Sheet feeding device to be connected to image forming apparatus

Abstract

The invention discloses a sheet feeding device to be connected to an image forming apparatus. The sheet feeding device is configured to feed a recording medium to an image forming device. The sheet feeding device includes a housing portion including a first frame, a second frame, a feeding unit, a first member, a weight unit fixed to the first member, and a support member, the support member is configured to support the recording medium and is movable in a first direction from a first position at which the feeding unit is capable of feeding the recording medium to a second position at which the recording medium is capable of being stacked in the support member. The housing portion is a portion of the sheet feeding device other than the support member. The first member and the weight unit are positioned upstream in the first direction with respect to a center of gravity of the housing portion. The weight unit is heavier than the first member.

Description

Technical Field

[0001] The present invention relates to a sheet feeding device to be connected to an image forming device. Background Art

[0002] Japanese Patent Publication No. 7-10366 describes a sheet feeding device equipped with a plurality of sheet trays and connected to an image forming apparatus. To prevent the image forming apparatus from toppling over when the sheet trays are pulled out, the image forming apparatus imposes restrictions on the number and types of sheet trays that can be pulled out simultaneously.

[0003] The present invention provides a sheet feeding device having improved stability, thereby improving the stability of an image forming device to which the sheet feeding device is connected. Summary of the invention

[0004] An aspect of the present invention is as follows.

[0005] A sheet feeding device is configured to be connected to an image forming device and to feed a recording medium to the image forming device.

[0006] The sheet feeding device includes: a shell part, which includes a first frame; a second frame; a feeding unit, which is positioned between the first frame and the second frame in the direction of the rotation axis of the feeding unit and is configured to feed the recording medium; a first member, which is fixed to the first frame and the second frame, and a weight unit, which is fixed to the first member.

[0007] The sheet feeding device also includes a supporting member configured to support the recording medium and capable of moving in a first direction from a first position to a second position, wherein the first position is a position where the feeding unit can feed the recording medium and the second position is a position where the recording medium can be stacked in the supporting member.

[0008] The casing portion is a portion of the sheet feeding device excluding the supporting member.

[0009] The first member and the weight unit are positioned upstream in the first direction relative to the center of gravity of the housing portion, and the weight unit is heavier than the first member.

[0010] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a schematic diagram illustrating an image forming apparatus and a sheet feeding apparatus according to Example 1.

[0012] Figure 2is another schematic diagram illustrating the image forming apparatus and the sheet feeding apparatus according to Example 1.

[0013] Figure 3 is a schematic diagram illustrating an image forming apparatus of Example 1.

[0014] Figure 4 is a perspective view illustrating a sheet feeding device of Example 1.

[0015] Figure 5 is another perspective view illustrating the sheet feeding device of Example 1.

[0016] Fig. 6A and Figure 6B is a schematic diagram illustrating a sheet feeding device of Example 1.

[0017] Fig. 7A , Figure 7B and Figure 7C is a schematic diagram illustrating a sheet feeding device of Example 1.

[0018] Figure 8 is a perspective view illustrating a sheet feeding device according to Example 2.

[0019] Fig. 9 is another perspective view illustrating the sheet feeding device of Example 2.

[0020] Fig.10 is a perspective view illustrating a sheet feeding device according to Example 3.

[0021] Fig.11 is a perspective view illustrating a sheet feeding device according to Example 4.

[0022] Fig.12 is a perspective view illustrating a sheet feeding device according to Example 5.

[0023] Fig.13 is another perspective view illustrating the sheet feeding device of Example 5.

[0024] Fig.14 is a perspective view illustrating a sheet feeding device according to Example 6.

[0025] Fig.15 is a schematic diagram illustrating a sheet feeding device of Example 6. DETAILED DESCRIPTION

[0026] Example 1

[0027] Will refer to Figure 1Figure 7 describes the image forming device 1 according to Example 1. In the following description and the accompanying drawings, the Z direction is defined as the vertical direction when the image forming device 1 is placed on a horizontal surface. The Y direction is defined as the extension direction of the rotation axis of the pickup roller 103 (to be described later), which intersects with the Z direction. The X direction is defined as the moving direction of the box 102 (to be described later), which intersects with both the Z direction and the Y direction. The X direction and the Y direction can extend horizontally. The X direction, the Y direction, and the Z direction can intersect orthogonally with each other. As indicated by the arrows in the figure, the +X direction points to the +X side, and the -X direction points in the opposite direction, in other words, to the -X side. The +Y direction points to the +Y side, and the -Y direction points in the opposite direction, in other words, to the -Y side. The +Z direction points to the +Z side, and the -Z direction points in the opposite direction, that is, to the -Z side.

[0028] Overall structure of image forming device and sheet feeding device

[0029] Will refer to Figure 1 and Figure 2 The overall structures of the image forming apparatus 1 , the sheet feeding device 100 , and the sheet feeding device 200 are described. Figure 1 The image forming apparatus 1 , the sheet feeding apparatus 100 , and the sheet feeding apparatus 200 are schematically illustrated.

[0030] First, the structure of the image forming apparatus 1 will be described. Figure 1 A laser beam printer is illustrated as an example of the image forming apparatus 1 of this example. Types of recording media to be used for the image forming apparatus 1 may include paper (such as plain paper and thick paper), plastic film, cloth, surface-treated paper material (such as coated paper), or paper material of a special shape (such as envelope or index paper). In other words, various types of paper of different sizes and materials may be used as the recording medium.

[0031] The image forming apparatus 1 includes a scanner unit 7, a scanner bracket 71, a photosensitive drum 8, a cartridge 2, a pickup roller 3 (or a feeding unit), a conveying roller pair 4, a process cartridge 6, a transfer roller 9, a fixing unit 10, a discharge roller pair 11, and a discharge tray 12. The process cartridge 6 includes a developing member 80. The process cartridge 6 is detachably attached to the image forming apparatus 1.

[0032] The scanner unit 7 is used to form an electrostatic latent image on the photosensitive drum 8 according to image data. The scanner bracket 71 supports the scanner unit 7. The photosensitive drum 8 is an image bearing member that bears the electrostatic latent image. The developing member 80 develops the electrostatic latent image on the photosensitive drum 8 using a toner. The box 2 is a supporting member that can support the sheet S1. The pickup roller 3 is a roller that contacts the sheet S1 supported by the box 2 and picks up the sheet S1 and sends it to the conveying roller pair 4. The conveying roller pair 4 conveys the sheet S1 from the pickup roller 3 to the transfer roller 9. The transfer roller 9 transfers the image to the sheet S1. The fixing unit 10 fixes the image transferred to the sheet S1 by heating and pressurizing the sheet S1. After passing through the fixing unit 10, the sheet S1 is sent to the discharge roller pair 11, and the discharge roller pair 11 discharges the sheet S1 onto the discharge tray 12.

[0033] Next, we will refer to Figure 1 The structure of the sheet feeding device 100 is described. Note that the structure of the sheet feeding device 200 is the same as that of the sheet feeding device 100, and a detailed description of the sheet feeding device 200 may be omitted. Figure 1 As shown, the sheet feeding device 100 is configured to be connected to the image forming device 1 and is configured to supply sheets thereto. In this example, the sheet feeding device 100 is detachably connected to the image forming device 1. The sheet feeding device 200 is configured to be connected to the sheet feeding device 100 and is configured to send sheets thereto. In this example, the sheet feeding device 200 is detachably connected to the sheet feeding device 100. Therefore, a plurality of sheet feeding devices can be connected to the image forming device 1 to increase the number of sheets and the types of sheets to be stored. Although two sheet feeding devices are connected to the image forming device 1 in this example, the number of sheet feeding devices to be connected is not limited to this example.

[0034] The sheet feeding device 100 includes a box 102, a pickup roller 103 (or a feeding unit), a conveying roller pair 104, and a weight unit 150. Similarly, the sheet feeding device 200 includes a box 202, a pickup roller 203 (or a feeding unit), a conveying roller pair 204, and a weight unit 250. The box 102 is a supporting member having a supporting surface 102b for supporting the sheet S2. Here, the housing portion 108 is defined as a portion of the sheet feeding device 100 other than the box 102. The housing portion 108 includes a pickup roller 103 (or a feeding unit), a conveying roller pair 104, and a weight unit 150. The housing portion 108 also includes a left plate 131, a right plate 132, a rear top plate 133, and a front top plate 135 to be described later. The pickup roller 103 is a roller that contacts the sheet S2 supported by the box 102 and picks up the sheet S2 and sends it to the conveying roller pair 104. The conveying roller pair 104 conveys the sheet S2 from the pickup roller 103 to the conveying roller pair 4. The conveying roller pair 104 also sends the sheet S3 from the conveying roller pair 204 of the sheet feeding device 200 to the conveying roller pair 4. The weight unit 150 and the weight unit 250 are members for improving the stability of the respective sheet feeding devices. These weight units will be described in detail later.

[0035] Next, refer to Figure 1 and Figure 2 The movement of box 102 is described. Figure 2 1 is a schematic diagram illustrating a state where the box 102 is pulled out in the +X direction (or in the first direction). The box 102 can be moved relative to the housing portion 108. Figure 1 The position shown (i.e., the first position) and Figure 2 When the box 102 is in the first position, the support surface 102b of the box 102 is positioned inside the housing portion 108. When the box 102 is in the second position, the support surface 102b of the box 102 is positioned outside the housing portion 108. Figure 2 When positioned as shown, the user can set the sheet in the cassette 102. When the cassette 102 is in the first position, the pickup roller 103 can pick up and feed the sheet S2. The cassette 102 is configured to be movable in the first direction (ie, in the +X direction) from the first position to the second position.

[0036] The movement of the cassette 2 and the movement of the cassette 202 are the same as the movement of the cassette 102 described above, and the description of these movements will be omitted. In this example, the sheet feeding device 200 is the same in shape as the sheet feeding device 100 .

[0037] Connection between image forming device and sheet feeding device

[0038] Next, we will refer to Figures 3 to 5Description of the connection structure between the image forming apparatus 1 and the sheet feeding device 100. First, the connection structure of the image forming apparatus 1 is described. Figure 3 is a schematic diagram of the image forming apparatus 1. Figure 3 As shown in , the image forming apparatus 1 includes a left plate 31 and a right plate 32. The left plate 31 has abutment portions 22b and 22d and first positioning holes 23b and 23d formed at the end of the left plate 31 facing the -Z direction. Similarly, the right plate 32 has abutment portions 22a and 22c and first positioning holes 23a and 23c formed at the end of the right plate 32 facing the -Z direction.

[0039] The left plate 31 and the right plate 32 are metal plates stretched in the X direction and the Z direction. Figure 3 As shown in , the end of the scanner bracket 71 facing the -Y direction is connected to the left plate 31, and the end of the scanner bracket 71 facing the +Y direction is connected to the right plate 32. In addition, the end of the process cartridge 6 facing the Y direction is supported by the left plate 31, and the end of the process cartridge 6 facing the +Y direction is supported by the right plate 32. In other words, the scanner bracket 71, the scanner unit 7, and the process cartridge 6 are disposed between the left plate 31 and the right plate 32 in the Y direction. The scanner unit 7 is fixed to the left plate 31 and the right plate 32, and the process cartridge 6 is supported by the left plate 31 and the right plate 32 to be movable relative to the left plate 31 and the right plate 32.

[0040] Figure 3 The abutment portions 22a to 22d in the sheet feeding device 100 are configured to contact the sheet feeding device 100 when the image forming apparatus 1 is placed vertically on the sheet feeding device 100. The first positioning holes 23a to 23d are holes for receiving respective positioning pins 140 to 143 of the sheet feeding device 100 to be described later.

[0041] Next, we will refer to Figure 4 and Figure 5 The connection structure of the sheet feeding device 100 is described. Figure 4 and Figure 5 is a perspective view illustrating the sheet feeding device 100 .

[0042] like Figure 4 As shown in FIG. 1 , the sheet feeding device 100 includes positioning pins 140 to 143, a pull-out connector 160, a left plate 131 (or a first frame), a right plate 132 (or a second frame), a front top plate 135, and a rear top plate 133 (or a first member). The left plate 131 and the right plate 132 are metal plates stretched in the X direction and the Z direction. Figure 5 As shown in FIG. 1 , the pickup roller 103 is disposed between the left plate 131 and the right plate 132 in the Y direction.

[0043] The front top plate 135 and the rear top plate 133 are metal plates constituting the end of the sheet feeding device 100 facing the +Z direction. The front top plate 135 is closer to the end of the sheet feeding device facing the +X direction than the end of the sheet feeding device 100 facing the -X direction. The rear top plate 133 is closer to the end of the sheet feeding device facing the -X direction than the end of the sheet feeding device 100 facing the +X direction. The ends of the front top plate 135 and the rear top plate 133 facing the -Y direction are fixed to the left plate 131, and the ends of the front top plate 135 and the rear top plate 133 facing the +Y direction are fixed to the right plate 132. In other words, both the front top plate 135 and the rear top plate 133 are fixed to the left plate 131 and the right plate 132. The weight unit 150 (to be described further later) is fixed to the rear top plate 133. Therefore, the weight unit 150 applies a force in the -Z direction to the rear top plate 133. In this example, the rear top plate 133 is fixed to both the left plate 131 and the right plate 132 , which enables the rear top plate 133 , the left plate 131 , and the right plate 132 to receive the force from the weight unit 150 in combination.

[0044] The positioning pins 140 to 143 are disposed at the ends (i.e., surfaces) of the front top plate 135 and the rear top plate 133 facing the +Z direction. The positioning pin 140 is configured to enter the first positioning hole 23a. The positioning pin 141 is configured to enter the first positioning hole 23b. The positioning pin 142 is configured to enter the first positioning hole 23c. The positioning pin 143 is configured to enter the first positioning hole 23d. These pins and holes enable the sheet feeding device 100 to be properly positioned relative to the image forming device 1. The positioning pins 140 to 143 constitute a connection portion for connecting the sheet feeding device 100 to the image forming device 1. The positioning pin 140 is positioned closer to the end of the front top plate 135 facing the +Y direction than the end of the front top plate 135 facing the -Y direction. The positioning pin 141 is positioned closer to the end of the front top plate 135 facing the -Y direction than the end of the front top plate 135 facing the +Y direction. The positioning pin 142 is positioned closer to the end of the rear top plate 133 facing the +Y direction than the end of the rear top plate 133 facing the -Y direction. The positioning pin 143 is positioned closer to the end of the rear top plate 133 facing the -Y direction than the end of the rear top plate 133 facing the +Y direction. The pull-out connector 160 is configured as a pull-out connector to be connected to the image forming apparatus 1 to supply power to the sheet feeding device 100.

[0045] Connection between the sheet feeding device 100 and the sheet feeding device 200

[0046] Next, the connection structure between the sheet feeding device 100 and the sheet feeding device 200 will be described. Figure 4 As shown in FIG. 1 , the sheet feeding device 200 has positioning pins 240 to 243. Figure 5As shown in , the sheet feeding device 100 has second positioning holes 123a to 123d. The positioning pin 240 is configured to enter the second positioning hole 123a. The positioning pin 241 is configured to enter the second positioning hole 123b. The positioning pin 242 is configured to enter the second positioning hole 123c. The positioning pin 243 is configured to enter the second positioning hole 123d. These pins and holes enable the sheet feeding device 200 to be properly positioned relative to the sheet feeding device 100. The positioning pins 240 to 243 constitute a connecting portion for connecting the sheet feeding device 200 to the sheet feeding device 100. Note that in this example, the structure for positioning the sheet feeding device 100 relative to the image forming device 1 is the same as the structure for positioning the sheet feeding device 200 relative to the sheet feeding device 100.

[0047] Structure of the weight unit

[0048] Next, refer to Figure 4 and Figure 5 The structure of the weight unit 150 is described. The weight unit 150 is a member for improving the stability of the sheet feeding device 100. The weight unit 150 includes five weight members. Since the weight unit 150 is formed by a plurality of weight members, it is easy to adjust the weight of the weight unit 150. The weight unit 150 may include at least one weight member. Each weight member is a metal plate shaped like a rectangular parallelepiped and stretched in the X direction and the Y direction.

[0049] In the Z direction, the thickness of the weight member is smaller than the thickness of the rear top plate. The weight member has a hole. Figure 5 As shown in , the fixing member 137 is arranged to pass through the hole of the weight member and is fixed to the end of the rear top plate 133 facing the -Z direction (that is, the lower surface of the rear top plate 133 in the vertical direction). In this example, the fixing member 137 is a screw fixed to the rear top plate 133. The fixing member 137 can be any member that can pass through the hole of the weight member and can fix the weight member to the end of the -Z direction of the rear top plate 133 (that is, the lower surface of the rear top plate 133 in the vertical direction). For example, the fixing member 137 can be a rivet.

[0050] In the Y direction, one end of each weight member (i.e., the end facing the +Y direction) is closer to the right plate 132 than the left plate 131. In the Y direction, the other end of each weight member (i.e., the end facing the -Y direction) is closer to the left plate 131 than the right plate 132. In addition, in the Y direction, the length of the weight member is greater than the distance between the right plate 132 and the left plate 131. Figure 5 As shown in FIG. 1 , the weight member passes through a hole formed in the right plate 132 , and also passes through a hole formed in the left plate 131 .

[0051] Although the weight unit 150 is directly fixed to the rear top plate 133 in Example 1, a different member may be interposed between the weight unit 150 and the rear top plate 133. The weight member does not need to be a metal plate.

[0052] Stability of the sheet feeding device

[0053] Next, refer to Figure 1 and Figure 4 The structure related to the stability of the sheet feeding device 100 is described. Figure 1 and Figure 4 The center of gravity G of the housing portion 108 is shown. Figure 1 and Figure 4 As shown in , the weight unit 150 is positioned upstream in the +X direction (i.e., the first direction) relative to the center of gravity G. Compared with the case where the weight member is not deployed, the deployment of the weight unit 150 at the upstream position of the center of gravity G can further shift the center of gravity of the sheet feeding device 100 in the -X direction. This can improve the stability of the sheet feeding device 100 when the box 102 is pulled out in the first direction, thereby improving the stability of the image forming device 1 to which the sheet feeding device 100 is connected. Similarly, the rear top plate 133 is also deployed at an upstream position in the +X direction (i.e., the first direction) relative to the center of gravity G, which further improves the stability of the sheet feeding device 100. The weight unit 150 is heavier than the rear top plate 133.

[0054] The weight unit 150 and the rear top plate 133 are positioned closer to the end of the housing part 108 facing the -X direction than the end of the housing part 108 facing the +X direction. In addition, the weight unit 150 and the rear top plate 133 are positioned above the level of the box 102 in the Z direction. In the area inside the sheet feeding device 100 that is closer to the end of the housing part 108 facing the -X direction than the end of the housing part 108 facing the +X direction and is positioned above the level of the box 102 in the Z direction, sufficient space for accommodating components is available. Therefore, the weight unit 150 can be deployed inside the sheet feeding device 100 without increasing the product size of the sheet feeding device 100.

[0055] In addition, if Figure 1 As shown in FIG. 1 , the end portion 150e of the weight unit 150 facing downward in the vertical direction is positioned above the level of the end portion 103e of the pickup roller 103 facing downward in the vertical direction. Figure 1As shown in , the weight unit 150 is closer to the upstream end 100f of the housing portion 108 (i.e., the housing upstream end 100f) in the first direction than the box 102 is relative to the housing upstream end 100f. When the box 102 is in the first position, the weight unit 150 is positioned directly above the support surface 102b of the box 102. In other words, the position of the weight unit 150 overlaps with the position of the support surface 102b in the X direction. Deploying the weight unit 150 in this way can reduce the increase in the size of the sheet feeding device 100.

[0056] A large amount of sheets may be set in the cassette 102 depending on the needs of the user. In this case, when the cassette 102 is moved in the first direction, the center of gravity of the sheet feeding device 100 is further shifted in the first direction compared to a case where a large amount of sheets are not set in the cassette 102. This reduces the stability of the sheet feeding device 100. In this example, the sheet feeding device 100 is formed to satisfy the following relationship in order to improve the stability of the sheet feeding device 100.

[0057] Mr>Mp

[0058] Mp=S×N×m

[0059] in

[0060] Mr: weight of the upstream portion of the shell portion 108;

[0061] Mp: weight of the maximum number of first standard size sheets to be stacked in the sheet feeding device 100; S: area (m 2 );

[0062] N: the maximum number of sheets of the first standard size to be stacked; and

[0063] m: Unit weight of the first standard size sheet (g / m 2 ).

[0064] The following description is given to further describe the above relationship. The above Mr is the weight of the upstream portion of the housing portion 108. The upstream portion is the portion of the housing portion 108 located upstream of the center of gravity G in the first direction.

[0065] The standard size sheet corresponds to a sheet of a size defined in, for example, ISO 21. For example, the standard size sheet may be A4 size or A3 size paper. Fig. 6A and Figure 6B Describes the first standard size sheet. Fig. 6A In FIG. 1 , L1 represents the length of the cassette 102 in the first direction when the cassette 102 is in the first state. In this state, the sheet S2a is set in the cassette 102. Figure 6B, L2 represents the length of the box 102 in the first direction when the box 102 is in the second state - in other words, when the box 102 is stretched from the first state in the -X direction (in the direction opposite to the first direction). In the second state, a standard-sized sheet S2b that is longer than the sheet S2a in the first direction can be set in the box 102. In this example, the length of the box 102 in the first direction can be increased from the first state to the second state. The end 100e is the downstream end of the housing portion 108 in the first direction (i.e., the downstream end of the housing). The end 100f is the upstream end of the housing portion 108 in the first direction.

[0066] In this example, if Figure 1 and Figure 4 As shown in , the pick-up roller (feeding unit) 103 is closer to the end 100e than the pick-up roller (feeding unit) 103 relative to the end 100f. When the box 102 is in the first state, the support surface 102b is positioned between the end 100e (downstream end of the shell) and the end 100f (upstream end of the shell) in the first direction. In this example, when observed in the +Y direction, the end 100f can be rotated clockwise. Since the end 100f rotates from the position of the first state, the stretched box 102 does not touch the end 100f. In the second state, when observed in the +Z direction, the end 100f overlaps with the support surface 102b. In this example, the first standard size sheet is defined as the maximum standard size sheet (S2a) that can be accommodated in the box 102 in the first state. Please note that unlike this example, the box 102 can be non-stretchable. In this case, the first standard size sheet is the maximum standard size sheet that can be accommodated in the box 102.

[0067] The following description refers to N above (i.e., the maximum number of first standard size sheets to be stacked). N above represents the maximum number of first standard size sheets that can be stacked in the cassette 102. In this example, the maximum number of sheets to be stacked is defined as the number of sheets when the first standard size sheets stacked on the supporting surface 102b reach a predetermined height (otherwise referred to as a "height limit") in the vertical direction. Fig. 7A A limiting member 138 is illustrated. The limiting member 138 is configured to contact the stack of first standard size sheets when the stack reaches a height limit, thereby preventing the first standard size sheets from being stacked more on the support surface 102b. The lower surface of the limiting member 138 is disposed at a position corresponding to the height limit (in other words, the height of the maximum number of recording media). The limiting member 138 prevents the first standard size sheets from being stacked on the support surface 102b above the level of the lower surface of the limiting member 138. Fig. 7AIn the example shown in , the maximum number of sheets to be stacked is defined as the number of sheets when the first standard size sheets stacked on the supporting surface 102 b hit the restricting member 138 .

[0068] Unlike this example, Figure 7B As shown in , a mark 238 may be provided on the side plate 102s of the box 102. The mark 238 may be used by the user to observe whether the first standard size sheet has reached the height limit. When the first standard size sheet has reached the height limit, the first standard size sheet overlaps with the mark 238 when observed in the +Y direction, which enables the user to recognize whether the first standard size sheet has reached the height limit. Figure 7B In the example shown in , the maximum number of sheets to be stacked is defined as the number of sheets when the first standard size sheet overlaps the mark 238 when viewed in the +Y direction.

[0069] Unlike this example, Figure 7C As shown in , a detector 338 may be provided, which is configured to detect the height of the first standard size sheet stacked on the support surface 102b. For example, the detector 338 may be a device that can optically detect the height limit of the first standard size sheet stacked on the support surface 102b, or a device that can detect the contact between the limiting member 138 and the first standard size sheet. Figure 7C In the example shown in , the maximum number of sheets to be stacked is defined as the number of sheets when the detector 338 detects the height limit of the first standard size sheet or detects the contact between the restriction member 138 and the first standard size sheet.

[0070] Alternatively, for example, the maximum number of sheets to be stacked may be the maximum number of sheets indicated in a product manual included with the image forming apparatus 1. Note that the sheet feeding device 100 may have a display. Figure 7B When an altitude restriction is detected, the detection result can be reported on the display.

[0071] In this example, the unit weight of the standard size sheet is 80g / m 2 , the area of ​​A4 sheet is 62370mm 2 (210mm×297mm), and the area of ​​A3 sheet is 124740mm 2 (297 mm x 420 mm) However, when the above relationship is applied, the unit weight and the area of ​​the A4 sheet and the A3 sheet do not need to take the above values.

[0072] By adjusting the weight balance of the sheet feeding device 100 having the weight unit 150 to satisfy the above relationship, the stability of the sheet feeding device 100 can be improved, thereby improving the stability of the image forming apparatus 1 to which the sheet feeding device 100 is connected. Note that the sheet feeding device 100 may be configured to satisfy the above relationship without disposing the weight unit 150.

[0073] Example 2

[0074] Will refer to Figure 8 and Fig. 9 Example 2 is described. Figure 8 and Fig. 9 is a perspective view illustrating the sheet feeding device 100. Note that elements denoted by the same reference symbols as those of Example 1 have substantially the same structures and advantageous effects as those described in Example 1, and repeated descriptions of these elements will be omitted. The same applies to subsequent examples, and descriptions of elements having the same reference symbols as those of Example 1 will be omitted.

[0075] In Example 1, the weight unit 150 has a plurality of weight members, and each weight member is shaped like a cuboid. However, in Example 2, the weight unit 350 has a single weight member shaped like a circular column. The weight unit 350 can be a hollow cylinder. For example, in the case where the weight unit 350 is a hollow cylinder, a liquid such as water or grease can be encapsulated therein to adjust the weight. In this case, a cover (not shown) is provided to seal the weight unit 350 containing the liquid.

[0076] Example 3

[0077] Will refer to Fig.10 Describe Example 3. Fig.10 is a perspective view illustrating the sheet feeding device 100 .

[0078] Fig.10 The sheet feeding device 100 shown in does not include the weight unit 150. In Example 3, a rear bottom plate 134 (third frame) is deployed in the sheet feeding device 100 configured as described in Example 1. The rear bottom plate 134 is a weight member constituting the end of the housing portion 108 facing the -Z direction. The rear bottom plate 134 is fixed to the left plate 131 and the right plate 132. In other words, the third frame is connected to the first frame and the second frame. This structure can increase the overall strength of the frame of the sheet feeding device 100 having the left plate 131, the right plate 132, the rear top plate 133, the front top plate 135, etc. The rear bottom plate 134 is positioned upstream of the center of gravity G in the +X direction, and thereby the center of gravity of the sheet feeding device 100 is offset in the -X direction compared to the case where the rear bottom plate 134 is not provided. Therefore, the stability of the sheet feeding device 100 is improved.

[0079] Example 4

[0080] Will refer to Fig.11 Describe Example 4. Fig.11 is a perspective view illustrating the sheet feeding device 100. In Example 4, the position of the weight unit is different from that in Example 1. Fig.11 As shown in , the rear top plate 133 includes a first metal plate 133a. The first metal plate 133a is stretched in the Z direction and the Y direction and is fixed to the ends of the left plate 131 and the right plate 132 facing the -X direction. The weight unit 450 is fixed to the end of the first metal plate 133a facing the -X direction (that is, the surface of the first metal plate 133a facing the -X direction). The weight unit 450 is deployed to stretch in the Y direction and the Z direction. In Example 4, the weight unit 450 is positioned upstream of the weight unit 150 of Example 1 in the +X direction. Therefore, the center of gravity of the sheet feeding device 100 of Example 4 is positioned upstream of the center of gravity of the sheet feeding device 100 of Example 1 in the first direction. As a result, the stability of the sheet feeding device 100 is further improved.

[0081] Example 5

[0082] Will refer to Fig.12 and Fig.13 Describe Example 5. Fig.12 and Fig.13 is a perspective view illustrating the sheet feeding device 100. In Example 5, the position of the weight unit is different from that in Example 1. Fig.12 and Fig.13 As shown in , the weight unit 550a is fixed to the left plate 131, and the weight unit 550b is fixed to the right plate 132. As in the case of Example 1, the weight units 550a, 550b are positioned upstream of the center of gravity G in the +X direction.

[0083] Example 6

[0084] Next, we will refer to Fig.14 and Fig.15 Describe Example 6. Fig.14 is a perspective view illustrating the sheet feeding device 100 . Fig.15 is a schematic diagram illustrating the sheet feeding device 100. In Example 6, the rear top plate 233 and the weight unit 150 are configured differently from those in Example 1. Fig.15As shown in, the rear top plate 233 is a metal plate having a first top plate portion 233a, a second top plate portion 233b and a third top plate portion 233c. The first top plate portion 233a is stretched in the X direction and the Y direction, and the second top plate portion 233b is stretched in the Z direction and the Y direction. The third top plate portion 233c is stretched in the X direction and the Y direction. The edge of the first top plate portion 233a facing the -X direction is connected to the edge of the second top plate portion 233b facing the +Z direction. The edge of the second top plate portion 233b facing the -Z direction is connected to the edge of the third top plate portion 233c facing the +X direction.

[0085] In other words, the third top plate portion 233 c is positioned further in the −Z direction than the first top plate portion 233 a .

[0086] The weight unit 150 is connected to the end of the third top plate portion 233c facing the +Z direction (i.e., the surface facing the +Z direction). Compared with the case of Example 1, deploying the weight unit 150 in this way improves the operability of replacing the weight unit 150. In addition, the end of the weight unit 150 facing the +Z direction is positioned upstream of the end of the first top plate portion 233a facing the +Z direction in the +Z direction.

[0087] With this configuration, when the weight unit 150 is mounted on the end portion of the rear top plate 233 facing the +Z direction, it is possible to prevent the size of the sheet feeding device 100 in the Z direction from increasing.

[0088] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A sheet feeding device configured to be connected to an image forming device and to feed a recording medium to the image forming device, the sheet feeding device comprising: A housing portion, the housing portion comprising: First frame, The second frame, a feeding unit that is positioned between the first frame and the second frame in a rotation axis direction of the feeding unit and is configured to feed a recording medium, a first member fixed to the first frame and the second frame, and a weight unit fixed to the first member; and a supporting member configured to support a recording medium and capable of moving in a first direction from a first position to a second position, the first position being a position where the feeding unit can feed the recording medium, and the second position being a position where the recording medium can be stacked in the supporting member, wherein the housing portion is a portion of the sheet feeding device excluding the supporting member, wherein the first member and the weight unit are positioned upstream in the first direction relative to the center of gravity of the housing portion, and The weight unit is heavier than the first member.

2. The sheet feeding device according to claim 1, Wherein the weight unit and the first member are positioned above the level of the support member in a vertical direction.

3. The sheet feeding device according to claim 2, Wherein in the vertical direction, the lower end of the weight unit is positioned above the level of the lower end of the feeding unit.

4. The sheet feeding device according to claim 3, The weight unit is fixed to a lower end of the first member in the vertical direction.

5. The sheet feeding device according to claim 4, The weight unit comprises at least one metal plate.

6. The sheet feeding device according to claim 5, The at least one metal plate is composed of at least two metal plates.

7. The sheet feeding device according to claim 6, Wherein in the first direction, the weight unit is closer to the upstream end of the shell part than the support member is to the upstream end of the shell part.

8. The sheet feeding device according to claim 7, further comprising: a fixing member configured to fix the weight unit to the first member, wherein the at least two metal plates have respective holes, wherein the fixing member is disposed to pass through the holes of the at least two metal plates and is fixed to the first member.

9. The sheet feeding device according to claim 8, The first member has a connecting portion configured to connect the sheet feeding device to the image forming device.

10. The sheet feeding device according to claim 9, further comprising: A third frame is positioned upstream of the center of gravity in the first direction and is fixed to the first frame and the second frame.

11. The sheet feeding device according to claim 10, Wherein in the first direction, the feeding unit is closer to the downstream end of the housing part than to the upstream end of the feeding unit relative to the housing part.

12. The sheet feeding device according to claim 11, In the vertical direction, the thickness of the metal plate is smaller than the thickness of the first component.

13. The sheet feeding device according to claim 1, Wherein the weight unit and the first member are positioned above the level of the support member in the vertical direction.

14. The sheet feeding device according to claim 1, Wherein in the vertical direction, the lower end of the weight unit is positioned above the level of the lower end of the feeding unit.

15. The sheet feeding device according to claim 1, The weight unit is fixed to the lower end of the first member in the vertical direction.

16. The sheet feeding device according to claim 1, The weight unit comprises at least one metal plate.

17. The sheet feeding device according to claim 16, The at least one metal plate is composed of at least two metal plates.

18. The sheet feeding device according to claim 17, In the vertical direction, the thickness of the metal plate is smaller than the thickness of the first component.

19. The sheet feeding device according to claim 1, Wherein in the first direction, the weight unit is closer to the upstream end of the shell part than the support member is to the upstream end of the shell part.

20. The sheet feeding device according to claim 17, further comprising: a fixing member configured to fix the weight unit to the first member, wherein the at least two metal plates have respective holes, and wherein the fixing member is disposed to pass through the holes of the at least two metal plates and is fixed to the first member.

21. The sheet feeding device according to claim 1, The first member has a connecting portion configured to connect the sheet feeding device to the image forming device.

22. The sheet feeding device according to claim 1, further comprising: A third frame is positioned upstream of the center of gravity in the first direction and is fixed to the first frame and the second frame.

23. The sheet feeding device according to claim 1, Wherein in the first direction, the feeding unit is closer to the downstream end of the housing part than to the upstream end of the feeding unit relative to the housing part.

24. A sheet feeding device configured to be connected to an image forming device and to feed a recording medium to the image forming device, the sheet feeding device comprising: A housing portion, the housing portion comprising: First frame, The second frame, a feeding unit that is positioned between the first frame and the second frame in a rotation axis direction of the feeding unit and is configured to feed a recording medium, a first member fixed to the first frame and the second frame, and a weight unit fixed to the first member; and a supporting member having a supporting surface configured to support a recording medium and being movable in a first direction from a first position to a second position, the first position being a position where the feeding unit can feed the recording medium and the second position being a position where the recording medium can be stacked in the supporting member, wherein the shell portion comprises a shell upstream end, the shell upstream end being the upstream end of the shell portion in the first direction, wherein the shell portion comprises a shell downstream end, the shell downstream end being a downstream end of the shell portion in the first direction, wherein when the support member is in the first position, the support surface of the support member is positioned between the upstream end of the housing and the downstream end of the housing in the first direction, wherein the housing portion is a portion of the sheet feeding device excluding the supporting member, wherein the shell portion includes an upstream portion, the upstream portion being a portion located upstream in the first direction relative to the center of gravity of the shell portion, wherein the first standard size sheet is the largest standard size sheet that can be stacked on the support surface, wherein the first maximum number of sheets is the maximum number of sheets of a first standard size that can be stacked in the support member, and Wherein a weight of the upstream portion is greater than a weight of the maximum number of sheets of the first standard size.

25. A sheet feeding device configured to be connected to an image forming device and to feed a recording medium to the image forming device, the sheet feeding device comprising: The housing part comprises: First frame, The second frame, a feeding unit that is positioned between the first frame and the second frame in a rotation axis direction of the feeding unit and is configured to feed a recording medium, a first member fixed to the first frame and the second frame, and a weight unit fixed to the first member; and a supporting member having a supporting surface configured to support a recording medium and being movable in a first direction from a first position to a second position, the first position being a position where the feeding unit can feed the recording medium and the second position being a position where the recording medium can be stacked in the supporting member, wherein the supporting member is configured to take a first state in which the supporting member has a predetermined length in the first direction, and also take a second state in which the supporting member is stretched from the first state in a direction opposite to the first direction, wherein the housing portion is a portion of the sheet feeding device excluding the supporting member, wherein the shell portion includes an upstream portion, the upstream portion being a portion located upstream in the first direction relative to the center of gravity of the shell portion, wherein the first standard size sheet is a largest standard size sheet that can be stacked on the supporting surface of the supporting member in the first state, wherein the first maximum number of sheets is the maximum number of sheets of a first standard size that can be stacked in the support member, and Wherein a weight of the upstream portion is greater than a weight of the maximum number of sheets of the first standard size.

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