JPH0466431A - Sheet feeding device - Google Patents

Abstract

PURPOSE:To facilitate the feeding of various sheets in an automatic manuscript feeding device by rotating a separating member having a separate face having the plural coefficients of friction to alter the separate face acting on the sheet when the feeding of the sheet can not be detected even after the lapse of specified time. CONSTITUTION:A separating member 6 is formed of plural separate faces 6a-6d having the different coefficient of friction. When a sheet P is fed, a sheet feed sensor 51 detects the fed sheet, and observes its feeding state. When the sheet feed sensor 51 has not detected the sheet P within a fixed time, the separate face to be abutting on the sheet P at present, for instance 6a is judged to be unsuitable, and a command is given to adopt the separate face having the following coefficient of friction for instance 6e as an abutting position. Thus a separating member changing means rotates a separate roller shaft 7 to rotate the separating member 6 so that a designated separate face may abut on the above position.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Industrial Application Field The present invention is based on the difference in the coefficient of friction between the sheet feeding section and the separating member that contacts this feeding member with a predetermined separating pressure. Regarding Sea 1 to feeding device that separates and conveys sheets,
More specifically, the present invention relates to a sheet feeding device having a separation member having at least two separation surfaces with different coefficients of friction.

(B) Prior Art An example of a conventional sheet feeding device of this type using a friction separation method is not shown in FIG.

In the figure, a notched circular call-out roller 12 fixed to a spindle 11 is disposed downstream of a sheet stacking table (original table) 10 on which a plurality of original sheets P are set. This calling roller 12 is connected to the lower guide plate 1.
The large diameter part extends from 3. The calling roller 12 has
A seat presser 17 whose base is pivoted to an upper guide plate 16 via a shaft 15 is in pressure contact with the sheet presser 17.
A compression spring 19 is disposed between the upper guide plate 16 and the upper guide plate 16 to urge the sheet presser 17 toward the pick-up roller 12 side.

On the downstream side of the pick-up roller 12, there is provided a feed roller 2 which is fixed to a spindle 3 and rotates in the direction of arrow 5 by a drive source (not shown) to feed the document (■). A conveying roller pair 20 consisting of a driving roller 20a and a driven roller 20b rotating in the direction of the arrow is provided. Separation pad 21 whose free end is in contact with the feeding roller 2
The base of the leaf spring on the lower surface side is fixed to a support member 23 provided on the main body cover 22. The base is supported by the shaft 2
The free end of the suppressing plate 26 pivotally connected to the support shaft member 23 by 5 is in contact with the separation pad 21, and this pressing plate 26 is located between the fixing member 27 provided on the body cover 22 and the pressing plate The separation pad 21 is pressed against the feeding roller 2 by the elasticity of a separation spring 29 formed of a compression spring.

Here, the friction coefficient of the feeding roller 2 with respect to the original P is set to be larger than the friction coefficient between the originals P, and the friction coefficient of the separation pad 21 with respect to the feeding roller 2 is set to be smaller than the friction coefficient between the originals P. has been done. When the calling roller 12, the feeding roller 2, the pair of conveying rollers 20, etc. are rotated with a plurality of documents P set on the sheet stacking table 10, most of the documents P are regulated by the sheet presser 17 and are moved to the lower side. The document P is conveyed to the feeding roller 2. The transported document P is transferred between the feeding roller 2 and the separation pad 21.
The sheets are separated and fed one by one due to the difference in the coefficient of friction between the two sheets, and are further transported in the direction of arrow 30 by a pair of transport rollers 20.

(c) Problems to be Solved by the Invention However, in the conventional sheet feeding device described above, the separation pad 21 for separating the document P has one friction coefficient selected and determined through repeated experiments, etc. Since the paper is made up of several members, it is difficult to pass through the paper if it is thin paper or thick paper, so the paper is biased toward one of the two. In addition, the range of types of sheets fed is narrow overall, and some sheets may not be fed.

In particular, when a sheet feeding device is used as a document feeding device, there is no universal separation pad 21 for all types of documents, and there are many methods for selecting and testing the friction coefficient of the separation pad 21. required a lot of effort. Also,
The feeding performance of a sheet feeding device is greatly influenced by differences in the environment in which the sheet feeding device is used, and there are currently no conditions that satisfy all conditions. The most common complaint was that it was a sheet feeding device that fed sheets as manuscripts.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a sheet feeding device in which a separation member having a plurality of separation surfaces having different coefficients of friction is provided, and sheets are separated by a separation surface suitable for the sheets being fed. This is the purpose.

(d) Means for Solving the Problems The present invention has been made in view of the above-mentioned circumstances, and is illustrated with reference to, for example, FIGS. , a feeding member (2) that is driven in a direction to feed a plurality of sheets (P) one by one; and a device that detects the sheets (P) fed by the feeding member (2). A sheet feeding device (1) comprising a sheet feeding sensor (51) disposed downstream of the feeding member (2).
), the sheet (P
) and a separating member (6) having separating surfaces (6a to 6d) with at least two or more different coefficients of friction (μa to μd), and a contact position of the separating member (6) command means (39, 53) for setting the command means (39, 53);
39, 53), the separation surface (6) of the separation member (6)
a to 6d) to a predetermined separation surface (6a to 6d), the feeding member (2)
When the sheet (P) fed by is not detected by the sheet feeding sensor (51) after a predetermined time (1) has elapsed, the separating surfaces (6a to 6d) of the separating member (6) are control means (70) for controlling the separation member changing means (4) to switch to the separation planes (6b to 6d);
It is characterized by having the following.

In addition, switching of the separation surfaces (6a to 6d) of the separation member (6) is performed so that the separation surfaces (6a to 6d) have a high coefficient of friction (μa to μd).
It is characterized in that it is carried out along separation surfaces (6b to 6d) having a low coefficient of friction.

Separation surfaces (6a to 6) of the set separation member (6)
d) information corresponding to (40a to 40d, 55a to 5
5d, 57a to 57d) Display means for displaying (4
0, 55, 57).

Further, one (6d) of the separation surfaces (6a to ad) is characterized in that it is a separation surface with a low friction coefficient that is smaller than the friction coefficient of the sheet (P) being fed.

(f) Effect Based on the above configuration, when the sheet (P) is inserted between the feeding member (2) and the separating member (6), the feeding member (2)
When receiving the feeding action from the sheet feeding sensor (51), if separation and feeding by the separating surface (6a) of the separating member (6,) is not detected by the sheet feeding sensor (51) in a predetermined period (1),
Assuming that the separation surface (6a) in contact with the feeding roller (2) has a friction coefficient μa suitable for the sheet (P) being fed, the separation surface (6b) has the following different friction coefficient μb. The contact position changes. In this state, the sheet (P) is fed again by the feeding roller (2), and this feeding operation is repeated until it is properly carried out.

Furthermore, when switching from the separation surface (6a to 6d) of the separation member (6) to another separation surface, the separation surface (6a
) along the lower separation plane (6b, 6c). As a result, separation planes (6a to 6d) with friction coefficients (μa to μd) suitable for the fed sheet (P) are sequentially determined. Also, if the separation surface is suitable for the sheet (P), information corresponding to the separation surface (for example, sheet thickness, etc.)
is displayed on the display means (40, 55, 57), etc.

Moreover, one separation surface (6d) of the separation member (6) is
It has a coefficient of friction (μd) lower than the coefficient of friction (μp) of the sheet (P) being fed, and as a result, the sheet (P) that has not been separated and fed by another separation surface can be separated by manual operation. Feed roller (2) and separation member (6) one by one
It becomes possible to easily insert and feed between the two.

(F) Example Hereinafter, an example of an automatic document feeder (hereinafter referred to as ADF) as a sheet feeder of the present invention will be described based on the drawings. Components having the same functions as those shown in FIG. 18 are denoted by the same reference numerals, and their explanation will be omitted.

FIGS. 1 and 2 show an apparatus (ADF) for feeding a document P in the form of a sheet. In the figure, a support shaft 3 to which a feeding roller (feeding member) 2 is fixed is pivotally supported by a pair of side plates 31 and 32 via bearings, respectively, as shown in FIG. A sheet conveyance motor 33 (see FIG. 13) as a drive source is attached to one end of the support shaft 3 (see FIG. 13).
A gear 35 connected to is fixed.

A separating member 6 fixed to a separating roller shaft 7 is in pressure contact with the feeding roller 2 as will be described later. They are each pivotally supported via. As shown in FIG. 3, the separating member 6 has at least two (four in this embodiment) different friction coefficients μ on the circumferential surface of the base roller 6A.
It consists of separated surfaces 6a to 6d having sizes a to μd fixed to each other. A pair of support members 34a fixed to the inner surfaces of the side plates 31 and 32 are each provided with a leaf spring 34b that presses the upper part of the separation roller shaft 7, and the elasticity of the leaf spring 34b causes the separation member 6 to be obtains separation pressure for the feed roller 2.

The friction coefficients μa to μd of the separation surfaces 68 to 6d are μC
〉μb〉μC〉μC. In particular, the last friction coefficient μd is selected to be a low friction coefficient such that μd≦μp with respect to the friction coefficient μp between documents P. For example, a member such as Mylar is used as the separation surface 6d having a low coefficient of friction μd. This separating surface 6d is not capable of separating double-fed originals P, and is particularly used when the originals P are manually fed one by one.

Furthermore, if μm is the friction coefficient of the feeding roller 2 with respect to the original P, then μm>μC, and the above μC is μC>μp(
(friction coefficient between originals). The separation member 6 is rotated by a command means to be described later, and one of separation surfaces 68 to 6d having a predetermined coefficient of friction is selected and pressed against the feeding roller 2.

1. At the end (right end in the figure) of the separation roller shaft 7 extending from the side plate 32, there is a gear 37 integrally formed with the position detection plate 36 (see FIG. 9); A knob (command means) 39 for manual operation for rotating the separating member 6 as described later is fixed to each. The above arrow 30 is
Feed roller 2 (This is for detecting the separation surfaces 68 to 6d that are pressurized. The outer peripheral surface 39a of this knob 39
As shown in FIG. 5, there is written information corresponding to the friction coefficients of the separation surfaces 68 to 6d of the separation member 6 that are in pressure contact with the feeding roller 2.

That is, characters 40a to 40d representing the type of document P to be separated by the selected separation planes 68 to 6d are displayed on the display 40. Above characters 40a-4
0d corresponds to each separation surface 6a to 6d of the separation member 6. For example, when feeding a document P made of plain paper, the corresponding separation surface 6b is connected to the feeding roller as will be described later. 2 and the characters 40b are displayed on the display section 40.

The knob 39 can be rotated from the outside of a window 22a provided in the main body cover 22 as shown in FIG.
0d is visible from the display unit 40. moreover,
A plurality of click recesses 39b are formed in the circumferential surface 39a of the knob 39, as shown in FIG. By engaging the free end of the knob 42, the selectively rotated position of the knob 39 is maintained.

The opposite extending end of the separation roller shaft 7 is attached to a bearing 45 via a one-way rotation clutch 43, and this bearing 45 is attached to a support member 4 fixed to the side plate 31.
5 so that it can be moved up and down within an appropriate range. Due to the action of the one-way rotation clutch 43, the separating member 6 rotates only in the direction of arrow 9 in FIG. 1, and is prevented from rotating in the opposite direction. Note that when the separation member 6 rotates in the direction of arrow 9, the separation surface 6a has a high coefficient of friction, and the separation surfaces 6b, 6 have gradually lower coefficients of friction.
The separating surfaces 6a, 6b, 6c, and 6d are arranged so as to come into pressure contact with the feeding roller 2 in this order.

As shown in FIG. 2, a gear 49 is fixed to the end of the support shaft 11 to which the above-mentioned pick-up roller 12 is fixed.
(see Figure 3). As shown in FIG. 1, on the upstream side of the calling roller 12, a sheet presence/absence sensor 5 is provided for detecting the presence or absence of a document P on the sheet stacking table 10.
This sheet presence/absence sensor 50 is connected to a sensor lever 50a that is rotated by the document P and a sensor lever 50a that is rotated by the document P.
It consists of a photointerrupter 50b that turns on and off.

Further, on the downstream side of the feeding roller 2, a sensor lever 51a is provided.
A sheet feeding sensor 51 consisting of a photointerrupter 51b and a photointerrupter 51b is also provided. This sheet feeding sensor 51 detects the original 1'JP fed by the feeding roller 2, and determines whether or not the original P is properly separated by the separation surfaces 68 to 6d that are currently being pressed. , that is, during pressure welding
This is to detect whether or not the separation surfaces 6a to 6d are suitable for the document P being fed.

The separating surfaces 6a to 6d to be brought into pressure contact with the feeding roller 2 can be set by manually operating the knob 39 as described above, or this setting can also be done by using the keyboard shown in FIGS. 7 and 8. In the same figure, a keyboard 53 for setting separation surfaces 6a to 6d to be used is provided on the negative side of a printer (image forming apparatus) to which an ADF (automatic document feeder) is applied as a sheet feeding device. or is arranged. As shown in FIG. 8, this keyboard 53 has operation buttons 56 (56a to 56a to
56d) and a display section 57 that displays the operated items using characters 57a to 57d.

This display section 57 displays the set operation button 5.
6a to 56d may be illuminated, or the corresponding characters 57a to 57d on the display section 57 may be illuminated from the back side to make them visible. Further, when the operation button 56 is operated, the status of the separation surfaces 6a to 6d may be displayed using the LCD display section 55 as shown in FIG.

When setting the separation plane using the keyboard 53, a driving force is required to drive the separation member 6 in response to the operated operation button 56, and this driving force is provided by the gear 37 (first gear) integrated with the separation member 6. (see Figure 2) by transmitting the rotation of the motor 59.

In addition, in order to detect the separation surfaces 6a to 6d that are in pressure contact with the feeding roller 2, a plurality of separation surface detection sensors 52 (52a to 52d) are arranged at predetermined positions as shown in FIG. 9(b). The separation surface detection sensor 52 is configured to be detected by a flag 36a provided on the position detection plate 36. The relationship between the positions of the separation surface detection sensors 52a to 52d and the separation surfaces 68 to 6d is shown in FIG. 9(b).
, are arranged correspondingly as shown in (C).

A command means 4 for setting the abutting position of the separation member 6 using the aforementioned knob 39 and the arrow 5 is also included.

FIG. 11 shows a mechanism for changing the separation pressure of the separation member 6.

In the same figure (a), an eccentric cam 60 is fixed to the separation roller shaft 7 which is integrated with the separation member 6.
A pressure member 61 is in pressure contact with the upper part of 0 by the elasticity of a tension spring whose one end is locked to a bell 63. This pressure member 61 is pivotally supported by a support shaft 62, and its upper end is connected to a solenoid 67 via a connecting member 66.

When the solenoid 67 is in the OFF state, the separation member 6 is pressed against the feeding roller 2 by the separation pressure generated by the elasticity of the tension spring 65, and the rotation of the separation member 6 causes the separation surface 68 to
When 6d is switched as described later, the separation pressure against the feed roller 2 is also changed by the action of the eccentric cam 600.

When changing the separation surfaces 6a to 6d of the separation member 6,
Since separation pressure is acting on both the separation member 6 and the feeding roller 2, the solenoid 67 is operated to maintain the separation pressure when switching the separation surfaces 68 to 6d so as not to put a load on the driving means such as the motor. is released to facilitate rotation of the separation member 6.

Alternatively, as shown in FIG. 11 (tl), the separation pressure can be changed by providing an Archimedes cam 71 on the separation roller shaft 7 and bringing the roller 61a provided on the pressure member 61 into pressure contact with the Archimedes cam 71.Separation member Since the elasticity of the tension spring 65 changes as the Archimedes cam 71 rotates together with the rotation position of the separation member 6, that is, the separation surfaces 68 to 6d
The separation pressure of the separation member 6 is changed in accordance with the switching of the pressure contact.

The above-mentioned position detection plate 36, one-way rotation clutch 43, sheet feeding sensor 51, separation surface detection sensor 52 and timer 69, CPU 70 (see FIG. 13) use the shade to control the road separation surface of the separation member 6 by the command means 4. Separation member changing means 4 for switching 68 to 6d to predetermined separation surfaces is mounted together.

Next, the operation of the automatic document feeder configured as described above will be explained with reference to the flowcharts shown in each of the above-mentioned figures, FIGS. 14 and 15. In addition, Figure 14 is the manuscript P.
FIG. 15 shows a flowchart for a case in which original documents P are loaded together.

First, the same type loading mode will be explained. When a plurality of documents P are placed on the sheet stacking table 10 and inserted, this is detected by the sheet presence/absence sensor 50. If the start operation is performed here, the sheet conveyance motor 33 shown in FIG.
rotates, the calling roller 12, the feeding roller 2, the pair of conveying rollers 20, etc. start rotating, and one sheet of the document P or a plurality of sheets taken out are fed to the feeding roller 2.

Before separating the documents P, the separation member 6 is normally in a state in which the separation surface 6a having the largest coefficient of friction is in pressure contact with the feeding roller 2 (81), and the separation surface 6a is returned to the original position. (home position). Among the documents P to be fed, there are thin documents that are difficult to separate and feed as documents P that are suitable for separation by the separation surface 6a having a large friction coefficient.
Next are normal manuscripts, thick manuscripts, etc.

Referring to FIG. 10, the separation operation of the original P will be explained. The document P located between the feeding roller 2 and the separating member 6 is separated by the feeding roller 2 and the separating member 6, which rotate in the directions of the arrows, respectively, in response to a paper feeding command by operating the start button, and the rotational speed of the feeding roller 2 increases. Move at the same speed as the arrow 3, or if there is a slip, move at a speed slightly slower than the rotation speed.
When the sheet moves in the 0 direction and is detected by the sheet feeding sensor 51 and is further conveyed by the pair of conveying rollers 20, the rotation of the feeding roller 2 is stopped.

Here, whether the document P that is being fed by slipping or the feed roller 2
The sheet feeding sensor 51 is inserted from the pressure contact position between the separating member 6 and the separating member 6.
If t is the time it takes to reach the sensor lever 51a of Become.

In this case, paper feeding is temporarily stopped, and the separation member 6 is rotated in the direction of arrow 9 by the motor 59, and this rotation is stopped by detection by the separation surface detection sensor 52. here,
The same separation action is repeated by rotating the feeding roller 2 again. In this way, by sequentially changing the separation surfaces 68 to 6d, if the document P is fed, it is OK, or if the document P is not fed, a warning (alarm sound, lamp lighting) is issued and the LCD display 57 etc. will be displayed.

As described above, when the separation surfaces 6a to 6d are automatically switched and set using the time t as a parameter and paper feeding is finished, the separation member 6 must be returned to its original position.

To explain the above operation along FIG. 14, an attempt is made to separate the document P on the separation surface 6a (side a) of the separation member 6 by the rotation of the feeding roller 2 (S2), and the document P is separated. If so, the process continues as it is and the paper is fed until the paper runs out (510), and the process ends (Sll).

If the separation by the separation surface 6a is not performed in (S2), the separation member 6 rotates due to the rotation of the sheet conveyance motor 33, and the separation surface 6b comes into pressure contact with the feeding roller 2 (S3). This state is detected by the separation surface detection sensor 52b in FIG. 9(b), the separation member 6 is stopped, and the display is displayed on the display section 57 or the display section 55 or the like.

If the document P is separated by the separation surface 6b in (S4), the paper continues to run out (5IO), and paper feeding continues until the paper runs out (Sll).
If separation is not possible in S4), the separating member 6 is rotated in the same manner as in the above (S2), and the next separating surface 6c comes into pressure contact with the feeding roller 2, and in S5), the document P is separated by the separating surface 6c ( S6). If separation can be performed, the paper is fed to 510) without any paper.

If separation is not possible in the above (S6), in this case, the separation member 6 will not automatically rotate and the paper feed will stop (S7).
). This non-separable state is indicated by an alarm or the like, and when displayed on the display section 55 (see FIG. 5), characters 55d1 are displayed. In this state, the operator operates the single-sheet document operation button 56d (see FIG. 8), thereby rotating the separating member 6 and bringing the separating surface 6d into pressure contact with the feeding roller 2 (S8). In the single original mode, the character 55d on the LCD is displayed as shown in Figure 6(d).
will be displayed.

Here, the single-sheet mode refers to a part of the separation member 6 (separation surface 6
d) is made of a material with a low friction coefficient, such as Teflon, and means that one document P can be fed without fail. The single-sheet mode is a mode that is facilitated when the original P is not fed even after changing the friction surface (separation surface) of the separation member 6, and is set at the end of switching the separation surfaces 68 to 6d. mode. Separation surface 6 as above
Switching between a to 6d is achieved by sequentially arranging and rotating the friction coefficients from the one with the largest coefficient of friction to the one with the smallest coefficient of friction, and this switching is performed automatically to enable paper feeding.

In the second one-sheet mode, the document P is inserted and fed one by one into the feeding roller 2 by the operator's manual operation (S9).
. During manual paper feeding, the friction coefficient μd between the separating surface 6d and the original P is set to be smaller than the friction coefficient μp between the originals P, so if multiple originals P are inserted into the cage, The document P continues to be fed in duplicate.

In other words, the separation surface 6d is set to have a coefficient of friction small enough to allow manual paper feeding, making it easy to feed one sheet at a time.

Furthermore, since the document P used is generally plain paper, the separation member 6b can be set by operating the knob 39 or the keyboard 53 in advance before starting paper feeding. In the separation process, the separation surface 6a is omitted and the separation action is started using the separation surface 6b (plane b), thereby saving working time.

Next, the document P is separated using each of the separation members 6 (Sl
l) When the process is finished, it is checked whether or not there are any keys on the keyboard 53 (S12). When there is a key input, the separation member 6 returns to its original position (home position) and starts the separation operation from (Sl) using the separation surface 6a. (
312), if there is a key input, it is checked whether the input is on the separation surface 6b (plane b). If the input is on the b side, the process returns to (S3) and the separation of the original P by the separation surface 6b is started, and if the input is not the b side, the process returns to (S5) and the separation of the original P by the separation surface 6C is started. .

FIG. 15 shows a flowchart of a so-called mixed loading mode in which each document P has different properties. In this figure, the sequential switching of the separation surfaces 68 to 6d when the document P cannot be separated at the start of paper feeding is the same as the same type loading mode in FIG. 13, and therefore the explanation thereof will be omitted.

The difference between this mixed loading mode and the same type loading mode described above is that the originals are
If separation is performed, one sheet of document P is fed (S1
4), the presence or absence of the document P is checked (S15) and the settings are changed. If there is a document P in (S15), it always returns to the original position (Sl), repeats the same process again, and then feeds only one sheet. When the document P continues to be fed and the document P runs out (Sll), the process ends, and the separating member 6 returns to its original position and stops.

By feeding the original P in this way, the original P
Sheet loading table 10 with a mix of paper types or different types
Even if the document is set to 1, the setting of the separation member 6 of the ADF changes accordingly, so documents P having a mixture of different properties can be set with confidence.

In the case of feeding the above-mentioned mixed documents P, operate the operation button 56 of the keyboard 53 shown in FIG.
It is also possible to predetermine the initial position of , and in this case, the separation member 6 returns to its original position at the above-determined position of the separation plane. As a result, when feeding paper, the separating action of the separating member 6 does not have to start from thin paper, but can also start from plain paper original P or thick paper original P, skipping the previous stage. Paper feeding work can be performed efficiently.

In addition, when the paper quality of the original P changes and the separation surface of the separation member 6 is changed as described above, the separation pressure suitable for the separation surface to be used is adjusted using the separation pressure switching means as explained in FIG. 11. It is also possible to change them at the same time.

FIG. 16 and FIG. 17 show the second sheet feeding device of the present invention.
An example of this is shown.

In this embodiment, instead of the rotatable separation member 6 in the above-described embodiment, a plurality of pressure members 72 and separation pads 80a to 80 with different friction coefficients are provided on the pressure members 72, respectively.
0c is used.

In the figure, a plurality of V-shaped pressure members 72 whose bases are pivotally supported on a support shaft 73 are biased clockwise in the figure by tension springs each having one end latched to a shaft 79. . The lower edge of the upper arm of each pressure member 72 is connected to a plurality of eccentric cams 7 each fixed to a cam 76.
5a to 75c, respectively. Each pressure member 72
Separation pads 80a to 80c are selectively or combinedly pressed against the circumferential surface of the feeding roller 2 and spaced apart from each other by m.
or each is fixed. In this embodiment as well, the command means for press-contacting the separation pads 80a to 80c is the same as in the previous embodiment, and the converting means for switching the pressure-contact separation pads is one, driven by the motor 59 connected to the camshaft 76. or some separation pads 80 (80a~
80C) are brought into contact with or separated from the feeding roller 2 in descending order of friction coefficient, thereby feeding documents P of a wide range of paper qualities.

(G) As described in detail, according to the present invention, a separating member for separating sheets is provided with a plurality of separating surfaces having different coefficients of friction, and the separating surfaces with high friction coefficients are used to separate sheets. When feeding is not performed within a predetermined time despite the feeding action of the feeding roller, the separation surface is sequentially switched to a separation surface with a different friction coefficient, so that it is possible to feed the sheet using the separation surface that is suitable for the sheet. Therefore, it can be widely used to feed various types of sheets.

In addition, since the friction coefficient of one of the separation surfaces is lower than the friction coefficient between sheets, manual feeding of sheets one by one, that is, feeding rollers that are in contact with each other, and separation members between The sheet insertion operation can be easily performed.

[Brief explanation of drawings]

FIG. 1 is a vertical side view of a sheet feeding device in which an embodiment of the present invention is applied to an automatic document feeding device, FIG. 2 is a developed plan view of the same, and FIG. 3(a) is a vertical side view of a separation member. , Figure 3 (
b) is a front view, FIG. 3(c) is a developed view showing another example of the separating member, FIG. 4(a) is a longitudinal cross-sectional side view of the manual knob part, and FIG. 4(b) is a front view. Similarly, FIG. 5 is a plan view showing the display section 40 provided on the knob, FIG. 6 is a plan view of the display section during keyboard operation, and FIG. 7 is an image forming apparatus to which the present invention is applied and its keyboard. 8 is an enlarged plan view of the keyboard, FIG. 9(a) is a position detection plate and a vertical side view of the position detection plate, FIG. 9(b) is a front view, and FIG. 9(c) is a plan view of the keyboard. ) is also a positional relationship diagram of the separation member with respect to the separation surface detection sensor, Figure ]0 is an operational view of the device in Figure 1, Figure 11(a) is a longitudinal cross-sectional side view of the separation pressure release mechanism, and Figure 11fb). 12 is a timing chart of the rotation of the paper feed roller and sheet detection after feeding, FIG. 13 is a block diagram of the control unit of the present invention, and FIG. 14 is a side view showing another example of the separation pressure release mechanism. 15 is a flowchart when sheets of the same type are loaded, FIG. 15 is a flowchart when sheets are mixedly loaded, FIG. 16 is a longitudinal cross-sectional side view of a sheet feeding device showing a second embodiment of the present invention, and FIG. 17 is the same. Developed plan, No. 18
The figure is a longitudinal side view showing an example of a conventional sheet feeding device. P... Sheet (original) t... Time from the start of sheet feeding until it is detected 2... Feeding roller (feeding member) 4... Separation member changing means, 6.
...Separation members 6a to 6d...Separation surface 33...
Sheet conveyance motor 37...Gear 39...Knob 39.53...Command means 40...Display section
40a to 40d... Display characters, 43... One-way rotation clutch (clutch member), 50... Sheet presence/absence sensor 51... Sheet feeding sensor 52...
Separation surface detection sensor 53...Keyboard 55a~
55d...Display characters 56...Operation buttons
57a to 57d...Display characters 59...Motor 60.61...Separation pressure release means, 70...CPU
, 72... Pressure member (separation member) 75a to 75
c...Cam 80a-80c...Separation pad.

Claims (1)

[Scope of Claims] 1. A feeding member that is driven in a direction to feed a plurality of set sheets one by one, and a device that detects the sheets fed by the feeding member, and a sheet feeding device having a sheet feeding sensor disposed on the downstream side of the feeding member, the sheet feeding sensor separating the sheets by contacting the feeding member, and having at least two or more different coefficients of friction; A separation member having a separation surface, a command means for setting a contact position of the separation member, and a separation member changing means for switching the separation surface of the separation member to a predetermined separation surface according to a command from the command means, When the sheet fed by the feeding member is not detected by the sheet feeding sensor after a predetermined time t has elapsed, the separating member changing means is controlled to switch the separating surface of the separating member to a separating surface having a different coefficient of friction. What is claimed is: 1. A sheet feeding device comprising: a control means for controlling a sheet; 2. The sheet feeding device according to claim 1, wherein the separation surface of the separation member is switched from a separation surface with a high coefficient of friction to a separation surface with a low coefficient of friction. 3. The sheet feeding apparatus according to claim 1, further comprising a display means for displaying information corresponding to the set separation surface of the separation member. 4. The sheet feeding device according to claim 1 or 2, wherein one of the separation surfaces is a separation surface with a low friction coefficient smaller than the friction coefficient of the sheet to be fed.