JP2645584B2 - Paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] A paper feeder for feeding forms and the like one by one from a stack thereof, and press-contacting the stack so as to sequentially feed out sheets and forms from the stack. A sheet feeding section provided with a pick roller that fits the sheet feeding section, and a sheet separating section provided with a torque limiter and a separation rolling element that rolls and engages with the sheet so as to separate and feed the fed sheets and forms one by one. The present invention provides a paper feeder for high-speed processing configured to be able to handle a wide variety of diversified sheets and forms in such a paper feeder. In this type of paper feeding device, the load applied to the stack by the pick roller is a
It is increased when the forms are fed, while the paper in the paper separation section
A pick-up roller is provided with a pick-roller load changing unit for reducing the number of sheets when the forms are separated from each other.

[Industrial applications]

The present invention relates to a printer, an optical character reading device (OCR) for feeding sheets, forms, etc., one by one from a stack thereof.
A paper feeding unit provided with a pick roller that presses and engages with the stack so as to sequentially feed the sheets and forms from the stack, and the fed paper and forms. The present invention relates to a paper feeder of a type having a torque limiter for separating and sending out one sheet at a time, and a sheet separating unit provided with a separation rolling element rollingly engaged with the torque limiter.

[Conventional technology]

Printers, optical character readers, and the like incorporate a paper feeder for feeding paper or forms from the stack to the printing unit or reading unit one by one,
As one type of such a sheet feeding device, a sheet feeding section provided with a pick roller which presses and engages with the stack to sequentially feed the sheets and forms from the stack, and the fed sheets and forms are provided. 2. Description of the Related Art There has been known a type including a torque limiter for separating and sending out one sheet at a time and a sheet separating portion provided with a separation rolling element which is rollingly engaged with the torque limiter. Referring to FIG. 4 and FIG. 5 (conventional example (1)),
The structure of such a paper feeder is schematically shown, the paper feeding section and the paper separating section being denoted by reference numerals 10 and 12 respectively.
Indicated by

The paper feeding section 10 is configured as a hopper structure for storing a stacked body S composed of papers P ₁ , P ₂ , and P ₃ to be fed, and a lifting table which is moved up and down by a suitable driving source on a bottom side thereof. A pick roller assembly 16 as shown in FIG. 5 is provided on the top side of the hopper structure. The pick roller assembly 16 includes a pick roller 18 and a drive roller 20, a support bracket 22 for rotatably holding both rollers, and a drive belt stretched between a gear of the pick roller 18 and a gear of the drive roller 20. 24. Support bracket 22 of pick roller assembly 16
Is supported on a suitable support frame (not shown) so as to be rotatable about the axis of rotation of the drive roller 20, and the support bracket 22 is provided with suitable elastic means, such as coil springs, at the location indicated by the reference numeral 25. the added elastic force, thereby brought into elastically pressed against the paper P ₁ of the topmost of the pick roller 18 is stack S. The drive roller 20 is connected to a drive motor M via a suitable clutch N, and when the clutch is engaged, the drive roller 20 is driven to rotate in a counterclockwise direction (FIG. 5), whereby the pick roller 18 is also driven. The belt 24 is driven to rotate counterclockwise. On the other hand, when the clutch is disengaged, the pick roller 18 is placed in an idling state and idles (see FIG. 5 (b)).

When the pick roller 18 in the sheet P ₁ and the pressure-contact state of the topmost portion is rotationally driven (in this case the above-mentioned clutch engagement state), the sheet P ₁ receives the feeding force from the pick roller 18 sheet stack S It will be fed out to the separation part 12. In this case, although it feeds only the paper P ₁ of the topmost from stack S is the ideal, in fact with the feeding of the sheet P ₁ is fed together also lower the sheet P ₂ and P ₃ of the Can be The sheets fed out in an overlapping manner are separated and fed one by one in the sheet separating section 12.

The sheet separating section 12 is provided with a separation belt assembly 26, which cooperates with a torque limiter 28. The separation belt assembly 26 has three pulleys 3
0, 32, and 34, a support bracket 36 for rotatably holding these pulleys, and a separation belt 38 stretched over the pulleys 30, 32, and 34. Pulley 30 is connected to a suitable drive motor to function as a drive pulley, while pulleys 32 and 34 are functioned as driven pulleys.
The support bracket 36 is supported on a suitable support frame (not shown) so as to be rotatable about the axis of rotation of the drive pulley 30, and the support bracket 30 has suitable elastic means at the location indicated by reference numeral 40. For example, an elastic force is applied by a coil spring, whereby a part of the separation belt 38, that is, a belt running portion between the driving pulley 30 and the driven pulley 32 is elastically pressed against the torque limiter 28.
That is, in the example shown in FIG. 4, the separation belt 38 functions as a separation rolling element rollingly engaged with the torque limiter 28. The torque limiter 28 is kept in a non-rotating state when the torque value applied thereto is equal to or less than a predetermined value,
The rotation is started only when the torque value exceeds a predetermined value. The torque limiter 28 and the separation belt 38 are both made of a material having a large frictional force with respect to the paper to be fed.

The paper fed from the paper feeding unit 10 is a torque limiter.
The clutch is disengaged between the belt 28 and the separation belt 38 elastically pressed against it, and at this time, the above-mentioned clutch is disengaged, and the pick roller 18 is brought into a state where it can idle. When ideal paper feeding is performed in the paper feeding section 10, that is, when only one sheet is fed, the torque limiter 28 is used.
Only one sheet of paper is introduced between and the separation belt 38,
At this time, the paper includes a torque limiter 28 and a separation belt 38.
The contact force of the separation belt 38 is transmitted to the torque limiter 28 due to a large frictional force between the sheet and the paper, so that the sheet is sent out from between the torque limiter 28 and the separation belt 38. On the other hand, when introduced between the sheet feeding unit 10 with a plurality of paper eg paper P ₁ and P ₂ are fed in overlapping state torque limiter 28 and the separation belt 38 (FIG. 4), the sheet P ₁ and frictional force between the P ₂ are smaller than the respective frictional force of the separating belt 38 and the torque limiter 28 for those sheets, never Therefore the driving force of the separation belts 38 is transmitted to the torque limiter 28, as a result the paper P only ₁ is to be fed from between the torque limiter 28 and the separating belt 38 in a state of being slid with respect to the sheet P _2.

Further, a gate plate 42 having a function of separating the fed sheet is disposed on the sheet feeding side of the sheet feeding unit 10, and the sheet fed from the sheet feeding unit 10 passes over the gate plate 42 and forms a torque limiter 28 and a separation belt 38. It is being introduced between. That is, when the fed sheet gets over the gate plate 42, the sheet receives resistance from the gate plate 42, so that at least the lowest sheet of the plurality of fed sheets cannot be passed over the gate plate 42 and is separated. become. Such a separating action depends on the relative height of the gate plate 42 with respect to the feeding position of the sheet. If the height is too low, the separating function of the sheet is deteriorated. It becomes impossible to get over the gate plate 42. In short, the gate plate 42 functions to limit the number of sheets introduced between the torque limiter 28 and the separation belt 38,
Preferably, only one sheet of paper has a torque limiter
It is set to be introduced between 28 and the separation belt 38.

In order for the paper feeding device shown in FIGS. 4 and 5 to reliably perform the paper feeding operation as described above, various parameters as listed below must be set under predetermined conditions. Must.

P _PK : Load at the application point of the pick roller 18 R _h : Horizontal distance between the pivot point of the support bracket 22 and the center of the pick roller 18 R _V : Distance between the pivot point of the support bracket 22 and the center of the pick roller 18 Vertical distance r: radius of pick roller 18 W: load applied to location 25 of support bracket 22 R _W : horizontal distance between pivot point of support bracket 22 and location 25 G _P : center of gravity of pick roller assembly 16 Load R _GP : Rotating fulcrum of support bracket 22 and pick roller assembly
Horizontal distance from the center of gravity of 16 Z ₁ : Number of gears of drive roller 20 meshing with drive belt 24 Z ₂ : Number of gears of pick roller 18 meshing with drive belt 24 P _SB : Load of action point of separation belt 38 R _SB : Horizontal distance between the pivot point of the support bracket 36 and the point of action of the separation belt 38 P _B : Load applied to the point 40 of the support bracket R _B : Between the pivot point of the support bracket 36 and the point 40 Horizontal distance G: Load of center of gravity of separation belt assembly 26 R _G : Rotation support point of support bracket 36 and separation belt assembly 26
R _SB : Radius of drive pulley 30 R _r : Radius of torque limiter 28 T: Set torque value of torque limiter 28 μ _PK : Coefficient of friction between pick roller 18 and paper μ ₁ : Paper P ₁ and the sheet P ₂ coefficient of friction between the mu _2: coefficient of friction mu _SB between the sheet P ₂ and the sheet P _3: coefficient of friction between the separating belt 38 and the paper P ₁ mu _rr: paper P ₂ Coefficient of friction between the torque limiter 28 and the torque limiter T _G : Resistance value of the gate plate 42 f ₁ : Repeated output of the sheet P _{1 in} the sheet feeding section 10 f ₂ : Repeated output of the sheet P ₂ in the sheet feeding section 10 F _1: sheet separating and conveying force of the sheet P ₁ in the portion 12 F _2: conveying force of the sheet P ₂ of the sheet separation section 12 first, the described feeding condition of the paper in the paper feeding section 10, the paper P ₁ Repetitive Repetitive output f ₂ output f ₁ and the sheet P ₂ is defined by the following equation.

f ₁ = (μ _PK −μ ₁ ) P _PK … f ₂ = (μ ₁ −μ ₂ ) P _PK … The load P _{PK at} the application point of the pick roller 18 is obtained from the balance of the moment around the axis of the drive roller 20. Desired. _{That, W · R W + G P} · R GP -P PK · R h + Z 1 / Z 2 · r · μ PK · P PK + μ pk · P PK (R V + r) = 0 W · R W + G P · R _{GP + (Z 1 / Z 2} · r · μ PK + μ PK (R V + r) -R h) P PK = 0 P PK = (W · R W + G P · R GP) / (R h -Z 1 / Z ₂ · r · μ _PK −μ _PK · (R _V + r)… In order for the paper fed from the paper feeding unit 10 to pass over the gate plate 42 and be introduced between the torque limiter 28 and the separation belt 38 , Repetitive output f ₁ of the paper P ₁ must overcome the resistance of the gate plate 42. that is, the following equation must be satisfied.

f ₁ = (μ _PK −μ ₁ ) P _PK ≧ T _G … Needless to say, if f ₁ ≦ T _G , the sheet is the gate plate 42.
Is not introduced between the torque limiter 28 and the separation belt 38, so that a so-called pick mistake may occur.

Also, if ideally the following equation is always satisfied, only the uppermost sheet of paper P ₁ That stack S is fed from the sheet feeding unit 10 to the sheet separating unit 12 side.

f ₁ = (μ _PK −μ ₁ ) P _PK ≧ T _G ≧ f ₂ = (μ ₁ −μ ₂ ) P _PK By the way, when paper is sequentially fed out of the stack S, the height of the topmost paper is Since the level gradually decreases, the lifting table 14 is intermittently raised to compensate for the decrease, and the load W is kept constant, and therefore the pick roller 18 is fixed.
Attempts to maintain a constant load at the point of application of
The friction coefficient μ _PK between the sheet 18 and the sheet and the friction coefficients μ ₁ and μ ₂ between the sheets of the stack S are not constant but varied.
Therefore, Repetitive output f ₂ of the formula and Repetitive output f ₁ sheet P ₁ defined by and the sheet P ₂ is always will vary. Therefore, during the sheet feeding operation, a relationship as shown in the following equation can be satisfied. In this case, the sheets P ₁ and P ₂ are both sent to the sheet separating unit 12 side, and a so-called double pick occurs. Will be.

f ₂ = (μ ₁ −μ ₂ ) P _PK ≧ T _G ... As is clear from the above description, the sheet feeding in the sheet feeding section 10 is achieved by one of the following expressions and / or conditions. .

Next, conditions for only paper P ₁ fed out from the paper separating unit 10 has the sheet P ₁ is sent securely from the paper separating unit 12 when introduced between the torque limiter 28 and the separation belt 38 State. In order to ensure reliable delivery of the paper P ₁ is to eliminate the slipping of the separation belts 38 for the sheet P _1, it shall transmit the driving force to the torque limiter 28. That is, by rotate with the torque limiter 28 by the drive of the drive belt 38 must to send out the sheet P ₁ from therebetween.
Delivery force or the conveying force F ₁ of the paper P ₁ at this time is defined by the following equation.

F ₁ = μ _SB・ P _SB −T / R _r −P _PK ′ ・ μ ₁ −T _G ... P _PK ′ is a pick when the clutch of the drive roller 20 of the paper feeding unit 10 is disengaged. This is the load at the point of action of the roller 18 (at this time, the pick roller 18 is allowed to idle), and can be expressed by the following equation.

P _PK ′ = (W · R _W + G _P · R _GP ) / R _h ... ′ In other words, Expression ′ corresponds to the case where μ _PK = 0 in the expression.

The load _{PSB at the} point of action of the separation belt 38 is determined from the moment balance about the axis of the drive pulley 30. _{That, P B · R B + G} · R G -P SB · R SB + μ SB · P SB · r SB = 0 P B · R B + G · R G = (R SB -μ SB · r SB) P SB P _{SB = (P B · R B} + G · R G) / (R SB -μ SB · r SB) ... second term of the equation (T / _{R r)} is the torque to overcome the set torque value of the torque limiter 28 The third term (P _PK ′ · μ ₁ ) of the equation is the force required to rotate the limiter 28.
_This is the force required to pull out the subsequent part of ₁ from the paper feeding unit 10. The fourth term of the equation is, of course, the force required to overcome the resistance of the gate plate 42, not to mention (T _G ).

In order to be able feeding the paper P ₁ without slipping the separation belts 38 to the paper P ₁ is the relationship as shown below must be satisfied.

F ₁ = μ _SB · P _SB −T / R _r −P _PK ′ · μ ₁ -T _G ≧ 0 The equation can be rewritten as follows from the equation. _{That, μ SB (P B · R} B + G · R G) / (R SB -μ SB · r SB) -T / R r -P PK '· μ 1 -T G ≧ 0 μ SB · R r (P _{B · R B + G · R} G) / (R SB -μ SB · r SB) -μ 1 · R r · P PK '-R r · T G ≧ T ... Meanwhile, overlapping paper P ₁ and P ₂ When the sheet P ₁ is introduced between the torque limiter 28 and the separation belt 38 in the state,
There will be described the conditions for being separated from the sheet P ₂ fed from the paper separating unit 12.

Torque limiter in a state where the paper P ₁ and P ₂ are overlapped
Paper P ₁ when introduced between separation belt 28 and separation belt 38 and
The sending power or carrying force of each of P ₂ is defined by the following equation. That is, for the sheet P ₁ is, F ₁ for _{'= (μ SB -μ 1)} P SB -μ 1 · P PK' -T G ... sheet _{P 2, F 2 '= μ} 1 · P SB -T / R _r − (μ ₁ −μ ₂ ) P _PK ′ −T _G ... Upper sheet of paper P ₁ and P ₂ overlapping each other
For only P ₁ is fed out from between the torque limiter 28 and the separating belt 38 has to hold the relationship F ₁ '≧ F _2', the contrary, the sheet P ₁ and P ₂ The paper is sent out from the paper separation unit 12 without being separated from each other, and a so-called double feed occurs. The relationship of F ₁ ′ ≧ F ₂ ′ can be expressed as follows from the equation.

(Μ _SB −2μ ₁ ) P _SB ≧ −T / R _r + μ ₂ · P _PK ′...

_{(Μ SB -2μ 1) (R} B · P B + G · R G) / (R SB -μ SB · r SB) ≧ -T / R r + μ 2 · P PK '∵- (μ SB -2μ 1) R _r (R _B · P _B + G · R _G ) / (R _SB -μ _SB · r _SB ) + μ ₂ · R _r · P _PK '≦ T… As is clear from the above description, from the paper separation unit 12 In order for the paper to be fed out one sheet at a time, it is necessary that the formulas and are satisfied.

Here is a summary of the above.

Regarding the feeding of paper In order for the paper feeding unit 10 to eliminate the double picking of paper and to be able to pick (feed) paper one by one, the following formula is used: (μ ₁ −μ ₂ ) P _PK ≧ _TG from increase T _G, it can be seen that it is sufficient to reduce the P _PK.

Meanwhile, in order to eliminate Pikkumisu of paper, wherein i.e., from _{(μ PK -μ 1) P PK} ≧ T G, reduces T _G, and μ _PK> μ _1, it is sufficient to increase the P _PK You can see that.

Even if a double pick of paper occurs in the paper feeding unit 10, the paper should be separated in the paper separating unit 12, so that the paper feeding unit 10 should focus on eliminating paper picking mistakes. It is.

To prevent slippage when feeding the only one paper sheet separating unit 12 for separating the paper, wherein _{i.e., μ SB · R r (P} B · R B + G · R G) / (R SB - μ _SB · r _SB ) −μ ₁ · R _r · P _PK ′ −R _r · T _G ≧ T, so that P _B is increased, T is reduced, _TG is reduced, and P _PK ′
It can be seen that it is only necessary to reduce and increase μ _SB .

Meanwhile, in order to prevent the double-feed of sheets by the sheet separating unit 12, wherein _{i.e., - (μ SB -2μ 1)} R r (R B · P B + G · R G) / (R SB -μ SB · r _SB ) + μ ₂ · R _r · P _PK ′ ≦ T, P _B is reduced, T is increased, P _PK ′ is reduced, μ
_SB> mu may it can be seen that if _1. Note that (R _SB −μ
_{If SB} · r _SB ) takes a negative value, the separation belt 24 is braked, so that R _SB −μ _SB · r _SB > 0.

Referring to FIG. 6, the correlation of the parameters between the above-described conditions is shown. In FIG. 6, the solid arrows show the conflicting relationship with respect to the resistance value (T _G ) of the gate plate 42. , And dashed arrows indicate conflicting relationships with respect to the load (P _PK and P _PK ′) at the point of action of the pick roller 18.
That is, when the resistance (T _G ) of the gate plate 42 is increased in the sheet feeding section 10 to prevent double picking, a pick mistake easily occurs and a slip easily occurs in the sheet separating section 12. On the other hand, when the loads P _PK and P _PK ′) at the application point of the pick roller 18 are increased in order to prevent picking mistakes in the paper feeding section 10, double picking is likely to occur and the paper is separated. On the side, double feed and slip are likely to occur.

Further, referring to FIG. 7, the parameters which are mutually contradictory between the double feed condition and the slip condition in the paper separating section 12, that is, the set torque value (T) of the torque limiter 28 and the location 40 of the support bracket 36 are applied. Load (P _B )
Is shown. In the FIG. 7, the slip generation region and double feed generation region is shown as a shaded area, respectively, which parameters are anti-slip condition when it is set to include both parameters T and P _B during the white area And the double feed prevention condition. The boundary between the slip occurrence area and the white area coincides with the equation, and the boundary between the double feed generation area and the white area coincides with the equation.

In addition, as a conventional example (part 2), a paper feeding portion shown in FIG.
10, based on the configuration of the sheet separating unit 12, the pick roller 18 and the support bracket 22 of the sheet feeding unit 10 in FIG. 4, that is, the sheet feeding unit 10 shown in FIG. There is a structure that separates the paper from the paper. This is illustrated in FIG.

FIG. 10 (a) shows the state when the sheet is fed, and FIG. 10 (b) shows the state when the sheet is separated.

The pick roller raising mechanism includes a solenoid 181 and an arm 182. When the solenoid 181 is turned off (when the paper is fed), the load of the pick roller assembly 16 itself is applied to the pick roller 18.
When the _PK is added and the solenoid 181 is ON, the pick roller
18 and the paper are separated, so _PKK '= 0. 183 is the center of rotation of the arm 182.

_{Therefore, μ SB · R r (P} B · R B + G · R G) upon separation as P _PK '= 0 from condition equation of the slip occurrence blocking _{/ (R SB -μ SB · r} SB) -R r · T _G T becomes, the boundary line Figure 7 at this time (-, -, -) for cysts on as shown in FIG.

Also, from the conditional expression of double feed prevention, P _PK ′ = 0
As _{- (μ SB -2μ 1) ·} R r (R B · P B + G · R G) / (R SB -μ SB · r SB) T , and the borders of this time in FIG. 7 (- Shift down as shown in ---).

As described above, the conventional example 2 increases the white blank portion in FIG. 7, that is, the area where the paper separation can be reliably performed.
This is effective for stabilizing and improving paper, report specifications, and paper supply capacity in relation to the environment.

However, in the second conventional example, the operation time is long because the support bracket 22 is moved mechanically.

In today's high-speed continuous paper (form) processing, the processing speed of the apparatus becomes slow, so that it cannot be used anymore. For this reason, it has been necessary to use the above-described first conventional apparatus (a configuration without a mechanism for raising the pick roller).

In short, in the conventional paper feeding device, various parameter values are set to be mutually compromised under the above-described conditions, so that a reliable paper feeding operation of the paper feeding device can be obtained.

In the above-described conventional example, the torque limiter 28 is cooperated with the separation belt 24 as a separation rolling element.However, a paper feeding apparatus in which a torque roller cooperates with a separation roller as a separation rolling element is also known. The paper feeding principle is the same as the case where the separation belt is used. An advantage of using the separation belt is that the load P _SB at the point of action can be made smaller than that of the separation roller, and thereby, the stain between the pencil-written forms can be reduced.

[Problems to be solved by the invention]

Now, with the recent spread of printers, optical character readers, etc., the forms of paper and forms used therein have also diversified, and therefore, paper feeders incorporated in printers, optical character readers, etc. Various diversified papers,
It is desired to handle high-speed processing over a wide range of forms. However, in reality, it is extremely difficult to make the paper feeding device correspond to a wide variety of diversified sheets and forms. This is because of the diversified variety of papers, forms and sizes, reams,
Μ _PK , μ ₁ , μ ₂ , μ _SB and μ _rr among the above parameters fluctuate widely due to paper quality, presence or absence of perforations, etc. It is virtually impossible to satisfy them. In addition, since the parameters μ _PK , μ ₁ , μ ₂ , μ _SB and μ _rr change depending on environmental conditions such as temperature and humidity, the paper feeder is diversified over a wide range of various papers and forms. It is even more difficult to deal with. Further, in particular, in an optical character reader, etc., in order to handle a form written with a pencil, it must be prevented from being transferred to another form, so that the load (P _PK And P _PK ′)
And the load ( _PSB ) at the application point of the separation belt 38 are limited. In this case, the paper feeding device is diversified into various types of paper,
It becomes increasingly difficult to deal with a wide range of forms.

Table I below shows the size of paper, forms, ream, paper quality,
The tendency of occurrence of pick mistake, double feed and slip due to the presence or absence of perforations is shown, and Table II shows the tendency of occurrence of pick mistake and double feed due to changes in temperature and humidity. In Tables I and II, ○ indicates a tendency to occur easily, and X indicates a tendency to not easily occur.

As shown in Table I, the greater the size of paper and forms, and the greater the amount of continuous paper, the greater the tendency for pick mistakes and slips to occur. I mean,
If the size of paper and forms and the amount of ream increase,
This is because the weight of the stack increases and the friction between the paper surfaces increases. On the other hand, when the continuous amount of papers and forms is reduced, the tendency of double feed is increased. Table I
As shown in the figure, double feed is more likely to occur with ordinary PPC paper than with OCR paper.
General PPC paper is more likely to generate static electricity than OCR paper,
This is because this apparently acts to increase the frictional force between the paper surfaces. Further, in an optical character reader (OCR), etc., a perforated form is often used,
Since the perforations also apparently act to increase the frictional force between the paper surfaces, the tendency of double feed is increased even in the case of a perforated form.

As shown in Table II, the occurrence of double feed is increased in a high-temperature and high-humidity environment, because the friction between the sheets decreases in such an environment. On the other hand,
In a low-humidity environment, the tendency of occurrence of pick errors increases. The reasons are that friction between the pick roller and the paper surface increases, and that the paper surfaces tend to attract each other electrostatically.

Also, in Table III below, the parameters μ _PK , μ ₁ , μ ₂ , μ
Increasing and decreasing _SB and mu _rr, Pikkumisu been shown or occurrence tendency of double feed and slip manner in which changes, during the table III, the tendency of increase arrow left-side up, and the left edge Arrows indicate a decreasing trend.

As is clear from the above table, the parameters μ _PK , μ ₁ , μ ₂ , μ _SB and μ _rr are large depending on the paper to be fed, the size of forms, ream weight, paper quality, presence or absence of perforations, etc. Therefore, in the conventional sheet feeding device, the sheets and forms that can be appropriately fed are limited to a predetermined narrow range. In other words, the fixed parameters, ie, (μ _PK , μ ₁ , μ ₂ , μ
_{If the} parameters (except _SB and _μrr ) are set to predetermined values, the papers and forms that can be appropriately fed are determined by the fixed parameters.

Therefore, an object of the present invention is to separate a sheet and a sheet one by one from a sheet feeding section provided with a pick roller which presses and engages with the stack to sequentially feed the sheets and forms from the stack. And a sheet separating section provided with a torque limiter and a separating rolling element rollingly engaged with the torque limiter, and feeds a wide variety of diversified sheets and forms. It is an object of the present invention to provide a paper feeding device configured to be able to handle the above.

[Means for solving the problem]

A sheet feeding device according to the present invention includes a sheet feeding section provided with a pick roller that presses and engages with the stack to sequentially feed sheets and forms from the stack, and the fed sheet,
It is a type that consists of a torque limiter and a paper separation unit provided with a separation rolling element that rolls and engages with it to separate and send out forms one by one. The load applied to the stack of sheets and forms is increased at the time of feeding the sheets and forms in the sheet feeding section, asynchronously with the operation of the sheet separation section, while separating the sheets and forms in the sheet separation section. Pick roller load changing means is provided on the pick roller to reduce the load of the pick roller by changing the magnetic force of the electromagnet in a non-contact state using an electromagnet. The point is to change it.

In the paper feeding apparatus according to the present invention, the pick roller load is increased when the paper and the form are fed out in the paper feeding section, and is reduced when the paper and the form are separated in the paper separating section. , The slip condition and the double feed condition in the sheet separation unit which are opposite to the pick mistake condition are also relaxed. The following is a specific example of this point.

In a paper feeder in which various fixed parameters are set to predetermined values for a form with standard specifications, for example, a case in which general paper that easily generates static electricity and is perforated at low temperatures is fed. In this case, the parameters μ _PK and μ _SB tend to decrease, and the parameters μ ₁ and μ ₂ tend to increase. In this example, the parameter _μrr is assumed to be constant.

First, the feeding of the paper will be described. From the formula, (μ _PK −μ ₁ ) P _PK ≧ _TG , the pick miss condition is illustrated as shown in FIG. In FIG. 8, the picking error occurrence area is shown as a hatched area, and its boundary line a coincides with the equal sign of the equation. Also, in FIG. 8, the parameters P _PK and T
The setting of _G is indicated by coordinates A, which are out of the picking error occurrence area, so that for a standard specification form, the feeding (for example, even if a double picking can occur) is surely performed. Will be performed.

However, when the above-mentioned general paper is fed, the parameter μ _PK decreases and the parameter μ ₁ increases, so that the slope of the boundary line a decreases and the boundary line a is shifted to the boundary line a ′. The coordinates A are taken into the pick mistake area, and the general paper is not fed.

Next, we describe the separation of the sheet, Formula and Formula _{i.e., μ SB · R r (P} B · R B + G · R G) / (R SB -μ SB · r SB) -μ 1 · R r P PK '-R _r · T _G ≧ T and _{- (μ SB -2μ 1) R} r (R B · P B + G · R G) / (R SB -μ SB · r SB) + μ 2 · R r · P PK From '≦ T, the slip condition and the double feed condition are illustrated as in FIG. 9 similar to FIG. In FIG. 9, the slip occurrence area and the double feed occurrence area are shown as hatched areas as in FIG. 7, and the boundary line b of the slip occurrence area is shown.
And the boundary line c of the double feed generation region coincides with the equation and the equal sign. Further, in the FIG. 9, setting for the form of the standard specifications of the parameters P _B and T are shown by the coordinates B, the coordinates B is in white areas between the slip generation region and a double feed occurrence region So
For a form with standard specifications, each sheet is reliably sent out. That is, when only one form is introduced between the separation belt 72 and the torque limiter, the form is sent out by rotating the torque limiter continuously without slipping of the separation belt 72, and When two sheets are introduced between the separation belt and the torque limiter, only the upper sheet is transmitted while the torque limiter is stationary.

However, when the above general paper is fed, the parameter μ _SB decreases and the parameters μ ₁ and μ ₂ increase, so that the boundaries b and c are shifted to the boundaries b ′ and c ′, respectively. As a result, the coordinates B are included in the slip occurrence area, and it is impossible to reliably send the general paper. The analysis of the shift of the boundary lines b and c will be described in detail below.

Regarding shift of boundary line b The boundary line b is expressed by the following equation.

_{T = μ SB · R r (} P B · R B + G · R G) / (R SB -μ SB · r SB) -μ 1 · R r · P PK '-R r · T G ... First, the boundary line Although the slope of b is determined by the first term of the equation, how the slope changes when the parameter μ _SB decreases will be examined. When representing the first term of the equation as a function of the _{following, L = μ SB · R r} (P B · R B + G · R G) / (R SB -μ SB · r SB) ∂L / ∂μ SB = R _{r (P B · R B +} G · R G) / (R SB -μ SB · r SB) + r SB · μ SB · R r (P B · R B + G · R G) / (R SB -μ SB · r _SB ) ² = R _SB · R _r (P _B · R _B + G · R _G ) / (R _SB- μ _SB · r _SB ) ² ∂L / ∂μ _SB · Δμ _SB = R _SB · R _r (P _{B · R B + G · R} G) / (R SB -μ SB · r SB) 2 · Δμ SB where [Delta] [mu _SB indicates the rate of change of the mu _SB, the slope of the boundary line b by the sign of the change rate [Delta] [mu _SB Decided. That is, the slope of the boundary line b becomes large if Δμ _SB > 0, and Δμ _SB
If <0, it is small. In the above example, since μ _SB is reduced, Δμ _SB <0, and the slope of the shifted boundary line b ′ is smaller than the slope of the original boundary line b.

On the other hand, the second and third terms of the equation for determining the intersection of the boundary line b and T axes, in the above example, because mu ₁ increases, the intersection of the boundary line b 'and T axis boundary It is below the intersection of the line b and the T axis.

Therefore, in the case of the above-described conventional example, the boundary line b is shifted to the boundary line b ', and the slip occurrence area is expanded,
The coordinates B are taken into the slip occurrence area.

T boundary c the shift of the boundary line c is represented by the following formula _{= - (μ SB -2μ 1)} R r (R B · P B + G · R G) / (R SB -μ SB · r SB ) + Μ ₂ · R _r · P _PK 'First, the slope of the boundary line c is determined by the first term of the equation. If the parameter μ _SB decreases and the parameter μ ₁ increases, how does the slope change? Consider what to do. When representing the first term of the equation as a function of the _{following, M = - (μ SB -2μ} 1) R r (R B · P B + G · R G) / (R SB -μ SB · r SB) ∂M / _{∂μ SB = -R r (R B} · P B + G · R G) / (R SB -μ SB · r SB) -r SB (μ SB -2μ 1) R r (R B · P B + G · R _{G) / (R SB -μ SB} · r) 2 = (2μ 1 · r SB -R SB) R r (R B · P B + G · R G) / (R SB -μ SB · r SB) 2 ∂ _{M / ∂μ 1 = 2R r (} R B · P B + G · R G) / (R SB -μ SB · r SB) = 2 (R SB -μ SB · r SB) R r (R B · P B + G · R _G ) / (R _SB- µ _SB · r _SB ) ² ∂M / ∂µ _SB · μµ _SB + ∂M / ∂µ ₁ · μµ ₁ = (R _B · P _B + G · R _G ) · R _{r (2μ 1 · r SB -R} SB) · Δμ SB +2 (R SB -μ SB · r SB) · Δμ 1) / ( change in _{R SB -μ SB · r SB)} 2 where [Delta] [mu _SB is mu _SB And Δμ ₁ is μ
₁ shows the rate of change. The inclination of the boundary line c the following terms in the above equation that _{is, 2μ 1 · r SB -R SB} ) Δμ SB +2 (R SB -μ SB · r SB) · Δμ 1)> determined by the sign of zero.

If _{Δμ 1 / Δμ SB> (R} SB -2μ 1 · r SB) / 2 (R SB -μ SB · r SB) ... a slope large next to the border c, also Δμ ₁ / Δμ _SB <( if _{R SB -2μ 1 · r SB)} / 2 (R SB -μ SB · r SB) ... a, the slope of the boundary line c is small. The paper feeder can be designed such that the right side of the equation and the right side of the equation are positive, whereas in the above example, the left side of the equation and the negative side is because of Δμ _SB <0 and Δμ ₁ > 0. . Therefore, the equation holds, and the inclination of the shifted boundary line c ′ is equal to the original boundary line c.
Is smaller than the inclination of.

On the other hand, the second term of equation determines the intersection of the boundary line c and T axes, in the above example, since the mu ₂ increases, the intersection of the T axis with the boundary line c 'is the boundary line c T It is above the intersection with the axis.

Therefore, in the case of the above-described conventional example, the boundary line c is shifted to the boundary line c ', and the double feed generation area is retreated downward.

As is apparent from the above description, in the paper feeder in which various fixed parameters are set to predetermined values for a form with standard specifications, the parameters μ _PK , μ _SB , μ ₁ , μ ₂ and μ
For paper and forms that change _rr to a large width,
The paper cannot be fed.

However, as in the present invention, when the pick roller load is increased at the time of feeding a sheet or a form at the sheet feeding section, as is clear from the formula, FIG. , So that such papers and forms can be fed out.

On the other hand, if the pick roller load is reduced when the paper and the form are separated in the paper separating section, the value of the second term of the equation (ie, -μ ₁ · R _r · P _PK ') increases, and the boundary value increases. Line b '
Translates upward along the T axis to become the boundary line b ″,
On the other hand, the value of the second term of the equation (that is, μ ₂ · R _r · P _PK ') decreases, and the boundary c' is translated downward along the T axis to become the boundary c ". The coordinate B escapes from the slip occurrence area and is included in a stable area between the slip occurrence area and the double feed occurrence area (that is, an area in which the sheet and the form are reliably transmitted one by one).

〔Example〕

Next, an embodiment of the sheet feeding device according to the present invention will be described with reference to FIG. 1 of the accompanying drawings.

FIG. 1 is a side view of a schematic structure of a sheet feeding device according to the present invention. In FIG. 1, a part of the outline of a stack S of sheets and forms to be fed is indicated by a two-dot chain line, and the stack S is accommodated in a hopper (not shown) forming a sheet feeding portion. You. An elevating table (not shown) which is moved up and down by an appropriate driving source is provided on the bottom side of the hopper, and the stack S is placed on the elevating table.

The sheet feeder includes a pick roller assembly 44, which has essentially the same configuration as the pick roller assembly 16 shown in FIG. That is, the pick roller assembly 44 is stretched between the pick roller 46 and the drive roller 48, the support arm 50 that rotatably holds both rollers, and the gear between the pick roller 46 and the drive roller 48. A driving belt (the driving belt is omitted in FIG. 1 to avoid complication of the drawing). Also, the support arm 50 of the pick roller assembly 44
Are supported on a suitable support frame (not shown) so that the pick rollers 46 can rotate about the rotation axis of the drive roller 48, and the pick rollers 46 are stacked by applying appropriate elastic means to the support arm 50. The point that the uppermost sheet S is elastically pressed against the sheet is the same as the pick roller assembly 16 shown in FIG. Further, the drive roller 48 is driven by a drive motor (not shown) via a suitable clutch (not shown in FIG. 1).
When the clutch is disengaged, the pick roller 46 is
Is placed in an idling state and idles in the same manner as in FIG. In addition, pick roller
Normally, a pair of reference numerals 46 are provided in a state where they are aligned in a direction perpendicular to the paper surface of FIG. 1, so that the feeding of sheets and forms can be stably performed.

The pick roller assembly 44 is the pick roller assembly of FIG.
16 is that the load applied to the stack S by the pick roller 46 is variable. That is, a pick roller load changing means is applied to the pick roller assembly 44. In this embodiment, the pick roller load changing means is a permanent magnet 52 attached to one end of the support arm 50, that is, the end on the pick roller 46 side. And an electromagnet 54 arranged close to the permanent magnet 52 in a non-contact state. Electromagnet 54 is core
It comprises a coil 56 surrounding it and one end of the core 56 is adjacent to one pole of the permanent magnet 52. electromagnet
The energization of the coil portion 58 of the 54 is performed such that the one end of the core portion 56 has the same polarity as one pole of the permanent magnet adjacent thereto. Accordingly, when the coil portion 58 of the electromagnet 54 is energized, a repulsive force acts between the permanent magnet 52 and the electromagnet 54, whereby the load on the pick roller 46 is increased compared to when the coil portion 58 is not energized. Become.

The sheet separating portion of the sheet feeding device is formed by a torque limiter 60 and a separation belt assembly 62 provided above the torque limiter 60. The separation belt assembly 62 is also essentially a fourth
It has the same configuration as the separation belt assembly 26 described with reference to the drawings. That is, the separation belt assembly 62 includes three pulleys 6.
4, 66 and 68, a support bracket 70 for rotatably holding these pulleys, and a separation belt 72 stretched over the pulleys 64, 66 and 68. 4, the pulley 64 is connected to a suitable drive motor (not shown) to function as a drive pulley, while pulleys 32 and 34 are operated as driven pulleys. Further, the support bracket 70 is supported by a suitable support frame (not shown) so as to be rotatable around the rotation axis of the drive pulley 64, and an elastic force is applied by a suitable elastic means (not shown). As in the case of the separation belt assembly 26 in FIG. 4, a part of the separation belt 72, that is, a belt running portion between the driving pulley 64 and the driven pulley 66 is elastically pressed against the torque limiter 60. . Further, when the torque value applied to the torque limiter 60 is equal to or less than a predetermined value, the torque limiter 60 is maintained in a non-rotation state,
It is the same as in the case of FIG. 4 that the motor is rotated only when the torque value exceeds a predetermined value.

As in the case described with reference to FIGS. 4 and 5, a gate plate having a function of separating fed paper is provided on the paper feeding side.
The gate plate 74 can be configured as a part of a hopper that forms a paper feeding portion. The paper and the form fed out of the stack S by the pick roller 46 are once introduced over the gate plate 74 and then introduced between the torque limiter 60 and the separation belt 72. The function itself of the gate plate 74 is the same as that of the gate plate 42 shown in FIGS. 4 and 5, and the material of the gate plate 42 may be hard such as metal or may have elasticity.

As described above, according to the present invention, the pick roller 46 is used to increase the load of the pick roller when the paper and the form are fed out from the stack S by the pick roller 46, and the paper and the form are separated by the torque limiter 60 and the separation belt 72. When separating, the pick roller load is reduced. That is, it is necessary to turn on the power supply to the electromagnet 54 when feeding out the paper and the forms, and to turn off the power supply to the electromagnet 54 when the papers and the forms are separated. The detection is performed by detecting the introduction of the sheet or the form between the torque limiter 60 and the separation belt 72 by a suitable detecting unit. In the present embodiment, a sensor including a light emitting element 76 and a light receiving element 78 is used as such a detecting means, and the light emitting element 76 is disposed adjacent to the end face side of the torque limiter 60, and the light receiving element 78 Is disposed on the side of and adjacent to the separation belt 72 in a relationship facing the light emitting element 76. The light emitting element 76 and the light receiving element 78 can be supported on a frame of the sheet feeding device via a suitable support bracket.
In short, in the present embodiment, when the light receiving element 78 is receiving light from the light emitting element 76, the energization of the electromagnet 54 is turned “on”, and the light receiving element 78 and the light emitting element 76 are placed between paper and a form. When the light from the light emitting element 78 is blocked
The power to 54 is turned off.

In this embodiment, the sensor including the light emitting element 76 and the light receiving element 78 is provided with another function, that is, to switch the clutch of the driving roller 48 of the pick roller assembly 44. As described above, it is necessary to put the clutch into an engaged state when feeding out papers and forms, and to disengage the clutch when separating papers and forms. Switching is also performed by such a sensor. That is, when the light receiving element 78 is receiving light from the light emitting element 76, the clutch is engaged, and paper and a form are introduced between the light receiving element 78 and the light emitting element 76, and the light emitting element
When light from 76 is blocked, the clutch is disengaged.

The control of the electromagnet 54 and the clutch as described above is performed using a control circuit (generally, a microcomputer is used) built in a printer or an optical character reader in which a paper feeder is to be incorporated. The control block diagram is shown in FIG. In FIG. 2, reference numeral 80 indicates a control circuit used for a printer or an optical character reader, but since the control system of the printer or the optical character reader itself is not directly related to the present invention, Has been omitted. The control circuit 80 is a central processing unit (CPU) 82
And a read-only memory (ROM) 84 storing an operation program of the paper feeder according to the present invention, constants, etc. together with an operation program of the printer device or the optical character reader.
And a writable / readable memory (RAM) 86 for storing temporary data and the like, and an input / output interface (I / O) 88
And A sensor including a power switch 90 of the electromagnet 54, a switch 92 for operating the clutch of the drive roller 48, and a light-receiving element 78 and a light-emitting element 76 is connected to a control circuit 80 via an input / output interface (I / O) 88. Is done.

The control block diagram of FIG. 2 is operated according to the control routine shown in FIG. The control routine shown in FIG. 3 is executed by turning on a power supply of a printer or an optical character reader in which the control device according to the present invention is to be incorporated.

In step 301, it is determined whether or not the sensors (76, 78) have detected sheets and forms. When papers and forms are not detected by the sensors (76, 78), the process proceeds to step 302, where the clutch of the driving roller 48 is engaged,
Next, in step 303, the energization of the electromagnet 54 is turned "on", whereby the pick roller 46 feeds out the sheets and forms from the stack S with the increased pick roller load, and the fed sheets and forms Classes are introduced between the torque limiter 60 and the separation belt 72 over the gate plate 74.

When the paper and the forms are introduced between the torque limiter 60 and the separation belt 72 and the light from the light emitting element 76 is blocked, in step 301, the introduction of the paper and the forms is detected. The clutch is disengaged, and then the energization of the electromagnet 54 is turned "off" in step 305, thereby reducing the load on the pick roller 46, and thereby reducing the load between the torque limiter 60 and the separation belt 72. , And one sheet at a time can be satisfactorily transmitted.

When all the sheets and forms (one sheet or several sheets) are sent out from between the torque limiter 60 and the separation belt 72,
The clutch of the driving roller 48 is again engaged (step 302), and the energization of the electromagnet 54 is turned "on" (step 303), whereby the feeding of the sheets and the forms is resumed.

In the control routine of FIG.
And step 303 may be reversed, which is equivalent to step 3
The same can be said for 04 and step 305.

In the above-described embodiment, the pick roller load changing means is constituted by the permanent magnet 52 and the electromagnet 54, but an additional load may be applied to the pick roller 46 by other means such as a mechanical lever mechanism. . However, when the paper and the form are fed at a high speed, as shown in the present embodiment, it is preferable to configure the pick roller load changing means by a permanent magnet and an electromagnet which can obtain a quick response.

Further, if the paper and the form can be fed and separated well with the initial load of the pick roller 46, it is not necessary to operate the pick roller load changing means, and the feeding and separation can be performed satisfactorily with the initial load. If not, it is only necessary to operate the pick roller load changing means. Therefore, it is preferable to provide a selection switch for allowing the user to select whether to operate the pick roller load changing means. Further, it is also preferable that the initial load of the pick roller 46 is made as small as possible, and the pick roller load can be increased stepwise or continuously by the pick roller load changing means. , It is possible to feed a wide range of sheets and forms.

〔The invention's effect〕

As is apparent from the above description, in the paper feeding apparatus according to the present invention, the pick roller load is increased when the paper and the form are fed out, and is decreased when the paper and the form are separated, so that the diversified various types are provided. Paper and a wide variety of forms can be handled by high-speed processing. In particular, in the present invention, since the pick roller load changing means is configured to change the magnetic force of the electromagnet in a non-contact state using the electromagnet, the load of the pick roller is a force applied from the electromagnet to the permanent magnet. Changes very quickly in a non-contact state. Also, in the present invention, since both the pick roller load changing means and the drive connection mechanism (clutch) for cutting off the drive of the pick roller when separating paper forms are provided, high-speed feeding and transport of paper forms is possible. And improvement of separation performance can be achieved at the same time.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing an embodiment of a sheet feeding device according to the present invention, FIG. 2 is a control block diagram of the sheet feeding device of FIG. 1, and FIG. 3 is an operation of a control block diagram of FIG. FIG. 4 is a schematic diagram for explaining the paper feeding principle of the conventional paper feeding device, FIGS. 5 (a) and (b) are detailed drawings of the paper feeding portion in FIG. 4, and FIG. FIG. 7 is an explanatory view showing the conflicting parameters between the prevention of double picking and picking mistake at the time of feeding of paper and forms and the prevention of double feed and slip at the time of separating paper and forms, and FIG.
Explanatory view showing the relationship of the parameter P _B and T slip generation and double feed occurrence of separation of the paper sheet, Figure 8 and Figure 9 is an explanatory diagram for explaining the operation of the present invention, FIG. 8 is FIG. 9 shows the occurrence of pick mistakes at the time of feeding paper and forms in relation to parameters _TG and _PK .
Shows drawing, FIG first 10 (a), the (b) conventional example (part 2) showing slip occurrence and double feed occurs parameters P _B and T relationship with likewise paper, the paper sheet separating and FIG It is. 44: Pick roller assembly, 46: Pick roller, 48: Drive roller, 50: Support arm, 52: Permanent magnet, 54: Electromagnet, 56: Core, 58: Coil, 60 …… Torque limiter, 62 …… Separation belt assembly, 64 …… Drive pulley, 66,68… Play pulley, 70 …… Support bracket, 72 …… Separation belt, 74 …… Gate plate, 76 …… Light emitting element , 78 ... Light receiving element.

Claims (2)

(57) [Claims] 1. A sheet feeding section provided with a pick roller (46) which presses and engages with a stacked body so as to sequentially feed sheets and forms from the stacked body (S);
A sheet separating unit provided with a torque limiter (60) and a separation rolling element (72) rollingly engaged with the torque limiter (60) for separating and sending out forms one by one; A pick for increasing the applied load when feeding the paper and the form at the paper feeding section asynchronously with the operation of the paper separating section and reducing the load at the time of separating the paper and the form at the paper separating section. Roller load changing means (52,5
4) In the paper feeder provided with the pick roller, the pick roller load changing means (52, 54) includes an electromagnet (5
A paper feeder, wherein the load of the pick roller is changed by changing the magnetic force of the electromagnet in a non-contact state by using 4). 2. A drive connection mechanism for driving the pick roller at the time of feeding out sheets and forms at the sheet feeding section, and interrupting the drive of the pick roller at the time of separating sheets and forms at the sheet separation section. The paper feeding device according to claim 1, wherein the paper feeding device is provided.