JPH06263280A - Sheet carrying device - Google Patents

Abstract

PURPOSE:To adjust variably pressure contact force between a feed roller and a reverse roller as a frictional separating roller in a simple mechanism. CONSTITUTION:In a paper feeder, a driven gear 8 of a reverse roller shaft 4 is arranged so as to move slidingly freely as well as to rotate integrally with the shaft, and a gear guiding and fixing member 40 is arranged to change a position of this driven gear. Thereby, since a teeth surface pressure operating position is changed when torque is given to a reverse roller 8 by meshing of the driven gear 8 and a driving gear 7, pressure contact force to a feed roller situated above can be adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying device adopted in a paper using machine such as an image forming apparatus such as a copying machine, a facsimile machine, a printer, a printing machine, a packaging machine, a cash voucher / stock processing machine, a cigarette making machine or the like. More specifically, it has a conveying member that comes into contact with a sheet to apply a conveying force in the conveying direction, and a friction separating roller that is applied with a torque in a direction opposite to the conveying direction and is in pressure contact with the conveying member. The present invention relates to a sheet conveying device that separates two or more sheets between a conveying member and the friction separation roller and conveys only one sheet in the conveying direction.

[0002]

2. Description of the Related Art FIG. 2 (a) is a schematic configuration diagram showing an example of a configuration in which a sheet conveying device of this type is applied to a sheet feeding device of an image forming apparatus, and FIG. 2 (b) is used in the same. It is a schematic structure figure of the reverse roller part as a friction separation roller.
In FIG. 2A, this apparatus includes a pickup roller 1 which can be brought into contact with and separated from an upper surface of a sheet S stacked on a bottom plate 22 pushed up by a lever 21 in a cassette 20 and which rotates in a sheet feeding direction. The feed roller 2 which is downstream in the direction and which rotates in the same direction in synchronization with the pickup roller 1 and presses against the feed roller 2 sandwiching the paper path, and the torque limiter 10 moves in the direction opposite to the paper feeding direction. A reverse roller 3 to which a constant torque is applied, and a difference between a frictional force between the roller and the sheet and a frictional force between the sheets and a torque applied to the reverse roller 3 by these frictional forces. When only one sheet of paper is fed from the pickup roller 1 between the feed roller 2 and the reverse roller 3, the paper is fed as it is, and when two or more sheets are double-fed. Is separates it, a frictional separation roller feeding apparatus adapted to feed the only one in contact with the feed roller 2.

The reverse roller 3 has an elbow-shaped lever 6 whose shaft 4 normally swings around a reverse roller drive shaft 5.
1 is fixed by the engagement of a drive gear 6 which is pivotally supported on the tip of one arm and which is fixed to a drive shaft 5 and a connecting gear 8 which is pivotally supported by a reverse roller shaft 4 and which is connected to the shaft 4 via a torque limiter 10. Torque is applied. A tension spring 9 is provided between the end of the other arm of the lever 5 and the machine frame.
The static pressure is applied to the reverse roller 3 in the normal direction by the force of the tension spring 9, and the additional pressure contact force is further applied by the pressure between the tooth flanks of the gears 7 and 8 during driving. The pressure between the tooth flanks is proportional to the limiting torque of the torque limiter 10.

In FIG. 2 (b), the reverse roller shaft 4 has a bearing 11 attached to its rear end, and a bearing 12 also attached between the fixing position of the connecting gear 8 and the attaching position of the torque limiter 10. Has been. Of these, the bearing 11 on the back side is supported by the machine frame by a support mechanism (not shown) so that the reverse roller shaft 4 can swing around this support point. Then, the torque limiter 10
The side bearing 12 is loosely fitted in a vertically elongated hole formed in a vertical plate (not shown) fixed to the machine frame so that the swing of the reverse roller shaft 4 is regulated so as to be substantially within the vertical plane. At the same time, pressure P ₃ is applied to the arm of the elbow-shaped lever 6 from below.
Can be pushed up with. In addition, reference numeral P ₁ in the drawing indicates a pushing force by the drive gear 7 based on the above-mentioned tooth surface pressure, and reference numeral 13 indicates a bearing of the reverse roller 3. Since the other reference numerals are used in the description of the embodiments described later, the description thereof will be omitted here. As described above, such a friction separation roller sheet feeding device is excellent in that the reverse roller 3 does not slip with the feed roller 2 and the sheet, and the occurrence of fluffing of the sheet due to friction with the roller and generation of paper dust are small. It is a thing.

Further, in Japanese Utility Model Publication No. 2-8915, in a friction separating roller sheet feeding device as shown in FIG. 2, a predetermined feeding roller 2 is used irrespective of a change in sheet quality or surface state. An invention is disclosed in which the sheet conveying speed is detected and the pressure contact force of the reverse roller 3 with respect to the feed roller 2 is controlled so that the conveying speed can be obtained. As a mechanism for changing the pressure contact force of the reverse roller 3 (hereinafter referred to as a friction separation roller pressure contact force varying mechanism), the drive gear 7 and the coupling gear 8 are slid on the drive shaft 5 and the reverse roller shaft 4 in the axial direction. It is provided so as to freely rotate together with the shaft, and a pair of plate members slidable with respect to the shafts 5 and 4 hold both gears 7 and 8 to move integrally in the axial direction. Thus, a mechanism is adopted in which the point of application of the pushing force P ₁ by the drive gear 7 based on the tooth surface pressure between the both gears 7 and 8 is moved to control the additional pressure.

Further, in Japanese Examined Patent Publication No. 2-1049, the friction separating / conveying device of FIG. 2 and the above-mentioned Japanese Utility Model Publication No. 2-8915 is applied to the reverse roller 3 in the direction opposite to the conveying direction of the feed roller 2. Instead of applying torque via a torque limiter, the same torque application is performed via a one-way clutch, but otherwise basically the same friction separating / conveying device is used. The paper feed mechanism used in the above is disclosed. This device discloses a method of detecting double feeding of documents and changing the pressure contact force of the reverse roller with respect to the feed roller to set an optimum reverse roller pressure contact force that does not cause double feeding. The friction separating roller pressure contact force varying mechanism mechanism in this is to engage the reverse roller pressure contact force through the spring with the end portion of the other arm of the elbow-shaped lever that pivotally supports the reverse roller shaft at the tip portion of one arm. It is disclosed to electrically change the drive of an actuator composed of a solenoid for changing the.

[0007]

As described above, the conveying member that comes into contact with the sheet and applies the conveying force in the conveying direction, and the friction that the torque is applied in the direction opposite to the conveying direction and presses against the conveying member. In a sheet conveying device having a separating roller, which separates two or more sheets when the conveying member and the friction separating roller enter between them and conveys only one sheet in the conveying direction. There is a demand to adjust and control the separability and the transportability by appropriately changing the pressure contact force of the friction separation roller with respect to the transport member.

The present invention has been made in view of the above background, and an object of the present invention is to apply a torque in a direction opposite to a conveying direction of a conveying member that comes in contact with a sheet and applies a conveying force, and the conveying is performed. It is an object of the present invention to provide a sheet conveying device that employs a novel mechanism that changes the pressure contact force of a friction separating roller that is in pressure contact with a member with respect to the conveying member.

[0009]

In order to achieve the above object, a sheet conveying apparatus according to a first aspect of the present invention comprises a conveying member that comes into contact with a sheet and applies a conveying force in the conveying direction, and a conveying member in a direction opposite to the conveying direction. And a friction separating roller which is in contact with the conveying member under pressure, and when two or more sheets enter between the conveying member and the friction separating roller, these are separated to move in the conveying direction. In a sheet conveying device that conveys only one sheet, the torque is applied via a driven gear provided on the shaft of the friction separation roller so as to mesh with the driving gear, and the torque between the driving gear and the driven gear is applied. One of the drive gear and the driven gear, which can change the point of action of the tooth surface pressure in the axial direction, can be moved in the axial direction within a range in which meshing with the other gear is possible. Provided and
A fixing means is provided for fixing the one gear in the axial direction after the one gear is moved. A sheet conveying device according to a second aspect of the present invention is the sheet conveying device according to the first aspect, in which the fixing means is engaged with the one gear and one end portion thereof extends to a visible portion, in the axial direction. It is characterized in that it comprises an operating member that is movably provided in the first and a means that fixes the operating member in the axial direction after the operation. A sheet conveying device according to a third aspect is the sheet conveying device according to the second aspect, in which a contact pressure between the friction separating roller and the conveying member corresponding to the position of the one gear is applied to one end of the operation member. It is characterized in that an adjustment index such as a usage state suitable for the contact pressure is displayed. A sheet conveying device according to a fourth aspect is the sheet conveying device according to the first aspect, wherein the other gear is composed of a module provided on the same axis and a plurality of gears having the same number of teeth. It is what A sheet conveying device according to a fifth aspect is the sheet conveying device according to the first aspect, wherein each of the one gear and the other gear is a plurality of gears provided on the same axis and having different numbers of teeth. Then, depending on the position of the one gear in the axial direction, any one of the plurality of gears forming the other gear is one of the plurality of gears forming the one gear. It is characterized in that it is configured to mesh with one gear.

[0010]

In the sheet conveying apparatus of the present invention, the friction separating roller which is in pressure contact with the conveying member is driven by the shaft of the friction separating roller so that the torque in the direction opposite to the conveying direction of the conveying member is engaged with the drive gear. Apply via gear. Here, the torque may be applied through a torque limiter as in the device described in Japanese Utility Model Publication No. 2-8915, or as in the device described in Japanese Patent Publication No. 2-1049. It may be applied via a directional clutch. Further, the meshing relationship between the drive gear and the driven gear may be either a relationship in which the tooth surface pressure between the two increases the pressure contact force between the conveying member and the friction separating roller or a relationship in which the pressure decreases. good. Then, any one of the drive gear and the driven gear, which can change the operating point of the tooth surface pressure between the drive gear and the driven gear in the axial direction, can be meshed with the other gear. Movably in the axial direction within a certain range, and by moving the one gear, the point of action of the pushing-up force or the pushing-down force by the drive gear based on the tooth surface pressure between the two gears is moved to convey the paper. The pressure contact force between the member and the friction separating roller can be changed. Further, a fixing means is provided so that the position of the one gear can be fixed after the one gear is moved until the pressure contact force between the conveying member and the friction separating roller reaches a desired magnitude.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a sheet feeding device of an electrophotographic copying machine (hereinafter referred to as copying machine) which is an image forming apparatus will be described below. The sheet feeding device of this embodiment is shown in FIG.
Similar to the friction separating roller sheet feeding device shown in FIG. 1, the feed roller 2 is fed to the reverse roller 3 via the torque limiter 10.
The torque is applied in the direction opposite to the conveyance direction of.

First, here, FIG. 3 (a), (b), (c)
By using the torque limiter 10, a proper pressure contact force between the feed roller 2 and the reverse roller 3 in a friction separation roller type sheet feeding model for applying a torque in the opposite direction to the feed roller 2 to the reverse roller 3 via the torque limiter 10. Will be described. In FIG. 3A, there is one sheet of paper between the rollers 2 and 3.
Explanatory drawing of the force acting on the sheet when entering the sheet, FIG.
FIG. 7B is an explanatory diagram of a force that acts on the double-fed sheet on the reverse roller 3 side when two sheets enter between the rollers 2 and 3. In the figure, Fb is the feeding force that the feed roller gives to one sheet, Fc is the feeding force that the first sheet gives to the second sheet, Fde is the return resistance between sheets, and Tr is
Is a torque limiter torque, Ta is a torque limiter returning force, Pb is a reverse roller operating force, Ra is a sheet resistance force, and Rs is a reverse roller radius. The condition for feeding one sheet is Fb> Fa + Ra from FIG. 3 (a). Here, Fb≡μr · Pb, Ra≡μp · m, Ta = Tr /
Since it is Rs,

[Formula 1] Pb> (1 / μr) · Ta + (μp / μr) · m Here, m is the weight of one sheet, μr is the coefficient of friction between the roller and the sheet, and μp is the coefficient of friction between the sheets. The condition for returning the second sheet is Ta> Fc + as shown in FIG.
It is Fd + Fe. Here, Fc≡μp · Pb, Fd≡
Since μp · m and Fe ≡ μp · 2m, Ta> μp ·
It can be expressed as (Pb + 3m). If you transform this,

[Formula 2] Pb <(1 / μp) · Ta-3m. In this model, one sheet can be separated and fed between the conditional expressions 1 and 2. The interval is called the paper feed range, and the formula is

[Formula 3] (1 / μp) ・ Ta-3m>Pb> (1 / μ
r) · Ta + (μp / μr) · m. In Expression 3, μp (coefficient of friction between sheets),
m (weight of one sheet) varies depending on the type and size of the sheet and is determined by determining the target sheet. The μp (coefficient of friction between sheets) of commercially available copy sheets is generally about 0.5. The lowest value including variation is about 0.3, and the highest value is close to 0.75. Furthermore, the paper absorbs moisture during the rainy season, and the recycled paper with high moisture absorption reaches 1 in some cases. The μp (coefficient of friction between the roller and the paper) is almost determined by the kind of the paper and the rubber material, but is generally about 1.5 to 2, and 1.2 to about 1.2 due to deterioration with time.
Consider up to 1.5. Ta (torque limiter return force)
Are those that use the overrun torque of the coil spring and those that use the magnetic attraction of the magnetic powder.
It is possible to set from 00 to 600 gf.

The relational expression [Pb = α · Ta + P ₀ ] between the reverse roller pressure Pb and the torque limiter restoring force Ta is called an actuation line type. By substituting the variation range of the above-mentioned variation factor into the equation 3, a single-sheet feeding area for FRR sheet feeding is obtained. Figure 3 (c)
Is a graph showing this single-sheet feed area. When μp increases, the multi-feed area A widens, and when μr decreases due to roller deterioration, the non-feed area B widens, compressing the single-feed area of the operating line. For example, the reason why double feeding of paper frequently occurs in the rainy season is that the multi-feeding area is widened and is approaching the operating line because the μp is high due to the moisture absorption of the paper. Further, if the paper is fed for a long period of time, it is easy for the paper not to be fed because .mu.r is lowered and is close to the operating line. As a countermeasure in such cases,
Conventionally, in the case of frequent double feeding, the paper should be kept in a state of not absorbing moisture as much as possible, and in the case of non-feeding, the feed roller 2 and the reverse roller 3 must be replaced. In the present embodiment, since the inclination α of the operating line can be changed as will be described later, it is possible to take measures against the above-mentioned inconvenience more easily than before.

Next, referring to FIGS. 3 (d) and 2 (b), a pressure mechanism (lever pressure system) for automatically adjusting the reverse roller pressure Pb with respect to the fluctuation of the torque limiter returning force Ta. ) Will be described. FIG. 3D is an explanatory diagram of the force acting on the reverse roller 3, and FIG. 2B is an explanatory diagram of the force acting on the reverse roller portion. T in the figure
a, Pb and Rs respectively indicate the torque limiter returning force, the reverse roller pressure and the reverse roller radius, as in the case of FIGS. 3 (a) and 3 (b) described above. Then, Tb is returned to the resistance, P ₁ is the pushing force by the gear, P ₂ is the weight of the lever portion, P ₃ is the pressure by the pressure arm, and R is
z is the driven gear radius, Rb is the reverse roller bearing (1
2) Radius, L _{1 to} L ₄ are distances between respective parts shown in the figure. Incidentally, L ₂ is the distance between the position of the center of gravity of the lever and the fulcrum.
The Y axis is the vertical axis and the X axis is the horizontal axis (reverse roller axis 4
Coincides with the axis line). In FIG. 3D, the driving force of the reverse roller shaft is given by the drive gear 7. This force is a force that balances the torque limiter return force Ta and the return resistance Tb, but since the reverse roller shaft 4 is guided only in the Y axis direction, it is sufficient to consider the Y axis direction.
Therefore, the Y-axis direction component force P ₁ of the pushing force by the gear is obtained as the following relationship. Rz · P ₁ = Rs · Ta + Rb · Tb

[Equation 4] ∴P ₁ = (Rs / Rz) · Ta + (Rb / Rz) · Tb Also, from the balance of moments around the fulcrum, L ₁ · P ₁ + L ₃ · P ₃ = L ₂ · P ₂ + L ₄ · _{pb ∴Pb = (L 1 / L} 4) · P 1 + (L 3 · P 3 -L 2 · P 2)
/ L ₄ Substituting equation 4

[Formula 5] Pb = (L ₁ / L ₄ ) · ((Rs / Rz) · Ta
+ (Rb / Rz) · Tb) + (L ₃ · P ₃ −L ₂ · P ₂ ) /
L ₄ However, Tb is a force generated by the reverse roller pressure Pb, and if the friction coefficient of the reverse roller shaft 4 receiving portion is μb,

[Formula 6] Tb = μb · Pb Substituting equation 6 into equation 5

[Formula 7] Pb = (L ₁ / L ₄ ) · ((Rs / Rz) · Ta
+ (Rb / Rz) ・ μb ・ Pb) + (L ₃・ P ₃ -L ₂・
To organize the P ₂ ) / L ₄ equation, (L ₁ / L ₄ ) · (Rs / Rz) = K, (L ₃ · P ₃ −L ₂
If P ₂ ) = P _{0 is set} and (Rb / Rs) · μb = k is set, then Equation 7 can be rewritten as Pb = K (Ta + k · Pb) + P ₀ . Therefore, if P ₀ is rearranged, Pb (1−Kk) = K · Ta + P ₀

[Formula 8] ∴Pb = (K / (1−K · k)) · Ta + P ₀
/ (1-K · k) However, K = (Rs / Rz) · (L ₁ / L ₄ ), k = μb · (Rb
/ Rs) P ₀ = 1 / L ₄ (L ₃ · P ₃ −L ₂ · P ₂ ) From the above, Equation 8 is a lever pressurizing operation line type. Here, when a radial ball bearing is used for the river roller bearing, K · k ≈ 0, so equation 8 can be simply

Equation 9 can be expressed as Pb = K · Ta + P ₀ . Therefore,

[Formula 10] α = K = (Rs / Rz) · (L ₁ / L ₄ ). From Equation 10, the distance L from the fulcrum to the driven gear 8
₁ , that is, by changing the position of the driven gear 8, the inclination α of the operating line can be changed. Therefore, in this embodiment, the position of the driven gear 8 is variable.

Next, the sheet feeding device of this embodiment will be described with reference to FIGS. 1, 4 and 5. FIG. 1A is a perspective view of a variable mechanism according to this embodiment, FIG. 1B is an explanatory view of movement of a driven gear 8 in the mechanism, and FIG. 4 is a friction separation roller sheet feeding device according to this embodiment. FIG. 5 is an overall perspective view, and FIG. 5 is a partial explanatory view of the variable mechanism. The sheet feeding device of this embodiment has the same basic configuration as the device shown in FIG. The difference is that the mechanism for varying the pressure contact force between the rollers 2 and 3 moves both the driven gear 8 and the drive gear 7 of the reverse roller shaft 4 in the axial direction in the apparatus of FIG. On the other hand, the variable mechanism of the present embodiment is that only the driven gear 8 is moved in the axial direction. In FIG. 1A, members corresponding to those in FIG. 2 are designated by the same reference numerals. In this embodiment, the drive gear 7 is fixed to the drive shaft, and only the driven gear 8 is provided so as to be slidable on the reverse roller shaft 4 and rotate integrally with the reverse roller shaft 4. In the figure, reference numeral 32 is both shafts 3
2 is a support plate for the front end of the reverse roller shaft 4
Is formed with a vertically elongated hole into which the bearing 12 mounted on the bearing is loosely fitted, and a reverse roller shaft 4 is biased upward through the bearing 12 at a location hidden behind the supporting back surface side from, for example, a spring. Is provided. Then, as shown in FIG. 1B, the tooth width of the drive gear 7 is
It is set according to the inclination width of the operating line you want to adjust. For example, in the case of 0.9α to 1.1α, (0.2 × L ₁ )
It is set to + (the tooth width of the reverse roller 3 driven gear 8). In this case, when the driven gear 8 and the drive gear 7 are fixed by aligning the end faces, inclinations of 0.9α and 1.1α are obtained. The gear 8 is fixed after being adjusted and moved to a predetermined position by, for example, screwing an immobilizer (hexagon socket set screw) 31 into a screw hole provided in the gear hub portion. Instead of or in accordance with such a fixing method, the driven gear 8 is movably guided on the reverse roller shaft 4.
A guide member 40 may be provided and this may be used as a fixing means. In the illustrated example, a gear guide / fixing member 40 having an engaging portion 41 for engaging the driven gear 8 on the rear side of the device is provided with a guide 43 formed on the bottom plate of the device or a guide formed on the lower part of the support plate 32. Through the hole 44, it is possible to advance and retreat in parallel with the reverse roller shaft 4. The front end of the gear guide / fixing member 40 is provided with a plurality of notches 42, and the window 5 formed on the front side plate 51 of the sheet feeding device 50 as shown in FIG.
The driven gear 8 can be positioned and fixed depending on which of the cutout portions 42 is locked to the side wall portion of the window 52 by projecting through 2 to the outside. Of course, the notch 42 is provided so that the inclination α of the operating line can be varied and fixed within a desired range. In FIG. 4, reference numeral 20 is a cassette, reference numeral 53 is a conveying roller, and reference numeral 23 is a pickup arm.

In the above structure, when it is desired to reduce the inclination α of the operating line, it is sufficient to shift the position of the driven gear 8 toward the fulcrum side and reduce L ₁ , and conversely to increase the inclination α of the operating line. To this end, the position of the driven gear 8 may be shifted to the reverse roller 3 side. For example, when double feed occurs frequently, the single feed area is shifted downward by reducing the inclination α of the operation line. This alone can prevent double feeding. However, in this case, although the margin is reduced with respect to the decrease of μr, if the period of the moisture absorption state is not long, there is no problem as long as the feed roller which is not deteriorated to some extent in this period is used. In addition, when used in an air-conditioned office, etc., μp is not so high and stable, so if paper misfeeds occur frequently, increase the inclination α of the operating line to increase the single-feed area. It is possible to prevent upward movement by shifting upward. Therefore, the life of the feeding roller is improved.

It should be noted that, for example, as shown in FIG. 5A, a display or a scale corresponding to the inclination α of the operating line is provided at a portion between the notches 42 at the front end of the guide member 40, for example. By doing so, the workability of the worker may be improved.
Further, as shown in FIG. 5 (b), the display may be such that the inclination α of the operation line can be changed in the roller state. When the roller is new, μr (coefficient of friction between roller and paper)
Therefore, the inclination α of the operating line is set to be low, the contact pressure of the reverse roller is lowered, and the margin for double feeding and the durability of the roller can be improved. In addition, since μr (coefficient of friction between the roller and the paper) is set low when the roller is deteriorated, the inclination α of the operating line is set high, the reverse roller contact pressure Pb is increased, and the margin for non-feeding can be improved. I have to. The same can be applied to high and low humidity.

FIG. 6 shows a modification of the drive gear 7. In the drive gear 7 of this example, for example, three gears 60 each having a shape capable of being fitted to each other at the boss portion 60a are fitted to each other, and the drive shaft 5 is provided with the spring pins 61 and E.
It is configured to be fixed by a ring 62. Therefore, with respect to the movement of the driven gear 8, it becomes possible to accurately set the value of the contact pressure set on the display of the guide member 40, and the inclination of the operating line, that is, the reverse roller contact pressure changes due to the variation of the parts. Things will disappear.

FIG. 7 shows a modification of the driven gear 7 and the drive gear 8. The driven gear 7 and the drive gear 8 of this example, and the multistage gears 60, 65, 63, 64 are configured. This makes it possible to change the rotation speed of the reverse roller 3 as well as the inclination α of the operation line. When the inclination α of the operating line is lower than that shown in the figure,
Move the gear mesh from 63,65 to 64,60.
As a result, the rotation speed of the reverse roller 3 becomes faster. Therefore, the speed of separating the sheets is increased, and the margin for double feeding is further improved.

As described above, in this embodiment, the driven gear 8 is moved on the shaft, but instead of this, the drive gear 7 is moved on the shaft to move the point of action of the pressure between the tooth flanks. The inclination α of the operating line may be changed.

In the friction separating roller type sheet feeding device of the above-mentioned Japanese Utility Model Publication No. 2-8915, the contact pressure of the friction separating roller detects the state of the sheet at the time of sheet feeding, that is, the sheet conveying speed and the double sheet feeding. The adjustment is controlled based on the detection of. Therefore, in addition to the detection means, a driving means for adjustment and a control means for adjustment control are required, and there are drawbacks in that the number of parts is large, the cost of parts is increased, and the configuration / control of assembly is complicated. Considering the recent improvement in the quality of copying paper and the stabilization of the torque of the torque limiter 10, it is not necessary to adjust the friction separating roller contact pressure for each sheet. Here, it is necessary to set the friction separation roller contact pressure lower than a predetermined reference value, for example, when feeding a paper having a very high friction coefficient between the papers (a rag paper, a recycled paper after absorbing moisture). . If it is desired to extend the life of the conveying rollers (feed roller 2, friction separation roller), it is desirable to set the friction separation roller contact pressure as low as possible. Therefore, if the paper to be used is a copy paper and does not absorb moisture, there is no problem if the contact pressure is set to a low value so that there is no conveyance delay. However, if the frictional force between the roller and the paper is reduced due to the deterioration of the transport roller over time, the transport failure of the paper is likely to occur unless the contact pressure is set to a certain high value. If the friction separating roller contact pressure is optimized, the value can be standardized from the calculated value and the empirical value if the roller material, paper type, environment and other conditions are known. Therefore, as in the present embodiment, by simplifying the structure of the friction separating roller contact pressure varying means and moving only the position of the friction separating roller pressure gear, the friction separating roller contact pressure can be easily varied. As described above, it is possible to achieve stable paper feeding and a longer life of the roller without increasing the cost as in the conventional case. However, the driven gear moving mechanism of the present embodiment is, of course, similar to the friction separating roller type sheet feeding device of the above-mentioned Japanese Utility Model Publication No. 2-8915, in which the friction separating roller contact pressure is set to the state of the sheet at the time of sheet feeding. The present invention can be applied to the detection control, that is, the control for adjustment based on the detection of the sheet conveyance speed and the double feed.

[0022]

According to the first aspect of the present invention, the teeth between the drive gear and the driven gear are used to apply the torque in the direction opposite to the conveying direction of the conveying member to the friction separating roller that is in pressure contact with the conveying member. By the movement of only one of the drive gear and the driven gear that can change the acting point of the surface pressure in the axial direction, the action of the pushing up force or the pushing down force by the drive gear based on the tooth surface pressure between both gears Since the pressure contact force between the conveying member and the friction separating roller can be changed by moving the point, for example, as in the device disclosed in Japanese Utility Model Publication No. 2-8915, both the driving gear and the driven gear are integrated. There is an excellent effect that the configuration of the moving mechanism can be simplified as compared with the case of moving.

According to a second aspect of the invention, in the sheet conveying apparatus of the first aspect, the fixing means is engaged with the one gear and the axial center is extended to a position where one end is visible. Since the operation member is provided so as to be movable in the direction, and the operation member is fixed in the axial direction after the operation member is operated, the operation member is variably adjusted in pressure contact force between the conveying member and the friction separating roller. Can be easily performed, and the operability of variable adjustment can be improved.

According to the third aspect of the invention, in the sheet conveying apparatus according to the second aspect, the contact pressure between the friction separating roller and the conveying member corresponding to the position of the one gear is applied to one end of the operating member. Since the adjustment index such as the usage condition suitable for the contact pressure and the contact pressure is displayed, the user can easily perform the variable adjustment of the pressure contact force between the conveying member and the friction separating roller without requiring special knowledge. Operability can be improved.

According to the invention of claim 4, in the sheet conveying apparatus of claim 1, the other gear is composed of a module provided on the same axis and a plurality of gears having the same number of teeth. The width of each of the plurality of gears can be reduced as compared with the case where the other gear is composed of a single gear having a predetermined width. Therefore, the moldability of the gear is relatively good, and the manufacturing cost of the gear and thus the cost of the sheet conveying device can be suppressed. Further, by arranging a plurality of gears in parallel on the same axis center with a space, the variable amount of the pressure contact force between the conveying member and the friction separating roller can be made discontinuous. According to this, as in the sheet conveying device according to claim 3, for example, the contact pressure between the friction separating roller and the conveying member corresponding to the position of the one gear and the contact pressure at one end of the operation member are provided. When displaying an adjustment index (usually a discontinuous index) such as a usage state suitable for, it is possible to realize a variable amount that exactly matches the displayed adjustment index.

According to the invention of claim 5, in the sheet conveying device of claim 1, each of the one gear and the other gear is a plurality of gears provided on the same shaft center and having different numbers of teeth. By using any one of the plurality of gears forming the other gear in accordance with the position of the one gear in the axial direction, Since it is configured to mesh with one of the gears, it is possible to change the rotational speed of the friction separating roller at the same time as changing the pressure contact force between the conveying member and the friction separating roller. Therefore, the rotational speed of the friction separation roller is reduced in conjunction with increasing the pressure contact force to improve the life of the roller, and the rotational speed of the friction separation roller is increased in conjunction with decreasing the pressure. The effect of preventing double feeding can be improved.

[Brief description of drawings]

FIG. 1A is a perspective view of a variable mechanism according to the present embodiment.
(B) is explanatory drawing of movement of the driven gear 8 in the same mechanism.

FIG. 2A is a schematic configuration diagram of a sheet feeding device according to a conventional example.
FIG. 3B is a schematic configuration diagram of a reverse roller unit of the paper feeding device.

FIG. 3A is an explanatory diagram of a force acting on a sheet when a sheet enters between the rollers 2 and 3; FIG. 6B is an explanatory diagram of a force that acts on the double-fed sheet on the reverse roller 3 side when two sheets enter between the rollers 2 and 3. (C)
Is a graph showing a single-sheet feeding area by both rollers 2 and 3.
FIG. 6D is an explanatory diagram of a force that acts on the reverse roller 3.

FIG. 4 is a perspective view of the entire friction separation roller sheet feeding device according to the present embodiment.

FIG. 5 is a partial explanatory view of the paper feeding device.

FIG. 6 is an explanatory diagram of a modified example of a drive gear 7.

FIG. 7 is an explanatory diagram of a modified example of the driven gear 8 and the drive gear 7.

[Explanation of symbols]

 2 Feed Roller 3 Reverse Roller 4 Reverse Roller Shaft 5 Drive Shaft 7 Drive Gear 8 Driven Gear 10 Torque Limiter 11 Bearing 31 Imimo Screw 40 Gear Guide / Fixing Member 41 Engagement 42 Notch

Claims (5)

[Claims] 1. A conveyance member which is in contact with a sheet and applies a conveyance force in a conveyance direction, and a friction separation roller which is applied with a torque in a direction opposite to the conveyance direction and is in pressure contact with the conveyance member. In a sheet conveyance device that separates two or more sheets between a member and the friction separation roller and conveys only one sheet in the conveyance direction, the torque is made to mesh with a drive gear. The driven gear and the driven gear that can be applied to the shaft of the friction separation roller via a driven gear to change the action point of the tooth surface pressure between the drive gear and the driven gear in the axial direction. One of the gears is provided so as to be movable in the axial direction within a range where it can mesh with the other gear, and a fixing means for fixing the one gear in the axial direction after the movement. Sheet conveyance characterized by having apparatus. 2. An operating member provided so as to be movable in the axial direction in a state where the fixing means is engaged with the one gear and one end portion extends to a visible portion, and the operating member. The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is configured to be fixed in the axial direction after the operation. 3. An adjusting index such as a contact pressure between the friction separating roller and the conveying member according to the position of the one gear and an operating condition suitable for the contact pressure is displayed at one end of the operating member. The sheet conveying device according to claim 2, wherein 4. The sheet conveying apparatus according to claim 1, wherein the other gear is composed of a module provided on the same axis and a plurality of gears having the same number of teeth. 5. The one gear and the other gear are respectively formed by using a plurality of gears arranged on the same shaft center and having different numbers of teeth, and the one gear and the other gear are arranged in accordance with the position of the one gear in the shaft center direction. , One of the plurality of gears forming the other gear is configured to mesh with any one of the plurality of gears forming the one gear. The sheet conveying device according to claim 1.