Image forming device

Abstract

To precisely detect the position of a side restriction member of a paper feed cassette.SOLUTION: An image formation device comprises: a paper feed cassette 5 where sheets P are stacked; side restriction members 50, 51 which abut on end parts of the sheets P stacked in the paper feed cassette 5, and restrict the sheets P so that the end parts are aligned; a cassette cam 53 which has a rib part 53r, and moves in a direction orthogonal to a direction in which the side restriction member 50 moves according to a movement quantity of the side restriction member 50; a cassette rail 85 which guides the paper feed cassette 5; and a size detection part 66 which is provided at the cassette rail 85, has a main body cam 65, and detects the size of the sheets P stacked in the paper feed cassette 5 based upon the movement quantity of the main body cam 65. When the paper feed cassette 5 is inserted into the image formation device 100, the rib part 53r abuts on the main body cam 65, and the main body cam 65 energizes the rib part 53r in the opposite direction from the direction in which the paper feed cassette 5 is inserted into the image formation device 100 once the paper feed cassette 5 is loaded in the image formation device 100.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus such as a copying machine, a printer, or a facsimile machine. [Background technology]

[0002] Conventionally, image forming apparatuses equipped with a sheet feeding device, which feeds sheets from the sheet feeding device to an image forming section to form an image, have been widely used. The sheet feeding device is detachably attached to the image forming apparatus main body, and has a configuration in which a sheet stored in a sheet feeding cassette, which is a sheet storage section, is fed to the image forming section by a feeding roller. Since sheets of various sizes are used for image formation, a technology for detecting the size of the sheets stored in the sheet feeding cassette has been proposed. For example, Patent Document 1 discloses a configuration in which two cam members interlocking with the positions of side regulating members are arranged in the sheet feeding cassette, and one of the cam members pushes a sliding variable resistor arranged in the image forming apparatus main body to detect the size of the sheet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-1227 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the sheet size detection technology disclosed in the above-mentioned Patent Document 1 has the following problem. That is, since two cam members that are interlocked with the position of the side regulating member are arranged, the variation in the position of the cam members increases due to the influence of the variation and backlash of the component dimensions, and as a result, the variation in the detection of the sheet size also increases. In addition, one of the two cam members has a large sliding resistance due to its linear motion. Therefore, there is also a problem that a large force is required to move the position of the side regulating member.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to detect the position of a side regulating member of a paper feed cassette with high accuracy. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the present invention has the following configuration.

[0007] (1) An image forming apparatus for forming an image on a sheet, the image forming apparatus comprising: a loading section on which sheets are loaded; a regulating section movably disposed on the loading section, which abuts against an edge of the sheet loaded on the loading section and regulates the edge of the sheet so that the edge is aligned; a link section having a rib section and moving in a direction perpendicular to a direction in which the regulating section moves according to an amount of movement of the regulating section; a rail section for guiding the loading section when the loading section is attached to or detached from the image forming apparatus; and a detection means provided on the rail section, having a cam section, for detecting a size of the sheet loaded on the loading section based on an amount of movement of the cam section. When the loading section is inserted into the image forming apparatus while being guided by the rail section, the rib section abuts against the cam section, and when the loading section is attached to the image forming apparatus, the cam section urges the rib section in a direction opposite to a direction in which the loading section is inserted into the image forming apparatus. The link portion moves in the same direction as the direction in which the loading portion is inserted into the image forming apparatus, and the rib portion pushes the cam portion in the loading portion insertion direction by an amount of movement of the link portion in accordance with an amount of movement of the regulating portion. 1. An image forming apparatus comprising: Effect of the Invention

[0008] According to the present invention, the position of the side regulating member of the paper feed cassette can be detected with high accuracy. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing a configuration of an image forming apparatus according to first and second embodiments. [Diagram 2] FIG. 1 is a diagram showing the configuration of a paper feed cassette in the first and second embodiments; [Diagram 3] FIG. 1 is a diagram showing the configuration of a side regulating member in the first and second embodiments; [Figure 4]FIG. 1 is a diagram illustrating components of the image forming apparatus main body according to the first embodiment. [Diagram 5] FIG. 1 is a diagram illustrating components of the image forming apparatus main body according to the first embodiment. [Figure 6] FIG. 1 is a diagram for explaining a cassette cam of a paper feed cassette in the first and second embodiments; [Figure 7] FIG. 1 is a diagram for explaining a main body cam on the main body side of the image forming apparatus according to the first embodiment; [Figure 8] FIG. 13 is a diagram for explaining the movement of the cassette cam according to the size of the sheet in the first and second embodiments. [Figure 9] FIG. 13 is a diagram illustrating the relationship between the side regulating member and the cassette cam in the first and second embodiments. [Figure 10] FIG. 13 is a diagram for explaining components on the main body side of an image forming apparatus according to a second embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative positions, etc. of the components described in the embodiments are not intended to limit the scope of the present invention unless otherwise specified. EXAMPLES

[0011] [Configuration of image forming device] Fig. 1 is a cross-sectional view showing the configuration of an electrophotographic image forming apparatus 100 of Example 1. In the image forming apparatus 100 shown in Fig. 1, a sheet P, which is a recording material, is fed from a feeding section 1 to an image forming section 2, and in the image forming section 2, a toner image is transferred onto the sheet P conveyed from the feeding section 1. Thereafter, the sheet P is conveyed to a fixing section 3 where the toner image is fixed onto the sheet P, and then the sheet P is discharged to a discharge section 4.

[0012] The image forming operation in the image forming apparatus 100 will be described in detail. A paper feed cassette 5 constituting the feeding section 1, which stores sheets P, is attached to the lower part of the image forming apparatus 100. The sheets P stacked in the paper feed cassette 5, which is a stacking section, are sent to a conveying path in order from the topmost sheet P by a feed roller 6 rotating counterclockwise in the figure, and are conveyed to the image forming section 2 by a conveying roller pair 7 and a registration roller pair 8.

[0013] The process cartridge 30 constituting the image forming section 2 has a photosensitive drum 10 that rotates in a clockwise direction in the drawing. A laser scanner 9 is disposed on the upper part of the process cartridge 30, and an electrostatic latent image is formed on the photosensitive drum 10 by a laser beam (shown by a two-dot chain line in the drawing) that is irradiated from the laser scanner 9 in accordance with image information. A toner is attached to the electrostatic latent image formed on the photosensitive drum 10 by a developing section (not shown) inside the process cartridge 30, and a toner image is formed. Then, the toner image formed on the photosensitive drum 10 is transferred by a transfer roller 11 to a sheet P fed from a paper feed cassette 5. The sheet P to which the toner image has been transferred is conveyed to the fixing section 3, where it is heated and pressed in the fixing unit T, and the toner image is fixed to the sheet P. Thereafter, the sheet P is conveyed by a conveying roller pair 13 and a discharge conveying roller pair 14, and is discharged to a discharge section 4 at the upper part of the image forming apparatus 100.

[0014] The image forming operation described above is an image forming operation when printing on one side of the sheet P. Next, an image forming operation when double-sided printing on the front and back sides of the sheet P will be described. When recording images on both sides of the sheet P, the sheet P with an image formed on the front side passes through the fixing unit 3, and then the sheet P is switched back to the double-sided conveying path 21 and conveyed by rotating the pair of discharge conveying rollers 14 in the opposite direction to the rotation direction during single-sided printing. Then, the sheet P conveyed to the double-sided conveying path 21 is conveyed again to the image forming unit 2 by the pair of conveying rollers 16 and 17. Then, as in the case of printing on the front side, an image is formed on the back side of the sheet P, and after passing through the fixing unit 3, the sheet P is discharged to the discharge unit 4. The electrical equipment unit 15 has a power supply unit for the image forming apparatus 100 and a control board on which a CPU, which is a control means for controlling the image forming apparatus 100, is mounted.

[0015] When feeding sheets P from the manual feed section 19, the manual feed tray 18 is opened and the sheets P are stacked on the manual feed tray 18. The sheets P stacked on the manual feed tray 18 are fed out in order from the topmost sheet P by the manual feed roller 20 rotating clockwise in the figure, and are transported to the image forming section 2 by the registration roller pair 8. After being transported to the image forming section 2, the image forming operation is the same as that described above, and a description thereof will be omitted.

[0016] 1, when the sheet feed cassette 5 is pulled out from the image forming apparatus 100 to refill or replace the sheets P, it is pulled out to the left in the figure. On the other hand, when the pulled-out sheet feed cassette 5 is to be mounted in the image forming apparatus 100, it is mounted in the image forming apparatus 100 by inserting it from the left side to the right side as viewed from the front side. Also, since the sheets P loaded in the sheet feed cassette 5 are fed to the conveying path by the feed roller 6, the sheet feeding direction is from the left side to the right side in the sheet feed cassette 5 in FIG. 1.

[0017] [Paper feed cassette configuration] FIG. 2 is a diagram for explaining the configuration of the paper feed cassette 5, and is a perspective view of the paper feed cassette 5 pulled out from the image forming apparatus 100, viewed obliquely from above. The paper feed cassette 5 has a cassette receptacle 52 on which the sheets P are stacked, and a pair of side regulating members 50, 51 for aligning and regulating the positions of the ends of the sheets P in a direction perpendicular to the sheet feeding direction of the sheets P stacked in the cassette receptacle 52 (hereinafter referred to as the width direction). Furthermore, the paper feed cassette 5 has rack portions 50r, 51r of the side regulating members 50, 51 as regulating portions, a pinion gear 58 (see FIG. 6) connected to the rack portions 50r, 51r, and a cassette cam 53 as a link portion. In FIG. 2, the sheet feeding direction of the sheets P stacked in the paper feed cassette 5 is a direction from the right side to the left side of the cassette receptacle 52 in the figure.

[0018] The side regulating members 50 and 51 are configured to be slidable (movable) in the width direction of the stacked sheets P relative to the cassette receptacle 52. When one of the side regulating members 50 and 51 is slidable, the other side regulating member is slidable in conjunction with the rack portions 50r and 51r and the pinion gear 58. Specifically, when the side regulating member 50 (first regulating member) is slid in a direction approaching the side regulating member 51 (second regulating member), the rack portion 50r integrated with the side regulating member 50 also moves in a direction approaching the side regulating member 51. In response to this, the pinion gear 58 connected to the rack portion 50r rotates, and the rotation of the pinion gear 58 causes the rack portion 51r integrated with the side regulating member 51 to move in a direction approaching the side regulating member 50. As a result, the side regulating member 51 moves in a direction approaching the side regulating member 50. On the other hand, when the side regulating member 50 is slid in a direction away from the side regulating member 51, the rack portion 50r integrated with the side regulating member 50 also moves in a direction away from the side regulating member 51. Accordingly, the pinion gear 58 connected to the rack portion 50r rotates, and the rotation of the pinion gear 58 causes the rack portion 51r integrated with the side regulating member 51 to move in a direction away from the side regulating member 50. As a result, the side regulating member 51 moves in a direction away from the side regulating member 50. Here, the operation when the side regulating member 50 is slid has been described, but the same applies when the side regulating member 51 is slid, and the side regulating members 50 and 51 are configured to slide by the same amount in opposite directions to each other.

[0019] FIG. 2(a) is a diagram showing a state where the side regulating members 50, 51 are slid to match the width of a sheet P of LTR (letter) size with a wide sheet width. Meanwhile, FIG. 2(b) is a diagram showing a state where the side regulating members 50, 51 are slid to match the width of a sheet P of 3×5 inch size. A cassette cam 53 is disposed under the side regulating member 50 and moves in conjunction with the side regulating member 50. As described above, the position of the side regulating member 50 changes depending on the width of the sheet P loaded in the paper feed cassette 5, and accordingly, the position of the cassette cam 53 also moves to the upstream side or downstream side in the sheet feeding direction. As shown in FIG. 2(a), in the case of a sheet P of LTR size with a large sheet width, the position of the cassette cam 53 is the upstream side in the sheet conveying direction. Meanwhile, as shown in FIG. 2(b), in the case of a sheet P of 3×5 inch with a small sheet width, the side regulating member 50 slides toward the center of the paper feed cassette 5. Therefore, the cassette cam 53 is also guided by the rail portion 56 in conjunction with the cassette cam 53 and moves downstream in the sheet feeding direction.

[0020] [Configuration of side regulation members] Fig. 3 is a perspective view of the side regulating member 50 and the cassette cam 53 shown in Fig. 2, seen from the bottom toward the top in Fig. 2. As shown in Fig. 3, the side regulating member 50 has a rack portion 50r integrated with the side regulating member 50. The cassette cam 53 is provided with a rail portion 57 for the side regulating member 50 to slide and a rib portion 53r for pushing a main body cam 65 (see Fig. 4), which will be described later, in the sheet feeding direction, and has two rollers 54 arranged thereon.

[0021] As shown in FIG. 2B, a rail portion 56 is provided on an inner wall of the cassette housing 52 facing the side regulating member 50. When the side regulating member 50 is attached to the cassette housing 52, two rollers 54 attached to the cassette cam 53 are fitted into the rail portion 56. A roller 55 is rotatably disposed on the side regulating member 50 and fitted into a rail portion 57 provided on the cassette cam 53. When the side regulating members 50 and 51 are slid in a direction narrowing the width of the stacked sheets P, the roller 55 provided on the side regulating member 50 is guided within the rail portion 57 of the cassette cam 53 and rotates. As a result, the cassette cam 53 slides downstream in the sheet feeding direction in conjunction with the side regulating member 50. In addition, when the cassette cam 53 slides downstream in the sheet feeding direction, the roller 54 provided on the cassette cam 53 is guided by the rail portion 56 in conjunction with this and moves within the rail portion 56 downstream in the sheet feeding direction.

[0022] On the other hand, when the side regulating members 50, 51 are slid in a direction to widen the width of the stacked sheets P, the roller 55 provided on the side regulating member 50 rotates while being guided within the rail portion 57 of the cassette cam 53. As a result, the cassette cam 53 slides in the upstream direction in the sheet feeding direction in conjunction with the side regulating member 50. Also, when the cassette cam 53 slides upstream in the sheet feeding direction, the roller 54 provided on the cassette cam 53 is guided by the rail portion 56 in conjunction with this and moves within the rail portion 56 upstream in the sheet feeding direction.

[0023] In this way, by providing rollers on the cassette cam 53 and the side regulating member 50, the sliding resistance during sliding movement is reduced. This reduces the force that the user must apply when operating the side regulating members 50, 51. Note that operation is possible with a configuration that does not use rollers, but this has the disadvantage that the sliding resistance against the rail portions 56, 57 when the cassette cam 53 or the side regulating member 50 is large, and therefore the force that must be applied during operation is large.

[0024] [Size detection unit overview] 4(a) is a perspective view showing the outer shape of the image forming apparatus 100 when the sheet feed cassette 5 is pulled out from the image forming apparatus 100 and removed from the image forming apparatus 100, as viewed from the left rear of FIG. 1. A cassette rail 85 is provided at the location where the sheet feed cassette 5 is attached at the bottom of the image forming apparatus 100, for guiding the sheet feed cassette 5 when attaching or detaching the sheet feed cassette 5. A main body cam 65, which is a component of a size detection unit 66 (see FIG. 4(b)) that detects the size of the sheets P loaded in the sheet feed cassette 5, is disposed inside the cassette rail 85. When the sheet feed cassette 5 is guided by the cassette rail 85 and attached to the image forming apparatus 100, the main body cam 65 comes into contact with a rib portion 53r of the cassette cam 53 shown in FIG. 3. The main body cam 65 is configured to be pushed (slid) in the insertion direction (direction from the front side to the back side in the figure) of the sheet feed cassette 5 by the rib portion 53r of the cassette cam 53. The insertion direction of the sheet feed cassette 5 is the same as the sheet feeding direction of the sheets P.

[0025] 4(b) is a diagram showing the configuration of size detection unit 66, which is a detection means for detecting the size of sheets P loaded in sheet feed cassette 5, and is a perspective view showing the overall shape when viewed from the side of main body cam 65. Size detection unit 66 has main body cam 65 having rib portion 65r with which the above-mentioned rib portion 53r abuts, a rotary variable resistor 60 (hereinafter abbreviated as resistor 60), a printed circuit board 61, a gear 62 (first gear), a tension spring 63, and a sector gear 64 (second gear).

[0026] [Size detection section configuration] Next, the configuration of the size detection unit 66 that detects the size of the sheets P stacked in the sheet feed cassette 5 shown in FIG. 4(b) will be described.

[0027] FIG. 5(a) shows the printed circuit board 61 and resistor 60 of the size detection unit 66. The resistor 60 is fixed to the printed circuit board 61 and electrically connected to the printed circuit board 61. As shown in FIG. 5(a), the resistor 60 is provided with a rotatable D-cut hole 60a. The resistor 60 has a resistive body (not shown) therein, and a gear 62 (described later) is inserted into the hole 60a. When the gear 62 rotates, the resistance value of the resistor 60 changes according to the amount of rotation of the gear 62. The printed circuit board 61 converts the resistance value of the resistor 60 into a voltage and outputs the converted voltage to the CPU of the electrical equipment unit 15, whereby the CPU of the electrical equipment unit 15 detects the amount of rotation of the hole 60a by the gear 62. The gear 62 rotates according to the amount of movement (length) by which the main body cam 65 is pushed in the insertion direction of the paper feed cassette 5 (which is also the sheet feeding direction of the sheets P) via the rib portion 65r of the cassette cam 53 (FIG. 3). The amount of movement by which the main body cam 65 is pushed in the insertion direction of the paper feed cassette 5 correlates with the amount of movement when the side regulating member 50 is moved in accordance with the width of the stacked sheets P. Therefore, by detecting the amount of rotation of the gear 62, the size of the sheets P stacked in the paper feed cassette 5 can be detected.

[0028] 5(b) is a diagram illustrating the shape of the printed circuit board 61 to which the resistor 60 is fixed, and the gear 62. A boss 62a is provided at the rotation center of the gear 62, and the side of the boss 62a facing the resistor 60 has a D-cut shape. The boss 62a is lightly press-fitted into a hole 60a of the resistor 60 having a D-cut shape. There is no backlash between the hole 60a of the resistor 60 and the resistive element inside the resistor 60, and the gear 62 press-fitted into the hole 60a, so that there is no phase shift between them.

[0029] FIG. 5(c) is a diagram showing a state in which a sector gear 64 is connected to a gear 62 inserted into a hole 60a of a resistor 60 fixed on a printed circuit board 61. The sector gear 64 has a rotation center 64a supported by a boss 85a (FIG. 5(e)) of a cassette rail 85, and is engaged with the gear 62. FIG. 5(f) is an enlarged view of the portion where the sector gear 64 and the gear 62 are engaged. As shown in FIG. 5(f), the sector gear 64 is assembled so that a two-tooth protruding portion 64b of the sector gear 64 and a two-tooth recessed portion 62b of the gear 62 are engaged with each other, and the sector gear 64, the gear 62, and the resistor 60 are assembled so that the phases of the resistor (not shown) inside the resistor 60 become specific phases.

[0030] Fig. 5(d) is a diagram showing a state in which the teeth of the rack portion 65a of the main body cam 65 mesh with the teeth of the gear 62 in the diagram shown in Fig. 5(c). As with the sector gear 64 in Fig. 5(c), the main body cam 65 is assembled so that the two-tooth protruding portion 65b of the rack portion 65a meshes with the two-tooth recessed portion 62b of the gear 62. As a result, the main body cam 65, the gear 62, and the resistor (not shown) inside the resistor 60 are assembled so that their phases become specific phases.

[0031] 5(e) is a diagram for explaining the configuration of the tension spring 63, showing the state when the printed circuit board 61 is viewed from the opposite side to the side where the resistor 60 is fixed. One end (one end) of the tension spring 63 is hung on a hook portion 64C provided on the side opposite to the side facing the main body cam 65 of the sector gear 64, and the other end (other end) of the tension spring 63 is hung on a hook portion 85b provided on the cassette rail 85. The sector gear 64 is biased by the tension spring 63 in the clockwise direction in FIG. 5(e) around the boss 85a of the cassette rail 85.

[0032] In FIG. 5(d), the main body cam 65 is pushed in the insertion direction of the paper feed cassette 5 (direction from right to left in FIG. 5(d)) by the rib portion 53r (FIG. 3) of the cassette cam 53. As a result, the main body cam 65 moves leftward in the figure, and the gear 62 also rotates accordingly, and the fan gear 64 also rotates clockwise in conjunction with the rotation of the gear 62. On the other hand, when the paper feed cassette 5 is removed (pulled out) to the outside of the image forming apparatus 100, the fan gear 64 is pulled back by the tension spring 63 and rotates clockwise in FIG. 5(e), and the gear 62 also rotates accordingly. Due to the rotation of the gear 62, the main body cam 65 moves from left to right in the figure. Then, the fan gear 64 comes into contact with the stopper portion 85c of the cassette rail 85 and stops rotating, and the gear 62 also stops rotating, and the movement of the main body cam 65 stops.

[0033] [Installing a paper cassette with sheets loaded] 6 and 7 are diagrams for explaining the operation of components of the sheet feed cassette 5 and the size detection unit 66 when sheets P are loaded in the sheet feed cassette 5 and the sheet feed cassette 5 is attached to the image forming apparatus 100. Note that the sheet feed cassette 5 and the cassette rails 85 are not shown in FIGS.

[0034] Fig. 6(a) shows a state in which the paper feed cassette 5 is pulled out and removed from the image forming apparatus 100 in order to load sheets P in the paper feed cassette 5, and the side regulating members 50, 51 are opened (the space between the side regulating members 50, 51 is maximized) in order to load sheets P. In the state shown in Fig. 6(a), the sheets P are loaded into the cassette receptacle 52 of the paper feed cassette 5. Next, the side regulating members 50, 51 are slid to the ends of the loaded sheets P in the width direction.

[0035] FIG. 6(b) is a diagram showing the positions of the side regulating members 50, 51 in a state where the side regulating members 50, 51 are slid to the end of the width direction of the sheet P. For example, the side regulating member 50 is slid to the left in the figure from the state shown in FIG. 6(a) so as to come into contact with the end of the width direction of the sheet P. By sliding the side regulating member 50 to the left, the rack portion 50r integrated with the side regulating member 50 also slides to the left. As a result, the pinion gear 58 meshed with the teeth of the rack portion 50r rotates in the clockwise direction in the figure. In conjunction with this, the rack portion 51r of the side regulating member 51, whose teeth are meshed with the teeth of the pinion gear 58, also slides to the right in the figure in conjunction with the rack portion 50r. As a result, the side regulating member 51 integrated with the rack portion 50r also moves to the right in the figure. Furthermore, when the side regulating member 50 moves leftward in the figure, the roller 55 provided on the side regulating member 50 is guided by the rail portion 57 of the cassette cam 53 and moves within the rail portion 57. As a result, the cassette cam 53 moves from the position shown in Fig. 6(a) (shown by a dashed line in Fig. 6(b)) to a position shown in Fig. 6(b) according to the size (here, width) of the sheets P loaded in the paper feed cassette 5. Note that the arrow in Fig. 6(b) indicates the moving direction of the cassette cam 53, and as shown in Fig. 6(b), the moving direction of the cassette cam 53 moves in a direction perpendicular to the moving direction of the side regulating members 50, 51.

[0036] 7(a) is a diagram for explaining the state of the size detection unit 66 provided in the cassette rail 85 and the state of the side regulating members 50, 51, etc. of the paper feed cassette 5 before the paper feed cassette 5 is mounted in the image forming apparatus 100. In FIG. 7(a), the state of each member of the paper feed cassette 5, such as the side regulating members 50, 51, etc., is shown as viewed from the left side in FIG. 6(b) when the state of each member shown in FIG. 6(b) is shown. Also, before the paper feed cassette 5 is inserted into the image forming apparatus 100, the rib portion 65r of the main body cam 65 is not in contact with the rib portion 53r of the cassette cam 53, so that the fan gear 64 is in contact with the stopper portion 85c of the cassette rail 85 as shown in FIG. 7(a).

[0037] FIG. 7(b) is a diagram showing a state in which the paper feed cassette 5 is inserted into the image forming apparatus 100 from the state shown in FIG. 7(a) and attached to the image forming apparatus 100. As shown in FIG. 7(b), by inserting the paper feed cassette 5 into the image forming apparatus 100, the rib portion 53r of the cassette cam 53 abuts against the rib portion 65r of the main body cam 65, and the rib portion 65r is pushed in the insertion direction of the paper feed cassette 5. At this time, the rib portion 65r of the main body cam 65 is pushed in the insertion direction of the paper feed cassette 5 (direction from right to left in the figure), so that the gear 62 rotates by the rack portion 65a of the main body cam 65, and the hole portion 60a of the resistor 60 rotates in conjunction with the rotation of the gear 62. The rotation of the hole portion 60a of the resistor 60 changes the resistance value of the resistor inside the resistor 60, and a voltage converted according to the resistance value is output to the CPU of the electrical equipment unit 15. The CPU of the electrical equipment unit 15 detects the amount of rotation of the hole 60a based on the input voltage value. Then, the CPU of the electrical equipment unit 15 can detect the positions of the side regulating members 50, 51 based on the detected amount of rotation of the hole 60a. As a result, the CPU of the electrical equipment unit 15 can detect the size of the sheets P loaded in the paper feed cassette 5 (here, the width of the sheets P) based on the detected positions of the side regulating members 50, 51.

[0038] 7B, the tension spring 63 biases the fan gear 64 with a force to rotate counterclockwise in the figure due to the spring force of the tension spring 63 trying to return to the original state, so that the fan gear 64 applies a force to the gear 62 to rotate clockwise in the figure. Therefore, the main body cam 65 is biased by the gear 62 in the opposite direction (from left to right in the figure) to the insertion direction of the paper feed cassette 5 (from right to left in the figure). In this way, when the paper feed cassette 5 is attached to the image forming apparatus 100, the tension spring 63 constantly applies a rotational force to the gear 62 via the fan gear 64. The force of the tension spring 63 is indirectly applied to the main body cam 65 via the gear 62 in the opposite direction to the insertion direction of the paper feed cassette 5. At this time, the rib portion 65r of the main body cam 65 is prevented from moving in the direction opposite to the insertion direction of the paper feed cassette 5 by the rib portion 53r of the cassette cam 53, so that backlash between the gear 62 and the rack portion 65a of the main body cam 65 can be absorbed.

[0039] Furthermore, the rib portion 53r of the cassette cam 53 is also subjected to a force from the rib portion 65r of the main body cam 65 in the direction opposite to the insertion direction of the paper feed cassette 5, so that the backlash between the components in the paper feed cassette 5 can be shifted to one direction. In this way, by applying the spring force of the tension spring 63 in the direction opposite to the insertion direction of the paper feed cassette 5, the variation due to the backlash of the gear portion, the variation in the rotation amount of the hole portion 60a, and the variation due to the backlash between the components in the paper feed cassette 5 can be absorbed. As a result, the CPU of the electrical equipment unit 15 can detect the positions of the side regulating members 50 and 51 with high accuracy and stability. Furthermore, since the backlash of the gear portion and the backlash between the components can be ignored, the positions of the side regulating members 50 and 51 can be detected with high accuracy even if the paper feed cassette 5 is replaced with sheets P of a different size.

[0040] [Changes in the state of side regulation members and size detection unit depending on sheet size] Fig. 8(a) is a diagram for explaining the state of the size detection unit 66 when the sheet feed cassette 5, which contains LTR (letter) size sheets P and has the side regulating member 50 set to match the width of the sheets P, is mounted in the image forming apparatus 100. Meanwhile, Fig. 8(b) is a diagram for explaining the state of the size detection unit 66 when the sheet feed cassette 5, which contains 3 x 5 inch size sheets P and has the side regulating member 50 set to match the width of the sheets P, is mounted in the image forming apparatus 100. Note that the sheet feed cassette 5 and the cassette rails 85 are not shown in Figs. 8(a) and 8(b).

[0041] 8(a) and (b), the smaller the width of the sheets P loaded in the paper feed cassette 5, the more the side regulating member 50 moves inward of the paper feed cassette 5 (toward the viewer in the figure). Also, the cassette cam 53, which moves in conjunction with the side regulating member 50, moves in the sheet feeding direction (direction from right to left in the figure) the smaller the width of the sheets P loaded in the paper feed cassette 5. As a result, the rib portion 53r of the cassette cam 53 presses the rib portion 65r of the main body cam 65 further in the sheet feeding direction, so that the amount of rotation of the gear 62 increases, and the amount of rotation of the hole portion 60a of the resistor 60 also increases.

[0042] [Positional relationship between side regulation member and cassette cam] 9 is a graph showing the relationship between the side regulation member 50 set according to the width of the sheets P loaded in the paper feed cassette 5 and the position of the cassette cam 53 at that time. In Fig. 9, the horizontal axis shows the type of sheets P loaded in the paper feed cassette 5, and the vertical axis shows the position of the cassette cam 53 in the sheet feeding direction in the paper feed cassette 5.

[0043] In this embodiment, when the sheets P loaded in the paper feed cassette 5 are of LTR (letter) size, the position of the cassette cam 53 is set to point a1 (FIG. 8(a)) when the side regulating member 50 is slid to the end of the width direction of the sheets P. On the other hand, when the sheets P loaded in the paper feed cassette 5 are of 3×5 inch size, the position of the cassette cam 53 is set to point b1 (FIG. 8(b)) when the side regulating member 50 is slid to the end of the width direction of the sheets P. The rail portion 57 provided on the cassette cam 53 has a linear shape (straight shape) as shown in FIG. 8(a), so that the positional relationship between the side regulating member 50 and the cassette cam 53 is linear.

[0044] As described above, in this embodiment, by connecting the tension spring 63 to the sector gear 64 of the size detection unit 66, a rotational force is applied to the gear 62 via the sector gear 64, and a spring force is applied to the main body cam 65 in a direction opposite to the insertion direction of the paper feed cassette 5. This absorbs backlash from the gears and absorbs play between the components in the paper feed cassette 5 in one direction, so that the CPU of the electrical equipment unit 15 can accurately detect the positions of the side regulating members 50 and 51. Furthermore, by having the above-mentioned configuration, the CPU of the electrical equipment unit 15 can accurately detect the positions of the side regulating members 50 and 51 regardless of the size of the sheets P that are reloaded.

[0045] As described above, according to this embodiment, the position of the side regulating member of the paper feed cassette can be detected with high accuracy. EXAMPLES

[0046] In the first embodiment, an embodiment that supports a variety of sheet sizes from LTR (letter) size to 3×5 inch size has been described as a sheet feed cassette that can be loaded in the paper feed cassette. In the second embodiment, an embodiment of a paper feed cassette that can support sheets with a small difference in size, such as LTR (letter) size and A4 size, will be described.

[0047] [Size detection section configuration] Fig. 10 is a diagram showing the configuration of a size detection unit 66 of this embodiment that detects the size of sheets P stacked in the sheet feed cassette 5. Fig. 10 is a diagram showing the size detection unit 66 when the printed circuit board 61 is viewed from the opposite side to the side where the resistor 60 is fixed, similar to Fig. 5(e) of the first embodiment. In the size detection unit 66 shown in Fig. 10, the fan gear 64 and the tension spring 63 are omitted, compared to the configuration shown in Fig. 5(e) of the first embodiment.

[0048] As described above, since sheets P with a small difference in size are loaded in the paper feed cassette 5, even if the sheets P are reloaded with sheets P of a different sheet size, the difference in the amount of movement of the side regulating members 50, 51 is small. Therefore, even if the sheets P are reloaded with sheets of a different size, the difference in the amount of rotation of the gear 62 is also small. As a result, as shown in FIG. 10, the size detection unit 66 of this embodiment is configured such that a torsion coil spring 86 is wound around the rotation shaft of the gear 62. One end of the torsion coil spring 86 is held by the stopper portion 62b of the gear 62, and the other end is held by the stopper portion 85d provided on the cassette rail 85.

[0049] In this embodiment, by inserting the paper feed cassette 5 into the image forming apparatus 100, the rib portion 53r of the cassette cam 53 comes into contact with the rib portion 65r of the main body cam 65, and the rib portion 65r is pushed in the inserting direction of the paper feed cassette 5. At this time, the rib portion 65r of the main body cam 65 is pushed in the inserting direction of the paper feed cassette 5, so that the gear 62 is rotated by the rack portion 65a of the main body cam 65, and the hole portion 60a of the resistor 60 rotates in conjunction with the rotation of the gear 62. In this embodiment, by the rotation of the gear 62, the torsion coil spring 86 wound around the rotation shaft of the gear 62 is further compressed by being tightly wound around the rotation shaft of the gear 62. Then, the torsion coil spring 86 wound around the gear 62 tries to return to its original state, and applies a rotational force in a direction to rotate the gear 62 in the reverse direction.

[0050] With this configuration, the torsion coil spring 86 applies a force to the gear 62 to rotate it in the opposite direction (the direction of the arrow A in the figure) opposite the insertion direction of the paper feed cassette 5. Furthermore, as a force to rotate the gear 62 in the direction opposite the insertion direction of the paper feed cassette 5 is applied to the main body cam 65, a force in the direction of the arrow A in the figure is also applied to the rib portion 53r of the cassette cam 53 (not shown) that abuts against the rib portion 65r of the main body cam 65.

[0051] In this way, by applying the spring force of the torsion coil spring 86 in the direction opposite to the insertion direction of the sheet feed cassette 5, it is possible to absorb variations due to backlash of the gears and variations due to play between parts in the sheet feed cassette 5. As a result, the size detection unit 66 can accurately detect the positions of the side regulation members 50, 51. Furthermore, because the torsion coil spring absorbs variations due to backlash and play between parts, the size detection unit 66 can accurately and stably detect the positions of the side regulation members 50, 51 even if the sheets P are reloaded.

[0052] As described above, when the size difference between the sheets P loaded in the paper feed cassette 5 is small, a rotational force is applied to the gear 62 using the torsion coil spring 86, and a spring force is applied to the main body cam 65 in the direction opposite to the insertion direction of the paper feed cassette 5. This absorbs backlash from the gear portion and further absorbs play between the parts in the paper feed cassette in one direction, so that the size detection unit 66 can accurately detect the positions of the side regulation members 50, 51. Furthermore, with this configuration, even if the sheets P are reloaded, the size detection unit 66 can accurately detect the positions of the side regulation members 50, 51.

[0053] As described above, according to this embodiment, the position of the side regulating member of the paper feed cassette can be detected with high accuracy. [Explanation of symbols]

[0054] 5 Paper Cassette 50, 51 Side regulating member 53 Cassette Cam 53r Rib section 65 Body Cam 66 Size detection unit 85 Cassette Rail

Claims

1. An image forming apparatus for forming an image on a sheet, a loading section on which sheets are loaded; a regulating portion that is movably disposed on the stacking portion and comes into contact with an edge of the sheet stacked on the stacking portion to align the edge of the sheet; a link portion having a rib portion and moving in a direction perpendicular to a direction in which the restricting portion moves in response to a movement amount of the restricting portion; a rail portion that guides the loading portion when the loading portion is attached to or detached from the image forming apparatus; a detection unit provided on the rail portion, having a cam portion, and detecting a size of the sheet loaded on the loading unit based on a movement amount of the cam portion; Equipped with When the loading section is guided by the rail section and inserted into the image forming apparatus, the rib section comes into contact with the cam section, When the loading unit is attached to the image forming apparatus, the cam portion biases the rib portion in a direction opposite to a direction in which the loading unit is inserted into the image forming apparatus, a direction in which the link portion moves is the same as a direction in which the loading portion is inserted into the image forming apparatus; The image forming apparatus according to claim 1, wherein the rib portion presses the cam portion in the insertion direction of the loading portion by an amount of movement of the link portion in accordance with an amount of movement of the regulating portion.

2. The detection means is A variable resistor whose resistance value changes as the shaft rotates; a first gear coupled to the shaft of the variable resistor; a cam portion having a rack portion meshing with the first gear, the cam portion moving to rotate the first gear via the rack portion and change the resistance value of the variable resistor; 2. The image forming apparatus according to claim 1, further comprising:

3. The rail portion is A spring having one end connected to the rail portion; a second gear connected to the other end of the spring and meshing with the first gear; having 3. The image forming apparatus according to claim 2, wherein the spring is stretched by the second gear which rotates in conjunction with the rotation of the first gear, and the stretched spring applies a rotational force to the first gear via the second gear in a direction that urges the rib portion in the opposite direction to the direction in which the cam portion inserts the loading portion.

4. 4. The image forming apparatus according to claim 3, wherein the spring is a tension spring.

5. the rail portion has one end connected to the rail portion and the other end connected to the first gear, and a spring wound around a shaft of the first gear; 3. The image forming apparatus according to claim 2, wherein the spring is wound around the shaft and compressed as the first gear rotates, and the compressed spring applies a force to rotate the first gear in a direction that urges the rib portion in the opposite direction to the direction in which the cam portion inserts the loading portion.

6. 6. The image forming apparatus according to claim 5, wherein the spring is a torsion coil spring.

7. a control unit for controlling the image forming apparatus, The image forming apparatus according to any one of claims 3 to 6, characterized in that the control means detects the amount of movement of the cam portion corresponding to the resistance value based on a voltage generated by the resistance value of the variable resistor of the detection means, detects the amount of movement of the link portion based on the detected amount of movement of the cam portion, and detects the size of the sheets loaded on the loading section based on the detected amount of movement of the link portion.

8. the regulating portion is disposed so as to align edges of the sheets stacked on the stacking portion in a feeding direction, 8. The image forming apparatus according to claim 7, wherein the size of the sheet is a length in a direction perpendicular to a sheet feeding direction.

9. the regulating section includes a first regulating member and a second regulating member that come into contact with respective ends of the sheets stacked on the stacking section in a direction perpendicular to the feeding direction and regulate the respective ends so as to be aligned, each of the first regulating member and the second regulating member has a rack portion; The rack portions are connected to each other via a pinion gear, 9. The image forming apparatus according to claim 8, wherein when the second regulating member or the first regulating member is moved, the first regulating member or the second regulating member moves in a direction opposite to a direction in which the second regulating member or the first regulating member moves.

10. The first regulating member has a roller, The link portion has a linear rail portion into which the roller is fitted, 10. The image forming apparatus according to claim 9, wherein the link portion moves in a direction perpendicular to the direction in which the first regulating member moves, by the roller moving along the rail portion when the first regulating member moves to abut against an end of a sheet loaded on the stacking portion.

Images