Image formation device

Abstract

To provide an image formation device capable of preventing a sheet from being rotated due to an impact when sheet storage means is inserted.SOLUTION: A side end position in a width direction of a sheet of a predetermined size stored in a sheet feed cassette 60, is regulated by a depth-side side regulating member 80 and a front-side side regulating member 81 provided on an upstream side of a depth-side side regulating plate 61 and a front-side side regulating plate 62 in a sheet feeding direction. Then, when a sheet of a small size S3 having a shorter width in the width direction than the sheet of the predetermined size is stored in the sheet feed cassette 60, an auxiliary side regulating member 82 is attached to the depth-side regulating member 80 and the front-side regulating member 81, thereby regulating the side end position in the width direction of sheet of the small size S3.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an image forming apparatus, and particularly to a configuration for regulating the position of a sheet.

Background Art

[0002] Today, in image forming apparatuses such as copiers, printers, facsimiles, etc., those configured to feed a sheet stored in a sheet storage means to an image forming unit to form an image have become widespread. As such a sheet storage means, there is one in which a plate-like sheet stacking means for stacking sheets is provided so as to be movable up and down.

[0003] When replenishing the sheet, the sheet stacking means is lowered, and when feeding the sheet, the sheet stacking means is raised to move the upper surface of the stacked sheet to a position where it can be fed by an upper pickup roller. Further, the sheet storage means is provided so as to be pullable out of the apparatus main body, and when storing the sheet, after pulling out the sheet storage means, the sheet is set on the sheet stacking means from above.

[0004] The sheet storage means is provided with a rear end regulating means for regulating the position of the upstream end (hereinafter referred to as the rear end) in the sheet feeding direction of the sheet stacked on the sheet stacking means so as to be movable along the sheet feeding direction so that sheets of different sizes can be stored. Further, the sheet storage means is provided with a side end regulating means for regulating the side end position of the sheet in a direction orthogonal to the sheet feeding direction (hereinafter referred to as the width direction) so as to be movable in the width direction. Then, by regulating the side end of the sheet by the side end regulating means and regulating the rear end of the sheet by the rear end regulating means, the position of the sheet is regulated to a predetermined position (see Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, when the paper feed cassette is inserted, if an impact is applied to the paper feed cassette, the sheet will rotate. As a result, the sheet will shift inside the paper feed cassette, and the image on the sheet will shift by the amount of the shift, or the sheet will skew and the image will be formed obliquely on the sheet.

[0007] Therefore, the present invention has been made in view of such a situation, and an object thereof is to provide an image forming apparatus capable of preventing the rotation of a sheet due to an impact at the time of insertion of a sheet storage means.

Means for Solving the Problems

[0008] One aspect of the present invention includes a sheet storage means for storing sheets, which is detachably provided on the main body of an image forming apparatus and is mounted on the image forming apparatus main body by being inserted in an insertion direction; a sheet feeding means for feeding a sheet stored in the sheet storage means mounted on the image forming apparatus main body in a direction orthogonal to the insertion direction by a roller disposed on the leading end side of the sheet; an image forming unit for forming an image on the sheet fed by the sheet feeding means; a side end regulating means provided on the sheet storage means so as to be movable in a sheet width direction parallel to the insertion direction, which regulates the position of the sheet by contacting a side end along a direction orthogonal to the insertion direction of the sheet stored in the sheet storage means; a rear end regulating means provided on the sheet storage means so as to be movable in a direction orthogonal to the insertion direction, which regulates the position of the sheet by contacting the central portion in the insertion direction of the rear end of the sheet stored in the sheet storage means; and an auxiliary regulating means detachably attached to the sheet storage means, which is attached at a predetermined position when a sheet of a specific size is stored, is disposed on the rear end side of the sheet of the specific size rather than the side end regulating means in a direction orthogonal to the insertion direction, contacts the downstream side end in the insertion direction of the sheet of the specific size stored in the sheet storage means, and regulates the rotation of the sheet of the specific size when the sheet storage means is mounted on the image forming apparatus main body. The auxiliary regulating means is detachable from the sheet storage means independently of the rear end regulating means, the rear end regulating means is movable independently of the auxiliary regulating means, when the sheet of the specific size is stored in the sheet storage means, the auxiliary regulating means at the predetermined position, the side end regulating means, and the rear end regulating means regulate the sheet of the specific size, the side end regulating means is disposed at a position where the distance between the contact point between the rear end of the sheet of the specific size and the side end of the sheet in the side end regulating means is larger than the distance between the contact point between the leading end of the sheet of the specific size and the side end of the sheet in the side end regulating means in a direction orthogonal to the insertion direction, and at the predetermined position in the auxiliary regulating means, the distance between the contact point between the rear end of the sheet of the specific size and the side end of the sheet in the auxiliary regulating means isAn image forming apparatus, characterized in that it is set at a position smaller than the distance between the tip of the sheet of the specific size and the contact portion between the side end of the sheet in the side end regulating means.

Advantages of the Invention

[0009] According to the present invention, rotation of the sheet can be prevented.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0011] Hereinafter, an example of the sheet feeding device of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a full-color laser beam printer which is an example of an image forming apparatus according to an embodiment of the present invention. In FIG. 1, 1 is a full-color laser beam printer (hereinafter referred to as a printer), 1A is a printer main body which is an image forming apparatus main body, 1B is an image forming unit that forms an image on a sheet, and 20 is a fixing unit. 2 is an image reading device which is an upper device installed substantially horizontally above the printer main body 1A, and a discharge space P is formed between the image reading device 2 and the printer main body 1A. Note that 30 is a sheet feeding device provided at the lower part of the printer main body 1A, and 15 is a toner cartridge.

[0012] The image information read by the image reading device 2 or the image information input from an external device such as a personal computer (not shown) is subjected to image processing and then converted into an electric signal and transmitted to the laser scanner 10 of the image forming unit 1B. Then, in the image forming unit 1B, the surface of the photosensitive drum 12 of each process cartridge 11 is scanned by laser light corresponding to the image information of the yellow, magenta, cyan, and black component colors emitted from the laser scanner 10. As a result, the surface of the photosensitive drum 12 whose surface is uniformly charged to a predetermined polarity and potential by the charger 13 is sequentially exposed, and electrostatic latent images of yellow, magenta, cyan, and black are sequentially formed on the photosensitive drums of the respective process cartridges 11.

[0013] Thereafter, the developing device 14 develops and visualizes this electrostatic latent image with yellow, magenta, cyan, and black toner of each color. Then, by the primary transfer bias applied to the primary transfer roller 19, the toner images of each color on each photosensitive drum are sequentially superimposed and transferred onto the intermediate transfer belt 16. As a result, a toner image is formed on the intermediate transfer belt 16.

[0014] On one hand, the sheet S fed out from the sheet feeding device 30 passes through the registration roller pair 40 and is sent to the secondary transfer section constituted by the driving roller 16a and the secondary transfer roller 17. In the secondary transfer section, the toner image formed by the image forming section 1B is collectively transferred onto the sheet S. Next, the sheet S onto which the toner image has been transferred in this way is conveyed to the fixing section 20, where it is subjected to heat and pressure and fixed as a color image on the sheet S.

[0015] After that, the sheet S on which the image has been fixed is discharged into the discharge space P by the discharge roller pair 25a, 25b and stacked on the stacking section 23 protruding from the bottom surface of the discharge space P. When forming images on both sides of the sheet S, after the image is fixed, the sheet S is conveyed to the re-conveying passage R by the reversible inversion roller pair 22 provided in the double-sided inversion section 1D, and then conveyed to the image forming section 1B again.

[0016] Here, the paper feed cassette 60, which is the sheet storage means, is detachably mounted on the mounting section 1E shown in FIG. 2 formed at the lower part of the printer main body 1A. As shown in FIG. 2, the paper feed cassette 60 is provided with a rear side regulation plate 61 that regulates one position in the depth direction (width direction) orthogonal to the sheet feeding direction of the sheet S, that is, the position on the downstream side in the depth direction, so as to be movable in the depth direction. Further, the paper feed cassette 60 is provided with a front side regulation plate 62 that is provided opposite to the rear side regulation plate 61 and regulates the position on the upstream side in the depth direction of the sheet S, so as to be movable in the depth direction. Note that the rear side regulation plate 61 and the front side regulation plate 62 that constitute the pair of side end regulation means 61A move in conjunction with each other by an interlocking mechanism (not shown) so as to regulate the side end positions on the upstream side and the downstream side in the depth direction of the sheet.

[0017] Further, in the sheet feeding cassette 60, a rear end regulating plate 63 for regulating the position of the rear end, which is the upstream end of the sheet S in the sheet feeding direction, is provided so as to be movable along the sheet feeding direction. Further, the sheet feeding cassette 60 is provided with a middle plate (not shown) on which sheets are stacked, and the position of the sheets stacked on this middle plate is regulated by the back side regulating plate 61, the front side regulating plate 62, and the rear end regulating plate 63.

[0018] On the back side wall 60a of the cassette body 60A of the sheet feeding cassette 60, a swing arm 64 having a swing pin 65 at its tip is supported so as to be swingable about a shaft 64a as a fulcrum. Further, on the inner wall surface of the back side of the mounting portion 1E, a drawing unit 66, which is a drawing means for drawing the sheet feeding cassette 60 into the mounting portion 1E, is arranged. The drawing unit 66 includes a drawing unit base 69 and a drawing arm 68 provided with a drawing hook 67 at its tip and supported so as to be rotatable about a fulcrum 70 on the drawing unit base 69.

[0019] A recess 91 for locking the swing pin 65 of the swing arm 64 is formed in the drawing hook 67 of the drawing arm 68. Further, an arm pin 71 is provided between the drawing hook 67 of the drawing arm 68 and the fulcrum 70, and the other end of a tension spring 73, one end of which is locked to a base pin 72 provided on the drawing unit base 69, is locked to this arm pin 71. Then, by this tension spring 73, the drawing arm 68 is urged to rotate about the fulcrum 70.

[0020] When pulling out the paper feed cassette 60, while the concave portion 91 locks the swing pin 65, the retracting arm 68 rotates counterclockwise from the position shown in Fig. 2 around the fulcrum 70 in the pulling-out direction against the pulling spring 73. After that, when the paper feed cassette 60 is further pulled out, the retracting arm 68 rotates to the standby position where the locking of the swing pin 65 by the concave portion 91 is released. Note that before rotating to the standby position, when the retracting arm 68 rotates by a predetermined amount, a force to rotate counterclockwise is applied to the retracting arm 68 by the pulling spring 73. Due to this force, after the retracting arm 68 moves to the standby position, it abuts against a stopper (not shown) and stops.

[0021] When in the standby position, the retracting arm 68 is at a position where the swing pin 65 of the swing arm 64 enters the concave portion 91 of the retracting hook 67 when the paper feed cassette 60 is mounted on the printer main body 1A. Therefore, when the paper feed cassette 60 is inserted into the mounting portion 1E, the swing pin 65 enters the concave portion 91 of the retracting hook 67. After that, when the paper feed cassette 60 is further pushed in, the retracting arm 68 is pressed toward the back side via the swing pin 65 and the retracting hook 67.

[0022] As a result, the retracting arm 68 rotates clockwise around the fulcrum 70 against the pulling spring 73. After that, when it rotates to a predetermined position, a biasing force by the pulling spring 73 is applied to the retracting arm 68 to rotate it clockwise. Then, in the process of the retracting arm 68 rotating clockwise like this, the concave portion 91 of the retracting hook 67 locks with the swing pin 65. As a result, when the retracting arm 68 rotates from the pulling spring 73, the paper feed cassette 60 is mounted while receiving a biasing force in the depth direction by the pulling spring 73 via the retracting arm 68.

[0023] As shown in FIG. 2, when the paper feed cassette 60 is attached to one end (right end) orthogonal to the depth direction on the upstream side in the depth direction of the cassette main body 60A, a positioning portion 74 for positioning the paper feed cassette 60 in the depth direction is provided. When the paper feed cassette 60 is attached, the positioning portion 74 positions the paper feed cassette 60 in the depth direction. Further, after the paper feed cassette 60 is attached, a middle plate rotatably provided in the vertical direction on the cassette main body 60A is lifted, and the sheet S on the middle plate abuts against the pickup roller 75.

[0024] Incidentally, in the present embodiment, as shown in FIG. 2, a back side side regulating member 80 is provided on the upstream side in the sheet feeding direction of the back side side wall 60a, and a front side side regulating member 81 is provided on the upstream side in the sheet feeding direction of the front side side wall 60b of the cassette main body 60A. The interval in the width direction between the back side side regulating member 80 and the front side side regulating member 81 constituting the pair of upstream side end regulating means 80A is set to the maximum sheet width of the sheets that can be accommodated in the paper feed cassette 60.

[0025] In the present embodiment, since the maximum sheet size is LGL, the interval in the width direction between the back side side regulating member 80 and the front side side regulating member 81 is set to the LGL width, and FIG. 2 shows a state when the LGL size sheet S1 is accommodated. Then, the back side side regulating plate 61, the front side side regulating plate 62, the rear end regulating plate 63, the back side side regulating member 80, and the front side side regulating member 81 prevent the sheet S1 from being displaced within the paper feed cassette 60.

[0026] Here, the front side side regulating member 81 has a regulating portion (regulating surface) 81a on its side surface for regulating the position in the width direction of a sheet of a predetermined size (LGL size sheet) having the maximum sheet width among the sheets that can be accommodated in the paper feed cassette 60 as shown in FIG. 3. Since the back side side regulating member 80 also has the same configuration, only the front side side regulating member 81 will be described below.

[0027] Further, the front side side regulating member 81 is provided with a mounting space 81c for selectively mounting an auxiliary side regulating member 82, which is an auxiliary side end regulating means, from an upper opening. Here, the auxiliary side regulating member 82 regulates the position in the width direction of a small-sized sheet smaller than the maximum sheet width that can be accommodated in the paper feed cassette 60, and is provided with a convex portion 82a that abuts against the side end of the small-sized sheet.

[0028] Also, at the center in the sheet feeding direction of the regulating portion 81a of the front side side regulating member 81, there is formed a slit groove 81b, which is an opening extending in the vertical direction that causes the convex portion 82a to protrude from the front side side regulating member 81 toward the sheet side when the auxiliary side regulating member 82 is mounted. As a result, when the auxiliary side regulating member 82 is inserted from the opening at the upper part of the mounting space of the front side side regulating member 81 as shown in Fig. 4(a), the convex portion 82a of the auxiliary side regulating member 82 protrudes from the front side side regulating member 81 toward the inside of the cassette body as shown in Fig. 4(b). Note that on the back side of the regulating portion 81a, there is formed a slide groove (not shown) extending in the vertical direction for guiding the mounting of the auxiliary side regulating member 82 from above into the mounting space 81c.

[0029] Then, in the present embodiment, when a small-sized sheet is accommodated in the paper feed cassette 60, the auxiliary side regulating member 82 is mounted on the rear side side regulating member 80 and the front side side regulating member 81. Thereby, the side end position of the small-sized sheet stored in the paper feed cassette 60 can be regulated.

[0030] As shown in Figs. 3 and 4, an auxiliary member accommodating portion 83 is provided adjacent to a position on the front side side wall 60b of the cassette body 60A that does not interfere with the stacking of the sheets in the vicinity of the front side side regulating member 81. And when the auxiliary side regulating member 82 is not used, that is, when a sheet with the maximum sheet width is accommodated in the paper feed cassette 60, the auxiliary side regulating member 82 is accommodated in the auxiliary member accommodating portion 83. Thereby, the loss of the auxiliary side regulating member 82 can be prevented.

[0031] Here, in the present embodiment, as shown in FIG. 5(b) described later, the regulation width by the auxiliary side regulation member 82 attached to the back side regulation member 80 and the front side regulation member 81 is set to the A4 width (210 mm), which is smaller than the LGL width (215.9 mm). When storing a sheet of a smaller size than this, for example, when it is desired to set the regulation width to the B5 width (182 mm), an auxiliary side regulation member with the protruding amount from the slit groove 81b set to the B5 width is prepared.

[0032] Also, in the present embodiment, the positions of the back side regulation member 80 and the front side regulation member 81 in the sheet feeding direction are set to positions where the side edges of the LTR (215.9 mm) and A4 (210 mm) size sheets can be regulated. Note that FIG. 5(a) shows a state in which the LTR size sheet S2 is accommodated in the paper feed cassette 60. Thereby, when the LTR size sheet S2 is stored, the vicinity of the rear end of the sheet S2 abuts against the regulation surfaces of the regulation portion 80a of the back side regulation member 80 and the regulation portion 81a of the front side regulation member 81, and the position of the sheet S2 in the width direction is regulated.

[0033] Also, FIG. 5(b) shows a state in which the A4 size sheet S3 is accommodated in the paper feed cassette 60. When storing the A4 size sheet S3 in this way, as described above, the auxiliary side regulation members 82 are attached to the back side regulation member 80 and the front side regulation member 81, respectively. Thereby, when the A4 size sheet S3 is stored, the vicinity of the rear end of the sheet S3 abuts against the convex portion 82a, which is the regulation surface of the auxiliary side regulation member 82, and the position of the sheet S3 in the width direction is regulated. When storing the LGL, which is the maximum sheet size in the present embodiment, since the sheet width of the LGL is the same as that of the LTR, the sheet is stored with the auxiliary side regulation member 82 removed as shown in FIG. 2.

[0034] As described above, when storing a sheet whose length in the depth direction (width direction) is shorter than that of a sheet of a predetermined size, the auxiliary side regulating member 82 is attached to the back side regulating member 80 and the front side regulating member 81 to regulate the side end position of the sheet. Thereby, rotation of the sheet due to the impact at the time of inserting the paper feed cassette 60 can be prevented. As a result, the sheet can be supplied to the image forming unit 1B while suppressing skew and position deviation, and image deviation with respect to the sheet can be suppressed.

[0035] In addition, in the present embodiment, the auxiliary side regulating member 82 is configured to be slidably attached and detached in the sheet stacking direction. Therefore, even if the user touches the auxiliary side regulating member 82 or inserts the paper feed cassette 60 with a strong force when storing the sheet, the auxiliary side regulating member 82 will not easily come off from the back side regulating member 80 and the front side regulating member 81. As a result, the regulation of the position of the sheet in the width direction by the auxiliary side regulating member 82 can be surely performed.

Explanation of Signs

[0036] 1... Full-color laser beam printer, 1A... Printer main body, 1B... Image forming unit, 1E... Mounting unit, 60... Paper feed cassette, 60A... Cassette main body, 60a... Rear side wall of the cassette main body, 60b... Front side wall of the cassette main body, 61... Rear side regulating plate, 61A... Side end regulating means, 62... Front side regulating plate, 63... Rear end regulating plate, 80... Rear side regulating member, 80A... Upstream side end regulating means, 81... Front side regulating member, 81a... Regulating part, 81b... Slit groove, 81c... Mounting space, 82... Auxiliary side regulating member, 82a... Protrusion, 83... Auxiliary member accommodating part, S, S1, S2, S3... Sheets

Claims

1. a sheet storage unit that stores sheets, is detachably provided on the image forming apparatus body, and is attached to the image forming apparatus body by being inserted in an insertion direction; a sheet feeding means for feeding the sheet stored in the sheet storage means attached to the image forming apparatus body in a direction perpendicular to the insertion direction by a roller disposed on the leading end side of the sheet; an image forming section for forming an image on the sheet fed by the sheet feeding means; a side end regulating means provided in the sheet storage means so as to be movable in a sheet width direction parallel to the insertion direction, the side end regulating means contacting a side end of the sheet stored in the sheet storage means along a direction perpendicular to the insertion direction to regulate a position of the sheet; a rear end regulating means provided on the sheet storage means so as to be movable in a direction perpendicular to the insertion direction, the rear end regulating means contacting a center portion of a rear end of a sheet stored in the sheet storage means in the insertion direction to regulate a position of the sheet; an auxiliary regulating means detachably attached to the sheet storage means, the auxiliary regulating means being attached at a predetermined position when a sheet of a specific size is stored, the auxiliary regulating means being disposed toward the rear end of the sheet of the specific size relative to the side end regulating means in a direction perpendicular to the insertion direction, and contacting a downstream side end in the insertion direction of the sheet of the specific size stored in the sheet storage means to regulate rotation of the sheet of the specific size when the sheet storage means is attached to the image forming apparatus main body; the auxiliary regulating means is detachable from the sheet storing means independently of the trailing end regulating means, the trailing edge regulating means is movable independently of the auxiliary regulating means, When a sheet of the specific size is stored in the sheet storage means, the auxiliary regulating means, the side end regulating means and the rear end regulating means at the predetermined positions regulate the sheet of the specific size, the side edge regulating means is disposed at a position where, in a direction perpendicular to the insertion direction, a distance between a rear end of a sheet of the specific size and a contact point of the side edge regulating means with the sheet is greater than a distance between a front end of a sheet of the specific size and a contact point of the side edge regulating means with the sheet, An image forming apparatus characterized in that the specified position of the auxiliary regulating means is set at a position in a direction perpendicular to the insertion direction such that the distance between the rear end of a sheet of the specific size and the contact point between the side end of the sheet on the auxiliary regulating means is smaller than the distance between the leading end of a sheet of the specific size and the contact point between the side end of the sheet on the side end regulating means.

2. An image forming apparatus as described in claim 1, characterized in that the length of the contact point of the auxiliary regulating means positioned at the specified position with the side end of the specific size sheet in a direction perpendicular to the insertion direction is shorter than the length of the contact point of the side end regulating means with the side end of the specific size sheet in a direction perpendicular to the insertion direction.

3. An image forming apparatus as described in claim 1 or 2, characterized in that the sheet of the specific size whose side edge is regulated by the auxiliary regulating means is stored in the sheet storage means with the side edge that intersects the insertion direction being the long side and the short side aligned with the insertion direction.

4. 4. An image forming apparatus as claimed in claim 1, wherein the sheet storage means and the auxiliary regulating means are configured so that the auxiliary regulating means can be attached to the sheet storage means by sliding downward and the auxiliary regulating means can be removed from the sheet storage means by sliding upward.

5. The sheet storage means is provided with an opening on the outer side in the sheet width direction with respect to a space for storing the sheets, An image forming apparatus as described in any one of claims 1 to 4, characterized in that the auxiliary regulating means is attached to the sheet storage means by inserting a portion of the auxiliary regulating means into the opening from above, and the auxiliary regulating means, the portion of which is inserted into the opening of the sheet storage means, is moved upward to remove the auxiliary regulating means from the sheet storage means.

6. The sheet storage means includes: a hole disposed on a bottom surface of the sheet storage means and into which a lower portion of the auxiliary regulating means is inserted; An image forming apparatus as described in any one of claims 1 to 4, characterized in that an opening is provided that is positioned outside the hole and the space for storing the sheet in the sheet width direction and above the hole in the sheet stacking direction, and into which a portion of the auxiliary regulating means is inserted from above.

7. 7. The image forming apparatus according to claim 1, wherein the auxiliary regulating means is configured to be detachably attached to a plurality of positions in the sheet storing means.

8. 6. The image forming apparatus according to claim 1, further comprising a retracting unit that urges the sheet storage unit in the insertion direction to retract the sheet storage unit into a mounting position.

Images