JPH07315595A - Paper feeding device for printer - Google Patents

Abstract

PURPOSE:To provide a paper feeding device for printers, which can surely feed paper sheets by detecting the shift amount of a cut paper sheet, judging the slide between a paper sheet feeding device and the cut paper sheet based on the shift amount and also providing a paper sheet changing means to change the contact condition between the paper sheet feeding roller and cut paper sheet based on sliding information. CONSTITUTION:The moment a cut paper sheet 2 is fed, a detection roller 7 is also turned in the direction of the arrow C, and the detected turning amount becomes shift amount information P through an encoded and a photocoupler and is input in a CPU 11A. The slide judging means in the CPU 11A judges whether the slide amount SL exceeding slide boundary value SLO has been caused or not, and if SL>SLO, the slide judging means judges that slide has been generated. The paper feeding changing means in the CPU 11A stops the generation of motor driving pulses MP for a specific delay time to stop the sliding state caused between the cut paper sheet 2 and the paper sheet feeding roller 5. After the elapse of delay time, a motor 6 is restarted to rotate the paper sheet feeding roller 5 again.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeding device for printers used in thermal transfer printers, electrophotographic printers, etc., and in particular, it is possible to feed paper without maintenance even if the paper feeding roller becomes dirty due to long-term use. Further, the present invention relates to a paper feeding device for a printer, which can feed paper even under adverse conditions in which papers are attracted by static electricity or the like.

[0002]

2. Description of the Related Art FIG.
FIG. 7 is a perspective view showing a main part of a conventional printer paper feeding device described in Japanese Patent Laid-Open No. In the figure, reference numeral 1 is a paper cassette of a paper feeding device for a printer, and 2 is a cut sheet stacked and accommodated in the paper cassette 1. Reference numeral 3 denotes a sheet separating claw provided at an end portion of the paper cassette 1 on the sheet feeding direction (arrow A) side, and separates the cut sheets 2 one by one when the cut sheets 2 are fed.

A paper cassette 1 in which cut sheets 2 are stacked and housed as shown in FIG. 14 is a printer body (not shown).
The cut sheets 2 are attached to the printer apparatus main body one by one. FIG. 15 is a schematic diagram showing a conventional printer paper feeding device, and 4 is a pressing spring for urging the stack of cut sheets 2 upward.

Reference numeral 5 denotes a sheet feeding roller provided on the upper portion of the paper cassette 1 and having a half-moon shape in cross section, which is rotatable in the direction of arrow B, and is arranged such that the outer periphery thereof contacts the cut sheet 2 at the time of rotation. ing. 6 is a motor for driving the paper feed roller 5 to rotate, 10 is a motor drive device that supplies electric power to the motor 6 to drive and control the motor 6, and 11 is a CPU that outputs a paper feed command MD to the motor drive device 10. Is. The paper feed roller 5 to the CPU 11 are provided in the printer body.

Next, the operation of the conventional printer paper feeder shown in FIGS. 14 and 15 will be described. First, the CPU 11 in the printer apparatus main body drives the motor drive device 10 in response to the paper feed command MD to rotationally drive the motor 6 to rotate the paper feed roller 5 in the arrow B direction.

On the other hand, the cut paper 2 in the paper cassette 1
Is urged upward by the pressing spring 4, so that the uppermost one is sequentially fed every time the paper feeding roller 5 is rotated. At this time, the sheet separation claw 3 separates the cut sheets 2 one by one, and prevents the cut sheets 2 from being fed (that is, double-fed) while being stacked.

However, in the printer paper feeding device, when a large number of printing operations are performed and the paper feeding roller 5 becomes dirty due to long-term use, the coefficient of friction μ of the paper feeding roller 5
And the paper feed error tends to occur. In addition, under adverse conditions in which the cut sheets 2 are easily attracted to each other due to static electricity,
A phenomenon (see FIG. 15) occurs in which the cut sheet 2 is prevented from coming off the sheet separating claw 3 of the paper cassette 1, and similarly, a paper feeding error is likely to occur.

Therefore, in order to prevent such a paper feed error, maintenance work such as periodic cleaning of the paper feed roller 5 and the like is indispensable. Further, in order to prevent a paper feeding error, if the biasing force of the pressing spring 4 is increased to increase the paper feeding force of the cut sheet 2,
A double feed phenomenon in which a plurality of cut sheets 2 are fed while being stacked is likely to occur. Further, since the movement amount of the cut sheet 2 at the time of feeding the sheet is not accurately managed, a jam phenomenon of the cut sheet 2 or the like occurs in the sheet feeding unit.

[0009]

As described above, the conventional printer paper feeding device is used for a long period of time when the paper feeding roller 5 is used.
If the cut paper 2 becomes dirty and the friction coefficient μ decreases, or if the cut papers 2 are attracted to each other due to static electricity or the like, no measure is taken to prevent a paper feed error of the cut papers 2.
There is a problem that regular maintenance work for the paper feed roller 5 and the like is required.

Further, even if the urging force of the pressing spring 4 is increased to increase the paper feeding force, there is a problem that the double feeding phenomenon easily occurs and the paper feeding error cannot be improved. further,
Since the movement amount of the cut sheet 2 at the time of feeding cannot be accurately managed and grasped, there is a problem that a jam phenomenon of the cut sheet 2 occurs.

The present invention has been made in order to solve the above problems, is maintenance-free even when used for a long period of time, and can feed sheets even if cut sheets are attracted to each other due to static electricity or the like. Further, it is another object of the present invention to obtain a printer paper feeder capable of accurately managing and grasping the movement amount of the cut paper to surely feed the paper.

[0012]

According to a first aspect of the present invention, there is provided a paper feeding device for a printer, comprising: a paper cassette in which cut sheets to be supplied to the printer are stacked and housed; In a paper feeding device for a printer, which is provided with a paper separating claw provided and a paper feeding roller having a half-moon shape in cross section, which is provided on an upper portion of a paper cassette and is arranged so that an outer periphery thereof is in contact with a cut paper when rotating The detection roller that is installed behind the paper feed roller in the direction and that detects the amount of movement of the cut paper by contacting the uppermost cut paper in the paper cassette, and the paper feed roller based on the movement of the cut paper. And a paper feed changing means for changing the contact state between the paper feed roller and the cut paper in response to the slip information from the slip determining means. Than it is.

Further, according to a second aspect of the present invention, in the first aspect of the present invention, the paper feed changing means intermittently rotates the paper feed roller in response to the slip information. .

According to a third aspect of the present invention, there is provided a printer sheet feeding device according to the second aspect, which comprises a motor for driving the sheet feeding roller and a clutch connected to the motor. The clutch is intermittently controlled in response to the slip information.

According to a fourth aspect of the present invention, in the paper feeding device for a printer according to the second or third aspect, the paper feeding changing means changes the driving speed of the paper feeding roller in response to the slip information. It is a thing.

A printer paper feeding device according to a fifth aspect of the present invention is the printer paper feeding device according to any one of the first to fourth aspects, further comprising a pressing means for pressing the cut paper in the paper cassette against the paper feeding roller. The paper feed changing means controls the pressing force of the pressing means in response to the slip information.

According to a sixth aspect of the present invention, there is provided a printer paper feeding device according to any one of the first to fifth aspects, wherein the detection roller is an electrically grounded conductive roller. Is.

[0018]

According to the first aspect of the present invention, the movement of the sheet is detected based on the information of the detection roller with respect to the movement of the sheet feeding roller to determine the slip between the sheet feeding roller and the cut sheet.
In response to the slip determination result, the contact state between the paper feed roller and the cut paper is changed to feed the paper under the optimum paper conveyance conditions, and the paper movement amount is measured and controlled to reliably feed the paper.

Further, according to the second aspect of the present invention, the rotation of the sheet feeding roller is intermittently controlled in response to the result of slip determination, and the maximum static friction force is repeatedly applied between the sheet feeding roller and the cut sheet. As a result, the paper is fed under the optimum paper conveyance conditions, and the paper movement amount is measured and controlled to reliably feed the paper.

In the third aspect of the present invention, the clutch connected to the motor of the sheet feeding roller is intermittently controlled to repeatedly apply the maximum static frictional force between the sheet feeding roller and the cut sheet. Thus, the paper is fed under the optimum paper conveyance conditions, and the paper movement amount is measured and controlled to reliably feed the paper.

Further, according to claim 4 of the present invention, the motor drive speed of the paper feed roller is controlled in response to the result of the slip determination, and the reduction of the paper transport speed is suppressed to the minimum while the optimum paper transport condition is satisfied. The paper is fed, and the amount of movement of the paper is measured and controlled to reliably feed the paper.

Further, according to the fifth aspect of the present invention, the pressing force of the cut sheet in the paper cassette against the feed roller is controlled in response to the result of the slip, and the optimum sheet conveyance speed is not brought about without lowering the sheet conveyance speed. The paper is fed under the conditions, and the paper movement amount is measured and controlled to reliably feed the paper.

According to the sixth aspect of the present invention, the static electricity generated in the cut sheets is released through the grounded conductive detection roller, so that even if static electricity is generated in the cut sheets, the static electricity between the cut sheets is maintained. Electro-adsorption is alleviated, and paper is easily and reliably fed.

[0024]

【Example】

Example 1. (Corresponding to Claim 1 and Claim 2) Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings. Figure 1
1 is a configuration diagram schematically showing Embodiment 1 of the present invention.
1A corresponds to the CPU 11, and 1 to 6 and 10 are the same as those described above.

Reference numeral 7 denotes a detection roller for detecting the amount of movement of the cut sheet 2, which is installed behind the sheet feeding roller 5 in the sheet feeding direction A and is located at the top of the paper cassette 1. By contacting with and rotating in the direction of arrow C, the amount of movement of the cut sheet 2 is detected. An encoder 8 is provided coaxially with the detection roller 7 and rotates integrally with the detection roller 7. Reference numeral 9 is a photocoupler for detecting the slit of the encoder 8 and transmits the rotation information of the encoder 8, that is, the movement amount information P of the cut sheet 2 to the CPU 11A as an electric signal.

In this case, the CPU 11A has the movement amount information P
The slip determination means for determining the slip between the paper feed roller 5 and the cut sheet 2, and the contact state between the paper feed roller 5 and the cut sheet 2 in response to the slip information from the slip determination means. And a paper feed changing unit for changing.

Next, the operation of the first embodiment of the present invention shown in FIG. 1 will be described with reference to the timing chart of FIG. 2 and the flowchart of FIG. In FIG. 2, the horizontal axis represents time t, and the vertical axis represents the motor drive pulse MP based on the paper feed command MD and the slip amount S based on the movement amount information P.
L and TD are delay times of the motor drive pulse MP, S
LO is a slip boundary value (an allowable upper limit value of the slip amount SL) that serves as a slip determination reference of the slip amount SL.

Now, when the printing operation of the printer main body starts, the CPU 11A outputs the paper feed command MD to drive the motor drive unit 10, and the motor drive pulse MP from the motor drive unit 10 starts the motor 6. (Step S1). As a result, the sheet feeding roller 5 rotates in the direction of arrow B, the cut sheet 2 moves in the direction A, and sheet feeding is started.

At this time, simultaneously with the feeding of the cut sheet 2, the detection roller 7 in contact with the cut sheet 2 also rotates in the direction of arrow C (step S2), and the rotation amount detected by the detection roller 7 is the encoder. The moving amount information P is input to the CPU 11A via 8 and the photo coupler 9.

As a result, the slip determining means in the CPU 11A causes the paper feed command M corresponding to the rotation command of the paper feed roller 5.
D and the movement amount information P corresponding to the movement amount of the cut sheet 2 are constantly compared, and their deviation (MD-P) is compared with the slip amount SL.
Calculate as. Then, it is judged whether or not a difference exceeding the slip boundary value SLO (see FIG. 2), that is, a slip amount SL has occurred (step S3), and if a slip amount SL such that SL> SLO has occurred, a slip occurs ( That is, it is determined as YES).

At this time, the paper feed changing means in the CPU 11A stops the motor drive pulse MP for a predetermined delay time TD in response to the slip determination result (step S4). In this way, the slipping state generated between the cut sheet 2 and the paper feed roller 5 is stopped, and after the delay time TD has elapsed (step S5), the motor 6 is restarted to rotate the paper feed roller 5 again. (Step S6), the process returns to the step S2 for driving the paper feed roller 2.

If the slip amount SL exceeding the slip boundary value SLO occurs again, the occurrence of slip is determined in step S3, and the operations in steps S4 to S6 are performed again. That is, the paper feed roller 5 is intermittently driven to rotate as long as the slip occurrence state is continuously determined.

On the other hand, in the slip determination step S3,
If it is determined that there is no slip (that is, NO), the CPU
11A feeds the cut sheet 2 by driving the feed roller 5 (step S7), and after confirming that the cut sheet 2 has been sent by a preset movement amount, prints (prints). Execute (step S8). At this time, in step S7, since the movement of the predetermined amount of the cut sheet 2 can be grasped and managed, the cut sheet 2 can be positioned with high accuracy with respect to the next conveying roller (not shown).

Further, after the printing is completed, the paper is normally discharged (step S9), and it is judged whether or not the printing command is completed (step S10). If the printing command has not ended, the process returns to the motor starting step S1 again and repeats a series of printing operations. If the printing command has ended, execution of the routine of FIG. 3 ends.

Thus, the processing by the slip determining means and the paper feed changing means in the CPU 11A (steps S3 to S)
By repeating 6), the cut paper 2 and the paper feed roller 5
The maximum static friction force is repeatedly applied between and. Therefore, due to the large friction coefficient μ, the cut sheets 2 in the paper cassette 1 are reliably fed one by one from the top regardless of adverse conditions such as the dirt state and static electricity state of the sheet feeding roller 5.

Further, based on the movement amount information P, it is possible to surely detect the end of feeding the cut sheet 2 by the predetermined amount.
Therefore, it is possible to omit maintenance, and it is possible to reliably prevent a paper feed error, a jam phenomenon, and the like.

Example 2. (Corresponding to claim 1 and claim 3) In the first embodiment, the motor drive pulse MP is intermittently stopped for the delay time TD when the slip between the cut sheet 2 and the sheet feed roller 5 occurs. The clutch between the motor 6 and the paper feed roller 5 may be intermittently released.

FIG. 4 is a schematic diagram showing a second embodiment of the present invention in which the clutch is controlled to be engaged and disengaged.
B corresponds to the CPU 11A, and 1 to 10 are the same as those described above. Reference numeral 12 is an electromagnetic clutch provided between the paper feed roller 5 and the motor 6. Reference numeral 13 denotes an electromagnetic clutch drive device that drives the electromagnetic clutch 12, and the CPU 1
The electric power CP is supplied to the electromagnetic clutch 12 according to the clutch control command CD from 1B.

Next, the operation of the second embodiment of the present invention shown in FIG. 4 will be described with reference to the timing chart of FIG. 5 and the flowchart of FIG. In FIG. 5, TD, SL and SLO are the same as described above. CP is a pulse of electric power supplied from the electromagnetic clutch drive device 13, and corresponds to the operation timing of the electromagnetic clutch 12. Further, in FIG. 6, S12 corresponds to the motor stop step S4, and S1 to S3, S4 and S7 to S10 are the same steps as described above.

When the print command is activated, the CPU 11B
A paper feed command MD is generated to start the motor 6 (step S
1) Further, the clutch control command CD is generated, the electric power CP is output from the electromagnetic clutch drive device 13, and the electromagnetic clutch 12 is connected (step S11). As a result, the supply roller 5 rotates, the cut sheet 2 moves, and the detection roller 7 rotates (step S2).

The slip determination means in the CPU 11B constantly compares the rotation command (paper feed command MD) for the paper feed roller 5 with the movement amount information P of the cut sheet 2 detected by the detection roller 7 to determine whether or not a slip has occurred. It is determined whether or not (step S3). If the slip amount SL (MD-P) based on the paper feed command MD and the movement amount information P is the slip boundary value SLO.
Slip occurs (that is, YE
S), the paper feed changing means in the CPU 11B disconnects or releases the electromagnetic clutch 12 for the delay time TD (step S12).

Subsequently, in step S5, the driving force of the motor 6 is not transmitted to the sheet feeding roller 5 for the delay time TD, and the slippage between the cut sheet 2 and the sheet feeding roller 5 is stopped. . Then, step S11
Then, the electromagnetic clutch 12 is reconnected and the paper feed roller 5 is rotated. Therefore, similarly to the above, the maximum static frictional force is repeatedly applied between the cut sheet 2 and the sheet feeding roller 5, and the cut sheet 2 is reliably fed.

The processes of the clutch engagement step S11 to the delay time step S5 described above are repeated until the slip amount SL does not exceed the slip boundary value SLO, and in the slip determination step S3, SL≤SLO (that is, NO) is determined. Then, the above-mentioned normal printing step S
The processing of 7 to S10 is executed.

In this case, since the motor drive pulse MP is constantly output and the motor 6 is rotating at a constant speed without being stopped, as compared with the first embodiment in which the motor 6 is restarted,
The operation of the paper feed roller 5 can be stably controlled.

Example 3. (Corresponding to claim 1 and claim 4) In the first and second embodiments, the paper feed roller 5 is stopped for the delay time TD when the slip occurs, but the rotation speed of the motor 6, that is, the paper feed roller 5 is stopped. The rotation speed of may be changed to provide a portion having a large friction coefficient μ.

FIG. 7 is a schematic diagram showing a third embodiment of the present invention in which the speed of the paper feed roller 5 is intermittently controlled. 11C corresponds to the CPU 11A or 11B, and 1 to 10 indicate. It is similar to the above. Reference numeral 10b is a motor speed controller inserted between the CPU 11C and the motor drive device 10, and controls the electric power MP supplied from the motor drive device 10 in response to a paper feed command MD from the CPU 11C.

Next, the operation of the third embodiment of the present invention will be described with reference to the timing chart of FIG. 8 and the flowchart of FIG. 8, TD, SL
And SLO are the same as those described above, and RM is the rotation speed of the motor 6. In addition, in FIG. 9, S1 to
S3, S5 and S7 to S10 are the same steps as described above.

Similarly to the above, the CPU 11C controls the motor 6
Is started (step S1), the paper feed roller 5 is rotated to rotate the detection roller 7 (step S2), and
The slip determination means in the CPU 11C compares the rotation command (paper feed command MD) for the paper feed roller 5 with the movement amount information P from the detection roller 7 and determines whether or not a slip has occurred (step S3).

If the slip amount SL based on the paper feed command MD and the movement amount information P is the slip boundary value SLO (see FIG. 8).
When it exceeds the predetermined value, it is determined that a slip has occurred, and the paper feed changing means in the CPU 11C firstly determines a predetermined amount ΔR.
The rotation speed of the motor 6 is reduced by M (step S13). As a result, the rotation speed of the paper feed roller 5 is reduced, the paper feed speed of the cut sheet 2 is suppressed, and a paper feed error is suppressed.

In this state, depending on whether the slip amount SL based on the paper feed command MD and the movement amount information P exceeds the slip boundary value SLO, the slip determination operation is performed again (step S1).
4) is repeated, and if slip occurs (that is, YE
If it is determined to be S), the process returns to step S13 to further reduce the rotation speed of the motor 6 by a predetermined amount ΔRM.
As a result, the rotation speed of the paper feed roller 5 is further reduced, and a paper feed error of the cut paper 2 is further suppressed. Figure 8
Shows the case where the motor 6 is sped down in two steps.

By repeating the motor speed down process (step S13), the slip determination step S14 is performed.
If it is determined that the slip amount SL is equal to or less than the slip boundary value SLO (that is, NO), the rotation speed of the motor 6 at that time is set to the delay time TD (step S
5) Only maintain. As a result, the slippage state generated at the time of the slippage determination step S3 is stopped. afterwards,
The drive speed of the motor 6 is returned to the original speed (step S15), and the process proceeds to normal printing steps S7 to S10.

That is, the CPU 11C confirms that the cut sheet 2 has been sent by the preset movement amount (step S7), then executes printing (printing) (step S8), and normally discharges (step S9). ) Is performed, and a series of printing operations is completed (step S10).

After that, when the slip amount SL exceeding the slip boundary value SLO occurs again, the above processing step S
13 to S15 are repeated again. In this case, even if slippage occurs, the rotation speed is changed down without stopping the motor 6, so that the reduction of the conveyance speed of the cut sheet 2 is suppressed to the minimum and the extension of the printing time can be suppressed. .

Example 4. (Corresponding to claim 1 and claim 5) In each of the above embodiments, the driving state of the sheet feeding roller 5 is changed by the sheet feeding changing means, but the pressing force of the cut sheet 2 against the sheet feeding roller 5 is changed. May be. FIG. 10 is a configuration diagram schematically showing Embodiment 4 of the present invention in which the pressing force of the cut sheet 2 against the sheet feeding roller 5 is changed.
D corresponds to the CPUs 11A to 11C, and 1 to 10 are the same as those described above.

Reference numeral 14 denotes a piston arranged below the pressing spring 4, and constitutes a pressing means for controlling the seat surface position of the pressing spring 4 and changing the pressing force of the cut sheet 2 against the sheet feeding roller 5. ing. 15 is the CPU 11D and the piston 1
4 is a piston drive device inserted between the CPU and
In response to the piston control command PD from 11D, the power supply PP to the piston 14 is controlled to control the seat surface position of the pressing spring 4.

Next, the operation of the fourth embodiment of the present invention will be described with reference to the timing chart of FIG. 11 and the flowchart of FIG. In FIG. 11, T
D, SL and SLO are the same as above and PS
Is a pressing force (spring pressure) of the pressing spring 4. In addition, FIG.
In, S1 to S3, S5 and S7 to S10 are the same steps as described above.

First, the CPU 11D activates the piston drive device 15 in response to the piston control command PD, and the piston 1
4 controls the power supply PP to 4 to control the spring pressure P during normal operation.
S is set (step S0). Hereinafter, similar to the above,
The motor 6 is started (step S1), the paper feed roller 5 is rotated to rotate the detection roller 7 (step S2), and it is determined from the paper feed command MD and the movement amount information P whether or not slippage has occurred (step S1). S3).

When the slip determining means in the CPU 11D determines that the slip has occurred (that is, YES) in step S3, the paper feed changing means in the CPU 11D supplies the power PP supplied from the piston drive device 15 by the piston control command PD. Cut the paper 2 against the paper feed roller 5
The pressing force PS of is increased by a predetermined amount ΔPS (see FIG. 11) (step S16). In addition, the pressing force PS when increasing
Is normally set to a pressure value with which a plurality of sheets are stacked (multi-fed).

The step S16 for driving the piston 14 for increasing the spring pressure PS is executed for the delay time TD in step S5. As a result, the cut paper 2 surely contacts the paper feed roller 5 with a high pressing force, so that the frictional force between the cut paper 2 and the paper feed roller 5 increases,
The slip occurring at the time of the slip determination step S3 is stopped. Then, the power supply PP to the piston 14 is returned to the initial value, the spring pressure PS is returned to the original normal pressure (step S17), and the process returns to the slip determination step S3.

Thereafter, the normal printing steps S7 to S10 are performed, and when the slip amount SL exceeding the slip boundary value SLO occurs again, the above-mentioned processing steps S16 to S1.
Execute 7 again. In this case, only the pressing force PS increases during the extremely short delay time TD, and it is not necessary to reduce the rotation speed of the paper feed roller 5, and the motor 6
Since the paper is operated at a constant speed, it is possible to prevent a paper feed error in a short time, and it is possible to significantly improve the paper feed performance.

Example 5. (Corresponding to Claim 6) In each of the above-mentioned embodiments, the material of the detection roller 7 is not particularly mentioned, but it is preferable that the cut sheet 2 is formed of a material capable of removing static electricity. FIG. 13 is a configuration diagram schematically showing a fifth embodiment of the present invention in which the static electricity of the cut paper 2 can be removed by the detection roller 7, and here, a case where the configuration is applied to the configuration of the first embodiment (FIG. 1). Shows.

In FIG. 13, 7A corresponds to the detection roller 7, and 1 to 6, 8 to 10 and 11A are the same as those described above. 7b is a bearing that serves as a rotation center of the detection roller 7A and the encoder 8, 7c is a metal shaft of the detection roller 7A pivotally attached to the bearing 7b, "+" on the cut sheet 2 is a charged static electricity, and an arrow D is a static electricity " It is a ground path of "+".

The detection roller 7A is a conductive roller which is electrically grounded, and its outer peripheral portion is formed of a conductive rubber roller containing carbon, for example. The metal shaft 7c at the core of the detection roller 7A is grounded to a frame (not shown) via a bearing 7b.

Next, the static electricity removing operation according to the fifth embodiment of the present invention will be described with reference to FIG. In the state where the cut sheets 2 stacked in the paper cassette 1 are attracted to each other by the static electricity “+”, the surface of the cut sheet 2 is charged with the static electricity indicated by “+”.

When the detection roller 7A made of a conductive rubber roller rotates on the cut sheet 2 in the direction of arrow C, static electricity "+" moves from detection roller 7A to metal shaft 7c to bearing 7b as shown by arrow D. Through to the ground in a continuous path to the frame. As a result, the static electricity “+” on the cut sheets 2 is neutralized, and the attraction between the cut sheets 2 is relaxed. Therefore, even when the friction coefficient μ of the paper feed roller 5 is lowered, the paper feed performance can be more reliably maintained.

The fifth embodiment of the present invention is the same as the first embodiment.
It is needless to say that the same effect can be obtained even if it is carried out in combination with at least one of 2, 3 or 4 or carried out independently.

[0067]

As described above, according to the first aspect of the present invention, a paper cassette in which cut sheets to be supplied to the printer are stacked and housed, and a sheet separating device provided at the end of the paper cassette in the paper feeding direction are provided. In a paper feeding device for a printer, which is provided with a claw and a paper feeding roller having a half-moon shape in cross section, which is provided on an upper portion of a paper cassette and is arranged so that an outer periphery thereof comes into contact with a cut sheet, a paper feeding device in a paper feeding direction. A detection roller installed behind the paper roller to detect the amount of movement of the cut sheet by contacting the uppermost cut sheet in the paper cassette,
A slip determining unit that determines slippage between the feed roller and the cut sheet based on the amount of movement of the cut sheet, and a contact state between the feed roller and the cut sheet in response to slip information from the slip determining unit Since it is equipped with a paper feed changing means for changing the paper feed so that the paper is always fed under the optimum paper feeding conditions, it is maintenance-free even if it is used for a long period of time, and even if cut sheets are attracted to each other due to static electricity. There is an effect that a paper feeding device for a printer that can feed paper and that can reliably feed paper by measuring and controlling the movement amount of paper is obtained.

According to a second aspect of the present invention, in the first aspect, the paper feed changing means intermittently rotates the paper feed roller in response to the slip information, and repeatedly uses the maximum static friction force. Therefore, it is maintenance-free even if it is used for a long period of time, and can feed even if cut sheets are attracted to each other due to static electricity. There is an effect that a paper feeder for a printer capable of paper is obtained.

According to a third aspect of the present invention, in the second aspect, a motor for driving the sheet feeding roller and a clutch connected to the motor are provided, and the sheet feeding changing means responds to the slip information. The clutch is controlled intermittently by using the maximum static friction force repeatedly, so it is maintenance-free even if it is used for a long period of time without stopping the motor. Even if paper is still fed, there is an effect that a paper feeding device for a printer that can reliably feed paper by measuring and controlling the amount of paper movement is obtained.

According to a fourth aspect of the present invention, in the second or third aspect, the paper feed changing means changes the drive speed of the paper feed roller in response to the slip information. It is maintenance-free even if it is used for a long period of time while suppressing a decrease in the paper transport speed to a minimum, and can feed paper even if cut sheets are attracted to each other due to static electricity. There is an effect that a paper feeding device for a printer that can measure and control and reliably feed paper can be obtained.

According to claim 5 of the present invention, in any one of claims 1 to 4, there is provided a pressing means for pressing the cut sheet in the paper cassette against the sheet feeding roller, and the sheet feeding changing means. Since the pressing force of the pressing means is controlled in response to the slip information, it is maintenance-free even if it is used for a long period of time without deteriorating the paper conveyance speed. It is possible to feed a sheet even if the sheet is adsorbed, and further, it is possible to obtain a sheet feeding device for a printer which can reliably feed the sheet by measuring and controlling the movement amount of the sheet.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the detection roller is a conductive roller that is electrically grounded, and is generated on the cut sheet. By discharging the static electricity, the electrostatic attraction between the cut sheets is eased and the paper is fed easily.Therefore, it is maintenance-free even if it is used for a long time. Can also feed paper by letting static electricity escape to the ground.
There is an effect that a paper feeding device for a printer that can reliably feed paper by measuring and controlling the amount of paper movement is obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram schematically showing a first embodiment of the present invention.

FIG. 2 is a timing chart for explaining the operation of the first embodiment of the present invention.

FIG. 3 is a flowchart showing the operation of the first embodiment of the present invention.

FIG. 4 is a schematic diagram showing a second embodiment of the present invention.

FIG. 5 is a timing chart for explaining the operation of the second embodiment of the present invention.

FIG. 6 is a flowchart showing the operation of the second embodiment of the present invention.

FIG. 7 is a configuration diagram schematically showing a third embodiment of the present invention.

FIG. 8 is a timing chart for explaining the operation of the third embodiment of the present invention.

FIG. 9 is a flowchart showing the operation of the third embodiment of the present invention.

FIG. 10 is a configuration diagram schematically showing a fourth embodiment of the present invention.

FIG. 11 is a timing chart for explaining the operation of the fourth embodiment of the present invention.

FIG. 12 is a flowchart showing the operation of the fourth embodiment of the present invention.

FIG. 13 is a configuration diagram schematically showing a fifth embodiment of the present invention.

FIG. 14 is a perspective view showing a main part of a conventional printer paper feeding device.

FIG. 15 is a configuration diagram schematically showing a conventional printer paper feeding device.

[Explanation of symbols]

1 paper cassette, 2 cut paper, 3 paper separating claw, 4 pressing spring, 5 paper feeding roller, 6 motor, 7
Detection roller, 7A Conductive detection roller, 7b Bearing,
7c metal shaft, 8 encoder, 9 photocoupler, 10 motor drive device, 10b motor speed controller, 11A to 11D CPU, 12 electromagnetic clutch, 13 electromagnetic clutch drive device, 14 piston (pressing means), 15 piston drive device, A supply Paper direction, D grounding path, MD paper feed command, MP motor drive pulse, P movement amount information, PS pressure (spring pressure), R
M motor speed, SL slip amount, SLO slip boundary value, S3 slip judgment step, S4 motor stop step, S7 feeding a predetermined amount, S12 clutch disconnecting step, S13
Step of changing (decreasing) motor speed, S16 Step of changing (increasing) pressing force.

Claims (6)

[Claims] 1. A paper cassette in which cut sheets to be supplied to a printer are stacked and housed, a paper separating claw provided at an end of the paper cassette in the paper feeding direction, and a paper cassette provided at an upper portion of the paper cassette. A paper feeding device for a printer, comprising: a paper feeding roller having a half-moon shape in cross section, the outer periphery being in contact with the cut paper when moving, wherein the paper feeding device is installed at a rear portion of the paper feeding roller with respect to the paper feeding direction. A detection roller that contacts the uppermost cut sheet in the paper cassette to detect the amount of movement of the cut sheet; and a slip between the paper feed roller and the cut sheet based on the amount of movement of the cut sheet. A slip determining unit for determining and a sheet feeding changing unit for changing a contact state between the sheet feeding roller and the cut sheet in response to slip information from the slip determining unit are provided. Paper feeder for a printer according to symptoms. 2. The paper feeding device for a printer according to claim 1, wherein the paper feeding changing unit intermittently rotates the paper feeding roller in response to the slip information. 3. A motor for driving the paper feed roller, and a clutch connected to the motor, wherein the paper feed changing means intermittently controls the clutch in response to the slip information. The paper feeding device for printer according to claim 2. 4. The paper feeding device for a printer according to claim 2, wherein the paper feeding changing unit changes the driving speed of the paper feeding roller in response to the slip information. 5. A pressing unit for pressing the cut sheet in the paper cassette against the paper feeding roller, wherein the paper feeding changing unit controls the pressing force of the pressing unit in response to the slip information. A sheet feeder for a printer according to any one of claims 1 to 4. 6. The paper feeding device for a printer according to claim 1, wherein the detection roller is a conductive roller that is electrically grounded.