Paper discharge unit

Abstract

To provide a paper discharge unit which can load a large amount of special sheets whose in-plane heights are different, without collapsing them.SOLUTION: A paper discharge unit 10 includes: a paper discharge tray part 11 for stacking conveyed recording media P1 in the vertical direction; a support part 12 for pivotally supporting the paper discharge tray part 11 so as to tilt; and an angle holding part 13 for returning the angle of the paper discharge tray part 11 inclined by the weight of the recording media P1 in the horizontal direction. The angle holding part 13 includes: a spring member 13a as energization means for energizing the paper discharge tray part 11; and a moment adjustment part 17 which can change a moment which the spring member 13a imparts to the paper discharge tray part 11.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a paper discharge unit. [Background technology]

[0002] Electrophotographic image processing devices such as multifunction machines are equipped with a paper discharge unit that vertically stacks and collects recording media such as paper with fixed toner images. In such devices, a paper discharge section provided in the image processing device detects the top surface, rotates a cam according to the number of sheets, and electrically controls the discharge stacking angle (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-169161 A Summary of the Invention [Problem to be solved by the invention]

[0004] An image forming apparatus may print on special paper with different in-plane heights, such as envelopes and delivery label paper that is a delivery slip. Conventional paper discharge units cannot accommodate a large amount of special paper with different in-plane heights because stacking such special paper in large quantities causes the special paper on top to tilt and collapse. Therefore, in a conventional paper discharge unit, when a certain amount of special paper is piled up, it is necessary to temporarily stop printing and dispose of the special paper in small portions. It is also possible to electrically control the angle at which the special paper is stacked using a motor, etc. In such a case, the control settings must be changed to accommodate the various types of special paper and regular recording media. For this reason, further improvements are desired in order to achieve high productivity through continuous printing while being compatible with special paper of various shapes.

[0005] An object of the present invention is to provide a paper discharge unit capable of stacking a large amount of special paper having different in-plane heights. [Means for solving the problem]

[0006] That is, the above-mentioned object of the present invention is achieved by the following configuration. (1) The paper discharge unit is characterized by comprising a paper discharge tray section which stacks the transported recording media vertically, a support section which axially supports the paper discharge tray section so that it can be tilted, and an angle holding section which returns the angle of the paper discharge tray section, which has been tilted due to the weight of the recording media, to the horizontal direction.

[0007] (2) The paper discharge unit described in (1) is characterized in that the angle holding portion has a biasing means for biasing the paper discharge tray portion, and a moment adjustment portion for enabling the moment applied by the biasing means to the paper discharge tray portion to be changed.

[0008] (3) The paper discharge unit according to (2), wherein the moment adjustment section is capable of adjusting the elastic force or the mounting direction of the biasing means.

[0009] (4) The paper discharge unit according to (2) or (3), wherein the biasing means biases at least one portion of the paper discharge tray in a direction in which the recording medium is discharged.

[0010] (5) The paper discharge unit according to (4), wherein the biasing means biases the paper discharge tray portion from its front end to its rear end in the direction in which the recording medium is discharged.

[0011] (6) The paper discharge unit according to claim 2, wherein the biasing means is an elastic member.

[0012] (7) The paper discharge unit according to (6), wherein the elastic member is a spring member.

[0013] (8) The paper discharge unit according to (1), wherein the recording medium is an envelope or label paper.

[0014] (9) The paper discharge unit described in (2) is characterized in that the moment adjustment section is adjustable to a moment that is measured in advance according to at least one of the type of recording medium, the direction in which the paper is discharged to the paper discharge tray section, or the number of sheets.

[0015] (10) The discharge unit according to (2), wherein the moment adjustment section is installed on either the left or right side edge in the discharge direction of the recording medium.

[0016] (11) A paper discharge unit as described in (1), characterized in that it comprises a cart section for placing and supporting the paper discharge tray section, wheels rotatably attached to the cart section, and a handle section attached to the cart section, and the paper discharge tray section is detachably attached to a paper discharge outlet of an image forming device from which the recording medium is discharged. Effect of the Invention

[0017] According to the present invention, a paper discharge unit is provided that can stack a large amount of special paper having different in-plane heights and can improve productivity through continuous printing. [Brief description of the drawings]

[0018] [Figure 1] FIG. 2 is a perspective view illustrating a configuration of a main part of the paper discharge unit according to the first embodiment of the present invention. [Diagram 2] 2 is a side view of an image forming apparatus to which the paper discharge unit is attached. FIG. [Diagram 3] FIG. 13 is a side view showing a state in which a plurality of special papers are stacked. [Figure 4] 11 is a side view illustrating a state in which special paper discharged from the image forming apparatus is placed on a tray unit. FIG. [Diagram 5] 11 is a side view illustrating a state in which a plurality of special papers discharged from the image forming apparatus are stacked on a tray and rotated. FIG. [Figure 6] 13 is a side view illustrating a state in which the rotation of the tray unit on which the special paper is placed stops. FIG. [Figure 7] FIG. 11 is a perspective view showing the configuration of the main part of a paper discharge unit according to a second embodiment of the present invention. [Figure 8] FIG. 11 is a perspective view showing the configuration of a main part of a paper discharge unit according to a third embodiment of the present invention. [Figure 9] FIG. 11 is a perspective view showing the configuration of the main part of a paper discharge unit according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, each embodiment of the present invention will be described in detail. FIG. 1 shows the configuration of an image forming device 2 and a paper discharge unit 10 detachably provided in the image forming device 2 in an image forming unit 1 according to the first embodiment. In this embodiment, for ease of understanding, a paper discharge outlet 9 is provided on the left side when the image forming unit 1 is viewed from the front, and a paper discharge direction F in which the recording medium P is discharged is defined. In addition, in this embodiment, the height direction of the image forming device 2 is defined as a vertical direction H. In addition, in this embodiment, the depth direction of the image forming device 2 that is perpendicular to the paper discharge direction F is defined as a horizontal direction W. [Paper output unit] First, a paper discharge unit 10 used in an image forming apparatus 2 will be described with reference to FIG. The paper discharge unit 10 includes a paper discharge tray portion 11 for stacking the recording media P conveyed by the image forming device 2 in the vertical direction, and a support portion 12 for supporting the paper discharge tray portion 11 about a shaft so that the paper discharge tray portion 11 can tilt.

[0020] The paper discharge unit 10 includes an angle holder 13 that returns the angle of the paper discharge tray 11, which has been tilted due to the weight of the recording medium P, to the horizontal direction. The discharge tray portion 11 is in the form of a rectangular plate when viewed from above, and has a flat upper surface 11d. The paper discharge tray section 11 is disposed at a position where the rear end 11b is close to the paper discharge outlet 9 of the image forming device 2. In this way, the paper discharge unit 10 can stack a large amount of recording media P discharged from the paper discharge outlet 9 on the upper surface of the paper discharge tray section 11 while being disposed on the side of the image forming device 2.

[0021] The support portion 12 has a rotation shaft that extends horizontally in the lateral direction. The rotation shaft of the support portion 12 is provided in the discharge tray portion 11, closer to the rear end 11b than the center position in the discharge direction F in which the recording medium P is discharged. The discharge tray section 11 can be tilted about the rotation axis of the support section 12 to move the front end 11a in the vertical direction. As a result, the upper surface 11d of the discharge tray section 11 can be tilted within a desired angle range in the discharge direction F.

[0022] The angle retaining portion 13 has a biasing means for biasing the front end 11a of the paper discharge tray portion 11 upward, i.e., the rear end 11b downward. The biasing means in the first embodiment includes a spring member 13a as an elastic member. The spring member 13a is made of a tension coil that receives a tensile load. An upper locking hook 13b is formed on one end of the spring member 13a. A lower locking hook 13c is formed on the other end of the spring member 13a. Of these, the upper locking hook 13b is locked to a tray-side locked projection 11c that protrudes from the side surface of the rear end 11b of the paper discharge tray portion 11.

[0023] The spring member 13a in the first embodiment biases the discharge tray section 11 downward at least at one location between the front end 11a and the rear end 11b in the discharge direction F in which the recording medium P is discharged, in this case the rear end 11b side.

[0024] Moreover, the angle holder 13 has a moment adjuster 17. The moment adjuster 17 is configured to make it possible to change the moment applied to the paper discharge tray section 11 by the spring member 13a. The moment adjustment unit 17 in the first embodiment is installed on the outside of the left side surface portion 14a in the discharge direction F of the recording medium P. The moment adjustment unit 17 has a locked plate 17a attached to the side surface portion 14a of the cart unit 14, and a plurality of locked projections 17b to 17e that protrude laterally at intervals from the locked plate 17a.

[0025] The locked plate 17a of the first embodiment is curved in a crescent shape with the tray-side locked protrusion 11c as the center of the arc. Furthermore, the multiple locked protrusions 17b are arranged along the curved shape of the locked plate 17a. Among them, the uppermost locked protrusion 17e is disposed forward of the support portion 12 in the paper discharge direction F (see FIG. 2).

[0026] The moment adjustment unit 17 thus configured selectively locks the lower locking hook 13c of the spring member 13a to any one of the locking projections 17b to 17e. The spring member 13a is detachable and can use at least one of a plurality of types of springs with different spring constants. The elastic force or mounting direction of the spring member 13a is changed according to the locking projection 17b to which the lower locking hook 13c is locked. As a result, the rear end 11b of the paper discharge tray portion 11 is pulled downward and urged by a different moment.

[0027] For example, when using spring members 13a with the same spring constant, the mounting angle of spring member 13a to discharge tray unit 11 is changed by selecting one of locked projections 17b to 17e to which lower locking hook 13c is locked. This allows moment adjustment unit 17 to reduce the vector component of the urging force in the circumferential direction about the axis of support unit 12 as the spring members 13a are sequentially locked from locked projection 17b to locked projection 17e. Therefore, the moment applied to the discharge tray portion 11 can be easily adjusted by changing the engagement projections 17b to 17e with which the lower engagement hook 13c is engaged.

[0028] Furthermore, the paper discharge unit 10 measures an appropriate moment in advance according to at least one of the type of recording medium P, the direction or number of sheets discharged to the paper discharge tray 11. The moment adjustment unit 17 then changes the locking position of the spring member 13a according to the type or number of recording media P to be discharged. This allows the moment adjustment unit 27 to set an appropriate moment so that the recording media P1 stacked on the top surface is approximately horizontal.

[0029] Furthermore, the paper discharge unit 10 includes a cart section 14 on which the paper discharge tray section 11 is placed and supported, a plurality of wheels 15 rotatably provided on the cart section 14, and a handle section 16 provided on the cart section 14. The paper discharge tray section 11 is attached to and detached from the side of the image forming apparatus 2 by the cart section 14 moving on the floor surface by the wheels 15.

[0030] The cart section 14 is configured to have a metal frame body 14b. A long abutment plate 18 is fixed to the frame body 14b in the vertical direction with a gap between it and the front end 11a of the paper discharge tray section 11 in the paper discharge direction F. The abutment plate 18 abuts against the front edge of the discharged recording medium P. This allows the recording medium P to be stopped at a desired position on the top surface of the paper discharge tray section 11, allowing multiple recording media P to be stacked in an aligned manner. In addition, left and right guide plates (not shown) may be provided on the left and right sides of the discharge tray section 11 in the discharge direction F to guide the left and right position of the recording medium P loaded on the discharge tray section 11 to a desired position.

[0031] Further, below the paper discharge tray 11 of the cart 14, a stopper surface portion 19 is provided on the upper surface of the frame 14b that faces the lower surface of the paper discharge tray 11. The stopper surface portion 19 of the first embodiment has an inclined surface on the upper surface side of the frame body 14b of the cart portion 14. The inclined surface of the stopper surface portion 19 is flat and inclined downward as it approaches the front in the paper discharge direction F. When the discharge tray section 11 rotates about the axis of the support section 12 to the lowest position, the stopper surface section 19 abuts against the lower surface side of the discharge tray section 11 to stop the rotation (see FIG. 6).

[0032] [Image forming device] The image forming apparatus 2 shown in Fig. 2 employs an intermediate transfer method that utilizes electrophotographic process technology. The image forming apparatus 2 mainly includes a control unit and a storage unit (not shown) that control each component based on an operation signal from reading an image from an object to be reproduced such as an original. The control unit includes a CPU (Central Processing Unit), a ROM (Read-Only Memory), and a RAM (Random Access Memory). The CPU reads out a program corresponding to the processing contents from the ROM and loads it in the RAM, and controls each component of the image forming apparatus 2 by using the loaded program in cooperation with various data stored in a storage unit such as a storage unit.

[0033] The image forming apparatus 2 also includes an image forming unit 5 that forms a toner image from the input image data read by the image reading unit 3, and a transport unit 6 that transports a recording medium P such as paper. The image forming unit 5 also includes a fixing device that applies pressure and heat to fix the toner image on the transported recording medium P, and the like.

[0034] Of these, the image reading unit 3 includes an ADF (Automatic Document Feeder) device and a scanner device. The ADF device transports one or more documents placed on a paper feed tray unit 7 using a transport mechanism and sends them to the scanner device. The scanner device optically scans the document transported from the ADF device or placed on a contact glass. The scanner device reads the reflected light from the document by forming an image on the light receiving surface of a CCD (Charge Coupled Device) sensor, and generates input image data.

[0035] The image forming unit 5 performs digital image processing according to initial settings or user settings on the input image data from the image reading unit 3. For example, the image forming unit 5 performs gradation correction based on gradation correction data (for example, a gradation correction table LUT) in the storage unit. The image forming unit 5 performs various correction processes such as gradation correction, color correction, shading correction, compression processing, etc. on the input image data.

[0036] The image forming unit 5 transfers the Y, M, C, and K components of the toner based on the input image data. Each of the image forming units 5 for each component includes an exposure device 5a, a developing device 5b, a photoconductor drum 5c, a charging device 5d, and a fixing device 5e.

[0037] In the image forming unit 5, the toner images of each color, Y (yellow), M (magenta), C (cyan), and K (black), formed on each photoconductor drum are sequentially transferred onto the intermediate transfer belt 5f so that the four color toner images are superimposed on each other. The superimposed toner images are then secondarily transferred onto the recording medium P transported from the paper feed tray unit 7 by the transport path 8.

[0038] The paper feed tray unit 7 has a plurality of paper feed tray portions, such as a first paper feed tray portion 7a, a second paper feed tray portion 7b, and a third paper feed tray portion 7c, each of which accommodates a plurality of types of recording media P. In the first embodiment, an envelope or label paper, which is a special paper having different in-plane heights, is used as the recording medium P1. The recording medium P1 is stored in at least one of the first paper feed tray section 7a, the second paper feed tray section 7b, and the third paper feed tray section 7c. The stored recording medium P is not limited to the recording medium P1, such as a label paper, which has a different in-plane height due to stacking of copy paper. For example, a tray other than the tray storing the recording medium P1 may store other types of special paper or paper with a uniform in-plane height.

[0039] Furthermore, the conveying path 8 conveys the recording medium P stocked in the paper feed tray unit 7 along a conveying path having a plurality of guide rollers to the fixing device 5e. The fixing device 5e applies heat and pressure to the toner image on the recording medium P to fix it onto the recording medium P. Then, the recording medium P on which the toner image has been fixed is transported along a transport path 8 and is discharged from a paper discharge outlet 9 to the outside of the image forming apparatus 2.

[0040] As shown in Fig. 3, the recording medium P1 of the first embodiment has copy paper or the like stacked on the front side in the paper discharge direction F. For this reason, the recording medium P1 has a thickness bias, with the front side being thicker than the rear side. Therefore, when multiple recording media P1 are transported and stacked on the upper surface 11d of the paper discharge tray section 11, the vertical dimension H2 of the front side is larger than the vertical dimension H1 of the rear side (H2>H1). And, the difference becomes even larger as the number of recording media P1 stacked increases.

[0041] As shown in FIG. 4, recording media P1 discharged from the discharge port 9 of the image forming apparatus 2 are stacked in order on the upper surface 11d of the discharge tray portion 11 of the discharge unit 10 mounted laterally. The paper discharge tray unit 11 stops tilting about the support unit 12 as the center of rotation when the weight of the stacked recording media P and the biasing force of the spring member 13a of the angle maintaining unit 13 are balanced. When the number of recording media P is small, the angle of the uppermost recording media P is maintained in a nearly horizontal state close to the initial position of the recording media P.

[0042] As shown in FIG. 5, when the number of stacked recording media P1 increases, the discharge tray section 11 tilts the front end 11a downward around the support section 12 as the weight of the stacked recording media P increases. At this time, as shown in Fig. 3, the vertical dimension H2 on the front side becomes larger than the vertical dimension H1 on the rear side (H2>H1). The increase in the vertical dimension H2 of the top surface of the stacked recording media P1 is offset by the amount of tilt caused by the increase in weight, so that the angle is maintained in a nearly horizontal state.

[0043] As shown in Fig. 6, when the number of recording media P1 increases further, the bottom surface of the discharge tray section 11 comes into contact with the stopper surface section 19 of the cart section 14 to stop the tilting. At this time, the top surface of the stacked recording media P is maintained at an angle in a nearly horizontal state. The front edge of the recording media P1 also comes into contact with the contact plate 18. Then, as necessary, the left and right guide plates provided on the left and right sides of the discharge tray section 11 in the discharge direction F come into contact with the left and right side edges of the stacked recording media P to guide them. This aligns the multiple recording media P in the front-to-back and left-to-right directions. Therefore, even if a desired number of conveyed recording media P1 are stacked in the vertical direction H, they will not collapse.

[0044] Therefore, the paper discharge unit 10 of the first embodiment can be easily moved using the handle portion 16. For example, even with special paper that has uneven thickness and is easily crumbled as in the past, there is no need to stop printing and carry it out in small pieces. Furthermore, the paper discharge unit 10 does not require electrically controlling the angle of the paper discharge tray with a motor or the like, and there is no need to change control settings or attach or detach electrical wiring. Therefore, it is possible to obtain high productivity through continuous printing while handling special paper of various shapes. Furthermore, other types of special paper or paper with a uniform thickness in the in-plane height may be placed in a paper feed tray other than the one containing the recording medium P1. In this case, the moment applied by the biasing means to the paper discharge tray section 11 by the moment adjustment section 17 can be easily changed according to the type of paper.

[0045] In the first embodiment, the spring members 13a having the same spring constant are used to appropriately select the latched projections 17b to 17e to which the lower latching hooks 13c are latched. This allows the moment adjustment unit 17 to increase or decrease the moment applied to the discharge tray unit 11. Also, spring members 13a having different spring constants may be further selected as the biasing means. In this way, the angle retaining section 13 of the first embodiment can easily increase or decrease the moment applied to the paper discharge tray section 11. Therefore, the paper discharge unit 10 can retain the angle of the paper discharge tray section 11 so as to return the inclination of the top surface of the loaded recording media P1 to the horizontal direction. Therefore, special papers having various weights and in-plane height deviations, and papers with uniform in-plane heights can be used as the recording media P.

[0046] Therefore, the angle of the recording medium P1 stacked on the top surface becomes almost constant according to the number of recording media P1 stacked on the paper discharge tray 11, and even if a large number of recording media P1 are stacked, they are unlikely to collapse. In addition, even if different types of paper are mixed, continuous printing can be performed, resulting in further high productivity. In this way, the paper discharge unit 10 of the first embodiment can provide a practically beneficial effect of being able to stack a large amount of special paper having different in-plane heights without collapsing it.

[0047] 7 shows a paper discharge unit 20 used in the image forming unit 102 of the second embodiment. Note that the same or equivalent parts as those in the image forming unit 1 of the first embodiment are given the same reference numerals and the description thereof will be omitted. The paper discharge unit 20 of the second embodiment has a spring member 23a as a biasing means for the angle retaining portion 23. The spring member 23a is composed of a tension coil that receives a tensile load. An upper locking hook 23b on one end side of the spring member 23a is locked to a carriage-side locked projection 18a that protrudes from the upper portion of the abutment plate 18. The other end of the spring member 23a is connected to the discharge tray section 21 and stretched in the vertical direction. As a result, the front end 21a of the discharge tray section 21 is biased upward by the spring member 23a and elastically supported so as to be tiltable around the support section 12 as the center of rotation.

[0048] A moment adjustment section 27 is provided on one side of the paper discharge tray section 21 . The moment adjustment section 27 has a first tray side engaging projection 27b, a second tray side engaging projection 27c, a third tray side engaging projection 27d, and a fourth tray side engaging projection 27e arranged in a straight line from the front to the rear along one side surface of the front end 21a of the paper output tray section 21.

[0049] The first tray side locked projections 27b to the fourth tray side locked projections 27e are each provided at a predetermined interval to protrude from one side surface. The lower locking hook 23c of the spring member 23a is locked to one of the first tray side locked projection 27b to the fourth tray side locked projection 27e. This makes it possible to change the mounting direction of the spring member 13a according to the projection 17b to which the lower hook 13c is engaged, thereby adjusting the moment around the support portion 12 of the discharge tray portion 21 as the center of rotation. Therefore, the moment adjustment section 27 can be set to an appropriate moment that is measured in advance according to at least one of the type of recording medium P, the direction in which the sheets are discharged to the discharge tray section 21, and the number of sheets.

[0050] Other configurations and functions and effects are similar to those of the paper discharge unit 10 of the first embodiment, so description thereof will be omitted.

[0051] 8 shows a paper discharge unit 30 used in the image forming unit 103 of the third embodiment. Note that the same or equivalent parts as those in the image forming unit 1 of the first embodiment are given the same reference numerals and the description thereof will be omitted.

[0052] The paper discharge unit 30 has a spring member 33a as a biasing means for the angle retaining portion 33. The spring member 33a is composed of a compression coil spring that receives a compression load. The spring member 33a has an upper end 33b on one end side and a lower end 33c on the other end side as flat contact surfaces.

[0053] A tray-side moment adjustment section 37 is provided on the lower surface of the paper discharge tray section 31. The moment adjustment section 37 is formed so that a first tray side seating surface 37a, a second tray side seating surface 37b, a third tray side seating surface 37c, a fourth tray side seating surface 37d, and a fifth tray side seating surface 37e are alternately formed in an uneven shape from the front to the rear of the paper output tray section 31. The upper end 33b of the spring member 33a is disposed in contact with any one of the first tray side seating surface 37a to the fifth tray side seating surface 37e.

[0054] Further, the bogie section 14 is provided with a bogie-side moment adjustment section 38. The moment adjustment section 38 has a first bogie-side seating surface 38a to a fifth bogie-side seating surface 38e against which the lower end 33c of the spring member 33a abuts. Of these, a first carriage side seating surface 38a is provided to protrude from the middle position of the contact plate 18 in the up-down direction H. Also, a frame upper surface 39 of the carriage section 14 has a second carriage side seating surface 38b, a third carriage side seating surface 38c, a fourth carriage side seating surface 38d, and a fifth carriage side seating surface 38e. These first carriage side seating surfaces 38a to fifth carriage side seating surfaces 38e are formed in an uneven shape alternately in the paper discharge direction F along the inclination of the contact plate 18 and the frame upper surface 39 at predetermined intervals.

[0055] In the paper discharge unit 30 of the third embodiment thus configured, the upper end 33b of the spring member 33a abuts against any one of the first tray side seating surface 37a to the fifth tray side seating surface 37e of the moment adjustment section 37. Also, the moment adjustment section 38 abuts against any one of the first cart side seating surface 38a to the fifth cart side seating surface 38e. As a result, the spring member 33a is disposed at a desired position between the lower surface of the paper discharge tray section 31 and the frame upper surface 39 of the cart section 14. Other configurations and functions and effects are similar to those of the paper discharge unit 10 of the first embodiment, so description thereof will be omitted.

[0056] 9 shows a paper discharge unit 40 used in the image forming unit 104 of the fourth embodiment. Note that the same or equivalent parts as those in the image forming unit 1 of the first embodiment are given the same reference numerals and the description thereof will be omitted. The paper discharge unit 40 has a torsion spring member (torsion spring) 41 as a biasing means for the angle holding portion. One end of the torsion spring member 41 abuts against the lower surface of the paper discharge tray portion 11. The other end of the torsion spring member 41 abuts against a frame portion on the side of the cart portion 14. This allows the torsion spring member 33a to be disposed between the cart portion 14 and the paper discharge tray portion 11 and to bias the paper discharge tray portion 11 upward. Other configurations and functions and effects are similar to those of the paper discharge unit 10 of the first embodiment, so description thereof will be omitted.

[0057] Although the first to fourth embodiments of the present invention have been described above, these embodiments are merely illustrative and do not limit the technical scope of the present invention. The present invention can take various other embodiments, and various modifications such as omissions and substitutions can be made without departing from the gist of the present invention. These embodiments and their modifications are included in the scope and gist of the invention described in this specification, etc., and are included in the scope of the invention described in the claims and their equivalents.

[0058] For example, in the embodiment, the moment adjustment unit 17 that can change the moment has been provided, but the present invention is not limited to this. For example, it is sufficient to provide an angle retaining unit 13 that returns the angle of the paper discharge tray unit 11 that has been tilted due to the weight of the recording medium P1 to the horizontal direction. The angle maintaining unit 13 may change the spring constant of the biasing means such as the spring member 13a. Furthermore, the angle maintaining unit 13 may have an elastically deformable rubber member or other types of springs, without being limited to the spring member 13a. In other words, the angle maintaining section 13 may be of any shape, number, material and combination as long as it applies a biasing force to return the angle of the output tray section 11 that has been tilted due to the weight of the recording medium P or P1, or more specifically, the topmost recording medium P1, to a horizontal direction.

[0059] Moreover, the moment adjustment unit 17 and the like may be any unit that can change the moment applied to the paper discharge tray unit 11 by the biasing means of the angle retaining unit 13, with the mounting angle and the support unit 12 of the paper discharge tray unit 11 as the tilt center. For example, the embodiment has been described as one that changes the magnitude of the moment in stages. However, the present invention is not limited to this, and moment adjustment section 17 may be configured to adjust the magnitude of the moment in a stepless manner. That is, moment adjustment section 17 may be configured in any shape, number, and combination. [Explanation of symbols]

[0060] 10 Paper ejection unit 11 Paper output tray 13 Angle holding part 13a Spring member (urging means) 17 Moment adjustment part P1 Recording medium

Claims

1. a paper output tray section for stacking the conveyed recording media vertically; a support portion that pivotally supports the paper ejection tray portion so that the paper ejection tray portion can tilt; and an angle maintaining section that returns the angle of the paper discharge tray section, which has been tilted due to the weight of the recording medium, to a horizontal direction.

2. 2. The paper discharge unit according to claim 1, wherein the angle maintaining portion has a biasing means for biasing the paper discharge tray portion, and a moment adjusting portion for changing the moment applied by the biasing means to the paper discharge tray portion.

3. 3. The paper discharge unit according to claim 2, wherein the moment adjustment section is capable of adjusting the elastic force or the mounting direction of the biasing means.

4. 4. The paper discharge unit according to claim 2, wherein the biasing means biases at least one portion of the paper discharge tray in a direction in which the recording medium is discharged.

5. 5. The paper discharge unit according to claim 4, wherein the biasing means biases the paper discharge tray portion from a front end to a rear end in a direction in which the recording medium is discharged.

6. 3. The paper discharge unit according to claim 2, wherein the biasing means is an elastic member.

7. 7. The paper discharge unit according to claim 6, wherein the elastic member is a spring member.

8. 2. The paper discharge unit according to claim 1, wherein the recording medium is an envelope or a label paper.

9. The discharge unit according to claim 2, characterized in that the moment adjustment section is adjustable to a moment measured in advance according to at least one of the type of recording medium, the direction or number of sheets discharged to the discharge tray section.

10. 3. The paper discharge unit according to claim 2, wherein the moment adjustment section is provided on either the left or right side edge in the paper discharge direction of the recording medium.

11. a carriage portion on which the discharge tray portion is placed and supported; Wheels rotatably provided on the carriage portion; A handle portion provided on the cart portion, 2. The paper discharge unit according to claim 1, wherein the paper discharge tray portion is detachably attached to a paper discharge outlet of an image forming apparatus through which the recording medium is discharged.

Images