is, if it is determined No in S32, the processing returns to S31.
In S33, the rotation of the paper feed roller 322 is stopped, and the processing proceeds to S34. In S34, it is determined whether the thick paper mode is set. If it is determined in S34 that the thick paper mode is set, that is, if it is determined Yes in S34, the processing proceeds to S35. If it is determined in S34 that the thick paper mode is not set, that is, the plain paper mode is set, that is, if it is determined No in S34, the processing proceeds to S36. In S35, the left tray 311 is lifted by the predetermined magnitude, and the processing proceeds to S36. In S36, the paper feed roller 322 rotates again to resume the paper feed processing, and the processing returns to S31.
Next, a description will be made on a first modification example of the lifting/lowering correction control during the paper feed processing.
The controller 200 has the counter 204 for counting the number of the fed sheets that is the number of the sheets fed to the conveyance path 330 by the paper feed unit 320. When the paper feed processing is initiated, the counter 204 counts the number of the fed sheets. In addition, when the number of the fed sheets reaches a predetermined threshold, the counter 204 resets a count of the number of the fed sheets.
In the thick paper mode, the lifting/lowering controller 202 controls the lifting/lowering motor 371 such that, in the case where it is determined that the number of the fed sheets has reached the predetermined threshold while the upper limit sensor 32 detects the detection piece 325 d, the left tray 311 is lifted by a predetermined magnitude. The predetermined magnitude herein is set on the basis of a value that is obtained by multiplying a thickness of the thick paper by the number of the fed sheets.
In this way, the left tray 311 can be lifted every time the number of the sheets in the sheet bundles M in the left tray 311 is reduced by a predetermined number. Accordingly, it is possible to prevent the position, at which the leading edge of the sheet abuts the guide surface 326 a, from being lowered excessively. Thus, it is possible to effectively suppress the pickup error, which occurs due to the increase in the slippage of the pickup roller 321 despite the fact that the upper limit sensor 32 detects the detection piece 325 d.
The description has been made on use of the second sheet (the thick paper) for the lifting/lowering control for the left tray 311 during the above-described paper feed processing. However, the present disclosure is not limited thereto, and the lifting/lowering control for the left tray 311 can also be used, for example, when the third paper (the thin paper) is used or when the fourth paper (the thick paper for the business card) is used.
A description will be made on a flow related to the first modification example of the lifting/lowering correction control for the left tray 311 during the paper feed processing with reference to FIG. 14 . FIG. 14 illustrates an example of the flow related to the first modification example of the lifting/lowering correction control during the paper feed processing by the controller 200. In the flow illustrated in FIG. 14 , it is assumed that the plain paper mode or the thick paper mode can be set as the sheet type. In the flow illustrated in FIG. 14 , it is assumed that the paper feed processing by the controller 200 is initiated. In the flow illustrated in FIG. 14 , it is assumed that the upper limit sensor 32 detects the detection piece 325 d.
In S41, it is determined whether the number of the fed sheets has reached the predetermined threshold. If it is determined in S41 that the number of the fed sheets has reached the predetermined threshold, that is, if it is determined Yes in S41, the processing proceeds to S42. If it is determined in S41 that the number of the fed sheets has not reached the predetermined threshold, that is, if it is determined No in S41, the processing returns to S41.
In S42, it is determined whether the thick paper mode is set. If it is determined in S42 that the thick paper mode is set, that is, if it is determined Yes in S42, the processing proceeds to S43. If it is determined in S42 that the thick paper mode is not set, that is, the plain paper mode is set, that is, if it is determined No in S43, the processing proceeds to S44. In S43, the left tray 311 is lifted by the predetermined magnitude, and the processing proceeds to S44. In S44, the count of the number of the fed sheets is reset, and the processing returns to S41.
In the configuration that has been described so far, the paper feeder (the document conveyor 30) includes: the tray (the left tray 311) in which the sheet can be placed; the delivery roller (the pickup roller 321) that delivers the sheet placed in the tray (the left tray 311); the paper feed roller 322 that feeds the delivered sheet to the conveyance path 330; the guide member 326 that guides the sheet delivered from the tray (the left tray 311) toward the paper feed roller 322 and is provided to be inclined upward toward the paper feed roller 322; the lifting/lowering mechanism 370 capable of changing the height of the tray (the left tray 311); and the controller 200 that executes the paper feed processing to feed the sheet, which is delivered from the tray (the left tray 311) by causing the paper feed roller 322 to rotate, to the conveyance path 330. The controller 200 has: the setting device 201 that accepts the job settings including the settings related to the plural types of sheets, the plural types of sheets including the first sheet (the plain paper) and the second sheet (the thick paper) that is thicker than the first sheet (the plain paper); and the lifting/lowering controller 202 that controls the lifting/lowering mechanism 370 such that, in the case where the second sheet (the thick paper) is set, before the initiation of the paper feed processing, the height of the tray (the left tray 311) with respect to the guide member 326 becomes higher by the first predetermined magnitude A1 than that in the case where the first sheet (the plain paper) is set.
In this way, it is possible to reduce the distance for the uppermost sheet (the thick paper), which is delivered by the delivery roller (the pickup roller 321), to move up on the guide member 326. Thus, it is possible to guide the sheet (the thick paper) toward the paper feed roller 322 while suppressing the pickup error.
In the configuration that has been described so far, the paper feeder (the document conveyor 30) includes: the tray (the left tray 311) in which the sheet can be placed; the delivery roller (the pickup roller 321) that delivers the sheet placed in the tray (the left tray 311); the paper feed roller 322 that feeds the delivered sheet to the conveyance path 330; the guide member 326 that guides the sheet delivered from the tray (the left tray 311) toward the paper feed roller 322 and is provided to be inclined upward toward the paper feed roller 322; the lifting/lowering mechanism 370 capable of changing the height of the tray (the left tray 311); and the controller 200 that executes the paper feed processing to feed the sheet, which is delivered from the tray (the left tray 311) by causing the paper feed roller 322 to rotate, to the conveyance path 330. In the paper feed method for the paper feeder (the document conveyor 30), the controller 200 has: accepting the job settings that include the settings related to the plural types of sheets, the plural types of sheets including the first sheet (the plain paper) and the second sheet (the thick paper) that is thicker than the first sheet (the plain paper); and controlling the lifting/lowering mechanism 370 such that, in the case where the second sheet (the thick paper) is set, before the initiation of the paper feed processing, the height of the tray (the left tray 311) with respect to the guide member 326 becomes higher by the first predetermined magnitude A1 than that in the case where the first sheet (the plain paper) is set.
The paper feeder (the document conveyor 30) further includes the first detector (the paper passing sensor 35) that is arranged on the downstream side of the paper feed roller 322 and detects the sheet fed by the paper feed roller 322. In the case where the fed sheet is not detected by the first detector (the paper passing sensor 35) in the paper feed processing, the controller 200 can execute the retry processing to stop the paper feed processing and thereafter restart the paper feed processing. In the case where the second sheet (the thick paper) is set, and the fed sheet is not detected by the first detector (the paper passing sensor 35) during the paper feed processing, the lifting/lowering controller 202 controls the lifting/lowering mechanism 370 to further lift the tray (the left tray 311) by the predetermined magnitude with respect to the guide member 326 in the period after the paper feed processing is stopped and before the paper feed processing is restarted in the retry processing. In this way, even in the case where the number of the sheets in the sheet bundle M in the tray (the left tray 311) is reduced during the paper feed processing, and the position at which the leading edge of the sheet abuts the guide member 326 is lowered, the position at which the leading edge of the sheet abuts the guide member 326 can be raised by lifting the tray (the left tray 311). Thus, it is possible to deliver the sheet to the paper feed roller 322 while suppressing the paper feed failure.
The paper feeder (the document conveyor 30) further includes the first detector (the paper passing sensor 35) that is arranged on the downstream side of the paper feed roller 322 and detects the sheet fed by the paper feed roller 322. In the case where the fed sheet is not detected by the first detector (the paper passing sensor 35) in the paper feed processing, the controller 200 can execute the retry processing to stop the paper feed processing and thereafter restart the paper feed processing. In the case where the first sheet (the plain paper) is set, and the fed sheet is not detected by the first detector (the paper passing sensor 35) during the paper feed processing, the lifting/lowering controller 202 executes the retry processing without lifting the tray (the left tray 311) with respect to the guide member 326. As it has been described so far, in the plain paper mode, the retry processing is executed without lifting the left tray 311. In this way, it is possible to deliver the sheet to the paper feed roller 322 while securing the distance for the delivered uppermost sheet to move up on the guide surface 326 a.
The controller 200 further includes the counter 204 for counting the number of the fed sheets that is the number of the sheets fed by the paper feed roller 322. In the case where the second sheet (the thick paper) is set, and it is determined that the number of the fed sheets is equal to or larger than the predetermined threshold during the paper feed processing, the lifting/lowering controller 202 controls the lifting/lowering mechanism 370 to further lift the tray (the left tray 311) with respect to the guide member 326. In this way, the tray (the left tray 311) can be lifted every time the number of the sheets in the sheet bundles M in the tray (the left tray 311) is reduced by the predetermined number. Accordingly, it is possible to prevent the position, at which the leading edge of the sheet abuts the guide member 326, from being lowered excessively. Thus, it is possible to effectively suppress the pickup error, which occurs due to the increase in the slippage of the delivery roller (the pickup roller 321) despite the fact that the upper limit sensor 32 detects the detection piece 325 d.
The paper feeder (the document conveyor 30) further includes the second detector (the document detection sensor 34) that detects the sheet placed in the tray (the left tray 311). In the case where the sheet placed in the tray (the left tray 311) is detected, and the instruction to initiate the job set for the second sheet (the thick paper) is accepted via the operation acceptor (the operation panel 40), the lifting/lowering controller 202 continuously lifts the tray (the left tray 311) from the initial position P1 to the height position P3 for the case where the second sheet (the thick paper) is set.
The paper feeder (the document conveyor 30) further includes the second detector (the document detection sensor 34) that detects the sheet placed in the tray (the left tray 311). In the case where the sheet placed in the tray (the left tray 311) is detected, and any operation input is accepted via the operation acceptor (the operation panel 40), the lifting/lowering controller 202 lifts the tray (the left tray 311) from the initial position P1 to the height position P2 for the case where the first sheet (the plain paper) is set. In the case where the instruction to initiate the job set for the second sheet (the thick paper) is accepted via the operation acceptor (the operation panel 40), the lifting/lowering controller 202 lifts the tray (the left tray 311) from the height position P2 for the case where the first sheet (the plain paper) is set to the height position P3 for the case where the second sheet (the thick paper) is set.
The guide member 326 has the guide surface 326 a that is inclined upward toward the paper feed roller 322. The guide member 326 has the guide surface 326 a that is inclined upward toward the paper feed roller 322. In the case where the second sheet (the thick paper) is set, the lifting/lowering controller 202 controls the lifting/lowering mechanism 370 such that the angle of the placement surface on which the sheet is placed in the left tray 311 with respect to the guide surface 326 a becomes smaller than that in the case where the first sheet (the plain paper) is set. In this way, it is possible to reduce the resistance at the time when the leading edge of the sheet in the tray (the left tray 311) abuts the guide surface 326 a. Thus, it is possible to suppress the occurrence of the pickup error.
The setting device 201 can accept, as one of the settings related to the plural types of sheets, the setting related to the third sheet (the thin paper), which is thinner than the first sheet (the plain paper). The lifting/lowering controller 202 controls the lifting/lowering mechanism 370 such that, in the case where the third sheet (the thin paper) is set, before the initiation of the paper feed processing, the height of the tray (the left tray 311) with respect to the guide member 326 becomes higher by the second predetermined magnitude A2, which is smaller than the first predetermined magnitude A1, than that in the case where the first sheet (the plain paper) is set. In this way, it is possible to reduce the distance for the uppermost sheet, which is delivered by the delivery roller (the pickup roller 321), to move up on the guide member 326 while securing the distance to some extent. Thus, it is possible to guide the sheet toward the paper feed roller 322 while suppressing the damage and the like of the sheet and the double feed.
The setting device 201 can accept, as one of the settings related to the plural types of sheets, the setting related to the fourth sheet (the thick paper for the business card) that is thicker than the first sheet (the plain paper) and is smaller in size than the first sheet (the plain paper). The lifting/lowering controller 202 controls the lifting/lowering mechanism 370 such that, in the case where the fourth sheet (the thick paper for the business card) is set, the height of the tray (the left tray 311) with respect to the guide member 326 before the initiation of the paper feed processing becomes higher by the third predetermined magnitude A3, which is larger than the first predetermined magnitude A1, than that in the case where the first sheet (the plain paper) is set. In this way, it is possible to reduce the distance for the uppermost sheet, which is delivered by the delivery roller (the pickup roller 321), to move up on the guide member 326. Thus, it is possible to guide the sheet toward the paper feed roller 322 while suppressing the pickup error.
The image forming apparatus 1 includes the paper feeder (the document conveyor 30).
The program causes the computer to operate as the controller 200 for the image forming apparatus 1 (the document conveyor 30).
The paper feeder (the document conveyor 30) described above is a device for feeding the sheet to the image reader 20. However, the paper feeder (the document conveyor 30) is not limited thereto, and may be a device for feeding the sheet to the printer 10. In this case, for example, the paper feeder may be configured to have the paper feeder 110 of the printer 10, or may be configured to have a manual feed tray for feeding the sheet to the printer 10.
The paper feeder (the document conveyor 30) described above can be realized by hardware, software, or a combination thereof. The paper feed method described above can also be realized by the hardware, the software, or the combination thereof. Here, being realized by the software means being realized when the computer reads and executes the program.
The program can be stored by using any of various types of non-transitory computer readable media and can be supplied to the computer. The non-transitory computer readable media include various types of tangible storage media. Examples of the non-transitory computer readable media are magnetic recording media (such as a flexible disk, a magnetic tape, and a hard disk drive), a magneto-optical recording medium (such as a magneto-optical disk), a CD-Read Only Memory (CD-ROM), a CD-R/W, and semiconductor memories (such as a mask ROM, a Programmable ROM (PROM), an Erasable PROM (EPROM), a flash ROM, and a random access memory (RAM)). The program may be supplied to the computer by any of various types of transitory computer readable media. Examples of the transitory computer readable media are an electric signal, an optical signal, and an electromagnetic wave. The transitory computer readable medium can supply the program to the computer via a wired communication path, such as an electric wire or an optical fiber, or a wireless communication path.

Claims

What is claimed is:

1. A paper feeder comprising:

a tray in which a sheet can be placed;

a delivery roller that delivers the sheet placed in the tray;

a paper feed roller that feeds the delivered sheet to a conveyance path;

a guide member that guides the delivered sheet from the tray toward the paper feed roller and is provided to be inclined upward toward the paper feed roller;

a lifting/lowering mechanism capable of changing a height of the tray; and

a controller that executes paper feed processing to feed the delivered sheet from the tray to the conveyance path by causing the paper feed roller to rotate, wherein

the controller has: a setting device that accepts job settings including settings related to plural types of sheets, the plural types of sheets including a first sheet and a second sheet that is thicker than the first sheet; and a lifting/lowering controller that controls the lifting/lowering mechanism such that, in the case where the second sheet is set, before initiation of the paper feed processing, a height of the tray with respect to the guide member becomes higher by a first predetermined magnitude than that in the case where the first sheet is set.

2. The paper feeder according to claim 1 further comprising:

a first detector that is arranged on a downstream side of the paper feed roller and detects the sheet fed by the paper feed roller, wherein,

in the case where the fed sheet is not detected by the first detector in the paper feed processing, the controller can execute retry processing to stop the paper feed processing and thereafter restart the paper feed processing, and the lifting/lowering controller controls the lifting/lowering mechanism such that, in the case where the second sheet is set, and the fed sheet is not detected by the first detector during the paper feed processing, the tray is further lifted by a predetermined magnitude with respect to the guide member in a period after the paper feed processing is stopped and before the paper feed processing is restarted in the retry processing.

3. The paper feeder according to claim 1 further comprising:

in the case where the fed sheet is not detected by the first detector in the paper feed processing, the controller can execute retry processing to stop the paper feed processing and thereafter restart the paper feed processing, and, in the case where the first sheet is set, and the fed sheet is not detected by the first detector during the paper feed processing, the lifting/lowering controller executes the retry processing without lifting the tray with respect to the guide member.

4. The paper feeder according to claim 1, wherein

the controller further has a counter for counting the number of the fed sheets that is the number of the sheets fed by the paper feed roller, and the lifting/lowering controller controls the lifting/lowering mechanism such that, in the case where the second sheet is set, and it is determined that the number of the fed sheets is equal to or larger than a predetermined threshold during the paper feed processing, the tray is further lifted with respect to the guide member.

5. The paper feeder according to claim 1 further comprising:

A second detector that detects the sheet placed in the tray, wherein,

in the case where the sheet placed in the tray is detected, and an instruction to start the job set for the second sheet is accepted via an operation acceptor, the lifting/lowering controller continuously lifts the tray from an initial position to a height position for a case where the second sheet is set.

6. The paper feeder according to claim 1 further comprising:

a second detector that detects the sheet placed in the tray, wherein,

in the case where the sheet placed in the tray is detected, and any operation input is accepted via an operation acceptor, the lifting/lowering controller lifts the tray from an initial position to a height position for a case where the first sheet is set, and, in the case where an instruction to start the job set for the second sheet is accepted via the operation acceptor, the lifting/lowering controller lifts the tray from the height position for the case where the first sheet is set to a height position for a case where the second sheet is set.

7. The paper feeder according to claim 1, wherein

the guide member has a guide surface that is inclined upward toward the paper feed roller, and the lifting/lowering controller controls the lifting/lowering mechanism such that, in the case where the second sheet is set, an angle of a placement surface on which the sheet is placed in the tray with respect to the guide surface becomes smaller than that in the case where the first sheet is set.

8. The paper feeder according to claim 1, wherein,

The setting device can accept, as one of the settings related to the plural types of sheets, a setting related to a third sheet that is thinner than the first sheet, and, the lifting/lowering controller controls the lifting/lowering mechanism such that, in the case where the third sheet is set, before initiation of the paper feed processing, the height of the tray with respect to the guide member becomes higher by a second predetermined magnitude, which is smaller than the first predetermined magnitude, than that in a case where the first sheet is set.

9. The paper feeder according to claim 1, wherein,

the setting device can accept, as one of the settings related to the plural types of sheets, a setting related to a fourth sheet that is thicker than the first sheet and is smaller in size than the first sheet, and, the lifting/lowering controller controls the lifting/lowering mechanism such that, in the case where the fourth sheet is set, before initiation of the paper feed processing, the height of the tray with respect to the guide member becomes higher by a third predetermined magnitude than that in a case where the first sheet is set.

10. An image forming apparatus comprising: the paper feeder according to claim 1.