JP2009292602A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device capable of certainly preventing the curl of paper regardless of a stacking number to a manual paper feed tray. <P>SOLUTION: In the image forming device equipped with a manual paper feeding mechanism, a paper stacking surface of a manual paper feed table 25 curves in a circular arc-shape in a vertical direction to a paper carrying direction. The paper stacking surface of the table 25 has a vertex of the circular arc positioned at a paper center in a paper feeding direction, and preferably extends downward in the circular arc-shape from the vertex. The paper stacking surface of the table 25 preferably has the different curvature of the circular arc at a paper leading end portion and a paper trailing end portion of the paper stacking surface. Furthermore, in the paper stacking surface of the table 25, the curvature of the circular arc at the paper trailing end portion is preferably larger than that of the paper leading end portion. The insertion table 25 is preferably provided with side fences 30, 31 movable along the curved surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus having a manual paper feed mechanism.

In a manual paper feed mechanism provided in an image forming apparatus such as a copying machine or a printer, there are few paper restraint portions in the paper feed tray to ensure ease of paper setting, and the paper loaded on the manual table is curled. When this occurs, the curled paper is fed, which causes problems such as paper breaks and paper jams in the transport section after feeding.
Conventionally, as a mechanism for paper restraint or correction in a manual feed table, a method of guiding paper by a paper pressing shape of a side fence has been used (for example, see Patent Document 1). Since it has a shape that can be accommodated, when the loading amount on the manual feed tray is small, the space between the paper and the guide becomes empty, and the guide cannot be fully provided.

Japanese Patent Laid-Open No. 2-100927

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus capable of reliably preventing paper curl regardless of the number of sheets loaded on the manual feed tray. And

The features of the present invention, which is a means for solving the above problems, are listed below.
The image forming apparatus of the present invention is characterized in that, in an image forming apparatus provided with a manual paper feed mechanism, the shape of the paper stacking surface of the manual feed table is curved in an arc shape in a direction perpendicular to the paper transport direction. .
Further, in the image forming apparatus of the present invention, the paper stacking surface of the manual feed table has a shape in which an apex of an arc is positioned at the center of the sheet with respect to the sheet passing direction, and the arc descends downward from the apex. It is characterized by.
The image forming apparatus according to the present invention is further characterized in that the sheet stacking surface of the manual feed table has different arc curvatures at the leading edge and the trailing edge of the sheet.
The image forming apparatus of the present invention is further characterized in that the sheet stacking surface of the manual feed table has a larger arc curvature at the trailing edge of the sheet than at the leading edge of the sheet.

The image forming apparatus according to the present invention is further characterized in that the sheet loading surface of the manual feed table is provided with a side fence movable along a curved surface.
The image forming apparatus of the present invention is further characterized in that the uppermost part of the side fence of the side fence is shaped to hold the paper in the direction of the paper stacking part.
Further, in the image forming apparatus of the present invention, the sheet stacking surface of the manual feed table has a shape in which the lowest point of the arc is located at the center of the sheet with respect to the sheet passing direction and rises upward in an arc shape from the apex. It is characterized by being.
The image forming apparatus according to the present invention is further characterized in that the sheet stacking surface of the manual feed table has different arc curvatures at the leading edge and the trailing edge of the sheet.

The image forming apparatus of the present invention is further characterized in that the sheet stacking surface of the manual feed table has a larger arc curvature at the trailing edge of the sheet than at the leading edge of the sheet.
The image forming apparatus according to the present invention is further characterized in that the sheet loading surface of the manual feed table is provided with a side fence movable along a curved surface.
The image forming apparatus of the present invention is further characterized in that the uppermost part of the side fence of the side fence is shaped to hold the paper in the direction of the paper stacking part.

  In the image forming apparatus as the means for solving the above problem, the curling of the sheet can be surely prevented regardless of the number of sheets loaded on the manual feed tray.

  The best mode for carrying out the present invention will be described below with reference to the drawings. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. The following description is an example of the best mode of the present invention, and does not limit the scope of the claims.

The image forming apparatus of this embodiment is an application example of a full-color printer that employs a so-called tandem method. FIG. 1 is a central sectional view showing an outline of the full-color printer 100, and FIG. 2 is a central sectional view showing an outline of an image forming unit in the printer.
First, the internal configuration of the full-color printer 100 will be described with reference to FIGS. The full-color printer 100 includes four latent images as image forming means for forming images of each color of yellow (Y), cyan (C), magenta (M), and black (Bk). Drum-shaped photoconductors 2Y, 2M, 2C, and 2Bk, which are bodies, are arranged in parallel at equal intervals in the left-right direction in the drawing. When the image forming apparatus 100 operates, the image forming apparatus 100 is rotated in the direction of the arrow by a drive source (not shown).
Around the photosensitive member 2, members and devices necessary for an electrophotographic image forming apparatus such as a developing device are provided and configured as image forming units at four locations. The toner color of an image to be formed For the sake of convenience, Y (yellow), C (cyan), M (magenta), and Bk (black) representing the color are appended as subscripts after the number indicating each image forming device for convenience. In particular, in the general description, these subscripts may be omitted. The four image forming units 1Y, 1C, 1M, and 1Bk all have the same configuration.

Focusing on the image forming unit 1Y including the yellow image photoreceptor 2Y shown in FIG. 2, a charging device 4Y including a charging roller 4aY, a developing roller 5aY, and a developing blade 5bY around the photoreceptor 2Y according to an electrophotographic process. Further, an image forming member such as a developing device 5Y having a screw 5cY and the like, a cleaning brush 3aY, a cleaning blade 3bY, a recovery screw 3cY and the like, and a cleaning device 3Y and the like are sequentially arranged.
The photoreceptor 2Y has a diameter of 30 to 120 mm, for example.
It has a layer structure in which an organic semiconductor layer, which is a photoconductive substance, is provided on the surface of an aluminum cylinder. The members arranged around the other photoconductors 2C, 2M, and 2Bk are the same. That is, only the color of the toner used for image formation is different. It is possible to use a belt-like photoconductor.

As shown in FIG. 1, a laser beam corresponding to image data for each color is scanned below the photoreceptors 2Y, 2C, 2M, and 2Bk on the surface of each photoreceptor 2 that has been uniformly charged by the charging means. An exposure device 8 for forming an electrostatic latent image is provided. Between each charging device 4Y and each developing device 5Y, an elongated space is secured in the direction of the rotation axis of the photoconductor 2 so that the laser beam irradiated by the exposure device 8 enters the photoconductor 2. Yes.
An exposure apparatus 8 in the illustrated example is a laser scanning type exposure apparatus using a laser light source, a polygon mirror, etc., and laser beams 8Y and 8C modulated from four semiconductor lasers (not shown) according to image data to be formed. , 8M, 8Bk. The exposure apparatus 8 accommodates optical parts and control parts by a metal or resin casing, and is provided with a light-transmitting dustproof member at the emission port on the upper surface. Although the embodiment is composed of a single housing, a plurality of exposure apparatuses can be individually provided in each image forming unit. In addition to an exposure apparatus that employs the above laser, an exposure apparatus that combines a known LED array and an imaging means can also be employed.

  When the yellow (Y), cyan (C), magenta (M), and black (Bk) toners are consumed by the developing devices 5Y, 5C, 5M, and 5Bk that handle the respective colors, they are detected by a toner detection unit (not shown). Then, the toner cartridges 40Y, 40C, 40M, and 40Bk containing the toners of the respective colors provided in the upper portion of the image forming apparatus 100 are supplied to the developing devices 5Y, 5C, 5M, and 5Bk by a supply unit (not shown). . The outer shell of each toner cartridge is a container made of resin or paper, and is partially provided with a discharge port. The discharge port can be easily attached to and detached from the mounting portion TS of the image forming apparatus 100. It is combined with individual toner replenishing means provided on the main body. In order to prevent the toner cartridge 40 of each color from being erroneously mounted and supplying toner to a developing device that handles different colors, the mounting portion TS and the toner cartridge 40 are paired with each other to provide a wrong mounting prevention means. is there.

The developing device 5Y includes two screws 5cY for stirring and conveying the toner and the carrier. When the developing device 5Y is mounted on the image forming apparatus 100, one end of the toner replenishing means is connected to the upper part of the left screw 5cY in FIG. The toner is supplied to the developing roller 5aY rotating in the direction of the arrow by the screw 5cY, but the thickness of the toner layer on the surface of the developing roller 5aY is regulated to a predetermined thickness by the blade 5bY. The developing roller 5aY is a cylinder made of stainless steel or aluminum alloy, and is supported by the frame of the developing device 5Y so that the distance from the photoreceptor 2 can be properly secured so as to be rotatable. A magnet is provided to be constructed.
The electrostatic latent image for each color formed on the surface of each photoconductor 2 by the laser beam is developed by a developing device 5 that handles toner of a predetermined color to become a visible image.

An intermediate transfer unit 6 is disposed above the photoreceptors 2Y, 2C, 2M, and 2Bk. The roller 6b rotates so that the intermediate transfer belt 6a as an image carrier supported and stretched by a plurality of rollers 6b, 6c, 6d, and 6e travels in the direction of the arrow.
The intermediate transfer belt 6a is endless, and is stretched and arranged so that a part of each photoconductor after the development process comes into contact. Primary transfer rollers 7 </ b> Y, 7 </ b> C, 7 </ b> M, and 7 </ b> Bk are provided on the belt inner peripheral portion so as to face each photoconductor.
A belt cleaning device 6h is provided on the outer peripheral portion of the intermediate transfer belt 6a at a position facing the roller 6e. The belt cleaning device 6h wipes off unnecessary toner remaining on the surface of the intermediate transfer belt 6a and foreign matters such as paper dust. The roller 6e facing the belt cleaning device 6h includes a mechanism that applies tension to the intermediate transfer belt 6a. Although it always moves to ensure an appropriate belt tension, the opposing cleaning device can also move in conjunction.
The intermediate transfer belt 6a has a base thickness of 50 to 600 μm, for example.
The belt has a resin film or rubber as a base, and has a resistance value that enables a toner image carried by each photoreceptor 2 to be electrostatically transferred to the belt surface by a bias applied to the primary transfer roller 7. . The members related to the intermediate transfer belt 6 a are configured as the intermediate transfer unit 6 and can be attached to and detached from the image forming apparatus 100.

As an embodiment of the intermediate transfer belt 6a, the intermediate transfer belt 6a is obtained by dispersing carbon in polyamide and adjusting the volume resistance of about 10 ⁶ to 10 ¹² Ωcm. Belt detent ribs for stabilizing the running of the intermediate transfer belt 6a are provided on one side or both ends of the belt. As an embodiment of the primary transfer roller 7, the primary transfer roller 7 is a metal roller that is a core metal, the surface of which is coated with a conductive rubber material, and a bias is applied to the core metal part from a power source (not shown). . In the conductive rubber material, carbon is dispersed in urethane rubber, and the resistance is adjusted to a volume resistance of about 10 ⁵ Ωcm. A metal roller that does not have a rubber layer can also be used.

A secondary transfer roller 14a is provided on the outer periphery of the intermediate transfer belt 6a in the vicinity of the support roller 6b. The secondary transfer roller 14a is formed by coating the surface of a metal roller serving as a metal core with a conductive rubber, and a bias is applied to the metal core part from the power supply 14b. Carbon is dispersed in the rubber, and the volume resistance is adjusted to about 10 ⁷ Ωcm. A toner image carried on the intermediate transfer belt 6a is electrostatically transferred to the sheet S by applying a bias while passing a recording medium (hereinafter referred to as a sheet S) between the intermediate transfer belt 6a and the secondary transfer roller 14a. The

A plurality of, for example, two-stage sheet cassettes 9A and 9B are arranged below the exposure apparatus 8 so as to be able to be pulled out. The paper S stored in these paper feed cassettes 9A and 9B is selectively sent out by the rotation of the corresponding paper feed rollers 10A and 10B, and the separating means 11A and 11B and the transport rollers 12Aa and 12Ba (described in FIG. 3). ) Are transported to the transport path P7 and the paper feed transport path P1 by the pair of transport rollers 12A and 12B.
A pair of registration rollers 13 is provided in the paper feeding / conveying path P1 in order to take a feeding timing for feeding the paper S to the secondary transfer unit. The sheet S is conveyed from the registration roller pair 13 toward a secondary transfer portion configured by the intermediate transfer belt 6a and the secondary transfer roller 14a.
When not in use, the manual feed table 25 provided on the right side of the figure can be rotated and stored in a part of the frame F of the image forming apparatus main body. The uppermost sheet S stored in the manual feed table 25 is fed by the sheet feeding roller 26 and separated by the separating means 27 so that only one sheet is reliably conveyed, and the sheet feeding / conveying path by the conveying rollers 22, 24. It is sent to the registration roller pair 13 via P1.
A fixing device 15 having a heating unit is provided above the secondary transfer unit. In this example, it is composed of rollers 15a and 15b with built-in heaters, but a type employing a belt and a heating method employing IH can also be appropriately employed.
The switching guide G1 is rotatable, and in the state shown in the figure, the sheet having been fixed is guided to the paper discharge path P3, and discharged and stacked on the paper discharge stack T at the top of the image forming apparatus 100 by the paper discharge roller 16. Let

  The full-color printer 100 in FIG. 1 includes a conveyance path and rollers for reversing and refeeding paper so that images can be automatically formed on both sides of the paper. Specifically, a switchback conveyance path P5 and a refeed path P6 are provided inside the frame F, and the switching guides G1, G2 and the reversal are performed so that the sheet on which image formation has been completed on one side is conveyed to the sheet conveyance path P1. The roller 18a which can be reversed, the conveyance roller 22 which can be reversed, etc. are provided. A roller 23 and a transport roller 24 are in contact with the reversible transport roller 22, and when the transport roller 22 rotates clockwise, the paper is transported from the manual feed table 25 in cooperation with the transport roller 24. When rotating counterclockwise, the paper is fed again in the direction of the registration roller pair 13 in cooperation with the roller 23. When the switching guide G1 is rotated clockwise from the state shown in the drawing, the sheet having been fixed is guided to the transport path P4 by the roller pair 17, and is transported to the rollers 18a and 18b through the switching guide G2, and is temporarily switched back. It is sent to the conveyance path P5. As the roller 18a rotates counterclockwise and the switching guide G2 rotates counterclockwise, the sheet is fed to the refeed path P6. The paper conveyed by the rollers 15 c and 20 and the rollers 14 c and 21 is further conveyed to the rollers 22 and 23 and reaches the registration roller pair 13.

The apparatus shown in FIG. 1 includes another sheet feeding device 50 at the bottom. In this example, two paper feed cassettes 9C and 9D, paper feed rollers 10C and 10D, separation means 11C and 11D, and transport roller pairs 12C and 12D are provided. It is also possible to use a type having a built-in paper cassette with a larger number of sheets.
A switching guide G3 above the fixing device and downstream of the conveying direction of the roller pair 17 rotates counterclockwise from the state of FIG. 1, guides the fixed sheet, and conveys it to the paper discharge path P8. The paper can be discharged to another paper discharge device not shown. As another discharge device, for example, a bin tray having several discharge trays is used.

The operation of the image forming apparatus 100 will be described below. An operation during single-sided printing in which an image is formed on one side of the paper S in such a configuration will be described.
First, an electrostatic latent image is obtained by irradiating the surface of the photoreceptor 2Y uniformly charged by the charging roller 4aY with the laser light 8Y corresponding to the image data for yellow emitted from the semiconductor laser by the operation of the exposure device 8. Is formed.
This electrostatic latent image is developed with yellow toner after being developed by the developing roller 5aY, becomes a visible image, and has a transfer action by the primary transfer roller 7Y on the surface of the intermediate transfer belt 6a that moves in synchronization with the photoreceptor 2Y. Received and primary transferred. Such latent image formation, development, and primary transfer operation are performed in the same manner sequentially at the timings of the photoreceptors 2C, 2M, and 2Bk.
As a result, yellow Y, cyan C, magenta M, and black Bk toner images are carried on the surface of the intermediate transfer belt 6a as sequentially overlapping four-color toner images in the direction of the arrow together with the intermediate transfer belt 6a. Moved. On the other hand, the remaining toner and foreign matter are cleaned on the surface of the photoreceptor 2 by the cleaning device 3.

The four-color toner image formed on the intermediate transfer belt 6a is transferred onto the sheet S conveyed in synchronization with the intermediate transfer belt 6a by receiving a transfer action by the secondary transfer roller 14a. The surface of the intermediate transfer belt 6a is cleaned by a belt cleaning device 6h to prepare for the next image formation / transfer process.
The sheet S on which the image has been transferred is subjected to a fixing action by the fixing device 15 and is discharged to the discharge stack unit T by the discharge roller 16 with the image surface facing downward (face down).

  An operation at the time of double-sided recording in which an image is formed on both sides of the paper S in such a configuration will be described. By the operation as described above, an image is first transferred from the intermediate transfer belt 6a to one side of the sheet S, and the sheet that has passed through the fixing device 15 is guided toward the roller pair 17 by the switching guide G1. The sheet that passes through the switching guide G3 and the conveying path P4 provided on the downstream side of the conveying path of the roller pair 17 and moves above the switching guide G2 at the rotation position in FIG. 1 is transferred to the switchback conveying path P5 by rollers 18a and 18b. The reversible roller 18a rotates in the clockwise direction. The roller pair 19 is also a roller capable of forward and reverse rotation, and once the paper is received in the switchback conveyance path P5, it is rotated backward to reversely feed the paper. At that time, the switching guide G2 is rotated counterclockwise from the posture shown in the drawing, and is conveyed toward the conveyance path P4 by the rollers 15c and 20 and the rollers 14c and 21 with the one that has been the rear end of the sheet as the leading end. . After that, the registration roller pair 13 is reached as described above. The toner image on the intermediate transfer belt 6a is conveyed by transporting the sheet S having an image on one side again toward the secondary transfer portion having the secondary transfer roller 14a at the timing of the registration roller pair 13. Is transferred to the other side of the sheet S.

  Images to be formed on the second surface of the paper are sequentially formed by an image forming process that is started when the paper S is conveyed to a predetermined position. The image forming process in this case is also the same as the full-color toner image formation at the time of single-side printing described above, and this full-color toner image is carried on the intermediate transfer belt 6a. However, since the front and back of the paper are reversed in the transport path, the creation of the image data emitted from the exposure device is controlled so that the image is formed in the reverse direction in the paper transport direction compared to when the image was first formed. Executed.

The sheet S on which the full-color toner image is transferred on both sides in this way is again used as the fixing device 15.
The paper is discharged onto the paper discharge stack T by the paper discharge roller 16 through the fixing process. In order to increase the efficiency of double-sided image formation, several sheets of paper can be transported simultaneously on the transport path. The formation timing of the images to be formed on the front and back of the paper is executed by a control means (not shown). Incidentally, in this embodiment, the polarity of the toner image formed on the photosensitive member 2 is negative, and the toner image on the photosensitive member 2 is transferred to the intermediate transfer belt 6a by applying a positive charge to the primary transfer roller 7. Is transferred to the surface.
Further, the toner image on the surface of the intermediate transfer belt 6a is transferred onto the sheet S by applying a positive charge to the secondary transfer roller 14a.

  The single-sided printing operation and the double-sided printing operation have been described with reference to an example in which full-color printing is performed. However, there are photosensitive members that are not used during black-and-white monochrome printing. In addition to not operating the unused photoreceptors 2Y, 2C, and 2M or the developing devices 5Y, 5C, and 5M, a mechanism for keeping the unused photoreceptors 2Y, 2C, and 2M and the intermediate transfer belt 6a in a non-contact state is provided. I have. In the present embodiment, the inner frame 6f that supports the roller 6d and the primary transfer rollers 7Y, 7C, and 7M is supported so as to be rotatable about the shaft 6g, and is rotated in a direction away from the photoreceptor (clockwise in FIG. 1). By moving it, only the photosensitive member 2K comes into contact with the intermediate transfer belt 6a, and an image forming process is executed to create a monochrome image using black toner. This is advantageous in terms of improving the service life.

When the necessity for maintenance or parts replacement occurs, the exterior cover (not shown) is opened and maintenance is performed. The members constituting the image forming unit 1Y shown in FIG. It is convenient to exchange.
When the image forming unit 1Y shown in FIG. 2 is configured as a process cartridge, a guide unit and a handle for mounting on the full-color printer 100 are provided to facilitate attachment / detachment. In addition, it is convenient to provide a storage device (for example, an IC tag) for storing the characteristics and operation status of the process cartridge, which is a guideline for maintenance. Further, the intermediate transfer unit 6
When performing maintenance, replacement, etc., the belt and the photosensitive member can be separated and the intermediate transfer unit can be pulled out.

FIG. 3 is a partial view showing a state in which the frame F is opened from the state shown in FIG. The lower rotation axis Fa is the rotation center, and the upper part can be opened. Prior to opening, most of the transport path can be opened by opening a lock lever (not shown), so that the jammed paper can be easily treated.
The secondary transfer unit 14 in which the transport path P2 and the switchback transport path P5 are formed on both sides has the center of the roller 23 as the center of rotation, and when the frame F is opened as shown in FIG. The secondary transfer unit 14 is given rotation habits so that it is separated from the intermediate transfer belt 6a and the roller 14c is separated from the roller 21. The secondary transfer unit 14 includes a power supply 14b inside, and a unit having a paper transport function outside the case. The fixing device 15 also has a roller 15c and a guide surface for conveyance, and a part of the fixing device 15 constitutes a refeed path P6. The fixing device 15 is supported in the state shown in FIG. 3 so that it can be pulled out to the right in the drawing. Therefore, it is possible to easily handle a paper jam that has occurred inside the fixing device.

FIG. 4 shows an embodiment relating to a manual feed table which is a main part of the present invention. FIG. 4 shows a state where the manual feed table 25 is opened to manually feed paper. As shown in FIG. 4, the sheet stacking surface of the manual feed table 25 has a shape curved in an arc shape in a direction perpendicular to the sheet passing direction. Specifically, the sheet stacking surface of the manual feed table 25 has a shape in which the lowest point of the arc is located at the center of the sheet with respect to the sheet passing direction and rises upward in an arc shape from the apex.
The manual feed table 25 is provided with side fences 30 and 31 for guiding both side portions of the paper, and the side fences 30 and 31 are slidable along the curved surface of the manual feed table 25 in a direction perpendicular to the paper passing direction. ing. The uppermost portions of the side fences 30 and 31 are shaped to hold the paper in the direction of the paper stacking portion. Further, regarding the curvature of the manual feed table 25, the curvature is different between the leading edge side and the trailing edge side of the sheet, the leading edge side of the sheet has a relatively small curvature, and the trailing edge side of the sheet has a relatively large curvature. It has a shape.

  FIG. 5 shows another embodiment of the present invention. FIG. 5 shows an embodiment in which the bending direction of the manual feed table 25 is opposite to that in FIG. 4, and the vertex of the arc is located at the center of the sheet with respect to the sheet passing direction, and the arc descends downward from the apex. As in FIG. 4, the side fences 30 and 31 are slidable along the curved surface of the manual feed table 25 in the direction perpendicular to the paper passing direction. Similarly, regarding the curvature of the manual feed table 25, the curvature differs between the front end side of the paper and the rear end side of the paper, the front end side of the paper has a relatively small curvature, and the rear end side of the paper has a relatively large curvature. The shape has changed.

  In the above-described embodiment, the paper stacking surface of the manual feed table 25 is curved in a direction perpendicular to the paper passing direction, so that curl can be reliably corrected even when curl occurs on the stacked paper. Can be straightened with respect to the paper direction. Further, this effect can prevent paper breakage and paper jam at the time of paper passing. Further, by reducing the curvature of the paper stacking surface of the manual feed table 25 on the leading end side of the paper, the paper after passing can be quickly returned to the horizontal posture. Furthermore, by providing the side fence, the paper stacked on the manual feed table 25 can be made to follow the curved shape of the paper stacking surface, and reliable paper correction can be performed.

FIG. 1 is an explanatory view showing an embodiment of the image forming apparatus of the present invention. 2 is a central cross-sectional view showing an outline of an image forming unit of the image forming apparatus of FIG. FIG. 3 is a partial view showing a state in which the frame is opened from the state shown in FIG. It is explanatory drawing which shows the detail of the manual feed table of FIG. The sheet stacking surface of the manual feed table has a shape in which the lowest point of the arc is located at the center of the sheet with respect to the sheet passing direction and rises upward in an arc shape from the apex. It is explanatory drawing which shows the detail of the manual feed table of FIG. The paper loading surface of the manual feed table has a shape in which an apex of an arc is located at the center of the sheet with respect to the sheet passing direction, and the arc descends downward from the apex.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image formation part 2 Photoconductor 3 Cleaning apparatus 3a Cleaning brush 3b Cleaning blade 3c Recovery screw 4 Charging apparatus 4a Charging roller 5 Developing apparatus 5a Developing roller 5b Developing blade 5c Screw 6 Intermediate transfer unit 6a Intermediate transfer belt 6b-6e Roller 6f Inside Frame 6g Axis 6h Belt cleaning device 7 Primary transfer roller 8 Exposure device 8Y, 8C, 8M, 8Bk Laser light 9A-9D Paper feed cassette 10A-10D Paper feed roller 11A-11D Separating means 12A-12D Conveying roller pair 12Aa, 12Ba Roller 13 Registration roller pair 14 Secondary transfer unit 14a Secondary transfer roller 14b Power supply 14c Roller 15 Fixing device 15a, 15b, 15c Roller 16 Paper discharge roller 17 Roller pair 18a, 18 b Roller 19 Roller pair 20 Roller 21 Roller 22, 24 Transport roller 23 Roller 25 Manual feed table 26 Feed roller 27 Separating means 30, 31 Side fence 40 Toner cartridge 50 Feed device 100 Full color printer (image forming device)
F frame Fa rotating shaft G1 to G3 switching guide P1 paper feed transport path P2 transport path P4 transport path P5 switchback transport path P6 refeed path P7 transport path P8 paper discharge path S paper T paper discharge stack section TS mounting section

Claims (11)

In an image forming apparatus provided with a manual paper feed mechanism,
An image forming apparatus, wherein the paper stacking surface of the manual feed table is curved in an arc shape in a direction perpendicular to the paper transport direction. The image forming apparatus according to claim 1.
The sheet forming surface of the manual feed table has a shape in which an apex of an arc is located at the center of the sheet with respect to the sheet passing direction, and the arc descends downward from the apex. The image forming apparatus according to claim 1, wherein:
The image forming apparatus according to claim 1, wherein the sheet loading surface of the manual feed table has different arc curvatures at the leading edge and the trailing edge of the sheet. The image forming apparatus according to any one of claims 1 to 3,
The image forming apparatus according to claim 1, wherein the sheet loading surface of the manual feed table has a larger arc curvature at the rear end of the sheet than at the front end of the sheet. 5. The image forming apparatus according to claim 1, wherein:
The image forming apparatus, wherein the manual feed table is provided with a side fence that is movable along a curved surface. The image forming apparatus according to claim 5.
The image forming apparatus according to claim 1, wherein an uppermost part of the side fence of the side fence is configured to hold a sheet toward the sheet stacking unit. The image forming apparatus according to claim 1.
The sheet forming surface of the manual feed table has a shape in which the lowest point of an arc is located at the center of the sheet with respect to the sheet passing direction, and the shape rises upward from the apex in an arc shape. The image forming apparatus according to claim 1, wherein:
The image forming apparatus according to claim 1, wherein the sheet loading surface of the manual feed table has different arc curvatures at the leading edge and the trailing edge of the sheet. The image forming apparatus according to claim 1, claim 7, or claim 8.
The image forming apparatus according to claim 1, wherein the sheet loading surface of the manual feed table has a larger arc curvature at the rear end of the sheet than at the front end of the sheet. The image forming apparatus according to claim 1, claim 7, claim 8, or claim 9.
The image forming apparatus, wherein the manual feed table is provided with a side fence that is movable along a curved surface. The image forming apparatus according to claim 10.
The image forming apparatus according to claim 1, wherein an uppermost part of the side fence of the side fence is configured to hold a sheet toward the sheet stacking unit.

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