JPH07196174A - Paper feeding device - Google Patents

Abstract

PURPOSE:To prevent the vertical motion of a push-up plate in a tray so as to lengthen the machine life of sheet push-up mechanism. CONSTITUTION:A paper feeding device has a paper feeding device body D, paper feeding trays A, B, C mounted in the body D so as to accommodate sheets, sensors for detecting the presence of sheets in the trays, sheet push-up plates 4 provided at the bottom parts of the trays, drive mechanism 5 for lifting the push-up plates 4, and a driving control means 24 for actuating the drive mechanism 5 to lift the push-up plate 4 when there is a printing demand and there are sheets in the tray.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device for a printer, a copying machine, a word processor, a facsimile, etc., and more particularly to a sheet feeding device in which sheets are accommodated in a tray and the tray is mounted in a sheet feeding device main body. Regarding

[0002]

2. Description of the Related Art This type of sheet feeding device comprises a sheet feeding tray for storing sheets used in a printer, and a sheet feeding device main body in which a plurality of stages of the sheet feeding tray are mounted. A sheet push-up plate is provided on the bottom of the tray so as to be swingable up and down. On the other hand, a detection unit that detects that the tray is attached to the main body of the sheet feeding device and a lift-up mechanism that pushes up the tray push-up plate. And a releasing means for releasing the driving force applied to the lifting plate of the lift-up mechanism when the tray is pulled out from the main body of the sheet feeding device.

Therefore, in this structure, when the tray is pulled out from the main body of the sheet feeding device, the driving force for pushing up the push-up plate is released, so that the push-up plate falls under its own weight to the bottom of the tray, while the sheet is placed on the tray. After replenishing
When the tray is pushed into the sheet feeding device main body, the detecting means detects it, drives the lift-up mechanism, pushes up the sheet in the tray and presses the sheet feeding roller in the sheet feeding device main body with an appropriate force.

[0004]

By the way, according to the above-mentioned conventional apparatus, the push-up plate is driven and released every time when the tray is inserted into and removed from the main body of the sheet feeding apparatus, which shortens the machine life. is there. That is, the tray is inserted / pulled out not only when replenishing a piece of paper but also when checking for the presence or absence of paper or at any time according to the user's intention, such as during maintenance, and the lifting plate moves up and down each time. When the machine life of the push-up plate is designed based on the number of times the paper is replenished, such as 100,000 times or 1 million times, the service life will be exhausted before the number is reached.

In view of the above problems, it is an object of the present invention to prevent the push-up plate from moving up and down when it is unnecessary and to extend the machine life of the drive mechanism.

[0006]

A sheet feeding device of the present invention detects a sheet feeding device main body, a sheet feeding tray for accommodating sheets and mounted in the main body, and the presence / absence of sheets in the tray. A sensor, a sheet push-up plate provided at the bottom of the tray, a drive mechanism for raising the push-up plate, a print request, and when there is a sheet in the tray, the drive mechanism is operated to raise the push-up plate. And a drive control means for raising.

[0007]

In the paper feeding apparatus of the present invention configured as described above, when the paper feeding tray is mounted in the main body of the paper feeding apparatus, the sensor for detecting the presence or absence of the paper in the tray detects the presence or absence of the sheet.
Then, when it is detected that there is a sheet and a print command is issued, the drive mechanism control means actuates the drive mechanism to raise the push-up plate.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A sheet feeding device according to the present invention will be described with reference to the drawings. FIG. 1 is a front sectional view showing the structure of a paper feeding device as an embodiment of the present invention. In the figure, A, B, and C are tray devices for accommodating transfer sheets (hereinafter referred to as sheets), and D is a housing structure for accommodating the tray devices A, B, and C in a direction perpendicular to the plane of the drawing. It is the paper device body. A printer E is mounted on the paper feeder main body D.

The sheet feeding device main body D slidably holds the tray devices A, B, and C at the illustrated positions by guide rails (not shown), and the tray devices A, B, and C from the tray devices A, B, and C along the left side wall 8a of the casing. Conveying path 200 for conveying a sheet of paper
Is formed up to the center of the housing top plate 8b. Transport path 20
The start ends 200a, b, and c of 0 are branched by the number of tray devices A, B, and C, and the feed rollers 210a, 210a, and
b, c, forward rotation separating rollers 220a, b, c, and reverse rotation separating rollers 230a, b, c are arranged. Paper feed roller 21
0a, b, and c are rotationally driven by a drive source (not shown) when a paper feed command is issued, and the sheets in the tray devices A, B, and C are fed out from the uppermost paper. Forward rotation separating roller 220a,
b and c and the reverse rotation separating rollers 230a, b and c give a separating action to the fed sheet and prevent the two sheets from being fed. The paper feed rollers 210a, b, c are arm rods 2 which are swingably supported by the axial centers of the normal rotation separation rollers 220a, b, c.
The sheet feed rollers 210a, b, c are pivotally supported by 40a, 40b, 40c, and 40c, and the sheet feed rollers 210a, 210b, 210c swing upward when the sheet is pushed up by a push-up plate in the tray device. A sensor (not shown) is provided to detect when the paper feed rollers 210a, 210b, 210c reach a predetermined height. This sensor is used to control the push-up plate to move up a small amount every time a predetermined number of sheets are fed, and is usually called a paper empty sensor.

Intermediate rollers 250 for driving the sheet conveyance are disposed at appropriate intervals along the conveyance path 200. A slit 260 through which a sheet passes is formed in the top plate 8b at the upper end of the transport path 200.
The sheet is supplied to the printer E through the. Printer E
An upper timing roller 80a, a lower timing roller 80b, and a paper leading edge detection lever 90 are arranged in the vicinity of the photosensitive drum 70 in order to match the position of the image formed on the photosensitive drum 70 with the sheet timing. Below the paper edge detection lever 90, a pair of intermediate rollers 10 is provided.
0a and 100b are arranged, and the transport path 20 of the main body D of the sheet feeding device is arranged.
It is designed to receive 0 seats.

Since the tray devices A, B and C have the same structure, the tray device A will be described below. As shown in FIG. 2, the tray device A includes a main tray body 1, paper edge regulating plates 2 and 3 in the tray body 1, a push-up plate 4 arranged on a bottom portion 1a in the tray body 1, and the push-up plate. It is composed of a drive mechanism 5 for pushing up the plate 4, a release mechanism 6 for releasing the operation of the drive mechanism 5, and a re-release means 7 provided in the sheet feeding device main body D.

The tray 1 is constituted by a relatively thin rectangular plate-like body in which four peripheral surfaces on the bottom portion 1a are surrounded by a plate material, and the front surface thereof is suitable for the front surface of the cabinet 8 which is the main body of the paper feeder main body D. A decorative plate 8b provided with a handshake is attached, and guide members 1c that engage and slide with guide rails (not shown) of the cabinet 8 are provided on both outer surfaces.

A sheet detection sensor 12 is installed below the push-up plate 4 at the bottom 1a of the tray 1. The sheet detection sensor 12 is provided on the bottom portion 1 of the tray 1 below the through hole 11.
It is installed in a and is realized by a light reflection type sensor. Furthermore, the cabinet 8 at the lower center of the rear side wall surface 1e of the tray 1
A tray-side connector 13 is projectingly provided on the storage direction side of. On the other hand, the cabinet-side connector 14 electrically connected to the tray-side connector 13 when the tray 1 is completely stored (inserted to the deepest part) is provided on the inner surface of the cabinet 8 at a position facing the tray-side connector 13. Is installed.

The paper edge regulating plates 2 and 3 are made of a plate material erected on the bottom portion 1a of the tray 1. Depending on the size of the sheets to be stored, the two edge pieces are brought into contact with one corner of the sheets. The end pieces of the stacked sheets are prevented from being disturbed. The push-up plate 4 is made of a flat plate material having an area slightly smaller than the size of the sheets stored in the tray 1. As shown in FIGS. 3 to 6, hinge portions 4a are provided on both sides of one end which is the base side. The hinge portion 4a is pivotally supported on the side wall of the tray 1, and the free end side of the push-up plate 4 swings upward through the hinge portion 4a.

The drive mechanism 5 collectively supports the lift-up motor 5a composed of a DC motor, the pinion gear 5s which rotates in conjunction with the motor 5a, and abuts against the operation lever 6d, which will be described later, above the side end. A drive frame 5b having an engaging surface 5d to be engaged with it, and a fan-shaped rack gear 5f arranged to face the pinion gear 5c in the meshing direction.
And a lift shaft 5g that rotates together with the rack gear 5f, and a lift arm 5h that fixes one end to the shaft 5g, gifts up the back surface on the free end side, and moves the push-up plate 4 upward. Has been done.

The drive frame 5b has a structure shown in FIG.
As shown in FIG. 3, a fulcrum shaft 5e is provided at an intermediate portion between the engagement surface 5d and the pinion gear 5c, and the drive frame 5b is oscillated about the fulcrum shaft 5e. The pinion gear 5c is brought into mesh with the fan-shaped rack gear 5f by the urging force of the spring.
Further, when the release lever 6 raises the operation lever 6d, and the protrusion 6e abuts and engages with the engagement surface 5d of the drive frame 5b, the engagement between the pinion gear 5c and the fan-shaped rack gear 5f causes the drive frame 5b to swing. The driving force is released by separating in the moving direction.

The release mechanism 6 is composed of brackets 6a and 6b which are erected on the rear side wall surface 1e of the tray 1, and an operating lever 6d which is a flat plate member pivotally supported by a shaft 6c. A projecting piece 6e that engages with the engaging surface 5d of the drive frame 5b is formed on the side that is the base side, and when the operating lever 6d is raised, the engaging surface 5d is formed by the projecting piece 6e. Press to drive frame 5b
The pinion gear 5c is meshed with the fan-shaped rack gear 5f, that is, the driving state is released.

Further, the re-releasing means 7 is, as shown in FIGS. 7 to 10, a releasing lever 7a pivotally supported on a stationary wall surface 8c of a cabinet 8 so as to be swingable only in one direction, and an engaging surface 5d of a drive frame 5b. And an engaging piece 7b formed with an inclined surface facing the release lever 7a.
The release lever 7a is a stationary wall surface 8c of the cabinet 8.
Is a bifurcated lever body swingably supported around a support shaft 7d by a support portion 7c extending from the lever 7e when one lever 7e is positioned in the hanging direction by its own weight.
f is in contact with the top plate of the support portion 7c and restricts the one lever 7e from swinging leftward in the drawing. 7e
Is positioned in the hanging direction by its own weight, the other lever 7f is in contact with the top plate of the support portion 7c and the one lever 7e
Is restricted from swinging to the left in the figure.

When the tray 1 is pushed in under such a state, the one lever 7e climbs up the slope of the engaging piece 7b while engaging with the slope of the engaging piece 7b, and reaches the top of the slope.
The drive frame 5b is pressed to release the meshing between the instantaneous pinion gear 5c and the fan-shaped rack gear 5f. A sheet detection sensor 12 is connected to the tray-side connector 13 as shown in FIG. 11, and a cabinet-side connector 14 is connected to a determination unit 15 provided on a control board. When the tray side connector 13 and the cabinet side connector 14 are connected from the terminals 20 and 21 of the control board provided in the cabinet 8, the sheet detection sensor 1
Powered to 2.

The sheet detecting sensor 12 is composed of a light emitting portion 16 formed of a light emitting diode, a light receiving portion 17 formed of a photodiode, and an inverter 18 which inverts a signal from the light receiving portion when the voltage becomes lower than a certain voltage. The light emitted from the light emitting portion 16 is reflected by the lower surface of the sheet 19 stacked on the sheet pushing-up plate 4 through the through hole 11, and the reflected light is again received by the light receiving portion 17 through the through hole 11, and the received light amount thereof. Exceeds a certain value, the switch is turned on and the detection signal is output to the inverter 18. The inverter 18 outputs an H level output when the output voltage from the light receiving unit 18 is, for example, about 0.9 V (threshold potential) or lower, and outputs an L level output when the output voltage is higher than that. The output from the inverter 18 is input to the terminal 22 of the determination unit 15 of the control board via the tray side connector 13 and the cabinet side connector 14.

FIG. 12 is a schematic diagram for explaining the operation of the sheet detection sensor 12. The light emitted from the sheet detection sensor 12 is transmitted through the through hole 11 formed in the sheet push-up plate 4.
When the paper 18 is stacked on the paper, the reflected light reflected by the paper is received. When the paper 18 is not stacked, the emitted light is reflected by the top plate 19, and the paper detection sensor 12 receives the reflected light.

The light reflecting surface of the top plate 19 is composed of the interior surface of the cabinet 8 or the outer surface of the bottom of the other paper tray device A accommodated in the upper stage, and the iron plate is black-painted. The amount of light is small compared to the light reflected from the sheet. FIG. 13 is a graph showing the relationship between the voltage at the terminal 24 of the light receiving unit 17 of the paper detection sensor 12 and the distance to the reflecting surface. The horizontal axis represents the distance (mm) to the reflecting surface, and the vertical axis represents the output voltage (V). The solid line in FIG. 13 shows white paper, the one-dot chain line shows an unpainted iron plate, and the broken line shows the case where a black-painted iron plate is the reflecting surface.

Then, referring to the schematic diagram shown in FIG. 12, the distance D1 to the top plate 19 is selected to be 110 mm, for example. When no sheets are stacked, the voltage of the terminal 24 of the sheet detection sensor 12 due to the reflected light from the top plate 19 which is a black painted iron plate is about 0.1V. Distance D2 to the seat with the seat lifting plate 4 lifted up
Is, for example, 30 mm. At this time, the voltage of the terminal 24 of the sheet detection sensor 12 due to the reflected light from the white sheet 19 is about 4.8V. This output voltage is output to the inverter 18 as a detection signal. In the inverter 18,
When the output voltage becomes 0.9 V or less, the output is inverted and a high level signal is output to the terminal 22 of the determination unit 15. Therefore, when the sheets are not stacked, the terminal 22 outputs a high level, and when the sheets are stacked, the terminal 22 outputs a low level. Terminal 22
The low-level and high-level signals of the tray 1 are input to the determination unit 15, and whether the tray 1 is set or not is determined here.
It is determined whether or not the sheets are stacked on the sheet.
That is, the fact that the terminal 22 is at a low level means that the connectors 13 and 14 are connected and the light receiving portion 17 is receiving a light amount of a certain amount or more, so that the tray 1 is set and the sheets are It means loaded in the tray 1.

The determination output of the determination unit 15 is input to the motor drive control circuit 24. The motor drive control circuit 24 outputs the determination output, the detection signal of the paper empty sensor 25, and the print command from the host computer (not shown). Is input, and the drive control of the motor 5a is performed based on these inputs. In FIG. 11, the motor drive control circuit 24 has one
Although only the motors 5a of one tray 1 are shown to be connected, the motors of all trays are actually connected. FIG. 14 is a main flowchart for explaining the control operation of the motor drive control circuit. The process starts each time there is a print command from the host computer, and after initial setting (S1), the specified print size, format, etc. are received from the host computer (S2), and the paper feed port determination process routine (S3). ) Determines the paper feed port for first raising (lifting up) the push-up plate, and then executes a lift-up prohibition check processing routine (S4) for determining whether or not lift-up of the paper feed tray is prohibited. Run. Then, the lift-up processing routine (S5) lifts up the determined tray push-up plate, and subsequently the display, fixing, image forming operation and other processing routines (S6) are executed. After this, S3 to S6
It is determined by looking at the count value of the loop timer whether or not the specified time for repeating 1 time has passed (S
8, S9). Then, after confirming that the timer has timed out (in the case of Y in S8), the process returns to S3 again.

In the initial setting (S1) in the main flow, the lift-up prohibition flag is set to 1, and
Performs the process of setting the loop timer. In the input / output routine (S2), the print size designated by the host computer (for example, A3T, A4Y, A4T, A5Y, A5T, B4
T, B5Y, B5T) and format (eg, leisure T,
Read letter Y, letter T, invoice Y, invoice T).

The details of the paper feed port determination processing routine (S3) are shown in FIG. First, it is sequentially determined from the first to the fourth tray which sheet feed tray corresponds to the paper feed port of the print size and format designated by the host computer (S31, S33, S35, S37). . If there is a corresponding stage (Y in any of S31, S33, S35, and S37), the designated sheet feed port is fixed to that stage (S32, S34, S36, S38). If there is no paper feed port corresponding to the designated size and format, error processing is performed (S39). Although the number of trays is three in the paper feeding device of FIG. 1, it is assumed that there are four trays in the control operation for convenience.

FIG. 16 is a flow chart showing the lift-up prohibition check processing routine (S4). This process is a process of determining the presence or absence of a paper feed tray, the presence or absence of paper, etc. after determining the paper feed port, and setting a prohibition flag if there is no such. In this processing routine, F1, F2, F3, and F4 are the first stage,
A lift-up prohibition flag that is set to 1 when prohibiting lift-up in the second, third, and fourth paper feed trays and set to 0 when lifting up.

In this process, the processes from the first stage to the fourth stage are sequentially performed. First, it is determined whether the paper feed tray is mounted and there are sheets in the tray (S401, S40).
6, S411, S416). Then, the judgment of each stage is OK
If (YES in S401, S406, S411, S416), it is determined whether there is a print request (S403, S408, S413, S418). If there is a print request (S403, S408, S41)
3 and Y in S418), the lift-up prohibition flag F1, F2, F3, or F4 of the corresponding stage is set to 0.
Set to (S404, S409, S414, S41
9) Enables lift-up.

In the above processing from the first stage to the fourth stage, when the determination of the target stage (confirmed sheet feeding port) is not OK (S
(N in 401, S406, S411, S416), the lift-up prohibition flags F1, F of that stage are
Set 2, F3 or F4 to 1 to prohibit lift up. Further, when the paper feed tray is installed and there is no paper print request (S403, S408, S41)
(3, in the case of N in S418), proceed to the next step.

FIG. 17 is a flowchart showing the lift-up processing routine. In this process, M1, M
2, M3, and M4 are the first, second, and third stages, respectively.
It is a lift-up motor that operates to push up the fourth-stage push-up plate. Also, S1, S2, S3, S4
Are upper limit detection sensors for the first, second, third, and fourth trays, respectively, and are turned on when the uppermost sheet reaches the position where it comes into contact with the sheet feeding roller in the present embodiment, If it is lower than the height, it is off.

In this lift-up process, it is judged whether or not there is a print request (S501). When there is a print request, it is first determined where the designated paper feed port is (S502, S508, S514, S52).
0), and the lift-up drive motor M is turned on sequentially from the designated paper feed port determined by the paper feed port determination routine (FIG. 15).
It is determined whether or not N. That is, for example, when the second sheet feeding port is designated (S508), the lift-up prohibition flag F2 is 0 (S509), and the motors of the stages other than the second stage are stopped (S511). The motor of the second stage is driven under the condition ()) (S512), and the push-up plate of the second-stage tray is pushed up. Due to the pushing-up operation of the pushing-up plate, the sheet on the sheet eventually comes into contact with the sheet feeding roller and pushes up the sheet feeding roller. Then, since the paper empty sensor S2 is turned on when the paper feed roller moves upward to the predetermined height (S511), the motor M2 is stopped (S513). When the motor M2 is stopped, the program immediately proceeds from S513 to S515, and if the lift-up prohibition flag F3 is 0, then S516 → S517 → S.
Further proceeding to 518, the motor M3 of the third tray is driven to push up the push-up plate. In the third stage, when the paper feed roller is moved upward until the paper empty sensor S3 is turned on (S517), the driving of the motor M3 is stopped (S519). Then, the motor of the tray of the next order satisfying the two conditions that the lift-up prohibition flag is 0 and the paper empty sensor is OFF is driven. In this way, the lift-up plates of all trays are sequentially lifted up. In this way, the motors of the respective trays are driven one by one in order to avoid consuming a large amount of power more than the allowable amount at one time.

FIG. 18 is a time chart showing the lift-up operation of the push-up plate of each tray described above. FIG. 6A shows, for example, the insertion / extraction state of the second tray. Since there are no stacked sheets, pull out the tray,
The seat is replenished and pushed into the cabinet at time t1. At this time, the determination unit 15 has completed the tray mounting,
Moreover, it is determined that there is a sheet in the tray (Fig. (C)). Next, when a print command is input at time t2, it is understood that the motors (M2) at the stage where the paper feed port is fixed are sequentially driven.

In the above embodiment, when a print command is issued, not only the in-tray push-up plate of the confirmed paper feed port but
Although the in-tray push-up plates of the other paper feed ports are also pushed up sequentially, it is also possible to push only the in-tray push-up plates of the confirmed feed ports. This configuration
It is simpler than the control flow of the above embodiment. Further, in the above embodiment, both the tray mounting and the sheet stacking are detected by one detection sensor, but the present invention is not limited to this, and a sensor for detecting the presence or absence of the tray and the inside of the tray are detected. It goes without saying that the sensor for detecting the presence or absence of the sheet may be separately provided.

[0034]

As described above, according to the present invention, when there is a print request, the drive mechanism is operated to lift up the lifting plate, and the lifting plate is not lifted up only by mounting the tray. Therefore, the machine life of the drive mechanism that lifts up the push-up plate can be extended.

[Brief description of drawings]

FIG. 1 is a front cross-sectional view showing a configuration of a main part of a sheet feeding device of this embodiment.

FIG. 2 is a perspective view of a paper tray position showing an embodiment of the present invention.

FIG. 3 is a rear view with the operation of the paper tray device.

FIG. 4 is a rear view with the operation of the paper tray device.

FIG. 5 is a rear view with the operation of the paper tray device.

FIG. 6 is a rear view with the operation of the paper tray device.

FIG. 7 is a side view showing re-releasing means.

FIG. 8 is a side view showing the operation of the re-releasing means.

FIG. 9 is a side view showing the operation of the re-releasing means.

FIG. 10 is a side view showing the operation of the re-releasing means.

FIG. 11 is an electronic circuit diagram configured by the paper detection sensor 12 and the determination unit 15 when the first connector 14 and the second connector 13 are connected.

FIG. 12 is a schematic diagram for explaining the operation of the paper detection sensor 12.

FIG. 13 is a graph showing the relationship between the distance to the reflection surface and the output voltage of the terminal 24 of the light receiving unit 17.

FIG. 14 is a flowchart showing a control flow of the entire printer including the paper feeding device according to the present invention.

FIG. 15 is a flowchart showing a paper feed port determination processing routine in FIG.

16 is a flowchart showing a lift-up prohibition check processing routine in FIG.

17 is a flowchart showing a lift-up processing routine in FIG.

FIG. 18 is a time chart illustrating a sheet pushing-up operation of each tray when a print command is issued.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tray 2 Paper edge regulating plate 3 Paper edge regulating plate 4 Paper pushing plate 5 Drive mechanism 5a Lift up motor 6 Release mechanism 7 Re-releasing means 8 Cabinet 10 Sheet concealing plate 11 Through hole 12 Sheet detection sensor 13 Tray side connector 14 Cabinet side Connector 15 Judgment unit 16 Light emitting unit 17 Light receiving unit 18 Inverter 19 Paper 20 Top plate 22 Terminal 24 Motor drive control circuit 25 Paper empty sensor A, B, C Tray device D Paper feeder main body

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Gonda 2-3-13 Azuchi-cho, Chuo-ku, Osaka City Osaka International Building Minolta Camera Co., Ltd. (72) Inventor Mineo Yamamoto 2-chome, Azuchi-cho, Chuo-ku, Osaka No. 13 Osaka International Building Minolta Camera Co., Ltd.

Claims (1)

[Claims] 1. A sheet feeding device main body, a sheet feeding tray for accommodating sheets and mounted in the main body, a sensor for detecting the presence / absence of sheets in the tray, and a sheet provided at the bottom of the tray. A push-up plate, a drive mechanism for raising the push-up plate, and drive control means for operating the drive mechanism to raise the push-up plate when there is a print request and there is a sheet in the tray. And a paper feeder.