JP2898424B2 - Paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder which is used in connection with a recording device such as a printer and feeds paper to the recording device.

[0002]

2. Description of the Related Art Conventionally, a paper feeder connected to a recording device such as a printer and feeding cut sheets to the recording device has been widely used. FIG. 8 is a configuration diagram showing a conventional sheet feeding device, which will be described below with reference to the drawings.

[0003] In FIG. 8, a sheet feeding device 301 is provided with an elevator 303 which stacks sheets 302 and moves vertically. One of the elevators 303 is a wire 30
4 and the wire 304 is connected to the pulley 3
05, a roller 307 attached to the rotating shaft of the motor 306. The other of the elevator 303 is movably supported by a shaft 308. Therefore, when the roller 307 is rotated by the motor 306, the elevator 303 moves up and down.

A hopping roller 3 is provided above the paper 302.
09 is provided, and the hopping motor 310
The paper 302 is fed out by rotating in the direction. A separation pad 311 is provided facing the hopping roller 309. The separation pad 311 has a surface formed of a friction member and separates the sheets 302 one by one.
The spring 312 is pressed against the hopping roller 309. A paper feed sensor 313 is provided above the hopping roller 309 along the paper feeding path. The paper feed sensor 313 is for detecting a paper feeding failure of the paper 302.

[0005] The operation of the sheet feeding device 301 is controlled by a control unit 314. The control unit 314 includes a control circuit 315 including a CPU and the like and a motor driver 316. A control signal from a printer (not shown) is input to the control circuit 315, and the paper feed sensor 313 is controlled by the control circuit 315. It is connected. The motor driver 316 is connected to the motor 306 and the hopping motor 310, and drives these. Further, a lowering switch 317 for instructing lowering of the elevator 303 is provided.

Next, the operation will be described. When a paper feed command signal is input from a printer (not shown), the control circuit 315 drives the hopping motor 310 via the motor driver 316 and rotates the hopping roller 309 in the direction of arrow A. As a result, the sheet 302 is fed out, and the separation pad 3
11, only the uppermost sheet is fed and sent to a printer (not shown). At this time, the second and subsequent sheets remain sandwiched between the hopping roller 309 and the separation pad 311. When the feeding of the paper 302 is repeated, the position of the top surface of the paper is lowered by the thickness of the fed paper 302,
The control circuit 315 drives the motor 306 via the motor driver 316 to rotate the roller 307 in the direction of arrow B. As a result, the elevator 303 is raised and the paper 302
Is in contact with the hopping roller 309.

When the paper 302 is jammed during the feeding operation and the hopping roller 309 is rotated, the paper
If the sheet 302 does not reach 13, the sheet feed sensor 313 does not detect the sheet 302, and the control circuit 315 determines that a sheet jam has occurred, and rotates the motor 306 in the reverse direction to lower the elevator 303.

When the operator replenishes the sheet 302, the operator presses the down switch 317, and the control circuit 315 issues an instruction to lower the elevator 303.

[0009]

However, the above-mentioned conventional apparatus has the following problems. That is, when paper jams between the hopping roller and the separation pad and a jam occurs, the elevator is automatically lowered, so that the operator can easily put his hand from below the hopping roller.
The jammed paper is sandwiched between the hopping roller and the separation pad with a strong force, and there is a problem that it is difficult to remove the jammed paper.

When the operator replenishes sheets, the elevator is lowered by operating the lowering switch. Even when the hopping roller stops rotating, there are always two or three sheets of paper between the hopping roller and the separation pad. Are sandwiched, these sheets hang down when the elevator is lowered. In this state, it is difficult to replenish the paper, and if the elevator is raised again without removing the paper after the replenishment, there is a problem that the hanging paper is broken below the hopping roller and the paper cannot be fed. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to easily remove a jammed sheet by forcibly rotating a hopping roller in the case of occurrence of a sheet jam or refilling the sheet. It is an object of the present invention to provide an excellent paper feeding device which realizes prevention of unusable or impossible paper feeding.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a paper feeder for feeding out a sheet loaded on an elevator by forward rotation of a feed roller and feeding the same to a printing apparatus. A sheet separating unit that presses against a roller to separate the stacked first sheet, sandwiches the second and subsequent sheets, and sequentially separates one sheet at a time, an instruction unit that instructs the elevator to descend, and a lower limit of the elevator The lower limit detecting means for detecting the lowering state of the elevator, the display means for displaying the lowering state of the elevator and the abnormal state of the printer, and the lowering instruction to display the lowering state of the elevator and lower the elevator by a predetermined amount. Return the jammed paper to the loading position of the elevator by rotating it in the reverse direction, and lower the elevator again to detect the lower limit. There Without detect the lower limit be passed is provided with a control means for displaying an abnormality of the elevator. Further, in a paper feeder for feeding out the paper loaded in the elevator by the forward rotation of the feed roller and feeding the same to the printing apparatus, the paper is pressed against the feed roller to separate the first loaded paper and to remove the two sheets. Sheet separation means for sandwiching sheets after the first sheet and sequentially separating the sheets one by one; sheet detection means for detecting sheets to be fed through the feeding path; lower limit detection means for detecting the lower limit of the elevator; Display means for displaying an abnormal state of the printing apparatus, and, after feeding out the paper, if the paper detection means does not detect the paper even after a predetermined time has elapsed, a paper feeding failure is displayed, and the elevator is lowered by a predetermined amount. After that, the paper feed roller is rotated in the reverse direction to return the sandwiched paper to the loading position of the elevator, and the elevator is lowered again to detect the lower limit, an error of the printing apparatus is displayed, and a predetermined time has elapsed. It is also the not detect the lower limit that is provided and control means for displaying the elevator abnormality. Further, in a paper feeder that feeds out the paper loaded in the elevator by the forward rotation of the feed roller and feeds the paper to the printing apparatus, the paper is pressed against the feed roller to separate the first loaded paper and to remove two sheets. Insert the paper after the eyes,
Sheet separating means for sequentially separating sheets one by one; sheet detecting means disposed on the sheet feeding device side or the printing device side for detecting sheets fed in the feeding path; and lower limit detecting means for detecting the lower limit of the elevator. Display means for displaying a sheet feeding failure and an abnormal state of the printing apparatus; and displaying a sheet feeding failure corresponding to any of the sheet detecting means provided on the sheet feeding apparatus side or the printing apparatus side, Then, after lowering the elevator by a predetermined amount, the feeding roller is rotated in the reverse direction to return the sandwiched sheet to the loading position of the elevator, or the sheet having a feeding failure on the printing apparatus side is fed back and fed. The rollers are rotated in the reverse direction to return the sandwiched paper to the loading position of the elevator, and the elevator is lowered again to detect the lower limit. If the lower limit is detected, an error of the printing apparatus is displayed. And control means for displaying a data abnormality.

[0013]

According to the present invention having the above-mentioned structure, the first stacked paper is separated by the paper separating means pressed against the feed roller, and the second and subsequent sheets are sandwiched and separated one by one sequentially. However, the control means displays the elevator lowering state by the descending instruction of the instructing means for instructing the elevator to descend, or by the sheet detecting means detecting the sheet feeding failure, or the sheet feeding failure. Is displayed, and after the elevator is lowered by a predetermined amount, the feeding roller is rotated in the reverse direction to return the sandwiched sheet to the loading position of the elevator, or the sheet in which the feeding failure at the printing apparatus side has occurred is fed back. The feed roller is rotated in the reverse direction and the sandwiched paper is returned to the loading position of the elevator. The elevator is lowered again to detect the lower limit. Elapsed does not detect the lower limit even when displaying an abnormality of the elevator.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. Elements common to the drawings are assigned the same reference numerals.

FIG. 1 is a block diagram showing a first embodiment according to the present invention. First, the first embodiment will be described.

In FIG. 1, a sheet feeding device 101 according to the first embodiment is provided with an elevator 102 on which sheets 302 are stacked and which can move vertically. This elevator 1
Numeral 02 is suspended by a single wire 103 on both sides, so that it can move up and down while maintaining a precise horizontal state. Wire 103 is connected to pulleys 104a, 104b, 10
4c and 104d, one end of which is
7 Roller 307 is similar to the conventional example,
It is attached to the rotating shaft of the motor 306.

Sheets 30 stacked on elevator 102
2 above the hopping motor 31 as in the conventional example.
The hopping roller 309 rotated by the rotation of the hopping roller 309 is provided.
Is pressed.

Above the sheet 302, an upper limit sensor 1 is also provided.
05 is provided so that the upward moving range of the elevator 102 can be adjusted to the height of the hopping roller 309. In addition, a lower limit sensor 106 is provided below the elevator 102 so that the downward movement range of the elevator 102 can be limited. Plus paper 3
A paper end detection sensor 107 is provided above the image sensor 02. When the paper 302 on the elevator 102 ends, the lever enters a detection hole 102a formed in the elevator 102 to detect the end of the paper. I do. A sensor 108 for detecting opening and closing of a front cover (not shown) is provided below the sheet feeding device 101. Each of the above-mentioned sensors is not shown, but is
09 is connected to the control circuit 110.

The sheet feeding device 101 also includes an elevator 10
2. Lamp 111 and elevator 10 indicating abnormal operation
A lamp 112 indicating that the sheet 2 is down and a lamp 113 indicating the end of the sheet are provided. These lamps are controlled by the control circuit 110. The down switch 317 is a switch for the operator to lower the elevator 102 as in the conventional example.

The motor driver 316 in the control unit 109
Is connected to and drives the motor 306 and the hopping motor 309.

The printer 114 is located above the paper feeding device 101, and the paper 302 fed out by the hopping roller 309 is fed into the printer 114 one by one.

Next, the operation of the first embodiment will be described with reference to the flowchart shown in FIG.

When the power sensor is turned on or the front cover (not shown) of the sheet feeding device 101 is closed and the cover sensor 108 is turned on (step 1), the control circuit 110 sets a time monitoring timer (step 2). As the time monitoring timer, for example, a counter provided in control circuit 110 is used. Next, the control circuit 110 controls the motor driver 31
6, a motor drive command is issued, and the motor 306 is rotated in the direction of arrow B shown in FIG. 1 (step 3). Thereby, the elevator 102 is raised. When the elevator 102 rises, the stacked sheets 302 turn on the upper limit sensor 105 (step 4), but if the upper limit sensor 105 does not turn on even if the monitoring timer set in step 2 times out (step 5). ), Elevator 102
Then, the control circuit 110 turns on the display lamp 111 indicating the abnormality of the elevator 102 (step 6). At the same time, the control circuit 110 notifies the printer 114 of the abnormality (step 7) and stops the operation.

When the upper limit sensor 105 is turned on in step 4, it is determined whether or not the down switch 317 is pressed (step 8), and it is also determined whether or not a paper feed command signal has been sent from the printer 114 (step 9). If the down switch 317 of the elevator 102 has been pressed for reasons such as sheet replenishment, the process proceeds to step S16.

When a paper feed command signal is sent from the printer 114, the control circuit 110
6 through the hopping roller 309 shown in FIG.
(Step 10). With this, paper 3
02 is fed out, separated into one sheet by a separation pad 311 and fed to the printer 114 side. Repeat paper 3
When 02 is fed, the position of the top surface of the sheet 302 is lowered by the thickness of the fed sheet 302, and the upper limit sensor 105 is turned off (step 11). In this case, the control circuit 11
0 indicates that the motor 306 is rotated via the motor driver 316 and the elevator 1 is turned on until the upper limit sensor 105 is turned on.
02 is raised (step 12). When the sheet 302 is fed in this way and the sheet end is detected by the sheet end detection sensor 107 (step 13), the control circuit 110 notifies the printer 114 that the sheet is normal (step 14). ). When all the sheets 302 are fed and the sheet end sensor 107 detects that there is no sheet, the control circuit 110 turns on the display lamp 113 indicating the end of the sheet (step 15), and proceeds to step 20.

In step 8, the down switch 317
Is determined, the control circuit 110 turns on the display lamp 112 indicating that the elevator 102 is lowered (step 16). Next, the control circuit 110 reversely rotates the motor 306 via the motor driver 316 to lower the elevator 102 by a predetermined amount (step 17). Here, the gap between the top surface of the stacked sheets 302 and the hopping roller 309 is set so as not to be too large. Next, the control circuit 110 reversely rotates the hopping motor 310 via the motor driver 316. (Step 18).

When the down switch 317 is pressed, the sheet 302 is sandwiched between the hopping roller 309 and the separation pad 311.
When the sheet 9 rotates in the reverse direction, the sandwiched sheet 302 is returned to the stacking position. The predetermined lowering amount of the elevator 102 in step 17 is set so that the sandwiched sheet 302 is appropriately returned.

Next, the control circuit 110 sets a timer (step 19) and lowers the elevator 102 again (step 20). As a result, if the lower limit sensor 106 is turned on (step 21), the process proceeds to step 7 and the printer 1
14 is notified that there is an abnormality. If the lower limit sensor 106 is not turned on even if the set timer times out, the process proceeds to step 6 to display that the elevator 102 is abnormal, and further notifies the printer 114 of the abnormality.

As described above, in the first embodiment, when the operator presses the down switch 317 to lower the elevator 102, the paper sandwiched between the hopping roller and the separation pad is automatically returned to the original stacking position. Therefore, the sheet replenishing operation and the like become easy. Further, when the elevator is lowered, the display lamp indicating the cause of the lowering is turned on, so that the operator can take prompt action.

Next, a second embodiment according to the present invention will be described with reference to FIG. FIG. 3 is a configuration diagram showing a second embodiment according to the present invention.

In the sheet feeding device 201 according to the second embodiment, a sheet feeding sensor 202 is provided in the middle of a feeding path through which a sheet 302 fed by a hopping roller 309 is fed. The paper feed sensor 202 detects a feeding failure of the paper 302 and is connected to a control circuit 203 of the control unit 109 (not shown). Further, a display lamp 204 indicating that the paper 302 has jammed is provided, and this is also controlled to be turned on by the control circuit 203. The other configuration is the same as that of the first embodiment (except for the down switch for lowering the elevator), and the description is omitted.

FIG. 4 is a flow chart showing the operation of the second embodiment.
The operation of the embodiment will be described.

In FIG. 4, steps 31 to 3
7 is the same as Steps 1 to 7 in FIG. When the upper limit sensor 105 is turned on due to the elevation of the elevator 102 in step 34, it is determined whether or not there is a paper feed command signal from the printer 114 (step 38). Upon receiving the sheet feed command signal, the control circuit 203 sets a time monitoring timer (step 39). At the same time, the hopping motor 310 is connected via the motor driver 316 to FIG.
(Step 40). As a result, the hopping roller 309 rotates forward and the paper 302
Pay out. When the paper 302 is normally fed, the presence of the paper is detected by the paper feed sensor 202 during the feeding (step 41). The upper limit sensor 105 detects the sheet 302
If it is determined that the top surface is lowered (step 42),
The elevator 102 is raised (step 43). If the sheet end sensor 107 determines that the sheet is present (step 44), the printer 114 is notified that the sheet is normal (step 45), and the process returns to step 38. Paper end sensor 1
07, it is determined that there is no paper, and the control circuit 203 turns on the lamp 113 indicating the end of the paper (step 4).
6).

In steps 41 and 46, if the paper feed sensor 202 is not turned on even if the set time monitoring timer times out, the control circuit 2
03 is determined to be a paper jam and the display lamp 204 indicating the paper jam is turned on (step 47). Next, the control circuit 203 lowers the elevator 102 by a predetermined amount as in the first embodiment (step 48).
09 is rotated in the reverse direction (step 49). As a result, the jammed sheet 302 sandwiched between the hopping roller 309 and the separation pad 311 is returned to the stacking position. The subsequent steps 50 to 53 are the same as steps 18 to 22 of the first embodiment.

As described above, when a paper jam occurs, the lamp 204 indicating the fact is turned on, so that the operator can understand that the elevator 102 is lowered due to the paper jam. Further, since the jammed sheet is automatically returned to the elevator, the operator checks the state of the returned sheet, and if the sheet cannot be reused, discards the sheet and can easily recover the sheet.

Next, a third embodiment according to the present invention will be described with reference to FIGS. FIG. 5 is a configuration diagram illustrating a paper feeding device according to a third embodiment of the present invention, and FIG. 6 is a configuration diagram illustrating a printing device according to the third embodiment.

In the third embodiment according to the present invention, before the editing process of the print data is completed by the printer, the paper of the edit size is fed in advance and stopped in the printer. This is a paper feeder that starts printing on the paper at the same time, thereby reducing the paper feeding time to apparently zero and realizing high-speed printing.

Referring to FIG. 5, the sheet feeding device 205 of the third embodiment is shown.
Is provided with a descending lamp 112 for indicating that the elevator 102 is descending, and the lighting thereof is controlled by the control circuit 206. The other configuration is the same as that of the second embodiment, and the description is omitted.

Next, the printer 114 will be described with reference to FIG. In the figure, a print control circuit 207 receives data from an upper-level host, determines a paper size, and sends the paper size data together with a control signal to a paper feeding device 205.
Output to A paper feed sensor 209 is provided in the printer 114 in the middle of the paper feeding path 208 to detect a feeding failure of the paper 302. The paper feed sensor 209 is a print control circuit 207
It is connected to the. Further, a registration roller 210 and a backup roller 211 pressed against the registration roller 210 are provided on a feeding path of the sheet 302. The registration roller 210 includes a registration motor 212 driven by the print control circuit 207.
To prevent the skew of the sheet 302 and control the sheet traveling distance. Further, the printer 114
A photosensitive drum 213 for performing electrophotographic printing, a charger 214 and a fixing device 215 are provided therein. Further, a paper feed sensor 216 for detecting a feeding failure of the paper 302 in the printer 114 is provided.

With the above-described configuration, in the third embodiment, after a control signal is output from the printer 114 to the paper feeding device 205, even if the paper feeding device 205 normally performs a paper feeding operation, If a paper jam occurs during feeding to the printing position, the paper feed sensor 209 is not turned on, so that the print control circuit 207 can detect the paper jam. In this case, the print control circuit 207 notifies the paper feeding device 205 of the paper jam.

Further, even if the paper feed sensor 209 detects the paper 302 normally, for example, when the paper 302 is multi-fed, a feeding failure may occur between the registration roller 210 and the backup roller 211 thereafter. That is, if the registration motor 212 becomes overloaded due to double feeding of the sheet 302 and stops rotating, the sheet cannot be fed, or the sheet cannot be fed due to insufficient pressure between the registration roller 210 and the backup roller 211 or slippage of the sheet 302. There are cases. In this case, the print control circuit 207 detects the jam by the paper feed sensor 216, displays the jam on the printer 114 side, and outputs a command to lower the elevator 102 to the paper feed device 205.

Next, the operation of the third embodiment will be described with reference to the flowchart shown in FIG.

In FIG. 7, steps 61 to 6
Step 7 is the same as steps 1 to 7 in the first embodiment, and a description thereof will be omitted.

In step 68, it is determined whether an elevator lowering command signal has been sent from the print control circuit 207 of the printer 114. In step 69, it is also determined whether a paper feed command signal has been sent from the print control circuit 207. . When a paper feed command is sent, the control circuit 206 sets a time monitoring timer (step 7).
0), the stepping motor 310 is rotated forward (step 71). Subsequent steps 72 to 75
Up to this point, the same processing as steps 41 to 44 shown in FIG. 4 in the second embodiment is executed. If it is determined in step 75 that the paper is present, in step 76, it is determined whether or not there is a paper jam notification from the printer 114. When a paper jam is detected in the print control circuit 207 by the paper feed sensor 209 in the printer 114, a notification signal is sent to the control circuit 206, and the presence or absence of the notification signal is determined here. If a paper jam has not been received, the process returns to step 68;
Proceeding to 0, the control circuit 206 turns on the display lamp 204 indicating a paper jam.

If an elevator lowering command has been received from the printer 114 in step 68, the control circuit 206 displays an indicator lamp 1 indicating that the elevator 102 is lowering.
12 is turned on (step 78), and the routine proceeds to step 81. Also, in step 79, the paper feed sensor 202
If the control circuit 206 determines not to detect 02, the control circuit 206 turns on the lamp 204 to display a paper jam (step 80), and proceeds to step 81.

In step 81, the control circuit 206 lowers the elevator 102 by a predetermined amount, then rotates the hopping roller 309 in the reverse direction (step 82), and returns the jammed sheet 302 to the original position. In this case, the hopping roller 309 is rotated reversely enough to return the paper 302 jammed in the printer 114 to the original stacking position. The subsequent steps 83 to 86 are the same as the processing from steps 19 to 22 shown in FIG.

As described above, when the lamp 112 is turned on, the paper jam on the printer 114 side causes the elevator 102 to stop.
When the lamp 204 is turned on, it is understood that the elevator 102 has been lowered due to a paper jam in the paper feeding device 205 or on the feeding path.

In each of the above-described embodiments, the elevator descent factor is displayed by a lamp, but other characters may be displayed. Also, it is of course possible to display the information on the printer side instead of the paper feeding apparatus side.

[0049]

According to the present invention, the first stacked sheet is separated by the sheet separating means pressed against the feed roller, and the second and subsequent sheets are sandwiched between the stacked sheets.
The sheet is separated one by one, but the control means displays the elevator lowering state by the descending instruction of the instructing means for instructing the elevator to descend, or by the sheet detecting means detecting the feeding failure of the sheet, or After indicating the feeding failure and lowering the elevator by a predetermined amount, the feeding roller is rotated in the reverse direction to return the sandwiched paper to the loading position of the elevator, or the paper having a feeding failure on the printing apparatus side. And the feed roller is rotated in the reverse direction to return the sandwiched paper to the loading position of the elevator.When the elevator is lowered again and the lower limit is detected, an error of the printing apparatus is displayed,
If the lower limit is not detected even after the predetermined time has elapsed, an abnormality of the elevator is displayed. Therefore, the operator can promptly take appropriate measures depending on what factor causes the elevator to descend by looking at the display.
In addition, the paper sandwiched by the paper separating means, including the paper with poor feeding, is returned to the loading position of the elevator, and the lower limit is detected and an error is displayed, so that a sufficient paper handling space on the elevator is secured. And remove the poorly fed paper,
Paper can be easily replenished.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment according to the present invention.

FIG. 2 is a flowchart showing the operation of the first embodiment.

FIG. 3 is a configuration diagram showing a second embodiment according to the present invention.

FIG. 4 is a flowchart showing the operation of the second embodiment.

FIG. 5 is a configuration diagram illustrating a sheet feeding device according to a third embodiment of the present invention.

FIG. 6 is a configuration diagram illustrating a printing apparatus according to a third embodiment.

FIG. 7 is a flowchart showing the operation of the third embodiment.

FIG. 8 is a configuration diagram showing a conventional sheet feeding device.

[Explanation of symbols]

 101 Paper Feeder of First Embodiment 102 Elevator 110 Control Circuit 114 Printer 201 Paper Feeder of Second Embodiment 202 Paper Feed Sensor 203 Control Circuit 205 Paper Feeder 206 of Third Embodiment 206 Control Circuit 209 Paper Feed Sensor 302 Paper 309 Hopping roller

Claims (3)

(57) [Claims] 1. A sheet feeding device for feeding a sheet stacked in an elevator by a normal rotation of a feeding roller and feeding the sheet to a printing apparatus, wherein the sheet is pressed against a feeding roller to separate the stacked first sheet. Paper separating means for sandwiching the second and subsequent sheets, and separating the sheets one by one in sequence; instructing means for instructing the elevator to descend; lower limit detecting means for detecting the lower limit of the elevator; Display means for displaying an abnormal state, and a descending instruction, the descending state of the elevator is displayed, and after the elevator is lowered by a predetermined amount, the feeding roller is rotated reversely to return the sandwiched paper to the loading position of the elevator, When the elevator is lowered again and the lower limit is detected, an error in the printing device is displayed, and if the lower limit is not detected after the lapse of a predetermined time, an error in the elevator is displayed. Sheet feeding apparatus, wherein a control unit is provided for. 2. A sheet feeding device for feeding out a sheet loaded on an elevator by forward rotation of a feed roller and feeding the sheet to a printing apparatus, wherein the sheet is pressed against the feed roller to separate the first sheet loaded. Paper separating means for sandwiching the second and subsequent sheets and sequentially separating the sheets one by one; sheet detecting means for detecting the sheet to be fed through the feeding path; lower limit detecting means for detecting the lower limit of the elevator; Display means for displaying a feeding failure and an abnormal state of the printing apparatus; and displaying the paper feeding failure if the paper detecting means does not detect the paper even after a predetermined time has elapsed after the paper has been fed out. After lowering by a predetermined amount, the feed roller is rotated in the reverse direction to return the sandwiched paper to the loading position of the elevator, and when the elevator is lowered again to detect the lower limit, an error of the printing apparatus is displayed. There paper feeding apparatus characterized by the not detect the lower limit even after the lapse provided and control means for displaying an abnormality of the elevator. 3. A sheet feeding device for feeding a sheet stacked in an elevator by a normal rotation of a feeding roller and feeding the sheet to a printing apparatus, wherein the sheet is pressed against a feeding roller to separate the stacked first sheet. A sheet separating unit that sandwiches the second and subsequent sheets and separates them one by one in sequence; a sheet detecting unit that is disposed on the sheet feeding device side or the printing device side and detects a sheet to be fed through the feeding path; A lower limit detecting means for detecting a lower limit of the elevator; a display means for displaying a paper feeding failure and an abnormal state of the printing apparatus; and a paper detecting means provided on the paper feeding apparatus side or the printing apparatus side. After the elevator is lowered by a predetermined amount, the feeding roller is rotated in the reverse direction to return the sandwiched sheet to the loading position of the elevator, or the feeding on the printing apparatus side is performed. Cause defects Returning the sheet sandwiched by the reverse rotation of the feed roller with causes conveyed backward the paper to the loading position of the elevator, to display the abnormality of the printing apparatus for detecting the lower limit lowered elevator again,
And a control unit for displaying an elevator abnormality if a lower limit is not detected even after a predetermined time has elapsed.