JP2017171402A - Paper sheet feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper sheet feeder capable of preventing a paper sheet from a conveyance jam due to excessive slackness after skew correction.SOLUTION: A paper sheet feeder includes a pre-secondary paper sheet feeding roller pair 30 between a primary paper sheet feeding mechanism 10 and a secondary paper sheet feeding mechanism 20, the roller pair being for preventing a conveyance jam due to slackness generated in skew correction. A controller 40 determines whether to execute an anti-jam control during conveyance on the basis of information on at least one of a paper sheet kind and a paper sheet feeding speed included in a printing job. If the printing job needs to execute the anti-jam control during conveyance, the controller brings a second roller 32 of the pre-secondary paper sheet feeding roller pair 30 close to a first roller 31 at a previously-acquired drive start timing after a reception of a detection signal of a paper sheet P from a paper sheet detection sensor 23 to nip the paper sheet P at a position off the conveyance reference line L.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sheet feeding device that is mounted as a sheet feeding unit of a printing apparatus, for example, and takes out sheets one by one from a bundle of sheets stacked on a sheet feeding stand and feeds them to a printing unit.

  Conventionally, it is mounted on a printing apparatus such as an ink jet recording apparatus, a stencil printing apparatus, a copier, or a laser printer. As a paper feeding apparatus for paper, an apparatus disclosed in the following Patent Document 1 is known.

  In this type of paper feeding device, a primary paper feeding mechanism having a paper feeding roller and a separating plate, and a secondary paper feeding mechanism having a pair of registration rollers for performing skew correction when transporting paper to a subsequent printing unit And a paper detection sensor disposed between the primary paper supply mechanism and the secondary paper supply mechanism, and the primary paper supply mechanism separates the paper stacked on the paper supply table into one sheet, and the paper detection sensor After the sheet is detected in step 1, the sheet is conveyed by a predetermined amount, and the leading edge of the sheet is brought into contact with the registration roller pair to generate slack, thereby performing skew correction.

JP 2010-89912 A

  Incidentally, in recent years, it has been desired to increase the printing processing speed for the purpose of improving productivity, and in order to realize this, the primary paper feeding mechanism and the secondary paper feeding mechanism are also driven at high speed.

  However, since the paper feed roller in the primary paper feed mechanism is connected by a clutch mechanism, even if the paper feed clutch is turned off, it cannot be stopped immediately by the inertial force, and the paper overruns from the target stop position. There is a problem that the amount of slackening increases.

  In order to solve such problems, a method of controlling the amount of conveyance after the sheet passes the sheet detection sensor in consideration of the overrun amount corresponding to the print mode, and reducing the variation in the slack amount for each print mode. Is also known. However, if the paper feed speed is increased, the amount of slack will be excessive even if the paper feed clutch is turned off at the same time as the leading edge of the paper has passed the paper detection sensor, making it difficult to control the amount of slack appropriately. Met.

  Further, in order to allow some amount of slack due to overrun to some extent, there is some space between the primary paper feed mechanism and the secondary paper feed mechanism. However, when the slack occurs beyond this space, the slack is formed in a Z shape along the lower conveyance guide plate as shown in FIG. There was a problem that a jam occurred due to folding.

  Furthermore, when the amount of slack is excessive, there is a problem that the leading edge of the paper that has come into contact with the registration roller pair of the secondary paper feeding mechanism comes back and causes a conveyance failure.

  Accordingly, the present invention has been made in view of the above problems, and is a paper feeding device that can prevent an excessive amount of slack due to an increase in paper feeding speed and suppress a conveyance failure caused by excessive slack. Is intended to provide.

In order to achieve the above-described object, a first aspect according to the present invention includes a primary paper feed mechanism that feeds and conveys sheets stacked on a paper feed table one by one with a paper feed roller and a separating plate,
A secondary paper feed mechanism that transports to the subsequent stage at a predetermined timing after the registration correction is performed by abutting the leading edge of the sheet fed by the primary paper feed mechanism with a pair of registration rollers;
A paper detection unit that is provided upstream of the secondary paper feed mechanism and detects the leading edge of the paper that is fed by the primary paper feed mechanism before reaching the pair of registration rollers;
In a paper feeder provided with
Between the primary paper feed mechanism and the secondary paper feed mechanism, the paper is located at a position deviating from a conveyance reference line connecting a nip point between the paper feed roller and the separating plate and a nip point between the pair of registration rollers. Equipped with a pair of rollers before secondary feeding to nip
The pair of pre-secondary paper feeding rollers is a paper feeding device that nips at a predetermined timing after the paper detection means detects the paper.

  According to a second aspect of the present invention, in the paper feeding device according to the first aspect, the roller before secondary paper feeding is based on at least one of the paper type information and the paper feeding speed information. The sheet feeding device includes a determination unit that determines whether or not to perform nip processing by a pair.

According to a third aspect of the present invention, in the paper feeding device according to the first aspect or the second aspect, the roller pair before secondary paper feeding includes:
A first roller fixedly disposed at a position above the transport reference line in the upper transport guide plate of the secondary paper feed mechanism;
A second roller disposed below the transport reference line and provided on the lower transport guide plate of the secondary paper feed mechanism so as to be swingable about a hinge portion as a fulcrum;
The sheet feeding device according to claim 1, wherein the second roller moves toward the first roller and nips the sheet at a predetermined timing after the sheet detection unit detects the sheet.

  According to the sheet feeding device according to the first aspect, even when the slack generated when the sheet hits the registration roller pair becomes excessive, the sheet is transported from the conveyance reference line by the pair of rollers before secondary sheet feeding. Since the nipping is performed at the disengaged position, even if the conveyance by the secondary paper feeding mechanism is started, the slack portions of the paper are not overlapped and Z-folded unlike the conventional apparatus. Further, it is possible to prevent the conveyance jam while preventing the leading edge of the sheet from slipping back from the registration roller pair due to the excessive slack amount.

  According to the sheet feeding device according to the second aspect, at least one of the sheet type information indicating the sheet type included in the print job and the sheet feeding speed information indicating the sheet feeding speed synchronized with the printing speed is included. Based on this, the conveyance jam prevention control by the pair of rollers before secondary paper feeding is performed, so that the driving sound generated when the rollers before secondary paper feeding are driven is not inadvertently generated.

  According to the sheet feeding device of the third aspect, the second roller serves as a sheet conveyance guide by waiting below the conveyance reference line when the sheet is conveyed from the primary sheet feeding mechanism. When the sheet is nipped, excessive slackness of the sheet is accommodated to some extent by the slack allowance space generated below the second roller, so that the effect of preventing Z-folding can be further enhanced.

It is a schematic block diagram of the paper feeder of this invention. It is a block diagram which shows the structure of the control system of the apparatus. (A) is a figure before the conveyance jam prevention control by the roller pair before secondary paper feed of the same apparatus, (b) is after the execution of the conveyance jam prevention control by the roller pair before secondary paper feed of the same apparatus It is a figure which shows a state. It is a figure which shows the state at the time of conveyance jam generation in the conventional paper feeder.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In addition, the present invention is not limited by this embodiment, and all other forms, examples, operation techniques, and the like that can be considered by those skilled in the art based on this form are included in the scope of the present invention. Shall.

  The paper feeding device 1 according to the present embodiment supplies paper P as a printing medium to a printing unit (not shown) of a printing device (inkjet recording device, stencil printing device, copying machine, laser printer, MFP (Multifunction Peripheral), etc.). Mounted as a paper feeder. Note that the configuration of the printing apparatus is the same as that of the conventional apparatus, and thus the description thereof is omitted.

[Device configuration]
As shown in FIGS. 1 and 2, the paper feeding device 1 is a device that supplies (feeds) paper P to a printing unit (not shown) of the printing device, and includes a primary paper feeding mechanism 10 and a secondary paper feeding. The mechanism 20, the secondary pre-feed roller pair 30, a control unit 40, and a storage unit 50 are schematically configured.

−Primary paper feed mechanism−
The primary paper feed mechanism 10 includes a paper feed table 11, a paper feed roller 12, a paper feed motor 13, and a separating plate 14.

  The paper feed table 11 is a table having a lifting / lowering function for stacking a large number of sheets P (sheet bundle). The paper feed table 11 is controlled to be raised and lowered under the control of the control unit 40 so that the paper surface of the uppermost paper P in the stacked paper bundle is always in contact with the roller surface of the paper feed roller 12.

  The paper feed roller 12 is arranged on the upper side of the paper feed tray 11, and scraper rollers 12a for picking up the paper P stacked on the paper feed tray 11 one by one and the paper P picked up by the scraper roller 12a one by one. And a pickup roller 12b transported toward the registration roller pair 21.

  The paper feed roller 12 is rotated by the driving force of the paper feed motor 13 when the paper feed clutch 13a is turned on at the start of paper feed under the control of the control unit 40. Further, when the sheet P is conveyed by the registration roller pair 21, the sheet feeding clutch 13a is turned off and the driving of the sheet feeding roller 12 is disconnected. Therefore, the sheet feeding roller 12 rotates with the movement of the sheet P. . Further, a predetermined gap is provided between the pickup roller 12b and the upper surface of the sheet bundle in order to facilitate the sheet P.

  The separating plate 14 is for coping with the pickup roller 12b so as to convey the sheets P conveyed by the scraper roller 12a one by one, and is inclined at a predetermined angle along the conveying direction. And is provided in pressure contact with the roller surface of the pickup roller 12b from below.

-Secondary paper feed mechanism-
The secondary paper feeding mechanism 20 includes a registration roller pair 21, a registration motor 22, and a paper detection sensor 23. In the secondary paper feeding mechanism 20, the paper P conveyed from the primary paper feeding mechanism 10 passes between the upper guide plate 24 and the lower guide plate 25, and the leading end of the paper P abuts against the registration roller pair 21 to a predetermined amount. The skew correction is performed by the slack of. The skew-corrected paper P is conveyed to the printing unit at a predetermined operation cycle (for example, printing timing).

  The registration roller pair 21 is arranged on the downstream side of the paper feed roller 12, and after the paper P sent from the paper feed roller 12 is abutted, the registration roller 22 is driven to the printing unit at a predetermined operation cycle by the driving force of the registration motor 22. The paper P is transported toward it. The sheet P abuts against the registration roller pair 21 to generate a predetermined amount of slack, thereby correcting the skew of the sheet P.

  The paper detection sensor (corresponding to “paper detection means” in the claims) 23 is an optical sensor having a light projecting part and a light receiving part, for example, and is arranged between the primary paper feeding mechanism 10 and the registration roller pair 21. . When the paper detection sensor 23 detects the leading edge of the paper P conveyed from the paper supply roller 12 toward the registration roller pair 21, the paper detection sensor 23 outputs a detection signal to the control unit 40.

-Roller pair before secondary feeding-
The pre-secondary feed roller pair 30 is provided between the primary feed mechanism 10 and the secondary feed mechanism 20. The pair of pre-secondary feed rollers 30 includes a first roller 31 that contacts the surface of the paper P, a second roller 32 that can swing in a direction perpendicular to the transport direction of the paper P (up and down in the figure), and a second roller 32. The driving unit 33 is a driving source for driving the two rollers 32.

  The first roller 31 is a line connecting the nip point of the paper P between the paper feed roller 12 and the separating plate 14 in the primary paper feed mechanism 10 and the nip point of the registration roller pair 21 in the secondary paper feed mechanism 20 (hereinafter referred to as “the first roller 31”). This line is a driven roller fixedly arranged above the “conveyance reference line L”. In the present embodiment, it is provided on the upper guide plate 24 of the secondary paper feed mechanism 20. The first roller 31 nips the paper P with the second roller 32 that moves at a predetermined timing.

  The first roller 31 may be fixedly disposed as in the present embodiment as long as the paper P can be nipped at a position that is at least deviated from the transport reference line L and does not interfere with the paper transport. For example, similar to the second roller 32, a configuration in which the proximity / separation is possible in the vertical direction may be employed.

  The second roller 32 is provided below the conveyance reference line L so as to be swingable in a direction (vertical direction in the figure) perpendicular to the conveyance direction of the paper P by the driving force of the driving unit 33 with the hinge portion 32a as a fulcrum. Driven roller.

  As shown in FIG. 3A, when the paper P is transported from the primary paper feeding mechanism 10, the second roller 32 stands by at a position below the transport control line, and the paper P is guided to the lower guide. It functions as a part of the plate 25.

  Further, as shown in FIG. 3B, the second roller 32 is controlled by the control unit 40 after a predetermined time has elapsed since the paper P conveyed from the primary paper feeding mechanism 10 was detected by the paper detection sensor 23. The sheet P moves toward the first roller 31 and nips the sheet P at a position deviating from the conveyance reference line L. When the sheet P is conveyed by the registration roller pair 21, the sheet P moves away from the first roller 31 to a position (standby position) below the conveyance reference line L, and the next sheet P is detected by the sheet detection sensor 23. Wait at this position until detected.

  Further, as shown in FIG. 3B, in the state where the second roller 32 nipped the paper P, the second roller including the vicinity of the start end of the lower guide plate 25 (that is, the lower portion of the second roller 32 in the standby state) In the vicinity of 32), a slack allowable space E into which the slack paper P can enter is formed. By forming the slack allowance space E, even if the slack amount is excessive, slack enters the space and overlap of the slack portions can be reduced.

  The driving unit 33 is a unit that transmits energy (power) such as an actuator or a motor to the hinge portion 32a of the second roller 32 as a rotational force. The driving unit 33 transmits power to the second roller 32 at a predetermined timing under the control of the control unit 40 (that is, input of a control signal indicated by an arrow A shown in FIG. The two rollers 32 are swung in the direction of approaching / separating.

-Control unit-
The control unit 40 performs overall drive control of each unit constituting the sheet feeding device 1. Further, the control unit 40 controls the primary paper feed mechanism 10 and the secondary paper feed mechanism 20 based on the detection signal from the paper detection sensor 23 and the pulse signal from the encoder, respectively, and the productivity of the printing apparatus is ensured. Thus, the paper P stacked on the paper feed tray 11 is conveyed to the printing unit in accordance with the operation cycle of the registration roller pair 21.

  Further, the control unit 40 adjusts the slack shape by the roller pair 30 before the secondary paper feeding in order to prevent the conveyance jam due to the excessive slack amount caused when the paper P contacts the registration roller pair 21.

Here, the control of the roller pair 30 before secondary paper feeding related to the conveyance jam prevention will be described.
In the present invention, the amount of slack generated when the paper P conveyed from the primary paper feed mechanism 10 contacts the registration roller pair 21 is transmitted to the paper feed roller 12 as in the conventional apparatus. This is controlled for each sheet feeding speed in anticipation of an overrun amount after turning off the sheet feeding clutch (not shown).

  However, when the paper feeding speed is increased according to the print mode, or when the paper P is a thin paper with a relatively small basis weight or a paper P with a high smoothness, the paper is transported beyond the planned overrun amount. There is. This is because, as described in the above section [Problems to be Solved by the Invention], even if the sheet feeding clutch is turned off, the rotation of the sheet feeding roller 12 does not stop immediately due to the inertial force. Yes.

  Therefore, in the present invention, when the type of paper P and the paper feed speed tend to exceed the expected amount of overrun, the paper is fed by the roller pair 30 before the secondary paper feed mechanism 20 before being transported by the secondary paper feed mechanism 20. By niping P, even if the amount of slack is excessive, the number of contact portions between slack portions of the paper P is reduced as much as possible so that Z-shaped slack that causes a conveyance jam does not occur.

  Therefore, the control unit 40 first includes paper type information (information specifying the type of the paper P such as paper quality and basis weight) included in the print job, and paper feed speed information (information about the paper P by the primary paper feed mechanism 10). Based on at least one of the information (conveyance speed), it is determined whether or not to perform the conveyance jam prevention control by the roller pair 30 before secondary sheet feeding. That is, the control unit 40 functions as “determination means” in the claims.

  The conveyance jam prevention control is not performed for all print jobs so as not to inadvertently increase the driving sound when the second roller 32 is swung, and at least, it is difficult to control the slack amount. Targeted when high-grade paper P is used or when a print job with a relatively high paper feed speed (for example, a paper feed speed for printing 120 sheets per minute) is executed To do.

  Therefore, the control unit 40 may determine whether or not the conveyance jam prevention control is performed based on the paper type information and the paper feed speed information included in the printing conditions of the print job. For example, the user may determine whether or not the setting operation unit ( It may be determined on the basis of setting information in which whether or not to perform the conveyance jam prevention control is set from (not shown).

  When carrying out the conveyance jam prevention control, first, when the leading edge of the sheet P conveyed from the primary sheet feeding mechanism 10 is detected by the sheet detection sensor 23, a detection signal associated with this detection is output to the control unit 40. The control unit 40 outputs a control signal to the driving unit 33 after a predetermined time has elapsed with the input timing of the detected detection signal as a trigger, and causes the second roller 32 to approach the first roller 31 to nip the paper P.

  Next, when the sheet P is nipped by the roller pair 30 before the secondary sheet feeding, the control unit 40 controls the secondary sheet feeding mechanism 20 to convey the sheet P toward the subsequent printing unit at a predetermined timing. Let At this time, the excessive slack generated on the paper P is transported so that the slack portion overlapped by the transport by the secondary paper feeding mechanism 20 can be solved.

  In the conveyance jam prevention control described above, the driving unit 33 is controlled to start driving at a driving start timing suitable for the printing conditions. Therefore, the control unit 40 drives based on the paper type information and the paper feed speed information included in the printing conditions of the print job, and starts driving at a driving start timing suitable for the printing conditions (the leading edge of the paper P is detected as a paper. The time from the detection by the sensor 23 to the start of driving of the driving means 33) is obtained by a predetermined calculation process. Therefore, depending on the printing conditions, the drive start timing may be after a predetermined time has elapsed after the detection signal is input from the paper detection sensor, or may be substantially the same as the input timing of the detection signal from the paper detection sensor 23. .

  In addition to this method, a drive control table in which drive start times obtained by experiments or the like are associated in advance is created and stored in accordance with the combination of the type (basis weight, smoothness) of the paper P and the paper feed speed. When the print job is stored in the unit 50 and the print job is executed, the drive unit 33 may be controlled by selecting a drive start time suitable for the print job from the stored drive control table.

  When creating the drive control table, there are innumerable combinations of types of paper P and paper feed speeds. For example, as the type of paper P, the paper thickness is “thin paper, plain paper, thick paper” 3 Associate drive control time according to the combination of three types, “low, medium, high” for the type and smoothness, and the feed speed of “less than 120 sheets per minute, 120 sheets per minute” Just make it a table.

-Storage unit-
The storage unit 50 stores various information (computer program, application software, etc.) necessary for driving each unit of the sheet feeding device 1. Further, when carrying out the jam prevention control using the drive control table created in advance as described above, this table is also stored.

<About processing operation>
Next, a series of sheet feeding operations by the sheet feeding device 1 described above will be described.
In the following operation example, a print job is executed in a high-speed print mode (120 sheets per minute) on a thin paper P having a relatively high smoothness and a paper feed speed, and the control unit 40 includes a paper type included in the print condition. The drive start time appropriate for the print job is obtained from the information (in this example, the paper P is thin and the smoothness is relatively high) and the paper feed speed information (in this example, the print mode is the high-speed print mode). It is set as the form to do. Further, the conveyance jam prevention control is performed when the paper type information includes at least one condition of “thin paper” or “relatively high smoothness” and the paper feed speed information is set to “high-speed printing mode”. Will be implemented only.

  In executing the print job, the control unit 40 first determines whether or not the conveyance jam prevention control using the pre-secondary paper feeding roller pair 30 is performed from the paper type information and the paper feed speed information included in the print job. . In this operation example, since the paper P is thin, the smoothness is relatively low, and the paper feed speed is in the high-speed printing mode, it is determined to perform the conveyance jam prevention control.

  Further, the control unit 40 acquires a drive start time appropriate for the print job to be executed based on the paper type information and the paper feed speed information included in the print job.

  Next, when the print job is executed, first, the uppermost sheet P of the sheet bundle placed on the sheet feed tray 11 is picked up by the primary sheet feed mechanism 10 and conveyed to the secondary sheet feed mechanism 20. . When the paper detection sensor 23 detects the leading edge of the paper P conveyed to the secondary paper feeding mechanism 20, it outputs a detection signal to the control unit 40. Further, the paper P conveyed to the secondary paper feeding mechanism 20 passes through the paper detection sensor 23 and then comes into contact with the registration roller pair 21 to be loosened, and skew correction is performed.

  The control unit 40 controls driving of the driving unit 33 by outputting a control signal at a driving start time acquired before the job is started, using the detection signal input from the paper detection sensor 23 as a trigger. As a result, as shown in FIG. 3A, the second roller 32 is brought close to the first roller 31, and the sheet P is nipped at a position deviated from the conveyance reference line L.

  When the sheet P is nipped by the pre-secondary sheet feeding roller pair 30, the secondary sheet feeding mechanism 20 conveys the sheet P toward the subsequent printing unit at a predetermined timing. At this time, the paper P generated on the paper P is transported by the secondary paper feeding mechanism 20 so that the overlapping slack portions can be released without being transported in a Z-folded state. Further, it is possible to prevent the leading edge of the sheet from slipping back from the registration roller pair 21 due to an excessive amount of slack.

  When the paper P is conveyed to the subsequent printing section by the secondary paper feeding mechanism 20, the driving means 33 is controlled to return the second roller 32 to the standby position as shown in FIG. To prepare for loading paper P.

  Thereafter, for the number of prints designated by the print job, as described above, the secondary paper feed mechanism 20 is in a state where the paper P is nipped by the pre-secondary paper feed roller pair 30 after the paper P hits the registration roller pair 21. The operation of conveying to the printing unit is repeated.

  As described above, the sheet feeding device 1 described above is configured to perform secondary sheet feeding between the primary sheet feeding mechanism 10 and the secondary sheet feeding mechanism 20 in order to prevent a conveyance jam due to slack that occurs during skew correction. A front roller pair 30 is provided. The pair of pre-secondary paper feeding rollers 30 is perpendicular to the conveyance direction of the sheet P with the first roller 31 fixedly disposed above the conveyance reference line L and the hinge portion 32a below the conveyance reference line L as a fulcrum. The second roller 32 is provided so as to be swingable in the direction of movement (vertical direction in the drawing), and the sheet P is nipped by bringing the second roller 32 close to the first roller 31 at a predetermined driving start timing. .

  As a result, even if the slack generated when the paper P hits the registration roller pair 21 becomes excessive, the nip at the position where the paper P is deviated from the conveyance reference line L by the roller pair 30 before the secondary paper feeding. Therefore, even if the conveyance by the secondary paper feeding mechanism 20 is started, the slack portion of the paper P can be smoothly conveyed without being overlapped and Z-folded as in the conventional apparatus. In addition, it is possible to prevent the leading edge of the sheet from coming off from the registration roller pair due to an excessive amount of slack.

  Further, when the paper P is transported from the primary paper feed mechanism 10, it waits below the transport reference line L to serve as a transport guide for the paper P, and when the paper P is nipped, the second roller 32. Since the slack allowance space E is slightly generated below the sheet P, excessive slackness of the paper P can enter the slack allowance space E, so that the occurrence of Z-folding can be further suppressed.

  In addition, the control unit 40 determines whether or not to perform the conveyance jam prevention control based on at least one of the paper type information and the paper feed speed information included in the print job, and the drive start timing suitable for the print job. The drive start time for driving the driving means 33 is acquired, and the drive start acquired in advance after inputting the detection signal when detecting the paper P conveyed from the primary paper feed mechanism 10 from the paper detection sensor 23. After the time, the second roller 32 is brought close to the first roller 31, and the paper P is nipped at a position deviated from the conveyance reference line L.

  Therefore, the second roller 32 is not swung for a print job that does not require the conveyance jam prevention control, and the driving sound generated at the time of the swing or nip can be prevented from being inadvertently increased.

DESCRIPTION OF SYMBOLS 1 ... Paper feed apparatus 10 ... Primary paper feed mechanism 11 ... Paper feed stand 12 ... Paper feed roller (12a ... Scraper roller, 12b ... Pick-up roller)
13 ... paper feed motor (13a ... paper feed clutch)
DESCRIPTION OF SYMBOLS 14 ... Separation board 20 ... Secondary paper feeding mechanism 21 ... Registration roller 22 ... Registration motor 23 ... Paper detection sensor (paper detection means)
24 ... Upper guide plate 25 ... Lower guide plate 30 ... Secondary pre-feed roller pair 31 ... First roller 32 ... Second roller 33 ... Drive means 40 ... Control unit 50 ... Storage unit E ... Loose allowance space L ... Conveyance Reference line P ... paper

Claims (3)

A primary paper feed mechanism that transports paper stacked on a paper feed tray one by one with a paper feed roller and a paper board;
A secondary paper feed mechanism that transports to the subsequent stage at a predetermined timing after the registration correction is performed by abutting the leading edge of the sheet fed by the primary paper feed mechanism with a pair of registration rollers;
A paper detection unit that is provided upstream of the secondary paper feed mechanism and detects the leading edge of the paper that is fed by the primary paper feed mechanism before reaching the pair of registration rollers;
In a paper feeder provided with
Between the primary paper feed mechanism and the secondary paper feed mechanism, the paper is located at a position deviating from a conveyance reference line connecting a nip point between the paper feed roller and the separating plate and a nip point between the pair of registration rollers. Equipped with a pair of rollers before secondary feeding to nip
The pair of pre-secondary paper feeding rollers nips at a predetermined timing after the paper detection means detects the paper.   And determining means for determining whether or not to perform nip processing by the pair of rollers before secondary sheet feeding based on at least one of the sheet type information and the sheet feeding speed information. The paper feeding device according to claim 1. The roller pair before secondary paper feeding is
A first roller fixedly disposed at a position above the transport reference line in the upper transport guide plate of the secondary paper feed mechanism;
A second roller disposed below the transport reference line and provided on the lower transport guide plate of the secondary paper feed mechanism so as to be swingable about a hinge portion as a fulcrum;
3. The paper feed according to claim 1, wherein the second roller moves toward the first roller and nips the paper at a predetermined timing after the paper detection unit detects the paper. 4. apparatus.

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