Sheet storage device, sheet feeding device and image forming device

Abstract

To downsize a constitution in which an energization force for energizing a bottom plate member toward a feeding member is switched in accordance with a positional change of a restriction member.SOLUTION: A sheet storage device 100 includes: main energization means 111 for energizing a bottom plate member toward a feeding member 41 for feeding a sheet on the bottom plate member 110; auxiliary energization means 121 for energizing the bottom plate member toward the feeding member; and a sheet width direction position restriction member 104 for restricting the sheet width direction position of the sheet on the bottom plate member. It also includes: a pinching member 122 arranged between an energization part of the auxiliary energization means and a part to be energized of the bottom plate member, and pinched between the energization part and the part to be energized when the auxiliary energization means energizes the bottom plate member; and switching means 123 for switching the state of the pinching member between an energization possible state where the energization part can energize the part to be energized via the pinching member and an energization suppressing state where the energization force of the energization part energizing the part to be energized via the pinching member is suppressed further than that in the energization possible state, being interlocked with the positional change of a restriction member.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a sheet storage device, a sheet feeding device, and an image forming apparatus. [Background technology]

[0002] Conventionally, a sheet storage device has been known that has a bottom plate member on which sheets are stacked, a main urging means that urges the bottom plate member toward a feeding member that feeds the sheets stacked on the bottom plate member, and an auxiliary urging means that urges the bottom plate member toward the feeding member.

[0003] For example, Patent Document 1 discloses a sheet storage device in which a push-up lever rotates due to the biasing force of two push-up springs (a main biasing means and an auxiliary biasing means) and pushes up the underside of a push-up plate (a bottom plate member), causing sheets loaded on the push-up plate to contact a feed roller (a feed member). This sheet storage device is provided with a width regulating member (a sheet width direction position regulating member) that regulates the sheet width direction position of the sheets loaded on the push-up plate. This sheet storage device employs a configuration in which the biasing force that pushes up the push-up plate is changed in conjunction with the displacement of the width regulating member in order to reduce the difference in contact pressure between the feed roller and the sheets due to the size of the sheets.

[0004] Specifically, two rotating levers are provided on the rotation shaft of the lift lever, which rotate due to the biasing forces of the two lift springs. The first rotating lever corresponding to the first lift spring always rotates integrally with the rotation shaft of the lift lever. Meanwhile, the second rotating lever corresponding to the second lift spring is configured to be switchable between an engaged state in which it engages with the rotation shaft of the lift lever and a disengaged state in which it does not engage. When the width restriction member is displaced to a position corresponding to a large-size sheet, the second rotating lever engages with the rotation shaft of the lift lever, and the biasing forces of the two lift springs are applied to the lift lever via the two rotating levers, pushing the lift plate upward. When the width restriction member is displaced to a position corresponding to a small-size sheet, the second rotating lever disengages from the rotation shaft of the lift lever, and only the biasing force of the first lift spring is applied to the lift lever via the first rotating lever, pushing the lift plate upward. Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional sheet storage devices had a large configuration for switching the urging force that urges the bottom plate member toward the feeding member in conjunction with changes in the position of the regulating member that regulates the position of the sheets stacked on the bottom plate member, which posed a problem of increasing the size of the device. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the present invention provides a sheet storage device having a bottom plate member on which sheets are stacked, a main urging means for urging the bottom plate member toward a feeding member that feeds the sheets stacked on the bottom plate member, an auxiliary urging means for urging the bottom plate member toward the feeding member, and at least one regulating member selected from a sheet width direction position regulating member that regulates the position of the sheets stacked on the bottom plate member in a sheet width direction perpendicular to the sheet feeding direction, and a sheet feeding direction position regulating member that regulates the position of the sheets stacked on the bottom plate member in the sheet feeding direction. The device is characterized by having a clamping member that is arranged between the biasing portion of the auxiliary biasing means and the biased portion of the bottom plate member that is biased by the biasing portion, and is sandwiched between the biasing portion and the biased portion when the auxiliary biasing means biases the bottom plate member toward the feed member, and a switching means that switches the state of the clamping member between a biasable state in which the biasing portion can bias the biased portion through the clamping member and a bias-reducing state in which the biasing force with which the biasing portion biases the biased portion through the clamping member is reduced compared to the biasable state in response to a position change of the regulating member. [Effects of the Invention]

[0007] According to the present invention, it is possible to reduce the size of a sheet storage device that has a configuration that switches the urging force that urges the bottom plate member toward the feeding member in conjunction with a change in the position of the regulating member. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing a printer according to a first embodiment. [Figure 2] FIG. 2 is an enlarged schematic view showing a photosensitive member and its surrounding structure in the printer. [Figure 3] FIG. 2 is a perspective view showing a paper feed cassette in the printer. [Figure 4] FIG. 4 is an enlarged perspective view showing a bottom plate locking member in the paper feed cassette. [Figure 5]1A is a plan view of the paper feed cassette when the pressure lever pressing member is in the non-suppressing position, and FIG. 1B is a plan view of the paper feed cassette when the pressure lever pressing member is in the suppressing position. [Figure 6] FIG. 4 is an enlarged perspective view showing the configuration of an auxiliary spring and a pressure lever in the paper feed cassette. [Figure 7] FIG. 10 is an explanatory diagram showing a state in which the bottom plate is pushed up by the biasing force of the auxiliary spring via the pressure lever. [Figure 8] FIG. 10 is a cross-sectional view showing a pressure lever biased by the biasing force of an auxiliary spring. [Figure 9] FIG. 10 is an explanatory diagram showing a state in which the pressure lever pressing member is in a restraining position. [Figure 10] FIG. 4 is an explanatory diagram showing another example of the switching means in the first embodiment. [Figure 11] FIG. 10 is a plan view of a paper feed cassette according to a first modified example. [Figure 12] FIG. 11 is a plan view schematically showing a paper feed cassette according to a second modification. [Figure 13] FIG. 10 is a plan view schematically showing a paper feed cassette according to a second embodiment. [Figure 14] FIG. 10 is an explanatory diagram showing another example of the switching means in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Embodiment 1] Hereinafter, an embodiment (hereinafter, this embodiment will be referred to as "Embodiment 1") will be described, taking as an example an electrophotographic printer (hereinafter, simply referred to as printer) that forms images by electrophotography as an image forming apparatus to which the present invention is applied.

[0010] First, the basic configuration of the printer according to the first embodiment will be described. FIG. 1 is a schematic diagram showing a printer according to the first embodiment. In the figure, the printer includes a photosensitive member 1 as a latent image carrier, and a paper feed cassette 100 as a sheet storage device that is detachably configured with respect to a main body housing 50. Inside the paper feed cassette 100, a plurality of recording sheets S are stored in the form of a sheet stack.

[0011] The recording sheets S in the paper feed cassette 100 are fed out of the cassette by the rotational drive of the main body paper feed roller 41, which together with the paper feed cassette 100 constitutes a sheet feeding device. At the separation nip between the main body paper feed roller 41 and a separation roller (reverse roller) 48, only the topmost sheet is separated and fed into the main body paper feed path R1, which is the first conveyance path. The recording sheet S is then sandwiched (held) in the conveyance nip of the relay roller pair 42, which is the upper conveyance roller pair, and conveyed in the main body paper feed path R1 from the upstream side to the downstream side in the conveyance direction. Note that the conveyance roller pair may be a conveyance pair in which at least one of the conveyance roller pairs is a belt.

[0012] The downstream end of the main body paper feed path R1 communicates with a common transport path R3, and a registration roller pair 43 is disposed on the common transport path R3. A registration sensor 49 that detects the recording sheet S is disposed on the common transport path R3 upstream of the registration roller pair 43 in the transport direction. The transport of the recording sheet S is temporarily stopped when its leading edge abuts against the nip of the stopped registration roller pair 43. When the leading edge abuts against the nip, the skew of the recording sheet S is corrected. The registration sensor 49 is also used for initial operations and for checking remaining sheets (jam detection operations) when the device is restarted due to an abnormal stop.

[0013] The pair of registration rollers 43 starts rotating at a timing when the recording sheet S can be superimposed on the toner image on the surface of the photosensitive member 1 at the transfer nip, and sends the recording sheet S toward the transfer nip. At this time, the pair of relay rollers 42 also starts rotating at the same time, and resumes the transport of the recording sheet S that had been temporarily stopped.

[0014] The printer's main body 50 is provided with a manual paper feed unit 30, which includes a manual tray 31, a manual paper feed roller 32, and a separation pad 33. A recording sheet S manually fed into the manual tray 31 of the manual paper feed unit 30 is fed from the manual tray 31 to a second transport path, a manual paper feed path R2, by the rotation of the manual paper feed roller 32. The downstream end of the manual paper feed path R2, together with the downstream end of the main body paper feed path R1, merges with the common transport path R3. The recording sheet S fed by the manual paper feed roller 32 passes through a separation nip formed by the contact between the manual paper feed roller 32 and the separation pad 33 in the manual paper feed path R2, and is then fed into the common transport path R3 and transported to the registration roller pair 43. Then, like the recording sheet S fed from the paper feed cassette 100, it passes through the registration roller pair 43 and is transported to the transfer nip.

[0015] FIG. 2 is an enlarged schematic diagram showing the photosensitive member 1 and its surrounding structure in this printer. Around the drum-shaped photoreceptor 1, which is driven to rotate clockwise in the figure, are arranged a cleaning blade 2, a collection screw 3, a charging roller 4, a charging cleaning roller 5, a scraper 6, a latent image writing device 7, a developing device 8, a transfer roller 10, and the like. The charging roller 4, which has a conductive rubber roller portion, rotates while in contact with the photoreceptor 1, forming a charging nip. A voltage is applied to this charging roller 4 from a charging power source. As a result, the surface of the photoreceptor 1 is uniformly charged by a charging bias generated between the surface of the photoreceptor 1 and the surface of the charging roller 4 in the charging nip.

[0016] The latent image writing device 7 is equipped with an LED array and performs optical writing using LED light on the uniformly charged surface of the photoreceptor 1. The potential of the area of ​​the uniformly charged surface of the photoreceptor 1 that is irradiated with the writing light decays, and an electrostatic latent image is formed on the surface of the photoreceptor 1.

[0017] As the photoreceptor 1 rotates, the electrostatic latent image passes through a development area facing the developing device 8. The developing device 8 has a circulating transport section and a developing section, and the circulating transport section contains a developer containing toner and magnetic carriers. The circulating transport section has a first screw 8b that transports the developer to be supplied to the developing roller 8a, and a second screw 8c that transports the developer in an independent space located directly below the first screw 8b. It also has an inclined screw 8d that transfers the developer from the second screw 8c to the first screw 8b. The developing roller 8a, the first screw 8b, and the second screw 8c are arranged in parallel positions. In contrast, the inclined screw 8d is arranged in an inclined position relative to them.

[0018] As the first screw 8b rotates, it transports the developer from the rear to the front in a direction perpendicular to the paper surface of the figure. At this time, it supplies some of the developer to the developing roller 8a disposed opposite it. The developer transported by the first screw 8b to the vicinity of the front end in the direction perpendicular to the paper surface of the figure is dropped onto the second screw 8c.

[0019] The second screw 8c receives used developer from the developing roller 8a and transports the received developer from the rear side to the front side in a direction perpendicular to the paper surface as it rotates. The developer transported by the second screw 8c to the vicinity of the front end in the direction perpendicular to the paper surface is transferred to the inclined screw 8d. Then, as the inclined screw 8d rotates, the developer is transported from the front side to the rear side in the direction perpendicular to the paper surface, and is then transferred to the first screw 8b near the rear end in the same direction.

[0020] The developing roller 8a includes a rotatable developing sleeve made of a cylindrical non-magnetic material and a magnetic roller fixed inside the sleeve so that it does not rotate along with the developing sleeve. A portion of the developer transported by the first screw 8b is drawn up onto the surface of the developing sleeve by the magnetic force of the magnetic roller. The developer carried on the surface of the developing sleeve is transported as the developing sleeve rotates, and its layer thickness is regulated as it passes the position where the developing sleeve faces the doctor blade. The developer is then transported in the development region facing the photoreceptor 1, rubbing against the surface of the photoreceptor 1.

[0021] A developing bias of the same polarity as the uniform charging potential (background potential) of the toner and the photosensitive member 1 is applied to the developing sleeve. The absolute value of this developing bias is greater than the absolute value of the latent image potential and smaller than the absolute value of the background potential. Therefore, in the development area, a developing potential acts between the electrostatic latent image on the photosensitive member 1 and the developing sleeve, which electrostatically moves toner from the developing sleeve to the photosensitive member 1. Meanwhile, a background potential acts between the background of the photosensitive member 1 and the developing sleeve, which electrostatically moves toner from the photosensitive member 1 to the developing sleeve. As a result, in the development area, toner selectively adheres to the electrostatic latent image on the photosensitive member 1, developing the electrostatic latent image.

[0022] The developer that has passed through the development area enters the opposing area between the development sleeve and second screw 8c as the development sleeve rotates. In this opposing area, a repulsive magnetic field is formed by two magnetic poles of the same polarity among the multiple magnetic poles provided on the magnet roller. The developer that has entered the opposing area is separated from the surface of the development sleeve by the action of the repulsive magnetic field and collected by second screw 8c.

[0023] The developer transported by the inclined screw 8d contains developer recovered from the developing roller 8a, and the developer has a reduced toner concentration because it contributes to development in the development area. The developing device 8 is equipped with a toner concentration sensor that detects the toner concentration of the developer transported by the inclined screw 8d. Based on the detection result from the toner concentration sensor, the control unit 51, which is made up of semiconductor circuits such as a CPU, outputs a replenishment operation signal to replenish toner to the developer transported by the inclined screw 8d, as necessary.

[0024] A toner cartridge 9 is disposed above the developing device 8. The toner cartridge 9 agitates the toner contained therein with an agitator 9b fixed to a rotary shaft member 9a. The toner supply member 9c is rotationally driven in response to a supply operation signal output from the control unit 51, and supplies the inclined screw 8d of the developing device 8 with toner in an amount corresponding to the rotational drive amount.

[0025] The toner image formed on the photoreceptor 1 by development enters the transfer nip where the photoreceptor 1 and transfer roller 10 come into contact as the photoreceptor 1 rotates. A voltage of the opposite polarity to the latent image potential of the photoreceptor 1 is applied to the transfer roller 10, which forms a transfer bias in the transfer nip.

[0026] As described above, the pair of registration rollers 43 sends the recording sheet S toward the transfer nip at a timing that allows the recording sheet S to be superimposed on the toner image on the photosensitive member 1 within the transfer nip. The toner image on the photosensitive member 1 is transferred onto the recording sheet that has been brought into close contact with the toner image at the transfer nip by the action of the transfer bias and nip pressure.

[0027] After passing through the transfer nip, residual toner that has not been transferred to the recording sheet S adheres to the surface of the photoreceptor 1. The residual toner is scraped off from the surface of the photoreceptor 1 by a cleaning blade 2 that is in contact with the photoreceptor 1, and then transported by a collection screw 3 and sent to a waste toner bottle.

[0028] The surface of the photoreceptor 1 cleaned by the cleaning blade 2 is neutralized by a neutralization means and then uniformly charged again by the charging roller 4. Foreign matter such as toner additives and toner that was not completely removed by the cleaning blade 2 adheres to the charging roller 4, which is in contact with the surface of the photoreceptor 1. This foreign matter is transferred to the charging cleaning roller 5 in contact with the charging roller 4, and then scraped off from the surface of the charging cleaning roller 5 by the scraper 6 in contact with the charging cleaning roller 5. The scraped off foreign matter falls onto the collection screw 3 described above.

[0029] In FIG. 1, the recording sheet S that has passed through the transfer nip where the photosensitive element 1 and the transfer roller 10 come into contact is sent to the fixing device 44. The fixing device 44 forms a fixing nip by the contact of a fixing roller 44a containing a heat source such as a halogen lamp and a pressure roller 44b that is pressed against the fixing roller 44a. A toner image is fixed to the surface of the recording sheet S that has been sandwiched in the fixing nip by the action of heat and pressure. After passing through the fixing device 44, the recording sheet S then passes through a paper discharge path R4 and is sandwiched in the paper discharge nip of a pair of paper discharge rollers 46.

[0030] This printer can be switched between a single-sided mode in which an image is formed on only one side of the recording sheet S, and a double-sided mode in which images are formed on both sides of the recording sheet S. In the single-sided mode, or in the double-sided mode in which images have already been formed on both sides of the recording sheet, the pair of discharge rollers 46 continues to rotate forward, thereby discharging the recording sheet S in the discharge path R4 outside the machine. The discharged recording sheet S is stacked in a stack section provided on the top surface of the main body housing 50.

[0031] On the other hand, in the duplex mode, when an image is formed on only one side of the recording sheet S, the pair of discharge rollers 46 is driven in reverse when the trailing edge of the recording sheet S enters the discharge nip of the pair of discharge rollers 46. At this time, a switching claw 47 disposed near the downstream end of the discharge path R4 is activated, blocking the discharge path R4 and opening the entrance to the reverse re-feed path R5. The recording sheet S begins to return due to the reverse drive of the pair of discharge rollers 46 and is sent into the reverse re-feed path R5. The downstream end of the reverse re-feed path R5 meets the upstream side of the pair of registration rollers 43 of the common transport path R3. After being transported through the reverse re-feed path R5, the recording sheet S is re-fed to the pair of registration rollers 43 of the common transport path R3. Thereafter, a toner image is transferred to the other side at the transfer nip, and the recording sheet is discharged outside the apparatus via the fixing device 44, the discharge path R4, and the pair of discharge rollers 46.

[0032] Next, the configuration and operation relating to feeding of the recording sheets S will be described. FIG. 3 is a perspective view showing the paper feed cassette 100. As shown in FIG. The paper feed cassette 100 comprises a tray 101 as a structural body, a tray cover 102 disposed on the front side of the tray 101, and a bottom plate 110 disposed inside the tray. The tray cover 102 is provided with a handle that the user uses to open and close the paper feed cassette 100 by pulling it out or pushing it back into the printer body.

[0033] Inside the paper feed cassette 100, recording sheets S are stacked on a bottom plate 110. The position of the recording sheets S stacked in the paper feed cassette 100 in the conveying direction (sheet feeding direction) is regulated by an end fence 103 serving as a sheet feeding direction position regulating member. In addition, the position of the recording sheets S stacked in the paper feed cassette 100 in the direction perpendicular to the conveying direction (sheet width direction) is regulated by side fences 104A and 104B serving as sheet width direction position regulating members. The end fence 103 and the side fences 104A and 104B are configured to be movable by a user operation according to the size of the recording sheets S.

[0034] When the paper feed cassette 100 is set in the printer body, the bottom plate 110 provided inside the tray 101 is raised to a paper feed-enabled position (the position shown in FIG. 3) with the downstream portion in the transport direction raised. As a result, the recording sheet S on the bottom plate 110 comes into contact with the main body paper feed roller 41 located above the bottom plate 110, enabling feeding by the main body paper feed roller 41. Two pressure springs 111, which are main biasing members constituting the main biasing means, are provided between the underside of the bottom plate 110 and the inner bottom surface of the tray 101. The biasing forces of the two pressure springs 111 bias the downstream portion of the bottom plate 110 in the transport direction upward, causing the recording sheet S on the bottom plate 110 to come into contact with the main body paper feed roller 41 with a predetermined range of paper feed pressure.

[0035] The bottom plate 110 has an L-shaped bent portion 112a and an opening 112. As shown in Fig. 4, a bottom plate locking member 113 is provided on the inner bottom surface of the tray 101 at a location corresponding to the opening 112 of the bottom plate 110. The opening 112 is configured so that the bottom plate locking member 113 can pass through. The bottom plate locking member 113 is biased by a biasing spring 114 toward the bent portion 112a of the bottom plate 110 along the inner bottom surface of the tray 101.

[0036] For example, when the downstream portion of the bottom plate 110 in the transport direction is pushed downward by a user operation, the bottom plate locking member 113 slides over the bent portion 112a while passing through the opening 112, and when it reaches the top surface of the bottom plate 110, it is caught on the top surface of the bottom plate 110 by the biasing force of the biasing spring 114. As a result, the bottom plate 110 is locked by the bottom plate locking member 113 in a position where the downstream portion of the bottom plate 110 in the transport direction is pushed downward (a position substantially parallel to the inner bottom surface of the tray 101). Also, when the paper feed cassette 100 is pulled out of the printer body, the downstream portion of the bottom plate 110 in the transport direction is pushed downward due to contact with the rails of the paper feed cassette 100. In this case as well, the bottom plate 110 is locked by the bottom plate locking member 113 in a position where the downstream portion of the bottom plate 110 in the transport direction is pushed downward.

[0037] When the paper feed cassette 100 is inserted into the printer body, the bottom plate 110 is locked, and the bottom plate locking member 113 is pushed in a direction against the biasing force of the biasing spring 114 by the lock release members provided on the printer body and the paper feed cassette 100. This causes the bottom plate locking member 113 to move, releasing it from the catch on the top surface of the bottom plate 110 and taking a position that allows the bottom plate locking member 113 to pass through the opening 112. As a result, the biasing force of the two pressure springs 111 moves the downstream side of the bottom plate 110 in the transport direction upward, and the bottom plate 110 takes a position that allows paper feed.

[0038] If the contact pressure (paper feed pressure) between the recording sheets S on the bottom plate 110 and the main body paper feed roller 41 is too low, the recording sheets S cannot follow the rotation of the main body paper feed roller 41 and are not fed, which is likely to result in paper failure. On the other hand, if the paper feed pressure is too high, the number of recording sheets S fed following the rotation of the main body paper feed roller 41 increases, which makes it likely that sheet separation will fail at the separation nip between the main body paper feed roller 41 and the separation roller 48, resulting in double feeding. Therefore, in order to prevent paper feeding problems such as paper failure and double feeding, it is important to keep the paper feed pressure within a specified range.

[0039] Generally, the configurations for generating paper feed pressure are roughly classified into the following two types. The first configuration is a configuration in which the main body paper feed roller 41 is biased toward the recording sheets on the bottom plate 110. In this configuration, for example, a drive source that changes the height position of the bottom plate 110 is controlled based on the detection result of a sensor that detects the position of the topmost sheet, so that the height position of the topmost sheet in the paper feed cassette 100 remains constant. This makes it possible to maintain a substantially constant paper feed pressure regardless of the size or number of recording sheets S stacked.

[0040] In the second configuration, the height position of the main body paper feed roller 41 is fixed, and the biasing force of the biasing spring 114 biases the bottom plate 110 toward the main body paper feed roller 41, causing the recording sheets on the bottom plate 110 to abut against the main body paper feed roller 41. In this configuration, the greater the number of recording sheets S stacked, the greater the force (sheet weight) resisting the biasing force of the biasing spring 114, but since the compression amount of the biasing spring 114 is also large, the biasing force of the biasing spring 114 also becomes large, making it possible to maintain a substantially constant paper feed pressure.

[0041] However, in the second configuration, if the sizes of the recording sheets S are different, it is difficult to keep the paper feed pressure within a predetermined range for both sizes of recording sheets S. For example, when comparing large and small sizes with the same stacking number and paper thickness, the weight of the stacked recording sheets S is lighter for small-sized recording sheets. Therefore, if the biasing spring 114 is configured to maintain a substantially constant paper feed pressure for large-sized recording sheets, when small-sized recording sheets are loaded, the paper feed pressure will be greater than for large-sized recording sheets, resulting in excessive paper feed pressure and making it more likely that double feeding will occur. Conversely, if the biasing spring 114 is configured to maintain a substantially constant paper feed pressure for small-sized recording sheets, when large-sized recording sheets are loaded, the paper feed pressure will be less than for small-sized recording sheets, resulting in insufficient paper feed pressure and making it more likely that paper will not be fed.

[0042] Comparing the first and second configurations described above, the second configuration has the advantage of being lower cost and more space-saving, and is therefore often adopted, especially in small printers. In the present embodiment 1, the second configuration described above is adopted to suppress fluctuations in paper feed pressure due to differences in the sizes of the recording sheets S loaded in the paper feed cassette 100, thereby suppressing paper feed problems such as paper non-feeding and double feeding.

[0043] Next, a configuration for suppressing fluctuations in sheet feeding pressure due to differences in the size of the recording sheets S loaded in the sheet cassette 100 in the first embodiment will be described. 5(a) and (b) are plan views of the sheet feed cassette 100 in the present embodiment 1. For the sake of explanation, FIGS. 5(a) and 5(b) show the sheet feed cassette 100 with the bottom plate 110 removed.

[0044] In the paper feed cassette 100 of the first embodiment, in addition to two pressure springs 111 as biasing means for biasing the bottom plate 110 toward the main body paper feed roller 41, one auxiliary spring 121 is provided as an auxiliary biasing member as auxiliary biasing means. The auxiliary spring 121 is formed by a compression coil spring, and its lower end is fixed to a fixing portion 101a provided on the tray 101. Note that the auxiliary spring 121 is not limited to a compression coil spring, and for example, a biasing member having another configuration may be used, and it is particularly preferable to use a biasing member such as a conical spring to further reduce the solid height of the spring.

[0045] Additionally, the upper end of the auxiliary spring 121 is a biasing portion that applies an upward biasing force to the lower surface (biased portion) of the bottom plate 110. A pressure lever 122 is disposed between the upper end of the auxiliary spring 121 and the lower surface (biased portion) of the bottom plate 110. Therefore, in the first embodiment, the biasing force of the auxiliary spring 121 is applied from the upper end of the auxiliary spring 121 to the lower surface of the bottom plate 110 via the pressure lever 122, and biases the bottom plate 110 upward.

[0046] FIG. 6 is an enlarged perspective view showing the configuration of the auxiliary spring 121 and the pressure lever 122. As shown in FIG. FIG. 7 is an explanatory diagram showing a state in which the bottom plate 110 is pushed up by the biasing force of the auxiliary spring 121 via the pressure lever 122. As shown in FIG. As shown in Fig. 6, the pressure lever 122 of the first embodiment is made of a long plate-like member extending along the conveyance direction of the recording sheet S. As shown in Fig. 8, one longitudinal end of the pressure lever 122 is bent by approximately 90 degrees, and the bent portion, a base end 122a, is inserted into a groove 101c provided in the tray 101. The pressure lever 122 has an upper portion of the base end 122a pressed down by a pressure lever presser member 123 (described later), and is configured to be rotatable in the vertical direction substantially around the base end 122a.

[0047] The movable part 122c, which is the tip end of the pressure lever 122 (the end opposite to the base end 122a), is connected to the upper end of the auxiliary spring 121. Therefore, the biasing force of the auxiliary spring 121 pushes up the tip side of the pressure lever 122, causing the pressure lever 122 to rotate around the base end 122a. As a result, the movable part 122c of the pressure lever 122 comes into contact with the underside of the bottom plate 110 located above it, as shown in FIG. 7, and pushes the bottom plate 110 upward. In this way, the biasing force of the auxiliary spring 121 is applied from the upper end of the auxiliary spring 121 to the underside of the bottom plate 110 via the pressure lever 122, thereby biasing the bottom plate 110 upward.

[0048] The pressure applying lever 122 of the first embodiment is not limited in shape or configuration as long as it is configured to be displaceable in the biasing direction (i.e., upward) of the upper end of the auxiliary spring 121. For example, the pressure applying lever 122 may not be a plate-shaped member, but may be a cylindrical or rod-shaped member, or may be configured to include a rotation shaft portion pivotally supported by the tray 101 (configured to rotate around the axis of the rotation shaft portion). Furthermore, the pressure applying lever 122 may be configured, for example, to be formed entirely from an elastic member, and to bend as a whole due to the biasing force of the auxiliary spring 121, thereby displacing the tip portion (movable portion 122c).

[0049] Here, in the first embodiment, a pressure lever presser member 123 is provided as a displacement suppression member that constitutes a switching means for switching the state of the pressure lever 122. This pressure lever presser member 123 is disposed in a position where the pressure lever 122 is sandwiched between it and the tray 101. The pressure lever presser member 123 is guided by a rail 101b formed on the tray 101, and is configured to be slidable along the longitudinal direction of the pressure lever 122 (the sheet conveying direction).

[0050] As shown in Figures 5(a) and 6, the pressure lever presser member 123 can take a non-restraining position in which the tip of the presser portion 123a is located above the base end portion 122a of the pressure lever 122. This non-restraining position is a position in which the pressure lever presser member 123 does not restrain the displacement of the pressure lever 122 (movement in which the movable portion 122c of the pressure lever 122 rotates approximately around the base end portion 122a). Therefore, when the pressure lever presser member 123 is in the non-restraining position, the movable portion 122c of the pressure lever 122 can rotate approximately around the base end portion 122a due to the biasing force of the auxiliary spring 121. In other words, in this case, the pressure lever 122 is in an urging state in which the upper end portion (urging portion) of the auxiliary spring 121 can urge the lower surface (urged portion) of the bottom plate 110 via the movable portion 122c of the pressure lever 122.

[0051] When the pressure lever 122 is in the biasable state (the state shown in FIGS. 5A and 6), the biasing force of the auxiliary spring 121 is applied to the bottom plate 110 in addition to the biasing force of the two pressure springs 111. Therefore, the bottom plate 110 can be pushed up with a biasing force greater than when only the biasing forces of the two pressure springs 111 are applied (the bias-prohibited state described below). Therefore, when large-sized recording sheets, which are heavier, are loaded, the pressure lever presser member 123 is placed in the non-restraining position and the pressure lever 122 is switched to the biasable state, so that the contact pressure (paper feed pressure) between the recording sheets S on the bottom plate 110 and the main body paper feed roller 41 can be kept within a predetermined range. Therefore, even when large-sized recording sheets are loaded, problems such as paper failure due to insufficient paper feed pressure can be prevented.

[0052] 5(a) and 6, the pressure lever presser member 123 can slide toward the tip side (downstream side in the sheet conveying direction) of the pressure lever 122. Specifically, the pressure lever presser member 123 can take a suppression position in which the tip of the presser portion 123a is positioned closer to the tip side of the pressure lever than the base end portion 122a of the pressure lever 122, as shown in FIG.

[0053] When the pressure lever presser member 123 is in the restraining position, the pressure lever 122 is pressed from above by the pressure lever presser member 123 and cannot rotate substantially around the base end 122a. That is, in this case, the pressure lever 122 is in a force-restricted state in which the force with which the upper end (biasing portion) of the auxiliary spring 121 urges the lower surface (biased portion) of the bottom plate 110 via the movable portion 122c of the pressure lever 122 is suppressed compared to the biasable state.

[0054] In particular, in the first embodiment, the pressure lever 122 is pressed from above by the pressure lever presser member 123, so that the movable part 122c of the pressure lever 122 is maintained in a state separated from the lower surface of the bottom plate 110 against the biasing force of the auxiliary spring 121. Therefore, even in the bias suppressed state, the pressure lever 122 is in the bias prohibited state in which the pressure lever 122 is prohibited from entering the bias enabled state.

[0055] When the pressure lever 122 is in the bias-prohibited state (the state shown in FIGS. 5(b) and 9), the biasing force of the auxiliary spring 121 is not applied to the bottom plate 110, and only the biasing force of the two pressure springs 111 is applied. Therefore, the bottom plate 110 can be pushed up with a smaller biasing force than when the biasing forces of both the two pressure springs 111 and the auxiliary spring 121 are applied (the bias-enabled state described above). Therefore, when small-sized recording sheets, which are lighter in weight, are loaded, the pressure lever presser member 123 is set to the suppression position and the pressure lever 122 is switched to the bias-prohibited state (force suppression state), thereby keeping the contact pressure (paper feed pressure) between the recording sheets S on the bottom plate 110 and the main body paper feed roller 41 within a predetermined range. Therefore, even when small-sized recording sheets are loaded, problems such as double feeding due to excessive paper feed pressure can be suppressed.

[0056] In the first embodiment, the movement mechanism that moves the position of the pressure lever hold-down member 123 between the non-restraint position and the restraint position is configured to be linked to the change in the positions of the side fences 104A and 104B.

[0057] More specifically, in the first embodiment, the two side fences 104A, 104B are configured to move (change positions) toward or away from each other across the center in the seat width direction. Specifically, as shown in Figures 5(a) and 5(b), the two side fences 104A, 104B are provided with racks 105A, 105B, respectively, extending in the seat width direction, and gears 105a of these racks 105A, 105B are meshed with and connected to a pinion gear 106. When the corresponding side fence 104A, 104B moves along the seat width direction, each rack 105A, 105B moves linearly in the seat width direction in conjunction with the movement of the corresponding side fence 104A, 104B, causing the pinion gear 106 to rotate.

[0058] With this configuration, when one of the side fences (for example, side fence 104B) moves in the sheet width direction, the rack 105B of that side fence 104B moves in the sheet width direction, and the pinion gear 106 meshing with the rack 105B rotates. As a result, the rack 105A of the other side fence 104A meshing with the pinion gear 106 also moves in the sheet width direction, and the other side fence 104A also moves in the sheet width direction.

[0059] In the first embodiment, the rack 105B as a first gear member provided on one side fence 104B is provided with a gear portion 131 on the side opposite to the side on which the gear 105a that meshes with the pinion gear 106 is formed. A switching pinion gear 132 as a second gear member for moving the position of the pressure lever hold down member 123 between the non-restraint position and the restraint position described above is disposed at a location through which the gear portion 131 on the rack 105B passes when the rack 105B of the side fence 104B moves in the sheet width direction.

[0060] The gear portion 131 of the rack 105B is provided only at a portion of a lateral portion (an end edge on the downstream side in the sheet conveying direction) in the linear movement direction (sheet width direction) of the rack 105B. Therefore, the gear portion 131 of the rack 105B does not mesh with the switching pinion gear 132 over the entire range in which the side fence 104B can move, but meshes with the switching pinion gear 132 only in a portion of that range and does not mesh with the switching pinion gear 132 in the other portions of that range. In other words, the gear portion 131 is disposed at a portion where it meshes with the switching pinion gear 132 only when the side fences 104A, 104B pass through a specific position. Therefore, in the first embodiment, the switching pinion gear 132 rotates only when the side fences 104A, 104B pass through a specific position.

[0061] The switching pinion gear 132 is engaged with a rack gear 123b of the pressure lever presser member 123. The rack gear 123b is provided on a side portion in the sliding movement direction (sheet conveying direction) of the pressure lever presser member 123. When the switching pinion gear 132 rotates, the pressure lever presser member 123, which includes the rack gear 123b that is engaged with it, slides along the sliding movement direction (sheet conveying direction).

[0062] When lighter-weight recording sheets S of small size (narrow widthwise size) are loaded, the side fences 104A, 104B move (change position) toward the center in the sheet width direction, passing through the specific position. In conjunction with this movement (change of position) of the side fences 104A, 104B, the switching pinion gear 132 rotates in the forward direction, and the pressure lever presser member 123 slides from the non-suppressing position shown in Figures 5(a) and 6 to the suppressing position shown in Figures 5(b) and 9. As a result, the state of the pressure lever 122 switches to the bias-prohibited state (bias-suppressed state), and the biasing force of the auxiliary spring 121 is not applied to the bottom plate 110, but only the biasing force of the two pressure springs 111 is applied, so that the bottom plate 110 is pushed up with a small biasing force. Therefore, by simply moving the side fences 104A and 104B to fit a small-sized (small widthwise size) recording sheet S, the contact pressure (paper feed pressure) between the recording sheet S on the bottom plate 110 and the main body paper feed roller 41 can be kept within a predetermined range, thereby preventing problems such as double feeding due to excessive paper feed pressure.

[0063] Furthermore, when large-sized (large widthwise) recording sheets S, which are heavier, are loaded, the side fences 104A and 104B move (change their positions) in a direction away from the center in the widthwise direction of the sheets, passing through the specific positions. In conjunction with this movement (change of position) of the side fences 104A and 104B, the switching pinion gear 132 rotates in the reverse direction, and the pressure lever presser member 123 slides from the suppression position shown in Figures 5(b) and 9 to the non-suppression position shown in Figures 5(a) and 6. As a result, the state of the pressure lever 122 switches to an urging-enabled state, and the urging forces of both the two pressure springs 111 and the auxiliary spring 121 are applied to the bottom plate 110, pushing up the bottom plate 110 with a large urging force. Therefore, by simply moving the side fences 104A and 104B to accommodate a large-sized (large widthwise size) recording sheet S, the contact pressure (paper feed pressure) between the recording sheet S on the bottom plate 110 and the main body paper feed roller 41 can be kept within a predetermined range, thereby preventing problems such as paper failure due to insufficient paper feed pressure.

[0064] When the user or the like operates and moves the side fences 104A, 104B, the pressure lever holding member 123 that moves in conjunction with the operation slides against the pressure lever 122 that is biased upward by the biasing force of the auxiliary spring 121. Therefore, when the side fences 104A, 104B are operated, the pressure lever holding member 123 slides against the pressure lever 122, and an operating resistance (load) is applied.

[0065] However, when the side fences 104A and 104B are operated, the sheet feed cassette 100 is pulled out from the printer body. In this state, as described above, the bottom plate 110 is locked by the bottom plate locking member 113 with the downstream portion of the bottom plate 110 pressed downward in the conveyance direction. As a result, the bottom plate 110 is maintained in a position where the top surface (sheet placement surface) of the bottom plate 110 is approximately horizontal, against the biasing forces of the two pressure springs 111 and the auxiliary spring 121.

[0066] At this time, the pressure lever 122, which is biased upward by the biasing force of the auxiliary spring 121, is also pushed downward by the bottom plate 110 to a nearly horizontal state. When the pressure lever 122 is in this state, the contact pressure between the pressure lever 122 and the pressure lever presser member 123 is small, and the resistance (load) during sliding movement of the pressure lever presser member 123, which slides along with the pressure lever 122, is small. Therefore, according to the first embodiment, the operating resistance (load) caused by the sliding movement of the pressure lever presser member 123 when operating the side fences 104A, 104B is small, and the side fences 104A, 104B can be operated with a small operating force.

[0067] The locking mechanism for locking the bottom plate 110 so that the upper surface (sheet placing surface) of the bottom plate 110 is in a substantially horizontal position is not limited to a configuration using the bottom plate locking member 113. In other words, the locking mechanism may be configured to lock the bottom plate 110 in a nearly horizontal position (a state in which the movement of the bottom plate 110 is restricted against the biasing forces of the springs 111 and 121).

[0068] In addition, in the first embodiment, the gear portion 131 of the rack 105B is provided only at a partial location on the side of the rack 105B in the linear movement direction, so that the switching pinion gear 132 rotates only when the side fences 104A, 104B pass a specific position. As an alternative to this, for example, as shown in Fig. 10, the gear portion 132a of the switching pinion gear 132 that meshes with the rack gear 123b of the pressure lever holddown member 123 may be provided only at a partial location in the rotation direction of the switching pinion gear 132.

[0069] 10, the gear portion 131 of the rack 105B is provided so as to mesh with the switching pinion gear 132 at least over the entire range in which the side fence 104B can move. The switching pinion gear 132 has different configurations at an upper stage (one end side in the gear axial direction) and a lower stage (the other end side in the gear axial direction), and the lower stage of the switching pinion gear 132 that meshes with the gear portion 131 of the rack 105B has a gear provided over the entire circumference in the rotational direction of the switching pinion gear 132. Therefore, the switching pinion gear 132 is configured to rotate whenever the side fences 104A, 104B move.

[0070] On the other hand, in the upper stage portion of the switching pinion gear 132 that meshes with the rack gear 123b of the pressure lever hold-down member 123, gears are provided only at certain locations in the rotational direction of the switching pinion gear 132. More specifically, in the upper stage portion of the switching pinion gear 132, gears are provided at locations that mesh with the switching pinion gear 132 only when the side fences 104A, 104B pass through specific positions. Therefore, also in the example of Fig. 10, the pressure lever hold-down member 123 is configured to slide only when the side fences 104A, 104B pass through specific positions.

[0071] [Variation 1] Next, a modified example of the switching means for switching the state of the pressure lever 122 (hereinafter, this modified example will be referred to as "Modified Example 1") will be described. In the switching means in the above-described first embodiment, the pressure lever presser member 123 as the displacement suppression member is an example of a linearly moving member that moves linearly due to rotation of the switching pinion gear 132 as the second gear member. In the switching means in this first modified example, the displacement suppression member is an example of a rotationally moving member that rotates integrally with the gear portion as the second gear member that meshes with the gear portion 131 of the rack 105B.

[0072] Fig. 11 is a plan view of the sheet cassette 100 in the present modified example 1. For the sake of explanation, Fig. 11 shows the sheet cassette 100 with the bottom plate 110 removed. In the present modified example 1, the pressure lever presser member 124 serving as a displacement suppression member has a different configuration between its upper and lower sections. Specifically, in the present modified example 1, the gear portion 131 of the rack 105B is provided over at least the entire range within which the side fence 104B can move. The lower section of the pressure lever presser member 124, which meshes with the gear portion 131 of the rack 105B, is provided with a gear portion 124b along the entire circumference in the rotational direction of the pressure lever presser member 124. Therefore, when the side fences 104A, 104B move, the pressure lever presser member 124 is configured to always rotate around the axis of the gear portion 124b.

[0073] On the other hand, a pressing portion 124a that moves toward and away from the pressing lever 122, which is a clamping member, is formed on the upper portion of the pressing lever presser member 124. The pressing portion 124a of the pressing lever presser member 124 is formed so as to pass above the pressing lever 122 as the pressing lever presser member 124 rotates. In this first modified example, the pressing portion 124a is provided only at a portion of the pressing lever presser member 124 in the rotation direction. More specifically, the pressing portion 124a is provided at a portion that is located above the pressing lever 122 only when the side fences 104A, 104B pass through a specific position. This allows the pressing lever presser member 124 to move between a separated position (non-restraining position) where the pressing portion 124a is separated from the pressing lever 122, and a contact position (restraining position) where the pressing portion 124a is in contact with the pressing lever 122.

[0074] When the pressure lever holding member 124 is in the non-restraining position, the pressure lever 122 can rotate substantially around the base end 122a due to the biasing force of the auxiliary spring 121, and is in a biasable state. On the other hand, when the pressure lever holding member 124 is in the restraining position, the pressure lever 122 is pressed from above by the retaining portion 124a, and is in a bias-prohibited state (force-restrained state) in which the pressure lever 122 cannot rotate substantially around the base end 122a.

[0075] In this first modification, when lighter-weight recording sheets S of small size (small widthwise size) are loaded, the side fences 104A, 104B are moved (position changed) toward a specific position in the center of the sheet widthwise direction in response to this. In conjunction with this movement (position change) of the side fences 104A, 104B, the pressure lever presser member 124 rotates in the forward direction, and the pressure lever presser member 124 rotates from the non-suppression position to the suppression position. As a result, the state of the pressure lever 122 switches to the bias-prohibited state (bias-suppressed state), and the biasing force of the auxiliary spring 121 is not applied to the bottom plate 110, but only the biasing forces of the two pressure springs 111 are applied, so that the bottom plate 110 is pushed up with a small biasing force. Therefore, by simply moving the side fences 104A and 104B to fit a small-sized (small widthwise size) recording sheet S, the contact pressure (paper feed pressure) between the recording sheet S on the bottom plate 110 and the main body paper feed roller 41 can be kept within a predetermined range, thereby preventing problems such as double feeding due to excessive paper feed pressure.

[0076] Furthermore, when large-size (large widthwise) recording sheets S, which are heavier, are loaded, the side fences 104A and 104B are moved (positionally changed) away from the center of the sheet widthwise direction accordingly. In conjunction with this movement (positional change) of the side fences 104A and 104B, the pressure lever presser member 124 rotates in the reverse direction, rotating from the suppression position to the non-suppression position. As a result, the state of the pressure lever 122 switches to the biasable state, and the biasing forces of both the two pressure springs 111 and the auxiliary spring 121 are applied to the bottom plate 110, pushing the bottom plate 110 up with a large biasing force. Therefore, simply by moving the side fences 104A and 104B to accommodate the large-size (large widthwise) recording sheets S, the contact pressure (paper feed pressure) between the recording sheets S on the bottom plate 110 and the main body paper feed roller 41 can be kept within a predetermined range, preventing problems such as paper feed failure due to insufficient paper feed pressure.

[0077] In this first modification, depending on the positions of the side fences 104A and 104B, the end of the pressure lever presser member 123 may separate from the top of the base end 122a of the pressure lever 122. In this case, as in the first embodiment described above, simply inserting the base end 122a, which is the bent portion of the pressure lever 122, into the groove 101c of the tray 101 may result in the pressure lever 122 coming off the tray 101. In such a case, it is preferable to provide a support mechanism for the pressure lever 122 that prevents the pressure lever 122 from coming off the tray 101.

[0078] [Variation 2] Next, another modification of the switching means for switching the state of the movable part 122c of the pressure lever 122 (hereinafter, this modification will be referred to as "Modification 2") will be described. In the switching means in the above-described first embodiment and modified example 1, the pressure lever hold-down member 123 as a displacement suppression member is configured as a separate member from the side fences 104A and 104B as restricting members, and is movable separately. In the switching means in this modified example 2, the displacement suppression member moves integrally with the side fences 104A and 104B as restricting members.

[0079] Fig. 12 is a plan view that schematically shows the sheet cassette 100 in Modification 2. For the sake of explanation, Fig. 12 shows the sheet cassette 100 with the bottom plate 110 removed. In the present modified example 2, auxiliary springs 121A and 121B, pressure levers 122A and 122B, and pressure lever hold-down members 125A and 125B are provided corresponding to the two side fences 104A and 104B, respectively.

[0080] Specifically, in this second modification, the pressure levers 122A, 122B are arranged so that their longitudinal direction is in the seat width direction, as shown in Fig. 12. As in the first embodiment described above, each pressure lever 122A, 122B is sandwiched between the upper end of the respective auxiliary springs 121A, 121B and the lower surface (biased portion) of the bottom plate 110, and is configured to be rotatable in the vertical direction approximately around the base end 122a. Each pressure lever 122A, 122B is arranged so that the movable portion 122c, which is the tip, is located toward the center of the seat width direction, and the base end 122a is located toward the end of the seat width direction.

[0081] The pressure lever hold-down members 125A, 125B in this modified example 2 are configured to move integrally with the two side fences 104A, 104B. In this modified example 2, the side fences 104A, 104B and the pressure lever hold-down members 125A, 125B are configured integrally. Note that the pressure lever hold-down members 125A, 125B do not need to be configured integrally with the side fences 104A, 104B, and may be configured as separate parts as long as they are configured to move integrally with the two side fences 104A, 104B.

[0082] In this second modification, when lighter-weight recording sheets S of small size (narrow widthwise size) are loaded, the side fences 104A and 104B move (change positions) toward the center in the sheet width direction accordingly. Accompanying this movement of the side fences 104A and 104B, the pressure lever presser members 125A and 125B also move toward the center in the sheet width direction. As a result, the pressure lever presser members 125A and 125B assume contact positions (restriction positions) in contact with the pressure levers 122A and 122B, respectively. As a result, the pressure levers 122A and 122B are pressed from above by the pressure lever presser members 125A and 125B, and are switched to a bias-prohibited state (bias-restricted state) in which they cannot rotate substantially about the base end 122a.

[0083] As a result, the biasing force of auxiliary springs 121A and 121B is not applied to bottom plate 110, but only the biasing force of two pressure springs 111 is applied, and bottom plate 110 is pushed up with a small biasing force. Therefore, simply by moving side fences 104A and 104B to match small-sized (small widthwise) recording sheets S, the contact pressure (paper feed pressure) between recording sheets S on bottom plate 110 and main body paper feed roller 41 can be kept within a predetermined range, and problems such as double feeding due to excessive paper feed pressure can be prevented.

[0084] Furthermore, when large-sized (large widthwise) recording sheets S, which are heavier, are loaded, the side fences 104A and 104B move (change position) away from the center of the sheet width direction accordingly. Accompanying this movement of the side fences 104A and 104B, the pressure lever hold-down members 125A and 125B also move away from the center of the sheet width direction. As a result, the pressure lever hold-down members 125A and 125B assume a spaced position (non-restraining position) away from the pressure levers 122A and 122B, respectively. This switches the state of the pressure levers 122A and 122B to an activatable state, and the biasing forces of both the two pressure springs 111 and the two auxiliary springs 121A and 121B are applied to the bottom plate 110, pushing up the bottom plate 110 with a large biasing force. Therefore, by simply moving the side fences 104A and 104B to accommodate a large-sized (large widthwise size) recording sheet S, the contact pressure (paper feed pressure) between the recording sheet S on the bottom plate 110 and the main body paper feed roller 41 can be kept within a predetermined range, thereby preventing problems such as paper failure due to insufficient paper feed pressure.

[0085] In this second modification, too, depending on the positions of the side fences 104A and 104B, the ends of the pressure lever hold-down members 125A and 125B may separate from the tops of the base ends 122a of the pressure levers 122A and 122B. In this case, as in the first embodiment described above, simply inserting the base ends 122a, which are the bent portions of the pressure levers 122A and 122B, into the grooves 101c of the tray 101 may result in the pressure levers 122A and 122B coming off the tray 101. In such a case, it is preferable to provide a support mechanism for the pressure levers 122A and 122B that prevents the pressure levers 122A and 122B from coming off the tray 101.

[0086] In addition, in the configuration of Modification 2, the position of the side fence where the pressure lever hold-down member 125A of one side fence 104A switches between the non-restraint position and the restraint position may be different from the position of the side fence where the pressure lever hold-down member 125B of the other side fence 104B switches between the non-restraint position and the restraint position. In this case, it is possible to switch the biasing force that pushes up the bottom plate 110 in two or more stages.

[0087] As a specific example, when both pressure lever hold-down members 125A, 125B are in the non-restricting position, the bottom plate 110 is pushed up by a large biasing force generated by all of the biasing forces of the two pressure springs 111 and the two auxiliary springs 121A, 121B. When one pressure lever hold-down member 125A is in the non-restricting position and the other pressure lever hold-down member 125B is in the restricting position, the bottom plate 110 is pushed up by a medium biasing force generated by the biasing forces of the two pressure springs 111 and one auxiliary spring 121A. When both pressure lever hold-down members 125A, 125B are in the restricting position, the bottom plate 110 is pushed up by a small biasing force generated by the biasing force of only the two pressure springs 111.

[0088] The configuration of Modification 2 can also be combined with the configuration of the above-described Embodiment 1 or Modification 1. In this case, it is preferable that the positions of the side fences 104A, 104B at which the pressure lever holddown members 123, 124, 125A, 125B are switched from the non-restraint position to the restraint position be different between the first switching unit having the configuration of the above-described Embodiment 1 or Modification 1 and the second switching unit having the configuration of Modification 2.

[0089] With this configuration, it is possible to switch the biasing force for pushing up the bottom plate 110 between three or more stages. As a specific example, when both the pressure lever holding members of the first switching unit and the second switching unit are in the non-restricting position, the bottom plate 110 is pushed up by a large biasing force generated by the combined biasing forces of the two pressure springs 111 and both auxiliary springs. When the pressure lever holding member of the first switching unit is in the non-restricting position and the pressure lever holding member of the second switching unit is in the restricting position, the bottom plate 110 is pushed up by a medium biasing force generated by the biasing forces of the two pressure springs 111 and the auxiliary spring of the first switching unit. When both the pressure lever holding members of the first switching unit and the second switching unit are in the restricting position, the bottom plate 110 is pushed up by a small biasing force generated by the biasing force of only the two pressure springs 111.

[0090] In the above-described first embodiment (including the various modified examples), the pressure lever 122, which is biased upward by the auxiliary spring 121, is configured to abut against the bottom plate 110 even when the bottom plate 110 is in the highest position, but this is not limiting. For example, the pressure lever 122, which is biased upward by the auxiliary spring 121, may start to abut against the bottom plate 110 midway from the horizontal position in which the bottom plate 110 is in the locked state to the highest position.

[0091] [Embodiment 2] Next, another embodiment (hereinafter, this embodiment will be referred to as "Embodiment 2") will be described, taking a printer as an example of an image forming apparatus to which the present invention is applied. The second embodiment differs from the first embodiment, which employs a switching means for switching the urging force for pushing up the bottom plate 110 in conjunction with the movement (position change) of the side fences 104A, 104B, in that the second embodiment employs a switching means for switching the urging force for pushing up the bottom plate 110 in conjunction with the movement (position change) of the end fence 103. In the following explanation, the differences from the first embodiment will be explained, and explanations of points that overlap with the first embodiment will be omitted as appropriate.

[0092] Fig. 13 is a plan view schematically showing the sheet cassette 100 in the present embodiment 2. For the sake of explanation, Fig. 13 shows the sheet cassette 100 with the bottom plate 110 removed. In the second embodiment, two auxiliary springs 141A and 141B, two pressure levers 142A and 142B, and two pressure lever hold-down members 143A and 143B are provided corresponding to one end fence 103.

[0093] Specifically, in the second embodiment, the pressure levers 142A, 142B are arranged so that their longitudinal direction is in the sheet conveying direction, as shown in Fig. 13. As in the first embodiment described above, each pressure lever 142A, 142B is sandwiched between the upper end of the respective auxiliary springs 141A, 141B and the lower surface (biased portion) of the bottom plate 110, and is configured to be rotatable in the vertical direction approximately around the base end 142a. Each pressure lever 142A, 142B is provided so that the movable portion 142c, which is the tip, is located downstream in the sheet conveying direction, and the base end 142a is located upstream in the sheet conveying direction.

[0094] In the second embodiment, the pressure lever hold-down members 143A and 143B are configured to move integrally with one end fence 103. In the second embodiment, the end fence 103 and the pressure lever hold-down members 143A and 143B are configured integrally. Note that the pressure lever hold-down members 143A and 143B do not need to be configured integrally with the end fence 103, and may be configured as separate parts as long as they are configured to move integrally with the end fence 103.

[0095] In the second embodiment, when lighter-weight recording sheets S of small size (small size in the sheet conveyance direction) are loaded, the end fence 103 moves (changes position) toward the downstream side in the sheet conveyance direction accordingly. Accompanying this movement of the end fence 103, the pressure lever presser members 143A, 143B also move toward the downstream side in the sheet conveyance direction. As a result, the pressure lever presser members 143A, 143B assume contact positions (restraint positions) in contact with the pressure levers 142A, 142B, respectively. As a result, the pressure levers 142A, 142B are pressed from above by the pressure lever presser members 143A, 143B, and are switched to a bias-prohibited state (bias-restrained state) in which they cannot rotate substantially about the base end 142a.

[0096] As a result, the biasing force of auxiliary springs 141A and 141B is not applied to bottom plate 110, but only the biasing force of two pressure springs 111 is applied, and bottom plate 110 is pushed up with a small biasing force. Therefore, by simply moving end fence 103 to fit small-sized recording sheets S (small size in the sheet conveyance direction), the contact pressure (paper feed pressure) between recording sheets S on bottom plate 110 and main body paper feed roller 41 can be kept within a predetermined range, and problems such as double feeding due to excessive paper feed pressure can be prevented.

[0097] Furthermore, when large-sized (large in the sheet conveyance direction) recording sheets S, which are heavier, are loaded, the end fence 103 accordingly moves (changes position) toward the upstream side in the sheet conveyance direction. Accompanying this movement of the end fence 103, the pressure lever presser members 143A and 143B also move toward the upstream side in the sheet conveyance direction. As a result, the pressure lever presser members 143A and 143B assume a spaced position (non-restraining position) away from the pressure levers 142A and 142B. This switches the state of the pressure levers 142A and 142B to an activatable state, and the biasing forces of both the two pressure springs 111 and the two auxiliary springs 141A and 141B are applied to the bottom plate 110, pushing up the bottom plate 110 with a large biasing force. Therefore, by simply moving the end fence 103 to fit a large-sized (large widthwise size) recording sheet S, the contact pressure (paper feed pressure) between the recording sheet S on the bottom plate 110 and the main body paper feed roller 41 can be kept within a specified range, thereby preventing problems such as paper failure due to insufficient paper feed pressure.

[0098] In this second embodiment as well, depending on the position of the end fence 103, the ends of the pressure lever hold-down members 143A and 143B may separate from the top of the base end 142a of the pressure lever 142. In this case, as in the first embodiment described above, simply inserting the base end 142a, which is the bent portion of the pressure levers 142A and 142B, into the groove 101c of the tray 101 may cause the pressure levers 142A and 142B to come off the tray 101. In such a case, it is preferable to provide a support mechanism for the pressure levers 142A and 142B that prevents the pressure levers 142A and 142B from coming off the tray 101.

[0099] In addition, in the configuration of the second embodiment, the position of the end fence where one pressure lever hold-down member 143A switches between the non-suppression position and the suppression position may be different from the position of the end fence where the other pressure lever hold-down member 143B switches between the non-suppression position and the suppression position. In this case, it is possible to switch the biasing force that pushes up the bottom plate 110 in three or more stages.

[0100] In the second embodiment, two auxiliary springs 141A and 141B, two pressure levers 142A and 142B, and two pressure lever hold-down members 143A and 143B are provided for one end fence 103, but this is not limiting. For example, as shown in Fig. 14, one auxiliary spring 141, one pressure lever 142, and one pressure lever hold-down member 143 may be provided for one end fence 103.

[0101] Furthermore, the configuration of the present embodiment 2 can be combined with the configuration of the above-described embodiment 1 (including each of the modified examples). By configuring in this way, it is possible to switch the biasing force that pushes up the bottom plate 110 in three or more stages.

[0102] As a specific example, when the pressure lever holder members of both the first switching means having the configuration of the above-described embodiment 1 (including each modified example) and the second switching means having the configuration of the second embodiment are both in the non-restricting position, the bottom plate 110 is pushed up by a large biasing force resulting from the combined biasing forces of the two pressure springs 111 and both auxiliary springs. When the pressure lever holder member of the first switching means is in the non-restricting position and the pressure lever holder member of the second switching means is in the restricting position, the bottom plate 110 is pushed up by a medium biasing force resulting from the biasing forces of the two pressure springs 111 and the auxiliary spring of the first switching means. When the pressure lever holder members of both the first switching means and the second switching means are both in the restricting position, the bottom plate 110 is pushed up by a small biasing force resulting from the biasing force of only the two pressure springs 111.

[0103] The above description is merely an example, and each of the following aspects provides unique effects. [First aspect] A first aspect is a sheet storage device (e.g., a paper feed cassette 100) having a bottom plate member (e.g., a bottom plate 110) on which sheets (e.g., recording sheets S) are stacked, a main urging means (e.g., a pressure spring 111) that urges the bottom plate member toward a feeding member (e.g., a main body paper feed roller 41) that feeds the sheets stacked on the bottom plate member, an auxiliary urging means (e.g., auxiliary springs 121, 121A, 121B, 141, 141A, 141B) that urges the bottom plate member toward the feeding member, and at least one regulating member selected from the group consisting of sheet width direction position regulating members (e.g., side fences 104A and 104B) that regulate the position of the sheets stacked on the bottom plate member in the sheet width direction perpendicular to the sheet feeding direction, and a sheet feeding direction position regulating member (e.g., an end fence 103) that regulates the position of the sheets stacked on the bottom plate member in the sheet feeding direction. a clamping member (e.g., pressure levers 122, 122A, 122B, 142, 142A, 142B) that is sandwiched between the biasing portion of the auxiliary biasing means (e.g., the upper end of an auxiliary spring) and the biased portion of the bottom plate member (e.g., the lower surface of the bottom plate) that is biased by the biasing portion, and that is clamped between the biasing portion and the biased portion when the auxiliary biasing means biases the bottom plate member toward the feeding member, and that is linked to a position change of the regulating member The present invention is characterized in that it has a switching means (for example, pressure lever holding members 123, 124, 125A, 125B, 143, 143A, 143B, etc.) that switches the state of the clamping member between a biasable state in which the biasing portion can bias the biased portion through the clamping member and a bias-suppressed state (for example, a bias-prohibited state) in which the biasing force with which the biasing portion biases the biased portion through the clamping member is suppressed more than in the biasable state. In conventional sheet storage devices, the configuration for switching the biasing force that biases the bottom plate member toward the feeding member in response to a change in the position of a regulating member that regulates the position of sheets stacked on the bottom plate member is large, resulting in an increase in the size of the device. This is mainly due to the fact that the biased portion of the bottom plate member (the portion biased by the biasing portion of the auxiliary biasing means) and the biasing member of the auxiliary biasing means are located at separate locations. In other words, in a configuration in which the biased portion of the bottom plate member and the biasing member of the auxiliary biasing means are located at separate locations, the biasing force transmission member (such as the rotation shaft of the push-up lever or the second rotation lever in the device of Patent Document 1) from the biasing member of the auxiliary biasing means to the biased portion of the bottom plate member becomes large. This increases the overall size of the auxiliary biasing means, resulting in an increase in the size of the sheet storage device. In this aspect, as a configuration for switching the biasing force that biases the bottom plate member toward the feed member, a clamping member is disposed between the biasing portion of the auxiliary biasing means and the biased portion of the bottom plate member, and a switching means switches the state of the clamping member. This switching means switches the state of the clamping member between a biasable state in which the biasing portion is clamped between the clamping member and the biased portion and can bias the biased portion, and a bias-suppressed state in which the biasing force that the biasing portion applies to the biased portion is suppressed compared to the biasable state, in response to a position change of the regulating member. With this configuration, it is possible to employ a configuration in which the biasing member of the auxiliary biasing means, which switches the biasing force that biases the bottom plate member toward the feed member, is disposed close to the biased portion of the bottom plate member, for example, a configuration in which the biasing member is disposed in a position facing the biased portion of the bottom plate member via a clamping member. With such a configuration, the biasing force transmission member from the biasing member of the auxiliary biasing means to the biased portion of the bottom plate member can be made smaller than before, thereby enabling the overall size of the auxiliary biasing means to be reduced. Furthermore, the clamping member, which is responsible for switching the biasing force that biases the bottom plate member toward the feed member, is disposed between the biasing portion of the auxiliary biasing means and the biased portion of the bottom plate member, and is therefore disposed close to the biased portion of the bottom plate member, enabling miniaturization. Furthermore, the switching means also switches the state of the clamping member between a biasable state and a bias-suppressed state, and such switching means can be realized with a simple configuration, is easily miniaturized, and can be disposed close to the biased portion of the bottom plate member. Therefore, according to this aspect, the configuration for switching the urging force that urges the bottom plate member toward the feeding member in conjunction with the change in position of the regulating member can be made smaller than conventional configurations, thereby enabling the sheet storage device to be made smaller.

[0104] [Second mode] The second aspect is characterized in that, in the first aspect, the clamping member is configured to be displaceable in the biasing direction (e.g., vertical direction) of the biasing portion of the auxiliary biasing means, and the switching means switches the clamping member to the biasable state by bringing the clamping member into a state where the above-mentioned displacement is possible, and switches the clamping member to the bias-suppressed state by bringing the clamping member into a state where the above-mentioned displacement of the clamping member is suppressed. According to this aspect, it is easy to miniaturize the configuration for switching the urging force that urges the bottom plate member toward the feeding member in conjunction with a change in the position of the regulating member, thereby making it possible to miniaturize the sheet storage device.

[0105] [Third aspect] The third aspect is characterized in that in the second aspect, the switching means includes a displacement suppression member (e.g., pressure lever holding member 123, 124, 125A, 125B, 143, 143A, 143B) that suppresses the displacement of the clamping member by contacting the clamping member, and also includes a moving mechanism (e.g., gear portion 131, switching pinion gear 132, rack gear 123b, etc.) that moves the displacement suppression member in conjunction with a change in position of the regulating member between a suppression position where the displacement suppression member suppresses the displacement of the clamping member and a non-suppression position where the displacement suppression member does not suppress the displacement of the clamping member. According to this aspect, it is easy to miniaturize the configuration for switching the urging force that urges the bottom plate member toward the feeding member in conjunction with a change in the position of the regulating member, thereby making it possible to miniaturize the sheet storage device.

[0106] [Fourth aspect] A fourth aspect is characterized in that, in the second aspect, the switching means includes a displacement suppression member that suppresses the displacement of the clamping member by contacting the clamping member, and the displacement suppression member (e.g., pressure lever holding member 125A, 125B, 143, 143A, 143B) moves integrally with the regulating member. According to this aspect, it is easy to miniaturize the configuration for switching the urging force that urges the bottom plate member toward the feeding member in conjunction with a change in the position of the regulating member, thereby making it possible to miniaturize the sheet storage device.

[0107] [Fifth mode] The fifth aspect is characterized in that, in the third aspect, the moving mechanism includes a first gear member (e.g., gear portion 131 of rack 105B) that moves in conjunction with a change in position of the regulating member, and a second gear member (e.g., switching pinion gear 132, rack gear 123b) that rotates in mesh with the first gear member, and the displacement suppression member is moved between the non-suppression position and the suppression position by the rotation of the second gear member. According to this aspect, even if the direction of position change (movement direction) of the regulating member and the direction of movement of the displacement suppressing member are different directions, the size can be easily reduced, and the sheet storage device can be made smaller.

[0108] [Sixth aspect] The sixth aspect is the fifth aspect, wherein the first gear member moves linearly in conjunction with a change in the position of the regulating member, and is provided with a gear portion 131 that meshes with the second gear member only at a portion of the linear movement direction, and the gear portion is arranged at a position where it meshes with the second gear member only when the regulating member passes a specific position. With this, the second gear member rotates only when the restricting member passes through the specific position, and the position of the displacement restricting member can be switched to the non-restricting position or the restricting position.

[0109] [Seventh aspect] The seventh aspect is characterized in that, in the fifth aspect, the second gear member has a gear portion 132a that meshes with a gear provided on the displacement suppression member only at a certain point in the rotational direction of the second gear member, and the gear portion is arranged at a point where it meshes with a gear (e.g., rack gear 123b) provided on the displacement suppression member only when the regulating member passes through a specific position. With this, the displacement restraining member moves only when the restricting member passes through the specific position, and the position of the displacement restraining member can be switched between the non-restraining position and the restraining position.

[0110] [Eighth aspect] The eighth aspect is characterized in that in any of the fifth to seventh aspects, the displacement suppression member (e.g., the pressure lever pressing member 123) moves linearly along the sheet feeding direction due to the rotation of the second gear member. According to this aspect, it is easy to make the configuration compact even if the direction of position change (movement direction) of the regulating member and the direction of movement of the displacement suppression member are different directions, and the sheet storage device can be made smaller.

[0111] [Ninth aspect] A ninth aspect is the fifth aspect, characterized in that the displacement suppression member (for example, the pressure lever holding member 124) rotates integrally with the second gear member. According to this aspect, it is easy to make the configuration compact even if the direction of position change (movement direction) of the regulating member and the direction of movement of the displacement suppression member are different directions, and the sheet storage device can be made smaller.

[0112] [Tenth aspect] The tenth aspect is characterized in that in the fourth aspect, the regulating member with which the switching means is linked includes two sheet width direction position regulating members (e.g., side fences 104A, 104B) that regulate the positions of both sides of the sheet width direction of the sheets loaded on the bottom plate member, and the auxiliary biasing means, the clamping member and the switching means are provided corresponding to each of the two sheet width direction position regulating members. This provides two auxiliary urging means, which allows each auxiliary urging means to be smaller than when there is only one auxiliary urging means, thereby enabling the sheet storage device to be made smaller.

[0113] [Eleventh aspect] The eleventh aspect is characterized in that in the fourth aspect, the regulating member with which the switching means is linked includes one sheet feed direction position regulating member (e.g., end fence 103), and one auxiliary biasing means, one clamping member, and one switching means are provided for the one sheet width direction position regulating member. According to this aspect, it is easy to miniaturize the configuration for switching the urging force that urges the bottom plate member toward the feeding member in conjunction with a change in the position of the sheet feeding direction position regulating member, thereby making it possible to miniaturize the sheet storage device.

[0114] [12th aspect] The twelfth aspect is characterized in that in the fourth aspect, the regulating member with which the switching means is linked includes one sheet feed direction position regulating member (e.g., end fence 103), and two of the auxiliary biasing means, two of the clamping members, and two of the switching means are provided for one sheet width direction position regulating member. According to this aspect, it is easy to miniaturize the configuration for switching the urging force that urges the bottom plate member toward the feeding member in conjunction with a change in the position of the sheet feeding direction position regulating member, thereby making it possible to miniaturize the sheet storage device.

[0115] [13th aspect] The 13th aspect is characterized in that, in any of the 1st to 12th aspects, it has a bottom plate regulating member (e.g., a bottom plate locking member 113) that regulates the position of the bottom plate member so that the sheet placing surface of the bottom plate member maintains an approximately horizontal position against the urging forces of the main urging means and the auxiliary urging means. This allows the restricting member to be operated with a small operating force.

[0116] [14th aspect] The 14th aspect is a sheet feeding device having a sheet storage device (e.g., a paper feed cassette 100) for storing sheets and a feeding member (e.g., a main body paper feed roller 41) for feeding the sheets stored in the sheet storage device, characterized in that the sheet storage device is a sheet storage device of any of the 1st to 13th aspects. According to this aspect, it is possible to realize a sheet feeding device in which the sheet storage device is made compact.

[0117] [15th aspect] The 15th aspect is an image forming apparatus (e.g., a printer) that forms an image on a sheet (e.g., a recording sheet S) fed by a sheet feeding device, characterized in that the sheet feeding device is the sheet feeding device of the 14th aspect. According to this aspect, an image forming apparatus with a compact sheet storage device can be realized. [Explanation of symbols]

[0118] 100: Paper cassette 101: Tray 102: Tray cover 103: End fence 104A, 104B: Side fence 105A, 105B: Rack 105a: Gear 106: Pinion gear 110: Bottom plate 111: Pressure spring 112: Opening 112a: Bent section 113: Bottom plate locking member 114: bias spring 121, 121A, 121B: Auxiliary spring 122, 122A, 122B: Pressure lever 122a: Proximal end 122c: Moving part 123, 124, 125A, 125B: Pressure lever holding member 123a, 124a: Presser foot 123b: Rack gear 124b: Gear section 131: Gear section 132: Switching pinion gear 141, 141A, 141B: Auxiliary spring 142, 142A, 142B: Pressure lever 142a: Proximal end 142c: Moving part 143, 143A, 143B: Pressure lever holding member S: Recording sheet [Prior art documents] [Patent documents]

[0119] [Patent Document 1] Patent No. 6668927

Claims

1. a bottom plate member on which sheets are stacked; a main biasing means for biasing the bottom plate member toward a feeding member that feeds sheets stacked on the bottom plate member; an auxiliary biasing means for biasing the bottom plate member toward the feeding member; a sheet width direction position regulating member that regulates the position of the sheets stacked on the bottom plate member in a sheet width direction perpendicular to the sheet feeding direction, and a sheet feeding direction position regulating member that regulates the position of the sheets stacked on the bottom plate member in the sheet feeding direction, a clamping member that is disposed between the biasing portion of the auxiliary biasing means and the biased portion of the bottom plate member that is biased by the biasing portion, and is clamped between the biasing portion and the biased portion when the auxiliary biasing means biases the bottom plate member toward the feeding member; A sheet storage device characterized by having a switching means that switches the state of the clamping member between a biasable state in which the biasing portion can bias the biased portion through the clamping member and a bias-suppressed state in which the biasing force with which the biasing portion biases the biased portion through the clamping member is suppressed compared to the biasable state in response to a position change of the regulating member.

2. The sheet storage device according to claim 1, the pinching member is configured to be displaceable in a biasing direction of the biasing portion of the auxiliary biasing means, The sheet storage device is characterized in that the switching means switches the clamping member to the biasable state by putting it into a state where the clamping member can be displaced, and switches the clamping member to the bias-suppressed state by putting it into a state where the displacement of the clamping member is suppressed.

3. The sheet storage device according to claim 2, The sheet storage device is characterized in that the switching means includes a displacement suppression member that suppresses the displacement of the clamping member by contacting the clamping member, and a moving mechanism that moves the displacement suppression member in conjunction with a change in position of the regulating member between a suppression position where the displacement suppression member suppresses the displacement of the clamping member and a non-suppression position where the displacement suppression member does not suppress the displacement of the clamping member.

4. The sheet storage device according to claim 2, the switching means includes a displacement suppressing member that suppresses the displacement of the clamping member by contacting the clamping member, The sheet storage device is characterized in that the displacement suppression member moves integrally with the regulating member.

5. The sheet storage device according to claim 3, The sheet storage device is characterized in that the moving mechanism includes a first gear member that moves in conjunction with a change in the position of the regulating member, and a second gear member that rotates in mesh with the first gear member, and the rotation of the second gear member moves the displacement suppression member between the non-suppression position and the suppression position.

6. The sheet storage device according to claim 5, the first gear member moves linearly in conjunction with a change in position of the regulating member, and includes a gear portion that meshes with the second gear member only at a partial location in the linear movement direction; The sheet storage device, wherein the gear portion is disposed at a position where it meshes with the second gear member only when the regulating member passes through a specific position.

7. The sheet storage device according to claim 5, the second gear member includes a gear portion that meshes with a gear provided on the displacement suppression member only at a portion of the second gear member in a rotational direction, The sheet storage device is characterized in that the gear portion is disposed at a position where it meshes with a gear provided on the displacement suppression member only when the regulating member passes through a specific position.

8. The sheet storage device according to claim 5, The displacement suppression member moves linearly along the sheet feeding direction by rotation of the second gear member.

9. The sheet storage device according to claim 5, The sheet storage device, wherein the displacement suppression member rotates integrally with the second gear member.

10. The sheet storage device according to claim 4, the regulating member interlocked with the switching means includes two sheet width direction position regulating members that regulate positions on both sides in the sheet width direction of the sheets stacked on the bottom plate member, The sheet storage device is characterized in that the auxiliary biasing means, the pinching member, and the switching means are provided corresponding to the two sheet width direction position regulating members, respectively.

11. The sheet storage device according to claim 4, The regulating member interlocked with the switching unit includes one sheet feeding direction position regulating member, The sheet storage device is characterized in that the auxiliary biasing means, the pinching member, and the switching means are provided one by one for each of the sheet width direction position regulating members.

12. The sheet storage device according to claim 4, The regulating member interlocked with the switching unit includes one sheet feeding direction position regulating member, The sheet storage device is characterized in that two of the auxiliary biasing means, two of the pinching members, and two of the switching means are provided for one of the sheet width direction position regulating members.

13. The sheet storage device according to any one of claims 1 to 12, A sheet storage device characterized by having a bottom plate regulating member that regulates the position of the bottom plate member so that the sheet loading surface of the bottom plate member maintains an approximately horizontal position against the urging forces of the main urging means and the auxiliary urging means.

14. A sheet feeding device having a sheet storage device that stores sheets and a feeding member that feeds the sheets stored in the sheet storage device, A sheet feeding apparatus, comprising the sheet storage device according to claim 1 .

15. An image forming apparatus that forms an image on a sheet fed by a sheet feeding device, 15. An image forming apparatus, comprising the sheet feeding device according to claim 14 as the sheet feeding device.

Images