JP3937565B2 - Paper feeding device and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet feeding device capable of digitally displaying a sheet feeding pressure required when feeding a sheet such as paper, and image formation for forming an image on a sheet fed from the sheet feeding device. It relates to the device.
[0002]
[Prior art]
Conventionally, sheet feeding pressure adjustment in a cassette as a sheet storage unit of an image forming apparatus is performed by adjusting an auxiliary sheet feeding pressure in an analog manner, that is, continuously according to the height of a sheet separating plate, so that the sheet feeding pressure is always substantially constant. I was trying to get it.
[0003]
Hereinafter, description will be given with reference to the drawings. First, the structure of a pressure index for determining how much paper feed pressure is required will be described.
[0004]
As shown in FIG. 11, the conventional paper feeder has a pressure contact plate I as a sheet placing means. The pressure contact plate I is lowered by the weight of the sheet placed thereon, and the sheet separation plate a or the separation claw is lowered accordingly, and the transmission lever b is rotated by the displacement (a-1) in the height direction. Then, the index piece c integrated with the transmission lever b is rotated. An analog displacement (c-1) is generated by the rotation of the index piece c.
[0005]
12 is a display section for the paper feed pressure index, and d-2 is an arrow d-2 (this arrow is the index piece c having the displacement of c-1 already described). The optimum paper feed pressure was obtained when
[0006]
Next, an adjustment structure for supplying the optimum sheet feeding pressure will be described as to how to align the arrows.
[0007]
As shown in FIG. 12, by rotating the pressure adjustment dial e (e-1), the transmission gears f, g, h, i are rotated so that the spring fulcrum j having the rack moves in the front-rear direction (j-1). It was. As a result, as shown in FIG. 11, if the spring fulcrum j moves to the cassette front side, the force that the leaf spring k applies to the press contact plate 1 rotatably attached to the cassette body increases, It was supposed to get smaller as I moved.
[0008]
That is, by turning the pressure adjustment dial e and changing the fulcrum of the leaf spring k, the force applied to the pressure contact plate 1 rotatably attached to the cassette body is adjusted, and the height of the sheet separating plate a is set to a desired position. It was a structure to bring in.
[0009]
[Problems to be solved by the invention]
As described above, in the prior art, since the user needs to adjust the paper feed pressure with a dial in an analog manner or continuously, the usability is poor because the paper feed pressure needs to be adjusted in small increments. Due to the method of changing the fulcrum, the reproducibility of the feeding pressure was poor.
[0010]
In addition, when the load weight is light, such as a small load, the pressure switching index is shaken out, and there are cases where it is not used.
[0011]
In recent years, networking has progressed particularly in offices and the like, and there is an increasing need for image forming apparatuses to form a large number of sheets of paper and the like. It has been difficult to make an analog adjustment of the sheet feeding pressure according to all the stacked sheets having such various specifications (for example, from 64 g paper A5 to 128 g paper A3).
[0012]
In the present invention, the sheet stacking amount is divided into two regions, a light side and a heavy side, and the indicator can be digitally determined regardless of the stacking amount and the paper type, and the auxiliary paper feeding pressure is set on the heavy side. In addition to the sheets, the sheet feeding pressure of all the sheets is stored in a desired sheet feeding pressure range, and the sheet feeding pressure is easily adjusted.
[0013]
[Means for Solving the Problems]
To achieve the above object, means of the present invention, there is provided a sheet feeding apparatus in an image forming apparatus main body that is detachable, the sheet is placed, it is movable in the sheet feeding device body pressure A member , a feeding roller for feeding the sheet placed on the pressure contact member, a biasing means for biasing the pressure contact member toward the feeding roller, and a weight of the placed sheet A separation member that can move according to the movement of the pressure contact member and separates the sheets fed by the feeding roller one by one, and a digital display of the sheet feeding pressure according to the movement of the separation member. display means for switching, in response to the displayed based rather operation of the display unit, characterized in that the sheet feeding pressure to said pressure contact member provided with an adjusting means for switching digitally.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
First, the overall configuration of the image forming apparatus and the paper feeding device will be described, and then the configuration of the paper feeding device will be described.
[0015]
[Overall configuration of image forming apparatus and paper feeding apparatus]
As shown in FIG. 7, an image forming apparatus (described in the example of a laser beam printer) α according to this embodiment irradiates information light based on image information from a laser scanner 1 to a drum-shaped electrophotographic photosensitive member. Then, a latent image is formed on the photosensitive member, and the latent image is developed to form a toner image.
[0016]
An example of an auxiliary paper feeding device will be described as an example of a paper feeding device for feeding a sheet onto which the toner image is transferred. A cassette mounting portion is provided at the lower part of the image forming apparatus main body, and an auxiliary paper feeding device β in which a large number of recording sheets γ are stacked and stored is detachably mounted on the mounting portion. In synchronization with the formation of the toner image, the sheet is conveyed from the auxiliary sheet feeding device β to the image forming unit 3 by the sheet conveying unit 2, and the sheet γ after image formation is discharged to the discharge unit 5 through the fixing unit 4. To do.
[0017]
The image forming unit uses an electrophotographic recording system in this embodiment, and includes a photosensitive drum 3a which is an electrophotographic photosensitive member, and a process cartridge 3b in which a primary charging unit, a developing unit, and a cleaning unit (not shown) are formed into a cartridge. It is configured to be detachable from the image forming apparatus α. Then, the photosensitive drum 3a is rotated in synchronization with the conveyance of the recording sheet γ, and is uniformly charged by the surface charging means, and the information light from the laser scanner 1 is transferred to the photosensitive drum 3a through the exposure unit. A latent image is formed by exposure. In accordance with the latent image, the toner frictionally charged by the developing means is transferred to form a toner image, and this toner image is applied to a transfer roller 6 as a transfer means by applying a voltage having a polarity opposite to that of the toner image to form a recording sheet γ. The image is recorded by transferring to The toner remaining on the photosensitive drum 3a after the toner image is transferred is removed by a cleaning means.
[0018]
On the other hand, the conveying means separates and feeds the recording sheet γ in the auxiliary sheet feeding device β one by one by the cooperative action of the feeding roller 2a and the sheet separating plate (separating member), and the retard roller 2b and the feed roller 2c Separation and feeding is ensured by the cooperative action. Further, the sheet roller γ is transferred to the image forming means in synchronism with the formation of the toner image by the conveying roller pair 2d, 2e and the registration roller pair 2f, and the sheet γ to which the toner image is transferred by the voltage application of the transfer roller 6 is fixed. 4, the fixing unit 4 applies heat and pressure to fix the transferred toner image, and the image γ-fixed sheet γ is discharged to a discharge unit 5 provided at the upper part of the apparatus by discharge roller pairs 2 g and 2 h. It is configured to do.
[0019]
[Configuration of paper feeding device]
Next, an example of an auxiliary paper feeding device β that is a universal cassette will be described as a paper feeding device that can be attached to and detached from the image forming device α.
[0020]
In FIG. 7, inside the cassette tray 8 which is a cassette body constituting the sheet storage frame of the auxiliary sheet feeding device β, a sheet is placed on the tray 8 so as to be rotatable, and a sheet is placed on the feeding roller 2a . A pressure contact plate (pressure contact member) 9 for pressure contact is provided. Further, on the bottom surface of the cassette tray 8 on the feeding side, a pressurizing spring ( a biasing means that abuts on a predetermined position on the back surface of the pressure contact plate 9 corresponding to the feeding roller 2a serving as the feeding means described above. biasing means) 10 is Ri Contact disposed urges the pressure plate 9 in the direction of the feeding roller 2a by the elastic force of the pressurizing spring 10.
[0021]
(First embodiment)
Next, an embodiment of a paper feeding device according to the present invention will be described.
[0022]
First, the configuration of the paper feed pressure index for determining how much paper feed pressure is required will be described. As shown in FIGS. 1 and 2, a sheet separating plate (separating member) A that separates the fed sheets one by one is pressed against the sheet located below the sheet separating plate A by a biasing means ( not shown ). are, the height of the pressure plate 9 (FIG. 7) of the pressing member is changed according to the weight of the sheet to be placed, displaced in conjunction therewith in the height direction (a-1). In conjunction with the displacement of the separation plate A, the transmission lever (transmission member) B rotates in the (B-1) direction . An index piece C as a display member is connected to the transmission lever B via a tension spring D as an urging member . The index piece C can be rotated in the (C-1) direction, and can be displayed digitally, that is, in a stepwise manner, as described later , according to the rotation position . In the present embodiment, the tip of the transmission lever B (the engagement portion with the tension spring D) is arranged such that the transmission lever B rotates according to the weight of the sheet placed on the pressure contact plate 9 when the transmission lever B rotates . It is located on both sides of the rotation spindle C-2 (see FIGS. 1 and 2).
[0023]
For this reason, the other end of the transmission lever B and the tension spring D draw a locus (B-1) sandwiching the rotation center of the index piece C. Therefore, the index piece C pulled by the tension spring D does not stop at the middle dead center of the movable range by operating a so-called toggle switch, and waits (stops) only at the two movable end points. The displacement in the height direction (A-1) of the plate A can be switched between digital “light” and “heavy” displays.
[0024]
In actuality, the user determines light or heavy based on the “◯ picture or mark” or “● picture” drawn on the upper surface of the index frame C appearing in the display window E shown in FIG. . As can be seen from FIG. 3, when the picture appearing in the display window E is ◯, the pressure switching lever (part of the adjusting means) F is tilted to the back side of the cassette tray (upstream side in the sheet feeding direction from the cassette tray). , ● for that kill frontward, it is possible to obtain switching Operation changeover the sheet feeding pressure. Next, the auxiliary paper feed pressure supply structure will be described.
[0025]
As shown in FIG. 4, for example, when the pressure switching lever F is tilted to the near side of the cassette, the pressure switching gear G rotates counterclockwise with the shaft H and the slide cam I, so that the fixed boss of the base J becomes the cam groove. The inserted slide cam I is moved to the left as can be seen from FIGS. Since the switch lever K is integral with the slide cam I in the axial direction, the switch lever K is also moved to the left side, and the tip boss K-2 of the lever K is inserted into the hole of the plate-like auxiliary paper feeding pressure member L. As a result, the switch lever K and the auxiliary paper feeding pressure member L can be integrally rotated about the axis H. If the tip boss K-2 of the lever K is not inserted into the hole of the auxiliary paper feed pressure member L, the switch lever K and the auxiliary paper feed pressure member L do not rotate integrally.
[0026]
4 to 6, the other end of the paper feed auxiliary spring M that is hooked on the latch pin K-3 of the switch lever K is hooked on the auxiliary paper feed pressure shaft N. When the cassette tray 8 is inserted into the auxiliary paper feeding device β , the auxiliary paper feeding pressure shaft N is lowered in the (N−1) direction by the cam provided on the inner wall of the auxiliary paper feeding device β. An attempt is made to lower the switch lever K in the (K-1) direction via M. Thus switch lever K and the rotary auxiliary paper feed pressure member are integrated in the direction L is rotated about the shaft H, acting portion L-2 of the one end is lifted (L-1) Direction It will be. Thereby, as will be described below, it is possible to increase the auxiliary paper feeding pressure for the pressure contact plate 9. The action portion L-2 is disposed on the back surface of the press contact plate 9 , for example, in an intermediate portion between the two springs 10 in FIG. 7, and applies an auxiliary paper feed pressure by the spring force of the paper feed auxiliary spring M to the press contact plate 9 . be able to. In this case, the spring M can be used for the main sheet feeding pressure.
[0027]
As described above, according to the present embodiment, the sheet feeding pressure required according to the weight of the sheet is displayed digitally, that is, stepwise, so that the display is discontinuous and clear, and the switching lever is accordingly displayed. Since F is operated digitally, its operation is simple, and usability as a paper feeding device can be improved. In addition, it is not necessary to change the sheet feeding pressure in an analog manner, and the reproducibility of the sheet feeding pressure is improved by using a single tension coil spring for the sheet feeding pressure.
[0028]
(Second Embodiment)
In the first embodiment, the switch lever K and the slide cam I are disposed only on the right side of the paper feeding pressure member L in FIGS. 5 and 6. In the second embodiment, the first embodiment In addition to the embodiment, the slide cam I, the switch lever K, and another paper feed assisting spring having a spring force different from that of the paper feed assisting spring M are used so as to be paired on the left side in FIGS. Thus, for example, three-stage switching can be performed.
[0029]
For the pressure index, for example, a digital three-stage display is possible by using a mechanism as shown in FIG.
[0030]
Hook position of receiving the displacement of the sheet separating plate (a-1) transmission lever which operates in a direction (transmission member) (a) and (d), the hook position of the index frame (display member) (b) and (c) As shown in FIG. 1, here, they are connected by a pressure indicator spring (not shown). Here, as a simple structure, the index piece (b) is only on a pair of fixed support portions (f), and the movable range is also limited by the stopper (g).
[0031]
When the transmission lever (a) moves to the right in FIG. 8 in the direction (a-1), the index piece (b) rotates about the right support part (f) , and (b-1 ) Direction displacement, and when the transmission lever (a) moves to the left in FIG. 8 , displacement in the (b-2) direction occurs. As a result, three faces are shown from the display window (e).
[0032]
As an example of multi-stage, three-stage switching has been described. By making two or more stages in this way, a wider range of paper types can be used, and a safer paper feed pressure can be used for all paper types and loading capacity. Can be realized.
[0033]
(Third embodiment)
Although the same applies to the first embodiment, the cassette tray normally has a side regulating plate (h) and a rear regulating plate (re) as shown in FIG. 9 to fix the position of the recording sheet. FIG. 10 shows an example of a mechanism according to the present embodiment that reads a combination of these positions and determines whether or not an auxiliary sheet feeding pressure is necessary only according to the paper size.
[0034]
General structure, the side regulating plates located on the right side regulating plates right axis is an axis that is caulked and fixed to the rear surface of the (Ji right) (j) and rear regulating plate axis is an axis that is caulked and fixed to the rear regulating plate (Li) (L), three axes of a shaft (wo) movable in the (wo-1) direction with respect to the tray are provided, and a strip such as a wire (wa) is wound around these three shafts. Naturally, the side restricting plate right axis (nu) moves in the (nu-1) direction and the rear restricting plate axis (le) moves in the (le-1) direction according to each restricting plate. Further, the moving shaft (W) is urged by a spring or the like toward the front side of the cassette tray (right direction in FIG. 10), and the right side shaft (nu) of the side regulating plate and the rear regulating plate shaft (le) The position is determined according to the adjustment movement. Here, only a configuration in which wires (wa) are hung on three points is shown for simplicity, but the movement of the moving shaft (wo) is transmitted to an index piece similar to that of the above-described embodiment, thereby being stored in a cassette. The sheet size can be displayed. When the moving axis (W) is on the right side of the middle part of the moving arrow ( Wo 1 ) in FIG. 10, that is, on the front side of the cassette tray, the paper size is small, and when it is on the right side, the digital display is displayed. be able to.
[0035]
In the present embodiment, a complicated pressure index mechanism that handles the multiple paper types of the first and second embodiments is not required, and display according to the sheet size is possible with a simple configuration.
[0036]
【The invention's effect】
As described above, according to the present invention, the display means for digitally displaying the required paper feed pressure in accordance with the movement of the separating member, and the paper feed pressure for the pressure contact member based on the display on the display means is digital. By providing the adjusting means for adjusting to the required sheet feeding pressure, the required sheet feeding pressure corresponding to the weight or size of the sheet to be fed is displayed digitally, that is, stepwise, and the display becomes clear. In addition, by switching the sheet feeding pressure, it is possible to easily secure the sheet feeding pressure that can be fed in a wide variety and any loading capacity, and to improve the usability of the sheet feeding apparatus.
[Brief description of the drawings]
FIG. 1 is a side view showing an embodiment of a paper feed pressure indicator in a paper feed apparatus according to the present invention.
FIG. 2 is an enlarged side view of a main part of a paper feed pressure indicator in FIG.
FIG. 3 is a top view illustrating an embodiment of a pressure switching operation unit in the sheet feeding device according to the present invention.
FIG. 4 is a side sectional view showing an embodiment of an auxiliary paper feed pressure setting structure according to the present invention.
FIG. 5 is a top view showing an embodiment of an auxiliary paper feed pressure setting structure according to the present invention.
FIG. 6 is a front view showing an embodiment of an auxiliary paper feed pressure setting structure according to the present invention.
FIG. 7 is a longitudinal sectional view showing an embodiment of an image forming apparatus according to the present invention.
FIG. 8 is a side view showing another embodiment of the paper feed pressure indicator in the paper feeder according to the present invention.
FIG. 9 is a top view showing a schematic appearance of a cassette tray of an auxiliary paper feeder according to the present invention.
FIG. 10 is a top view showing an embodiment of a paper size determination mechanism according to the present invention.
FIG. 11 is a side view showing a conventional example of an auxiliary paper feeder.
FIG. 12 is a top view illustrating a conventional example of an auxiliary sheet feeding device.
[Explanation of symbols]
α ... image forming apparatus β ... auxiliary paper feeding apparatus γ ... recording sheet 1 ... laser scanner 2 ... conveying means 2a ... feed roller 2b ... retard roller 2c ... feed rollers 2d, 2e ... conveying roller pair 2f ... registration roller pair 2g, 2h ... discharge roller pair 3 ... image forming means 3a ... photosensitive drum 3b ... process cartridge 4 ... fixing means 5 ... discharge section 6 ... transfer roller 7 ... controller board 8 ... cassette tray 9 ... pressure contact plate 10 ... pressure spring a ... Sheet separating plate b ... transmission lever c ... index piece d ... pressure indicator display e ... pressure adjusting dials f, g, h, j ... transmission gear j ... spring fulcrum k ... leaf spring l ... pressure contact plate A ... sheet separating plate B ... transmission lever C ... index piece D ... pressure indicator spring E ... display window F ... pressure switching lever G ... pressure switching gear H ... shaft I ... slide cam J ... base K ... switch lever L ... auxiliary feed pressure member M ... Paper supplement Spring N ... Auxiliary paper feed pressure shaft A ... Transmission lever B ... Indicator top ... Pressure indicator spring hook position D ... Pressure index spring hook position E ... Display window ... Fixing part ... Stopper ... Side regulating plate ... Rear regulating plate No ... Side restriction plate right axis ... Rear restriction plate axis ... Shaft ... Wire

Claims (4)

A sheet feeding apparatus that is provided detachably on the image forming apparatus main body,
A pressure contact member on which a sheet is placed and provided movably on the sheet feeding device body ;
A feeding roller for feeding a sheet placed on the pressure contact member;
An urging means for urging the pressure contact member toward the feeding roller;
A movable in response to movement of the pressing member due to the weight of the placed sheets, a separating member for separating one by one the sheet feeding by the feeding roller,
Display means for switching the display of digitally sheet feeding pressure in response to movement of the separating member,
In response to said brute based on the display of the display unit operation, the sheet feeding apparatus characterized by having a regulating means for switching the sheet feeding pressure digitally to said pressure contact member. The display means according to claim 1,
A rotatable around the support shaft, a display member for displaying a sheet feeding pressure from the window of the sheet feeding apparatus main body,
One end portion is connected to the separation member, and the other end portion is a transmission member that can move on both sides of the support shaft,
A paper feeding device comprising: an urging member provided between the other end of the transmission member and the display member. The display means according to claim 1,
Two support members spaced apart;
A display member capable of rotating in a state of being selectively supported by the two support members and displaying a paper feed pressure from a window of the paper feed device body;
A paper feeding device comprising: a transmission member that transmits the moving force of the separation member to the display member to operate the display member . An image forming apparatus comprising a sheet feeding apparatus according to any one of claims 1 to 3, further comprising image forming means for forming an image on a sheet fed from the sheet feeder.

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