JP3611740B2 - Paper feeder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet feeding device that separates one sheet from stacked recording sheets and supplies it to a printing unit such as a printer or a fax machine. More specifically, the present invention relates to a gradient of a separating plate as a method for separating recording sheets into one sheet. The present invention relates to a gradient separation type paper feeding device to be used.
[0002]
[Prior art]
The mechanism that separates a single sheet from a stack of recording sheets and supplies it to the printing unit is a separation claw system in which both ends of the sheet are held by a nail and one surface is separated by a roller over the nail. There is a reverse roller system in which a large number of stacked sheets are sent out by a pure-direction rotating roller, and the remaining sheets are stopped by a reverse roller. In addition, as a method for feeding thick paper (thick paper), a space method in which only one empty space of a blocking plate having one empty space is passed. Various methods such as a vacuum suction method in which one surface is lifted by vacuum suction are used. One of them is a separator plate system. This separation plate method uses the gradient of the paper presser, which is a separation plate, and separates one sheet into a printing mechanism by balancing the friction force between the feed roller and the paper, the friction force between the paper, and the paper feed prevention force of the separation plate. This is one of the paper feeding methods often used in the gradient separation method to be sent.
[0003]
[Problems to be solved by the invention]
Each of the paper feeding methods described above has characteristics of advantages and disadvantages, but it is necessary to select a suitable paper feeding method from the sheet thickness, the number of stacked sheets, the cost, and the like. Among them, A4, B4, A3 size recording paper similar to normal copy paper, A6 size thick paper such as postcards are fed by the same mechanism, and the mechanism is configured at low cost. There is a gradient separation method using a separation plate. However, even in this case, if a thick paper such as a postcard and a recording paper similar to a normal copying paper are fed by the same mechanism, a misfeed or a double feed occurs, and it is very difficult to feed stably. There was a problem.
[0004]
SUMMARY OF THE INVENTION An object of the present invention is to provide a paper feeding device capable of performing stable paper feeding that does not cause misfeeds and double feeds to various types of recording paper.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is a paper feeding device that supplies a plurality of types of recording papers having different sizes on a central basis,
A recording paper stacker for holding recording paper;
A recording paper guide for positioning the recording paper on the recording paper stacker with a central reference;
A pickup roller for feeding the recording paper in the paper feeding direction;
The depressing force corresponding to the thickness of the thick paper thicker than the copy paper , which is disposed in the central portion of the perpendicular direction that is perpendicular to the paper feed direction on the upstream side of the recording paper feed direction , A central separating plate having a first gradient according to a deterring force to inhibit separation and a paper width smaller than the copy paper ;
A deterring force corresponding to a paper thickness of the recording paper thinner than the thick paper and disposed at both ends in the perpendicular direction on the upstream side in the recording paper feeding direction, And a double-sided separation plate having a second gradient larger than the first gradient according to a paper width larger than the paper width .
[0006]
Further, the present invention is the paper feeding device described above, further comprising a paper pressing spacer provided above the both-end separation plate with a sufficient space for the passage of the recording paper.
[0007]
Furthermore, the present invention is the paper feeding device described above, wherein an elastic member which is deformed by being pushed by the recording paper to be fed is provided on a part of the both end separation plate .
[0008]
The present invention provides a method for stably feeding a normal recording paper and a thick paper with the same mechanism by limiting the thick paper to a postcard size or a size in the vicinity thereof. The central part of the recording paper separation mechanism reduces the gradient of the separation plate mainly to correspond to the thick paper, and both ends have a separation plate gradient to improve the separation performance of the recording paper similar to ordinary copying paper. It is getting bigger. Furthermore, in order to improve the separation capability at both ends, a spacer that restricts the passage of the paper is provided in a portion facing the separation plate. In order to perform stable separation over a wide range of paper thickness ranges over a wide range of environmental changes, an elastic film is attached to the separation plates at both ends to improve stability. .
[0009]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic diagram showing the structure of the paper feeding device of the present invention. The figure is a perspective view showing the positional relationship of each component of the sheet feeding device, except for the main component units. In FIG. 1, a plurality of recording sheets are stacked on a recording sheet stacker 11. Both sides of the recording paper are regulated by the recording paper guide 12 and are stacked with the center as a reference. The stacked recording sheets are picked up one by one by the pickup roller 13 and fed toward the front side of the sheet of FIG. The mechanism for separating the recording paper will be described later in detail, but the recording paper is separated into one sheet by the action of the center separating plate 15, the both end separating plate 16 and the pickup roller 13. The shaft for driving the pickup roller is also omitted in the figure to avoid complexity. 1 is attached to the upper device cover, and is disposed so as to face the separation plate 16 from above with the cover closed. The sheet passes through a gap between the sheet pressing spacer 14 and the both end separation plate 16. The sheet pressing spacer 14 and the both end separation plate 16 restrict the space through which the recording paper passes, thereby ensuring the operation of the separation plate.
[0010]
FIG. 2 is a sectional view of the sheet feeding device. In the figure, the recording paper stacked on the recording paper stacker 11 is rotatable about the stacker rotation shaft 21 and is pushed forward by the stacker pushing spring 22, that is, toward the pickup roller 13. Even if the number of sheets decreases, the first recording sheet automatically comes to the same position. In order to maintain the paper feeding performance, the recording paper stacker 11 is restricted by the stacker stop hook 23 so that the recording paper stacker 11 does not move forward more than necessary. The pick-up roller 13 is a half-moon roller. When the pick-up roller 13 is stopped, the cut-out surface of the roller faces the recording paper. Paper is fed in the paper feeding direction 24. When the pickup roller rotates once and one recording sheet is fed in the paper feeding direction 24 to the printing unit, a feeding roller (not shown) further feeds the recording sheet to a printing apparatus (not shown).
[0011]
FIG. 3 shows the principle of separation of the paper of this separation system. FIG. 3 shows a state where the pickup roller 13 is rotated and the first recording paper 31 is being sent out. In order to clarify the explanation, a gap is drawn between the pickup roller 13 and the first recording paper 31, the first recording paper 31 and the second and subsequent recording papers 32, but this gap is not actually present.
[0012]
In order to feed only one sheet by this method, the frictional force 34 between the roller and the first recording paper 31 is separated from the frictional force 35 between the first recording paper 31 and the second recording paper 32. It is necessary to be larger than the sum of the deterrence force 36 for the first recording paper 31 of the plate 26. Conversely, in order not to cause double feed, the friction force 35 between the first recording paper 31 and the second recording paper is the second and third friction forces (not shown) and the separation plate 26. It is necessary to be smaller than the sum of the deterrence 36 of the above. These frictional forces and the deterring force 36 of the separation plate 26 vary greatly depending on the thickness of the recording paper, environmental conditions, particularly humidity. The deterring force 36 of the separating plate 26 increases as the gradient 33 of the separating plate 26 increases. However, with thick paper such as postcards, if the gradient 33 is too large, the deterring force 36 of the separating plate 26 becomes too large, leading to a so-called misfeed in which no sheet is fed. Therefore, it is necessary to reduce the gradient 33 of the separation plate 26 for cardboard. On the other hand, with thin recording paper, the deterring force 36 of the separation plate 26 is reduced, and unless the gradient 33 of the separation plate is increased, double feed increases.
In this embodiment, the thickness of the cardboard is limited to the size of the postcard size, and the gradient of the separation plate at the center corresponding to the postcard size is reduced as shown by the dotted line in the enlarged view of the separation plate portion in FIG. For recording paper similar to normal A4, B4, and A3 size copy paper thinner than that, the gradient 33 of the both-end separator 16 is increased as shown by the solid line in the enlarged view of the separator of the paper feed mechanism. Double feed of recording paper similar to copy paper is prevented.
[0013]
Next, the structure of the part facing the center separator 15 and the both ends separator 16 will be described. In order to feed recording paper accurately and stably, in the case of center-sorted paper feeding, a stable paper feed driving force should be applied to the center, and no couple that may cause skew is applied to both ends of the recording paper. Is desirable. Therefore, in the present embodiment, the pickup roller 13 is a portion to which the sheet feeding driving force is applied, and is disposed in the center, and the pickup roller 13 provides a sufficient driving force that does not cause misfeed. A sheet pressing spacer 14 is arranged opposite to both end separation plates at both ends so as not to give unnecessary driving force to the recording sheet that may cause a skew. On the contrary, if the balance between the both ends of the paper feeding blocking force is shifted, this also causes a skew. Therefore, the paper pressing spacer 14 regulates the travel position of the recording paper so that the action of the both-end separating plate 16 works sufficiently. Limit the travel direction of the recording paper. Since this space has a sufficient distance compared to the recording paper, the generation of couples that cause skew is minimized.
[0014]
Furthermore, a characteristic improvement example using the elastic film 41 will be described with reference to FIG. An elastic film 41 is provided between the paper pressing spacer 14 and the both end separation plate 16. Specifically, a plastic film having appropriate elasticity and thickness is attached to the both-end separator 16. In the pasted state, this elastic film is in the middle of the sheet pressing spacer 14 and the both end separation plate 16. The elastic spacer 41 is bent by the elastic force generated according to the thickness of the recording paper when the strong paper is supplied at low humidity or when feeding a thick recording paper. It automatically becomes a suitable shape for preventing misfeeds. That is, when the recording paper is thick, it bends greatly, and when the recording paper is thin, the deflection is small and the double feed is prevented. Further, the elastic spacer 41 has a small friction coefficient, and can reduce the influence of unnecessary friction that greatly changes due to environmental conditions and the like. Thus, the elastic film 41 can widen the range of the thickness of the recording paper to be fed correctly and the range of environmental change.
[0015]
【The invention's effect】
As described above, in the paper feeding device according to the present invention, the gradient of the separation plate is changed between the center and both ends, the center of the paper is fed by the rollers, and the gap between the paper feeding portions is limited by the spacers at both ends. Accordingly, it is possible to feed a wide range of recording paper from a postcard to a thin paper at a low cost under a wide range of environmental conditions. In addition, the addition of an elastic film further stabilizes the paper feeding performance and can widen the range of usable paper thickness and the range of environmental conditions for normal paper feeding. That is, by using the center separation plate, it is possible to stably and accurately feed a recording sheet that is thicker than the copy sheet and has a smaller width than the copy sheet without misfeeding. By using the separation plates at both ends, it is possible to stably and surely feed a recording sheet that is thinner than the thick paper and wider than the paper width.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a part of the structure of a sheet feeding device according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of a paper feeding device according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a paper feeding mechanism of a paper feeding device according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating a state in which an elastic film is applied to the sheet feeding device according to the embodiment of the present invention.
[Explanation of symbols]
11 Recording Paper Stacker 12 Recording Paper Guide 13 Pickup Roller 14 Paper Holding Spacer 15 Central Separation Plate 16 Both End Separation Plate 22 Stacker Push Spring 23 Stacker Stopping Hook 41 Elastic Film

Claims (3)

A paper feeding device that supplies a plurality of types of recording paper of different sizes on a central basis,
A recording paper stacker for holding recording paper;
A recording paper guide for positioning the recording paper on the recording paper stacker with a central reference;
A pickup roller for feeding the recording paper in the paper feeding direction;
The depressing force corresponding to the thickness of the thick paper thicker than the copy paper , which is disposed in the central portion of the perpendicular direction that is perpendicular to the paper feed direction on the upstream side of the recording paper feed direction , A central separating plate having a first gradient according to a deterring force to inhibit separation and a paper width smaller than the copy paper ;
A deterring force corresponding to a paper thickness of the recording paper thinner than the thick paper and disposed at both ends in the perpendicular direction on the upstream side in the recording paper feeding direction, And a double-sided separation plate having a second gradient larger than the first gradient according to a paper width larger than the paper width . 2. The sheet feeding device according to claim 1, further comprising a sheet pressing spacer provided above the both-end separation plate with a sufficient interval for the recording sheet to pass therethrough. 3. A paper feeding device according to claim 1, wherein an elastic member which is deformed by being pushed by the recording paper fed out is provided on a part of the both-end separating plate.

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