IMAGE FORMING APPARATUS

Abstract

An image forming apparatus includes an image formation unit configured to form an image, a tray configured to stack the sheet, the tray being turnable between a closed position and an opened position, a feed unit configured to feed the sheet, and an extension tray configured to stack the sheet, the extension tray being movable between an extension position in which the extension tray is extended from the tray toward an upstream side and a stored position in which the extension tray is stored in the tray, wherein the apparatus main body has a first protruding portion protruding from the side surface of the apparatus main body toward the tray, and wherein when the tray is in the closed position and the extension tray is in the stored position, the first protruding portion presses an outer wall portion of the tray and the extension tray toward the opened position.

Description

BACKGROUND

Field

The present disclosure relates to an image forming apparatus that forms an image on a sheet.

Description of the Related Art

In recent years, image forming apparatuses, such as copiers and printers, with quieter operation has been highly demanded by customer needs. However, in operation, image forming apparatuses generate vibrations due to driving of motors, gears, fans, and the like disposed in the apparatuses. Because the vibrations propagate to various parts of the image forming apparatus, the operation noise is emitted outward from inside the apparatus to the surrounding space of the image forming apparatus.

One of the parts through which vibrations propagate is the exterior cover. The exterior cover is originally designed to block emission of operation noise generated inside the apparatus into the outside of the apparatus.

However, operation noise generated by the vibration of the exterior cover itself is still not blocked and is emitted directly into the surrounding space.

To reduce noise from the image forming apparatus, it is important to suppress the vibration of the exterior cover, that is, to isolate the exterior cover from vibration such that noise is not emitted from the exterior cover.

An example of a part of the exterior cover is an openable manual feed tray that is included in a manual feed unit. When not in use, the manual feed tray is stored in an apparatus main body and serves as a part of the exterior cover. The manual feed tray occupies a relatively large surface area in the exterior cover, and thus when vibration propagates, the manual feed tray emits loud noise.

Japanese Patent Application Laid-Open No. 2009-040555 discusses a configuration in which a sound-absorbing material is disposed inside a manual feed tray to use the manual feed tray as a sound-insulating board, whereby noise inside the apparatus is prevented from passing through the manual feed tray and leaking to the outside.

However, in the configuration discussed in Japanese Patent Application Laid-Open No. 2009-040555, since the sound-absorbing material is disposed inside the manual feed tray to provide the sound-insulating board, the size of the apparatus main body is increased and the complexity of the structure is increased. This may result in an increase in costs and manufacturing load and a reduction in space efficiency.

SUMMARY

In view of this, the present disclosure is directed to providing an image forming apparatus that is simple in structure, space-efficient, and capable of isolating vibration of a manual feed tray, whereby noise reduction is improved.

According to some embodiments, an image forming apparatus includes an image formation unit configured to form an image on a sheet, a tray disposed on a side surface of an apparatus main body of the image forming apparatus including the image formation unit and configured to stack the sheet thereon, the tray being turnable between a closed position in which the tray faces the side surface of the apparatus main body and an opened position in which the tray is opened from the apparatus main body to a position where the tray stacks the sheet thereon, a feed unit configured to feed the sheet stacked on the tray toward the image formation unit, and an extension tray configured to stack the sheet thereon, the extension tray being movable between an extension position in which the extension tray is extended from the tray toward an upstream side in a sheet feeding direction and a stored position in which the extension tray is stored in the tray, wherein the apparatus main body has a first protruding portion protruding from the side surface of the apparatus main body toward the tray, and wherein when the tray is in the closed position and the extension tray is in the stored position, the first protruding portion presses an outer wall portion of the tray and the extension tray toward the opened position.

Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view of an image forming apparatus according to a first exemplary embodiment.

FIG. 2 is a perspective view of a manual feed tray according to the first exemplary embodiment.

FIG. 3 is a diagram illustrating a result of noise emitted from the manual feed tray that is measured by using an acoustic camera according to the first exemplary embodiment.

FIG. 4 is a schematic diagram illustrating a first pressure portion according to the first exemplary embodiment.

FIG. 5A is a cross-sectional view of the manual feed tray according to the first exemplary embodiment in a state in which the manual feed tray is opened from an apparatus main body and an extension tray is pulled out from the manual feed tray, and FIG. 5B is a cross-sectional view of the manual feed tray according to the first exemplary embodiment in a state in which the extension tray is stored in the manual feed tray and the manual feed tray is closed to the apparatus main body.

FIG. 6 is a diagram illustrating a measurement result of noise-reduction effect of the manual feed tray according to the first exemplary embodiment.

FIG. 7A is a cross-sectional view of a manual feed tray according to a second exemplary embodiment in a state in which the manual feed tray is opened from an apparatus main body and an extension tray is pulled out from the manual feed tray, and FIG. 7B is a cross-sectional view of the manual feed tray according to the second exemplary embodiment in a state in which the manual feed tray is closed to the apparatus main body and the extension tray is stored in the manual feed tray.

FIG. 8A is a cross-sectional view of a manual feed tray according to a third exemplary embodiment in a state in which the manual feed tray is opened from an apparatus main body, and FIG. 8B is a cross-sectional view of the manual feed tray according to the third exemplary embodiment in a state in which the manual feed tray is closed to the apparatus main body.

FIG. 9 is a diagram illustrating a first modification example of the manual feed tray according to the third exemplary embodiment.

FIG. 10 is a diagram illustrating a second modification example of the manual feed tray according to the third exemplary embodiment.

FIG. 11A is a cross-sectional view of a manual feed tray according to a fourth exemplary embodiment in a state in which the manual feed tray is opened from an apparatus main body, and FIG. 11B is a cross-sectional view of the manual feed tray according to the fourth exemplary embodiment in a state in which the manual feed tray is closed to the apparatus main body.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, various exemplary embodiments, features, and aspects of the present disclosure will be described below with reference to the drawings. An image forming apparatus according to the present exemplary embodiment is an intermediate transfer-type image forming apparatus, such as a copier, a printer, a facsimile, or a multi-function peripheral thereof, by which a toner image is primarily transferred onto an intermediate transfer belt and then secondarily transferred onto a sheet. In the following exemplary embodiments, a description will be given of an intermediate transfer-type image forming apparatus in which four color image formation units are arranged on the intermediate transfer belt.

<Image Forming Apparatus>

An image forming apparatus of the present exemplary embodiment will be described with reference to FIG. 1. An image forming apparatus 100 illustrated in FIG. 1 is an intermediate transfer tandem-type color image forming apparatus including image formation units PY, PM, PC, and PK for four colors (yellow, cyan, magenta, and black) disposed inside an apparatus main body of the image forming apparatus 100 in positions facing the lower part of an intermediate transfer belt 8. Examples of a sheet P that is a recording material usable in the image forming apparatus 100 include various types of sheet materials, such as plain paper, thick paper, rough paper, textured paper, and coated paper, overhead projector (OHP) sheets, plastic films, and cloth.

The image forming apparatus 100 in the present exemplary embodiment produces a sheet with the toner image as a product by performing an image forming process for formation of a toner image and a conveyance process for conveyance of a sheet in synchronization with each other.

The sheet conveyance process will be described. A cassette feed unit 800 is disposed at the lower part of the image forming apparatus 100, and sheets P are stacked and stored in a cassette 72. The sheets P are fed one by one toward a conveyance path 74 by feed rollers 73 in accordance with the image formation timing. A manual feed unit 200 is disposed on a side of the image forming apparatus 100. The manual feed unit 200 is disposed with a manual feed tray 201. Sheets P placed on the manual feed tray 201 are separated one by one by manual feed rollers 79 that is a feed unit, and are fed to the conveyance path 74.

A sheet P fed from the cassette feed unit 800 or the manual feed unit 200 is conveyed toward registration rollers 75 disposed in a midway position along the conveyance path 74.

The registration rollers 75 correct the skew of the fed sheet P and correct the timing of image formation, and then sends the sheet P to a secondary transfer unit T2. The secondary transfer unit T2 is a transfer nip part formed by a secondary transfer inner roller 76 and a secondary transfer outer roller 77 that face each other.

At the secondary transfer unit T2, the toner image is secondarily transferred from the intermediate transfer belt 8 to the sheet P.

The image forming process of an image that is conveyed to the secondary transfer unit T2 in synchronization with the above-described conveyance process of the sheet P to the secondary transfer unit T2 will be described. The image formation units PY to PK will be described. The image formation units PY to PK are configured substantially the same as each other except that the colors of the toner that is used in developing devices 4Y, 4M, 4C, and 4K are different, that is, colors of yellow, magenta, cyan, and black, respectively, are used. The following description will be given taking the image formation unit PY of yellow as a representative example, and redundant descriptions of the other image formation units PM, PC, and PK will be omitted. For convenience of illustration, only a developer container 41Y and a developing roller 42Y of the image formation unit PY described below are denoted with reference signs.

The image formation unit PY mainly includes a photosensitive drum 1Y, a charging device 2Y, the developing device 4Y, a photosensitive drum cleaner 6Y, and the like. In image formation operation, the photosensitive drum 1Y is rotationally driven in a direction indicated by an arrow R1 at a predetermined process speed (circumferential speed). A charging voltage is applied to the charging device 2Y by a high-voltage power source, and a current flows between the charging device 2Y (charging roller) and the photosensitive drum 1Y, so that the surface of the photosensitive drum 1Y is uniformly charged at a predetermined polarity and potential.

After the charging, the photosensitive drum 1Y is exposed by an exposure device 3, based on image information and an electrostatic latent image is formed on the photosensitive drum 1Y. Toner is adhered to the electrostatic latent image by the developing device 4Y, and is developed into a toner image. The developing device 4Y includes the developer container 41Y that contains a developer, and the developing roller 42Y (also called a developing sleeve) that rotates while carrying the developer, and the electrostatic latent image is developed into a toner image by application of a developing voltage to the developing roller 42Y. Thereafter, a predetermined pressure force and a primary transfer voltage are applied by a primary transfer roller 5Y that is disposed in a position opposite to the image formation unit PY with respect to the intermediate transfer belt 8 interposed between the primary transfer roller 5Y and the image formation unit PY, and the toner image formed on the photosensitive drum 1Y is primarily transferred onto the intermediate transfer belt 8. A small amount of residual toner remaining on the photosensitive drum 1Y after the primary transfer is removed by the photosensitive drum cleaner 6Y, to prepare for the next image formation process.

The intermediate transfer belt 8 is tensioned by a tension roller 10, the secondary transfer inner roller 76, and idler rollers 7a and 7b as tension rollers, and is driven to move in a direction indicated by an arrow R2 in FIG. 1. In the present exemplary embodiment, the secondary transfer inner roller 76 also serves as a drive roller that drives the intermediate transfer belt 8. The image forming processes of colors by the image formation units PY to PK described above are performed at timings of sequentially superimposing the toner images which are primary transferred onto the intermediate transfer belt 8 from upstream in the movement direction. As a result, a full-color toner image is formed on the intermediate transfer belt 8 in the end of the processes, and is conveyed to the secondary transfer unit T2. After passage of the toner image through the secondary transfer unit T2, the residual toner is removed from the intermediate transfer belt 8 by a transfer cleaner device 11.

Through the above-described conveyance process and image forming process, the timings for the sheet P and the full-color toner image are synchronized at the secondary transfer unit T2, and the toner image is secondarily transferred from the intermediate transfer belt 8 to the sheet P. The sheet P is conveyed to a fixing device 103, where the toner image transferred to the sheet is fused and fixed onto the sheet P by pressure and heat applied to the toner image. The sheet P with the fixed toner image is ejected onto a discharge tray 601 by discharge rollers 78. These conveyance process and image forming process are controlled by a control unit 500 disposed in the image forming apparatus 100.

<Manual Feed Tray>

The manual feed tray 201 of the manual feed unit 200 according to the present exemplary embodiment will be described. FIG. 2 is a perspective view of the manual feed tray 201 of the manual feed unit 200 on which sheets are to be stacked.

The material for the manual feed tray 201 is resin acrylonitrile butadiene styrene (ABS). Sheets are stacked on a stacking surface 202 of the manual feed tray 201. In the stacking surface 202 serving as the placement surface, a pair of side regulation plates 203 for alignment of the end positions of sheets P in a sheet width direction orthogonal to a sheet feeding direction are disposed in such a manner that the positions of the side regulation plates 203 are changeable in the sheet width direction in accordance with the sheet size. The stacking surface 202 of the manual feed tray 201 has a sheet length detection sensor 211 thereon that detects the length of the sheets.

The manual feed tray 201 has latches 204 on the front and rear sides (FIG. 2 only illustrates the latch 204 on the front side of the apparatus main body of the image forming apparatus 100). The apparatus main body includes latch receivers 205 each having a hole portion in which a different one of the latches 204 is engaged, in the positions on the front and rear sides facing the latches 204 when the manual feed tray 201 is moved to a stored position in the apparatus main body (FIG. 2 illustrates only the latch receiver 205 on the rear side of the apparatus main body).

Thee latches 204 are each biased outward by a spring member and can protrude and contract in the direction of the latch receivers 205. The latches 204 engage with the holes in the latch receivers 205, so that the manual feed tray 201 is held in the stored position that is a closed position. In a case where the latches 204 are held by the latch receivers 205, the clearance between each of the latches 204 and the corresponding one of the latch receivers 205 is set to 0.2 millimeters (mm) in the opening direction of the manual feed tray 201. In a case where the manual feed tray 201 is opened from the stored position to a feeding position that is an opened position, the manual feed tray 201 is turned with fingers hooked on a manual feed tray handle unit 206. In this opening process, the latches 204 are contracted by the spring members to come over the edges of the holes of the latch receivers 205, and the latches 204 and are disengaged from the holes of the latch receivers 205, whereby the manual feed tray 201 is opened. In the present exemplary embodiment, the working force to open the manual feed tray 201 is about 500 gram-forces (gf), so that the manual feed tray 201 can be easily opened and closed.

The manual feed tray 201 includes an extension tray 207 that is used in a case where sheets longer in the sheet feeding direction than the size of the manual feed tray 201 are stacked. The sheet stacking surface can be extendable by pulling the extension tray 207 out from the manual feed tray 201 toward the upstream side in the sheet feeding direction. FIG. 2 illustrates a state in which the extension tray 207 is pulled out from the manual feed tray 201. In closing the manual feed tray 201, the manual feed tray 201 is stored in the apparatus main body with the extension tray 207 stored in the manual feed tray 201.

<Source of Vibration of Manual Feed Tray>

The manual feed tray 201 in the stored position where the manual feed tray 201 is stored in the apparatus main body, is one of the main sources of noise emission. Furthermore, the manual feed tray 201 is prone to amplify vibration due to the rattle of the opening/closing mechanism that is opened and closed with respect to the apparatus main body.

FIG. 3 illustrates a measurement result of the noise emitted from the manual feed tray 201 in the closed position with respect to the apparatus main body with the extension tray 207 stored in the manual feed tray 201 which is obtained by using an acoustic camera.

The inventors have verified that, in a case where the motor of a sheet feed drive unit that rotationally drives the feed rollers 73 disposed in the cassette feed unit 800 is operated, vibration of 527 hertz (Hz) is generated, for example, which is the meshing frequency of the gear included in the sheet feed drive unit. It was revealed that the vibration was propagated to the manual feed tray 201 through the fastening part between the apparatus main body of the image forming apparatus 100 and the manual feed unit 200, and the vibration of the manual feed tray 201 causes noise to be emitted from a manual feed tray outer wall surface 208, which is the outer wall portion of the manual feed tray 201. The manual feed tray outer wall surface 208 is the surface opposite to the stacking surface 202. The noise emission was observed in an area A of the manual feed tray outer wall surface 208 where the manual feed tray 201 forms a box shape with the stacking surface 202, both side surfaces, and the outer wall surface. In addition, the noise emission was also observed in a gap area B where the extension tray 207 slides with respect to the manual feed tray 201.

That is, the noise from the manual feed tray 201 includes noise that is emitted from the manual feed tray outer wall surface 208 due to the vibration that is propagated from the motor of the apparatus main body and amplified by the manual feed tray 201. In addition, the noise from the manual feed tray 201 includes noise that is generated due to the vibration that is transmitted to the manual feed tray 201, and amplified by rattling of the extension tray 207 due to the vibration. It was found that there are these two types of noise.

<Vibration-Damping Structure of Manual Feed Tray>

A structure to reduce the noise emitted in the area A of the manual feed tray outer wall surface 208 and in the gap area B where the extension tray 207 slides with respect to the manual feed tray 201 will be described.

FIGS. 5A and 5B are schematic cross-sectional views of a structure to suppress rattling of the manual feed tray outer wall surface 208, the manual feed tray 201, the extension tray 207. FIG. 5A illustrates a state in which the manual feed tray 201 is opened from the apparatus main body, and the extension tray 207 is pulled out from the manual feed tray 201. FIG. 5B illustrates a state in which the extension tray 207 is stored in the manual feed tray 201, and the manual feed tray 201 is closed to the apparatus main body.

In the present exemplary embodiment, a side wall surface 131 of the apparatus main body has a first pressure portion 220 serving as a first protruding portion protruding toward the stacking surface 202 of the manual feed tray 201. A protrusion length L1 of the first pressure portion 220 is set to be longer than a distance L2 between the side wall surface 131 and the stacking surface 202 of the manual feed tray 201, that is, L1>L2, when the manual feed tray 201 is closed in the stored position where the manual feed tray 201 is stored in the apparatus main body. In the present exemplary embodiment, the distance L2 is 11 mm, and the protrusion length L1 of the first pressure portion 220 is 11.5 mm.

A second pressure portion 231 serving as a second protruding portion is disposed on a surface 209 which is a surface opposite to the stacking surface 202 of the manual feed tray 201 pressed by the first pressure portion 220. The second pressure portion 231 protrudes, approximately coaxially with the first pressure portion 220, toward a stacking surface 233 of the extension tray 207. Furthermore, a third pressure portion 232 serving as a third protruding portion is disposed, approximately coaxially with the second pressure portion 231, on a surface 234 which is a surface opposite to the stacking surface 233 of the extension tray 207 pressed by the second pressure portion 231. The third pressure portion 232 faces a surface 210 which is a surface opposite to the manual feed tray outer wall surface 208 of the manual feed tray 201.

In the present exemplary embodiment, the first pressure portion 220, the second pressure portion 231, and the third pressure portion 232 are cylindrical portions with a diameter of 6 mm. Leading ends of these portions have a spherical shape so that their pressure are concentrated on the corresponding contact portions. In the present exemplary embodiment, the material for the side wall surface 131 is a resin PC+ABS, and the first pressure portion 220 is integrated with the side wall surface 131.

The length from the surface 209 which is the surface opposite to the stacking surface 202 of the manual feed tray 201 to the leading end of the second pressure portion 231 protruding from the surface 209 is defined as L5, and the length from the stacking surface 233 of the extension tray 207 to the leading end of the third pressure portion 232 is defined as L6. In this case, the sum (L5+L6) is set to be shorter than a distance LA between the surface 209 which is the surface opposite to the stacking surface 202 of the manual feed tray 201 and the surface 210 which is the surface opposite to the manual feed tray outer wall surface 208, in consideration of the workability of pulling out the extension tray 207. In the present exemplary embodiment, the dimension of the distance LA is 16 mm, and the sum of the lengths L5 and L6 is 15.8 mm.

With the above-described configuration, in a state in which the extension tray 207 is stored in the manual feed tray 201 and the manual feed tray 201 is closed to the apparatus main body, the first pressure portion 220 presses the stacking surface 202 of the manual feed tray 201, which suppresses the vibration of the stacking surface 202 of the manual feed tray 201. The pressure of the first pressure portion 220 on the stacking surface 202 of the manual feed tray 201 causes the second pressure portion 231 to press the stacking surface 233 of the extension tray 207, which further causes the third pressure portion 232 to press the surface 210 which is the surface opposite to the manual feed tray outer wall surface 208.

This configuration suppresses the rattling of the extension tray 207 with respect to the manual feed tray 201, and further suppresses the vibration of the manual feed tray outer wall surface 208, whereby the vibration of the entire portion of the manual feed tray 201 is suppressed. When the manual feed tray 201 is closed to the apparatus main body, the first pressure portion 220 bites into and presses the stacking surface 202 of the manual feed tray 201 so that the vibration of the stacking surface 202 of the manual feed tray 201 is suppressed, even with a backlash of the latch 204 described above. In the configuration of the present exemplary embodiment, the pressing forces of the first pressure portion 220 and the second pressure portion 231 are both about 50 gf. Because these pressing forces are smaller than the engagement force of the latches 204 described above, the manual feed tray 201 which is closed will not open unintentionally.

The first pressure portion 220, the second pressure portion 231, and the third pressure portion 232 may be disposed in a plurality of positions on the stacking surface 202 of the manual feed tray 201. The positions of pressing by the first pressure portion 220, the second pressure portion 231, and the third pressure portion 232 may not be coaxial with respect to the pressing direction. That is, the pressure portions can be disposed anywhere inside the ridge line of outer periphery of the manual feed tray 201 as long as there are no parts that hinder arrangement. For example, the sliding area of the side regulation plates 203 inside the manual feed tray 201 and the area where the bundled wire of the sheet length detection sensor 211 is disposed are not fastened with screws, so that the stacking surface 202 of the manual feed tray 201 and the manual feed tray outer wall surface 208 are likely to vibrate greatly in these areas. However, the vibration of the manual feed tray 201 is suppressed by pressing the area in the stacking surface 202 of the manual feed tray 201 with the first pressure portion 220 and pressing the area in proximity to the manual feed tray outer wall surface 208 with the second pressure portion 231.

The first pressure portion 220 may be separate from the side wall surface 131, or may be made of a material different from that of the side wall surface 131. For example, the first pressure portion 220 may be made of metal to increase the rigidity of the first pressure portion 220, and may be fastened to the side wall surface 131 made of resin.

The effect of noise reduction obtained by the above configuration will be described. With the manual feed tray 201 according to the present exemplary embodiment incorporated in the image forming apparatus 100, the feed drive motor was rotationally driven and the sound pressure level (unit: decibel (dB)) of the operation noise was measured. For the measurement, a microphone was used to detect the emitted sound waves and convert them into an electric signal. The microphone was connected to a preamplifier that amplified the electric signal and a calculation device that calculated the amplified electric signal into a sound pressure level and a frequency. The detection surface of the microphone was placed in a position facing the center of the right side of the image forming apparatus 100 on which the manual feed tray 201 was provided, at a distance of 1 meter (m) from the exterior surface of the image forming apparatus 100 and a height of 1.5 m from the floor surface.

FIG. 6 is a graph illustrating the measurement results of sound pressure level in the manual feed tray 201 having the vibration-damping structure according to the present exemplary embodiment. The graph illustrates the result with the first pressure portion 220, the second pressure portion 231, and the third pressure portion 232 and the result without them. With the first pressure portion 220, the second pressure portion 231, and the third pressure portion 232, the vibration of the manual feed tray 201 caused by the sheet feed drive unit was reduced, and a noise reduction effect of about 7 dB was obtained at 527 Hz that was the gear meshing frequency.

A second exemplary embodiment differs from the first exemplary embodiment in the respects described below. In the first exemplary embodiment, the first pressure portion 220 disposed on the side wall surface 131 of the apparatus main body abuts against the stacking surface 202 of the manual feed tray 201, whereas in the present exemplary embodiment, a first pressure portion 220 disposed on the side wall surface 131 of the apparatus main body abuts against the stacking surface 233 of the extension tray 207.

FIGS. 7A and 7B are diagrams illustrating the present exemplary embodiment and are schematic diagrams of a configuration in which the first pressure portion 220 disposed on the side wall surface 131 presses the stacking surface 233 of the extension tray 207, and the third pressure portion 232 of the extension tray 207 pressed by the pressure of the first pressure portion 220 presses the surface 210 which is the surface opposite to the manual feed tray outer wall surface 208.

FIG. 7A illustrates a state in which a manual feed tray 201 is opened from the apparatus main body, and the extension tray 207 is pulled out from the manual feed tray 201. FIG. 7B illustrates a state in which the manual feed tray 201 is closed to the apparatus main body, and the extension tray 207 is stored in the manual feed tray 201.

In the present exemplary embodiment, the manual feed tray 201 has a hole 242 in the stacking surface 202 of the manual feed tray 201 that faces the first pressure portion 220 when the manual feed tray 201 is stored.

As in the first exemplary embodiment, the first pressure portion 220 is a cylindrical portion with a diameter of 6 mm. The leading end of the first pressure portion 220 has a spherical shape so that pressure is concentrated on the contact portion with the stacking surface 233 of the extension tray 207.

A protrusion length L9 of the first pressure portion 220 is set to be longer than a distance L10 between the side wall surface 131 and the stacking surface 233 of the extension tray 207, that is, L9>L10, when the manual feed tray 201 is closed to the apparatus main body. In the present exemplary embodiment, the distance L10 is 20 mm, and the distance L10 of the first pressure portion 220 is 20.5 mm.

As described above, the present exemplary embodiment has the following configuration when the extension tray 207 is in the stored position where the extension tray 207 is stored in the manual feed tray 201 and the manual feed tray 201 is closed to the apparatus main body. In this configuration, the first pressure portion 220 presses the stacking surface 233 of the extension tray 207, and the third pressure portion 232 presses the surface 210 which is the surface opposite to the manual feed tray outer wall surface 208. With this configuration, the rattling of the extension tray 207 is suppressed, and the vibration of the manual feed tray outer wall surface 208 is also suppressed, whereby the vibration of the entire part of the manual feed tray 201 is suppressed. These advantageous effects are similar to those of the first exemplary embodiment illustrated in FIG. 6. The vibration of the manual feed tray 201 that is caused by the sheet feed drive unit is reduced, and the effect of a reduction of about 7 dB is obtained at the gear meshing frequency of 527 Hz.

In a third exemplary embodiment, a description will be given of a vibration-damping structure for a manual feed tray 201 in a case where the manual feed tray unit in the first and second exemplary embodiments is not disposed in the extension tray 207.

FIGS. 8A and 8B are cross-sectional views of a configuration of a manual tray feed unit in the present exemplary embodiment. FIG. 8A illustrates a state in which the manual feed tray 201 is opened from an apparatus main body when the manual feed unit 200 is used, and FIG. 8B illustrates a state in which the manual feed tray 201 is closed to the apparatus main body.

As in the first and second exemplary embodiments, the first pressure portion 220 is disposed on the side wall surface 131 that is the wall surface of the apparatus main body and faces the stacking surface 202 of the manual feed tray 201 when the manual feed tray 201 is closed to the apparatus main body. The first pressure portion 220 is a protrudes toward the stacking surface 202 of the manual feed tray 201. The first pressure portion 220 is a cylindrical portion with a diameter of 6 mm. The leading end of the first pressure portion 220 has a spherical shape so that pressure is concentrated on the contact portion with the stacking surface 202 of the manual feed tray 201 described below.

A length L1 of the first pressure portion 220 is set to be longer than a distance L2 between the side wall surface 131 of the apparatus main body and the stacking surface 202 of the manual feed tray 201, that is, L1>L2, when the manual feed tray 201 is closed in the stored position. In the present exemplary embodiment, the distance L2 is 11 mm, and the length L1 of the first pressure portion 220 is 11.5 mm.

A second pressure portion 231 is disposed on the surface 209 which is the surface opposite to the stacking surface 202 of the manual feed tray 201 pressed by the first pressure portion 220. The second pressure portion 231 faces the surface 210 which is the surface opposite to a manual feed tray outer wall surface 208 of the manual feed tray 201, approximately coaxially with the first pressure portion 220. The second pressure portion 231 is a cylindrical portion with a diameter of 6 mm. The leading end of the second pressure portion 231 has a spherical shape so that pressure is concentrated on the contact portion with the surface 210 which is the surface opposite to the manual feed tray outer wall surface 208.

A protrusion length L3 of the second pressure portion 231 is set such that the first pressure portion 220 presses the stacking surface 202 of the manual feed tray 201 when the manual feed tray 201 is closed to the apparatus main body. This pressing causes the stacking surface 202 of the manual feed tray 201 to be bent, and the second pressure portion 231 contacts and presses the surface 210 which is the surface opposite to the manual feed tray outer wall surface 208. In the present exemplary embodiment, the dimension of a distance LA between the surface 209 which is the surface opposite to the stacking surface 202 of the manual feed tray 201 and the surface 210 which is the surface opposite to the manual feed tray outer wall surface 208 is 16 mm, and the length L3 is 15.8 mm. In the present exemplary embodiment, one first pressure portion 220 and one second pressure portion 231 are disposed to press the portion in the area A illustrated in FIG. 3 where the emitted noise is the loudest.

The second pressure portion 231 may be configured to stably press the surface 210 which is the surface opposite to the manual feed tray outer wall surface 208 even if the surface 210 which is the surface opposite to the manual feed tray outer wall surface 208 is deformed to warp away from the second pressure portion 231. That is, the length L3 of the second pressure portion 231 may be longer than the distance LA between the surface 209 which is the surface opposite to the stacking surface 202 of the manual feed tray 201 and the surface 210 which is the surface opposite to the manual feed tray outer wall surface 208. For example, the distance LA is set to 16 mm and the length L3 is set to 16.2 mm to cause the second pressure portion 231 to be constantly pressed, and the vibration of the entire part of the manual feed tray 201 may be prevented by closing the manual feed tray 201. The contact portion of the surface 210 which is the surface opposite to the manual feed tray outer wall surface 208 may be a spherical convex portion 222 that faces the second pressure portion 231 as illustrated in FIG. 9. Furthermore, as illustrated in FIG. 10, an elastic member 223 may be disposed at the contact portion of the surface 210 which is the surface opposite to the manual feed tray outer wall surface 208, such that when being pressed, the leading end of the second pressure portion 231 may enter into the elastic member 223 and press the surface 210 which is the surface opposite to the manual feed tray outer wall surface 208.

A fourth exemplary embodiment differs from the third exemplary embodiment in that the first pressure portion 220 disposed on the side wall surface 131 of the apparatus main body directly presses the surface 210 which is the surface opposite to the manual feed tray outer wall surface 208.

FIGS. 11A and 11B are schematic diagrams of the configuration. FIG. 11A illustrates a state in which the manual feed tray 201 is opened from the apparatus main body when the manual feed unit 200 is used, and FIG. 11B illustrates a state in which the manual feed tray 201 is closed to the apparatus main body.

Similar to the second exemplary embodiment, a hole is in the area of the stacking surface 202 of the manual feed tray 201 that faces the first pressure portion 220 when the manual feed tray 201 is closed to the apparatus main body. The first pressure portion 220 is a cylindrical portion with a diameter of 6 mm. The leading end of the first pressure portion 220 has a spherical shape so that pressure is concentrated on the contact portion to the surface 210 which is the surface opposite to the manual feed tray outer wall surface 208. A protrusion length L7 of the first pressure portion 220 is set to be longer than a distance L8 between the side wall surface 131 and the surface 210 which is the surface opposite to the manual feed tray outer wall surface 208, that is, L7>L8, when the manual feed tray 201 is closed to the apparatus main body. In the present exemplary embodiment, the distance L8 is 32 mm, and the length L7 of the first pressure portion 220 is 32.5 mm.

With the above configuration, when the manual feed tray 201 is closed, the first pressure portion 220 presses the surface 210 which is the surface opposite to the manual feed tray outer wall surface 208, which causes a vibration of the surface 210 which is the surface opposite to the manual feed tray outer wall surface 208 to be suppressed, whereby the vibration of the manual feed tray 201 is suppressed.

While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

This application claims the benefit of priority from Japanese Patent Application No. 2023-203427, filed Nov. 30, 2023, which is hereby incorporated by reference herein in its entirety.

Claims

1. An image forming apparatus comprising: an image formation unit configured to form an image on a sheet;a tray disposed on a side surface of an apparatus main body of the image forming apparatus including the image formation unit and configured to stack the sheet thereon, the tray being turnable between a closed position in which the tray faces the side surface of the apparatus main body and an opened position in which the tray is opened from the apparatus main body to a position where the tray stacks the sheet thereon;a feed unit configured to feed the sheet stacked on the tray toward the image formation unit; andan extension tray configured to stack the sheet thereon, the extension tray being movable between an extension position in which the extension tray is extended from the tray toward an upstream side in a sheet feeding direction and a stored position in which the extension tray is stored in the tray,wherein the apparatus main body has a first protruding portion protruding from the side surface of the apparatus main body toward the tray, andwherein when the tray is in the closed position and the extension tray is in the stored position, the first protruding portion presses an outer wall portion of the tray and the extension tray toward the opened position.

2. The image forming apparatus according to claim 1, wherein the tray includes an engaging part that engages with the apparatus main body when the tray is in the closed position,wherein the apparatus main body includes an engaged part that is engaged with the engaging part, andwherein when the engaging part engages with the engaged part, the first protruding portion presses the outer wall portion of the tray and the extension tray toward the opened position.

3. The image forming apparatus according to claim 1, wherein the tray has a first stacking surface on which the sheet is stacked and includes a second protruding portion protruding from a surface of the tray that is a surface opposite to the first stacking surface on which the sheet is stacked, toward the outer wall portion of the tray,wherein the extension tray has a second stacking surface on which the sheet is stacked and includes a third protruding portion protruding from a surface of the extension tray that is a surface opposite to the second stacking surface on which the sheet is stacked, toward the outer wall portion of the tray, andwherein when the tray is in the closed position and the extension tray is in the stored position, the first protruding portion presses the first stacking surface of the tray, the second protruding portion presses the second stacking surface of the extension tray, and the third protruding portion presses the outer wall portion of the tray.

4. The image forming apparatus according to claim 1, wherein the first stacking surface of the tray has a hole through which the first protruding portion passes,wherein the extension tray has a second stacking surface on which the sheet is staked and includes a third protruding portion protruding from a surface of the extension tray that is a surface opposite to the second stacking surface on which the sheet is stacked, toward the outer wall portion of the tray, andwherein when the tray is in the closed position and the extension tray is in the stored position, the first protruding portion passed through the hole presses the second stacking surface of the extension tray, and the third protruding portion presses the outer wall portion of the tray.

5. An image forming apparatus comprising: an image formation unit configured to form an image on a sheet;a tray disposed on a side surface of an apparatus main body of the image forming apparatus including the image formation unit and configured to stack the sheet thereon, the tray being turnable between a closed position in which the tray faces the side surface of the apparatus main body and an opened position in which the tray is opened from the apparatus main body to a position where the sheet is stacked; anda feed unit configured to feed the sheet stacked on the tray toward the image formation unit,wherein the apparatus main body has a first protruding portion protruding from a side surface of the apparatus main body toward the tray, andwherein when the tray is in the closed position, the first protruding portion presses an outer wall portion of the tray toward the opened position.

6. The image forming apparatus according to claim 5, wherein the tray has a first stacking surface on which the sheet is stacked and includes a second protruding portion protruding from a surface of the tray that is a surface opposite to the first stacking surface on which the sheet is stacked, toward the outer wall portion of the tray, andwherein when the tray is in the closed position, the first protruding portion presses the first stacking surface of the tray, and the second protruding portion presses the outer wall portion of the tray.

7. The image forming apparatus according to claim 5, wherein the first stacking surface of the tray has a hole through which the first protruding portion passes, andwherein when the tray is in the closed position, the first protruding portion passed through the hole presses the outer wall portion of the tray.