JP2001324844A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To completely shorten the time for image forming operation by making the time when plural sheets of form pass through an image forming part the shortest in accordance with the length of an image formed on the form. SOLUTION: When a sensor SS1 detects the front edge of the form P1, a solenoid 45c is turned on so as to temporarily stop carrying the forms P1 to P3, and the solenoid 45c is turned off in specified timing so as to restart carrying the forms P1 to P3 (A). When the sensor SS1 detects the front edge of the form P2, the solenoid 45c is turned on so as to temporarily stop carrying the forms P2 and P3 (B). The front edge of the form P1 passes through a transfer position at the point of time when the sensor SS1 detects the front edge of the form P2, and the form P1 is continuously carried even in such a state. Thereafter, the solenoid 45c is turned off when the time required to carry the form 2 by the length of the form P2 from which a blank part on the front edge side is eliminated elapses (C). The carrying force of a resist roller 45 is supplied to the forms P2 and P3, and the form P2 is carried to a transfer position while keeping a state where the rear end of the form P1 is superposed on the front end of the form P2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a facsimile which forms an image on a sheet fed from a sheet feeding section in an image forming section. The present invention relates to an image forming apparatus that forms an image in a multiplexed state in which sheets are partially overlapped with each other when images are continuously formed.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, there is a strong demand for shortening an image forming operation. For this reason, in a conventional image forming apparatus, for example, as disclosed in Japanese Patent Application Laid-Open Nos. 9-314993 and 11-202683, it is difficult to form an image continuously on a plurality of sheets. By shortening the paper conveyance interval, the time from the front end of the first paper to the rear end of the last paper among the plurality of papers continuously conveyed is shortened to pass through the image forming unit, and the image forming state is reduced. In some cases, the image forming operation is shortened without increasing the image forming speed, which causes deterioration of the image forming speed.

In particular, in the construction disclosed in Japanese Unexamined Patent Publication No. 5-294496 and Japanese Patent Laid-Open No. 62-62373, a plurality of sheets on which images are continuously formed are overlapped by a predetermined length. The time required for a plurality of sheets to pass through the image forming unit is further shortened.

[0004]

However, in the structures disclosed in Japanese Patent Application Laid-Open Nos. 5-294496 and 62-62373, the length of overlapping each sheet in the transport direction is not clearly specified. However, if this length is constant, image formation is hindered in a state of being superimposed on another sheet, considering that the length of the image to be formed on the sheet in the transport direction changes in various ways. For this reason, the sheets cannot be overlapped only in a so-called void area where an image is not always formed on each sheet, and there is a problem that the time required for a plurality of sheets to pass through the image forming unit cannot be sufficiently reduced. Was.

In an image forming apparatus for forming an image by an electrophotographic method, it is necessary to heat and press a sheet on which a developer image has been transferred in a fixing unit, and a state in which two sheets are partially overlapped. If the sheet is passed through the fixing unit as it is, there is a problem that the two sheets come into close contact and cannot be smoothly discharged to the outside of the apparatus.

An object of the present invention is to delete a blank portion of an image in a paper transport direction from each of image data to be continuously formed, and to reduce the overlap amount in accordance with the length of the deleted blank portion in the transport direction. The papers positioned before and after are superimposed on each other, so that the time required for multiple sheets to pass through the image forming section is minimized according to the length of the image to be formed on the paper, and the image forming operation is sufficiently shortened. It is another object of the present invention to provide an image forming apparatus that can separate sheets from each other before reaching a fixing unit and can reliably prevent the sheets from sticking to each other.

[0007]

Means for Solving the Problems (1) In each of a plurality of image data to be continuously image-formed, a blank portion at a front end side or a rear end side in a sheet conveying direction is deleted and supplied to an image forming unit. And a control unit for operating the sheet conveying unit so as to convey a plurality of sheets to the image forming unit in a multiplexed state in which the deleted blank portion overlaps over the length of the sheet conveying direction.

According to the present invention, in each image data to be formed on each of a plurality of sheets conveyed continuously, a blank portion on the front end side or the rear end side in the sheet conveying direction is deleted, and the deleted blank portion is removed. Plural sheets of paper are conveyed in a state of being overlapped in the length in the paper conveyance direction. Therefore, a plurality of sheets are conveyed in a state where the respective sheets are superimposed on each other with the amount of superposition determined based on the image range in the sheet conveying direction in the image data, and the image forming state on each sheet is not hindered. In this state, the time required for a plurality of sheets to pass through the image forming unit is minimized.

(2) In the configuration of (1), the control section may extract a blank portion from the data compressed image data.

According to this configuration, the blank portion is expressed in a very simple form in the compressed image data, so that the blank portion can be easily extracted.

(3) The control section supplies a plurality of image data to the image forming section by deleting a margin on the rear end side of the front image data of the image data formed before and after each other. A rear end multiplexing process for conveying a plurality of sheets in a state in which a front end of a rear sheet is overlapped on a rear end of a front sheet among sheets conveyed before and after each other.

In this configuration, a margin at the rear end of the image data to be formed on the front paper is deleted, and the margin removed on the rear end of the front paper in the paper transport direction is removed. A plurality of sheets are conveyed to the image forming unit in a state where the front ends of the sheets behind by the length are overlapped. Therefore, the area where the rear sheet overlaps the front sheet, that is, the margin corresponding to the area not facing the image forming unit is deleted from the image data, so that the image data is located at the front end side of each sheet. The image is formed as it is, and a margin portion included in the image data is masked by the rear sheet on the rear end side of each sheet, so that the content of the image data formed on each sheet does not change.

(4) The controller supplies a plurality of image data to the image forming unit by deleting a margin on the front end side of the rear image data of the image data formed before and after each other. A front end multiplexing process is performed in which a plurality of stamps are conveyed in a state in which a rear end of a front stamp is overlapped on a front end of a rear sheet among sheets conveyed before and after each other.

In this configuration, the front end margin of the image data to be formed on the rear sheet is deleted, and the length of the deleted margin on the front end of the rear sheet in the sheet conveying direction is reduced. A plurality of sheets are conveyed to the image forming unit in a state where the rear ends of the sheets just ahead overlap. Therefore, the area where the front sheet overlaps the rear sheet, that is, the blank portion corresponding to the range not facing the image forming unit is deleted from the image data, so that the image data is added to the rear end side of each sheet. Is formed as it is, and a blank portion included in the image data is masked by the rear sheet on the front end side of each sheet, so that the content of the image data formed on each sheet does not change.

(5) The control unit, based on a selection operation,
A plurality of image data are supplied to the image forming unit by deleting a margin on the rear end side of the front image data of the image data formed before and after each other, and the paper conveyed before and after each other Rear end multiplexing processing in which a plurality of sheets are conveyed in a state where the front end of the rear sheet is overlapped on the rear end of the front sheet, or rear image data among image data formed before and after each other A plurality of image data is supplied to the image forming unit by deleting a margin on the front end side of the image forming apparatus, and the rear end of the front sheet is superimposed on the front end of the rear sheet among the sheets conveyed back and forth. And a selection unit for receiving any selection input of the front-end multiplex processing for transporting a plurality of sheets in a state in which the plurality of sheets are conveyed.

In this configuration, the rear end multiplexing process or the front end multiplexing process is performed according to the selection operation by the operator. Therefore, a plurality of sheets are superimposed on each other in a state selected by the operator according to a desired discharge state, a configuration of the sheet transport path, and the like. The corresponding fastest image forming operation is performed.

(6) The control section selectively executes either the rear end multiplexing processing or the front end multiplexing processing in accordance with the state of formation of a margin portion in each image data.

In this configuration, a plurality of sheets are automatically superimposed on each other in a state corresponding to the state of formation of a margin in image data to be formed on each of the plurality of sheets, and the fastest speed corresponding to the image data is obtained. An image forming operation is performed.

(7) The paper transport unit feeds a plurality of sheets from the paper feed unit by superposing a predetermined amount in the transport direction and feeds the paper between the paper feed unit and the image forming unit. And an adjusting unit for adjusting the amount of overlap of the sheets, wherein the control unit operates the adjusting unit in accordance with the length of the blank portion deleted from the image data in the sheet conveying direction.

In this configuration, each sheet fed from the sheet feeding section in a state of being overlapped by a fixed amount in the transport direction is not filled with the marginal portion deleted from the image data until it reaches the image forming section. The overlap amount is adjusted according to the length in the paper transport direction. Therefore, each sheet fed from the sheet feeding unit is guided to the image forming unit in a state where the sheets are overlapped by an overlapping amount corresponding to the length of the blank portion deleted from the image data.

In the constitutions (8) and (7), the adjusting means may be means for stopping the movement of each sheet for a time corresponding to the control data supplied from the control unit.

According to this configuration, of the sheets fed from the sheet feeding section in a state of being overlapped by a fixed amount, the overlap amount is reduced according to the time for operating the adjusting means on the rear sheet. . Therefore, by controlling the operation time of the adjusting unit for the rear sheet in accordance with the length of the blank portion deleted from the image data, the overlapping amount of each sheet can be set to an appropriate value.

(9) The adjusting means is a paper feed roller which is configured to be able to freely contact and separate from the upper surface of the paper stored in the paper storage position and feed the paper at any one of a plurality of paper feeding speeds. It is characterized by the following.

In this configuration, an appropriate overlapping amount of the front sheet and the rear sheet according to the image data can be easily realized when the rear sheet is fed from the sheet storage position.

(10) Separation that separates and conveys the preceding and succeeding papers between a transfer position where the image is transferred onto the paper in the image forming section and a fixing position where the paper that has passed the transfer position is heated and pressed. It is characterized by having a transport means.

In this configuration, each of a plurality of sheets that have passed the transfer position in a state where they overlap each other is
It is guided to the fixing position while being separated from each other. Therefore, each sheet is heated and pressed while being separated from each other,
Does not adhere to other paper.

(11) The separating / conveying means transfers the sheet at a speed higher than the sheet conveying speed at the transfer position from when the rear end of each sheet passes through the transfer position to when the front end of each sheet reaches the fixing position. It is characterized by being transported.

In this configuration, each sheet is transported at a speed higher than the transport speed at the transfer position from the time when the rear end passes through the transfer position to the time when the front end reaches the fixing position. Therefore, the front sheet that has passed the transfer position in a state where the rear sheet overlaps the rear sheet on the rear end side is conveyed at a higher speed than the rear sheet passing through the transfer position when the rear end passes the transfer position, Separate from the paper behind.

(12) The separation / conveyance means determines the sheet conveyance speed from the time when the rear end of each sheet has passed the transfer position to the time when the front end of each sheet reaches the fixing position in the margin portion obtained by deleting the image data from the image data. It is characterized by increasing or decreasing according to the length in the paper transport direction.

In this configuration, each sheet is transported at the fixing position in accordance with the amount of overlap with the following sheet from the time when the rear end passes through the transfer position to the time when the front end reaches the fixing position. Conveyed at a higher speed. Therefore, each sheet is reliably separated from the following sheet from the time when the sheet has passed the transfer position to the time when the sheet reaches the fixing position.

(13) Paper feed position control in which the paper transport section controls the vertical paper feed position of the paper stored in the paper storage position according to the selection state of the rear end multiplex processing or the front end multiplex processing. It is characterized by including a member.

In this configuration, the vertical paper feed position from the paper storage position is controlled depending on whether the rear end multiplexing processing or the front end multiplexing processing is selected. Therefore, the paper is fed downward or upward according to the processing selected from the rear end multiplexing processing or the front end multiplexing processing, and the front end of the rear sheet is located above or below the rear end of the front sheet. A space to be guided is formed.

(14) The sheet feeding position control member changes the front end of the rear sheet output from the sheet storage position to the rear end of the front sheet according to the selection state of the rear end multiplex processing or the front end multiplex processing. Is selectively guided to the upper side or the lower side.

In this configuration, the front end of the rear sheet fed from the sheet storage position is changed to the rear end of the front sheet, depending on whether the rear end multiplex processing or the front end multiplex processing is selected. Guided to the top or bottom of the part. Therefore, the rear end of the front sheet and the front end of the rear sheet are overlapped in a state suitable for the selected processing.

(15) The paper feed position control member moves the rear end of the front paper downward when the rear paper is output from the paper storage position according to the selection state of the rear end multiplex processing or the front end multiplex processing. Alternatively, it is moved upward.

In this configuration, depending on whether the rear end multiplex processing or the front end multiplex processing is selected, the rear end portion of the front sheet when the rear sheet is fed from the sheet storage position. Is displaced to a lower position or an upper position. Therefore, a space is formed above or below the rear end of the front sheet according to the selected process, to which the front end of the rear sheet is guided, and both are superposed in a state suitable for the selected process. Is done.

(16) In the configuration of (15), the paper feed position control member is configured to control the position of the front paper when the rear paper is output from the paper storage position in accordance with the selection state of the rear end multiplex processing or the front end multiplex processing. A guide member or a fan for moving the rear end portion of the paper feeding section below or above the paper outlet at the paper feeding position.

According to this configuration, depending on whether the rear end multiplexing processing or the front end multiplexing processing is selected,
The rear end of the front sheet when the rear sheet is fed from the sheet storage position is displaced to the lower position or the upper position by contact with the guide member or by blowing from a fan. . Therefore, a space is formed above or below the rear end of the front sheet according to the selected process, to which the front end of the rear sheet is guided, and both are superposed in a state suitable for the selected process. Is done.

(17) The paper feed position control member raises or lowers the front end of the rear sheet at the time of output of the rear sheet from the sheet storage position according to the selection state of the rear end multiplex processing or the front end multiplex processing. It is characterized by being moved to.

In this configuration, the front end of the rear sheet fed from the sheet storage position is placed on the upper side or the lower side depending on whether the rear end multiplexing processing or the front end multiplexing processing is selected. It changes to the position of. Therefore, the front end of the rear sheet is reliably guided above or below the rear end of the front sheet according to the selected process.

In the constitutions (18) and (17), the paper feed position control member is configured to control the rear feed position when the rear sheet is output from the useless storage position in accordance with the selection state of the rear end multiplex processing or the front end multiplex processing. It may be a lever member or a friction roller for moving the front end of the sheet below or above the exit of the sheet feeding position.

According to this configuration, depending on whether the rear end multiplexing processing or the front end multiplexing processing is selected,
The front end of the rear sheet fed from the sheet storage position is displaced to an upper position or a lower position by contact with a lever member or by rotation of a friction roller. Therefore, the front end of the rear sheet is reliably guided above or below the rear end of the front sheet according to the selected process.

(19) The sheet transport section constitutes at least two separate transport paths separated from each other between the sheet storage position and the image forming section, and each sheet is transported between the separate transport path and the sheet storage position. A separation claw that guides alternately to the separation conveyance path, and a rear end of the sheet that has passed through one separation conveyance path between the separation conveyance path and the image forming unit according to the selection state of the rear end multiplex processing or the front end multiplex processing. A stacking member that guides the front end of the sheet that has passed through the other separation conveyance path on the upper side or lower side of the set.

In this configuration, a plurality of sheets continuously fed from the sheet storage position are sequentially guided to each of the plurality of separation conveyance paths, and after being conveyed through each separation conveyance path. The image is superimposed before the image forming unit in accordance with the selection state of the rear end multiplex processing or the front end multiplex processing. Therefore, a plurality of sheets are superimposed and conveyed to the image forming unit in a state suitable for the rear end multiplexing process or the front end multiplexing process.

In the constitutions (20) and (19), the separation claw and the superimposing member may be divided and arranged at a plurality of positions in a direction orthogonal to the sheet conveying direction.

According to this configuration, the separation claw and the overlapping member can be brought into contact with the optimum position of the sheet according to the size of the sheet to be conveyed, and the sheet can be accurately transferred from the sheet storage position to each of the separation and conveyance paths. The sheet can be guided, and the sheet can be accurately moved to overlap the preceding and following sheets.

In the constructions (21) and (19), the separation claw may be formed with a plurality of sheet contact surfaces having the same curvature as the conveyance surface of each separation conveyance path.

According to this configuration, the paper fed from the paper storage position can be smoothly guided to each separation conveyance path.

(22) When the rear end multiplexing process is selected, the superposing member passes the rear end portion of the front sheet conveyed via one separation conveyance path via the other separation conveyance path. When the front-end multiplex processing is selected, the rear end of the front sheet conveyed via one separation conveyance path is separated from the other end by the other sheet. The sheet is lifted above the front end of the rear sheet conveyed along the conveyance path.

In this configuration, the superimposing member disposed between the separation conveyance path and the image forming section shifts the rear end of the front sheet to the rear according to the selection state of the rear end multiplex processing or the front end multiplex processing. Is moved below or above the front end of the sheet. Therefore, the sheets before and after being conveyed via each separation conveyance path are superposed in a state suitable for the rear end multiplexing processing or the front end multiplexing processing, and are guided to the image forming unit.

[0051]

FIG. 1 is a diagram showing a configuration of a digital copying machine which is an image forming apparatus according to an embodiment of the present invention. The digital copying machine 1 includes an image reading unit 2, an image forming unit 3, and a sheet conveying unit 4. Image reading unit 2
Has an original table 21 made of a transparent glass body on an upper surface, and an exposure lamp 22 and mirrors 23a to 23b below the original table 21.
c, a lens 24 and a photoelectric conversion element (hereinafter, referred to as a reading sensor) 25 are arranged. Exposure lamp 2
Reference numeral 2 reciprocates the lower surface of the document table 21 together with the mirror 23a, and exposes the entire image surface of the document placed on the document table 21. The mirrors 23b and 23c reciprocate on the lower surface of the document table 21 at half the speed of the exposure lamp 22 and the mirror 23a. The mirrors 23a to 23c
The light reflected from the image surface of the original is distributed to the lens 24. The lens 24 forms an image of the reflected light on the image surface of the document on the light receiving surface of the reading sensor 25. Read sensor 25
Outputs an electric signal corresponding to the amount of light received by the light receiving section as a read signal.

The image reading section 2 includes an image processing section. The image reading section 2 converts the read signal output from the reading sensor 25 into image data by binarizing the read signal, and then supplies the image data to the image forming section 3.

The image forming unit 3 includes a charger 32, a scan unit 33, a developing unit 34, a transfer unit 35, and a charge eliminator 3 around a photosensitive drum 31 having a photoconductive layer formed on the surface.
6 and the like are arranged. The photosensitive drum 31
It rotates at a constant speed in the direction indicated by the arrow in the figure. Charger 32
Applies uniformly a charge of a single polarity to the surface of the photosensitive drum 31. The scanning unit 33 irradiates the surface of the photosensitive drum 31 with image light modulated by image data supplied from the image processing unit. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 31 by photoconductive action. The developing unit 34 supplies the developer to the surface of the photosensitive drum 31 and visualizes the electrostatic latent image into a developer image. The transfer unit 35 constitutes the transfer position of the present invention, and transfers the developer image carried on the surface of the photosensitive drum 31 to the surface of the sheet conveyed between the transfer unit 35 and the photosensitive drum 31. The static eliminator 36 removes the electric charge remaining on the surface of the photosensitive drum 31 after the transfer process.

The paper transport unit 4 is provided via the image forming unit 3 from a paper feed cassette 41 mounted at the bottom of the digital copying machine 1 and a manual feed tray 42 mounted on one side of the digital copying machine 1. The main transport path 4a, the paper feed transport path 4b, the sub-transport path 4c, the manual feed path 4
d and the discharge path 4e. Paper cassette 4
1 stores a plurality of sheets P of the same size. The main transport path 4 a includes a registration roller 45 and a fixing roller 46, and passes through a transfer position in the image forming unit 3 to feed the paper feed path 4 a.
b and the manual feed path 4d and the discharge path 4e. The paper feed path 4b includes a pickup roller 43 and a paper feed roller 44.
and a. The sub-transport path 4d is
a to 47c, the paper discharge conveyance path 4e and the registration roller 4
5 is used to reverse the front and back surfaces of a sheet on which single-sided copying has been performed in the double-sided copying mode and to lead the sheet to the image forming unit 3 again. The manual feed path 4d is connected to the pickup roller 4
8 and a paper feed roller 49, and connects between the manual feed tray 42 and the main transport path 4a. The paper discharge transport path 4e includes a flapper 50 and a paper discharge roller 51, and connects between the main transport path 4a and the paper discharge unit 5.

In the sheet cassette 41 and the manual feed tray 42, a sheet separating member (not shown) is provided at the front end in the sheet feeding direction. The sheet separating member is configured by, for example, a friction sheet or a reverse rotation roller disposed to face the pickup rollers 43 and 48.

The registration roller 45 selectively supplies a conveying force to the paper fed from the paper feed cassette 41 or the manual feed tray 42. That is, the registration roller 45
The sheet fed before the rotation of the photosensitive drum 31 is temporarily stopped, and is guided to the transfer position at a timing synchronized with the rotation of the photosensitive drum 31. As a result, the front end of the sheet coincides with the front end of the developer image carried on the photosensitive drum 31 at the transfer position.

The fixing roller 46 constitutes the fixing position of the present invention, and heats and pressurizes the sheet after the transfer step to firmly fix the developer image on the surface of the sheet. On the downstream side of the fixing roller 46 in the main transport path 4a, a fixing detection switch S2 is disposed. Fixing detection switch S
2 detects that the sheet has passed the fixing roller 46,
It outputs a predetermined detection signal. The peripheral speed of the fixing roller 46 is
The peripheral speed of the photosensitive drum 31 is higher than the peripheral speed. Therefore, the paper transport speed at the fixing position is higher than the paper transport speed at the transfer position.

Further, the flapper 50 includes a discharge roller 51.
Cooperates with to determine the paper transport direction in the duplex copying mode. That is, when the image formation on the first side of the sheet in the double-sided copying mode is completed, the sheet discharging roller 51 once rotates in the sheet discharging direction, and then rotates in the opposite direction while holding the sheet, and the sheet having been copied on one side is rotated. Reverse the transport direction. At this time, the direction of the sub-transport path 4c is opened, the single-sided copied paper is guided to the sub-transport path 4c, and is conveyed via the transfer position into the main transport path 4a with its front and back surfaces reversed. When the image formation on the second side of the sheet in the double-sided copying mode is completed, the flapper 50 opens between the main transport path 4a and the paper discharge transport path 4e, and the paper having the image formed on both sides is discharged. The paper is discharged to the paper discharge unit 5 by the paper roller 51.

FIG. 2 is a view for explaining the state of paper transport in the digital copying machine. Digital copier 1
In the continuous copy mode for a plurality of sheets, in the image data to be formed on each sheet, each of the plurality of sheets is mutually separated according to the range of the margin formed at the front end side or the rear end side in the sheet conveyance direction. The sheet is conveyed to the image forming section 3 in a state of being overlapped.

For example, as shown in FIG. 2A, an image G1 having front margins Y1 to Y3 and rear margins Z1 to Z3 on three sheets P1 to P3 each having a length L in the transport direction. When G3 to G3 are formed, the length from the front end of the first sheet P1 to the rear end of the third sheet P3 is the state in which the front end of the rear sheet is overlapped on the rear end of the front sheet. 3L- (Z1 + Z
2) (see FIG. 2 (B)). In the front end multiplexing processing in which a plurality of sheets are conveyed in a state where the rear end of the front sheet is overlapped on the front end of the rear sheet, it becomes 3L− (Y2 + Y3). (See FIG. 2C). Therefore, as the margin portion increases in the image data formed on each sheet, the overlapping amount on each sheet also increases, and the time required for all of the plurality of sheets to pass through the transfer position is shortened, and the image forming time is further shortened. Will be done.

The following describes an example of a front end multiplexing process in which a plurality of sheets are conveyed in a state where the rear end of the front sheet is overlapped on the front end of the rear sheet.

FIG. 3 is a diagram showing the configuration near the paper feed path of the paper feed section in the digital copying machine. In the digital copying machine 1, a pickup roller in the paper feed path 4b is located at a transfer position between the paper feed cassette 41 of the paper feed unit 4 and the image forming unit 3 (a position where the photosensitive drum 31 and the transfer unit 35 face each other). 43, a paper feed roller 44 and a registration roller 45 are arranged. The pickup roller 43 and the sheet feeding roller 44 correspond to the sheet feeding unit of the present invention, and the registration roller 45 also corresponds to the adjusting unit.

Here, the paper feed cassette 41 includes a rotary plate 41a rotatably supported inside, and a spring 41b for urging the paper P placed on the rotary plate 41a upward together with the rotary plate 41a. Have. Further, the pickup roller 43 has a partially circular fox-shaped cross section in which a part of the peripheral surface is cut out.
In a state in which the sheet P is opposed to the uppermost surface of the sheet placed thereon, the sheet P is pivotally supported in a position facing the vicinity of the front end of the uppermost surface of the sheet P placed on the rotating plate 41a in the sheet feeding cassette 41. I have.

With this configuration, the pickup roller 43
Is rotated, the arc portion of the pickup roller 43 enters the paper feed cassette 41, and the paper P in the paper feed cassette 41 is pushed down together with the rotating plate 41a. As a result, the uppermost sheet is pressed against the circular arc portion of the peripheral surface of the pickup roller 43 by the elastic force of the sling 41b, and is fed toward the sheet feed roller 44 with the rotation of the pickup roller 43. At this time, the uppermost sheet is separated from the second sheet by the aforementioned separating member. Therefore, each time the pickup roller 43 makes one rotation, one sheet is fed out of the sheet cassette 41.

In this configuration, when the pickup roller 43 is rotated while a part of the uppermost sheet fed from the sheet cassette 41 is located in the sheet cassette 41, the arc of the pickup roller 43 is changed. The sheet P is pressed down together with the rotating plate 41a while contacting the middle part and the upper part of the uppermost sheet. This allows the spring 41 to move from the middle part of the top surface of the paper located
Due to the elastic force of b, the roller comes into pressure contact with the arc portion of the peripheral surface of the pickup roller 43, and the second sheet also moves toward the feed roller 44 with the rotation of the pickup roller 43 due to the frictional force with the lower surface of the uppermost sheet. Be fed out. At this time, the second sheet is separated from the third sheet by the separating member.

Therefore, by rotating the pickup roller 43 a plurality of times while a part of the paper fed from the paper feed cassette 41 is located in the paper feed cassette 41, a plurality of papers are superimposed on each other. It can be delivered in a state. At this time, the rear end of the front sheet overlaps the front end of the rear sheet. The amount of superposition of each sheet is determined by the pickup roller 43.
Changes according to the interval of one rotation of.

On the other hand, the registration roller 45 includes a driving roller 45a and a driven roller 45b.
The drive roller 45a receives a supply of rotational force via a transmission mechanism (not shown), and conveys a sheet sandwiched between the drive roller 45a and the driven roller 45b to a transfer position where the photosensitive drum 31 and the transfer device 35 face each other. . The driven roller 45b is
It moves to a position separated from or in contact with the drive roller 45a according to the ON / OFF state of the solenoid 45c. When the solenoid 45c is turned on, the driven roller 45b moves to a position separated from the driving roller 45a, and the conveyance of the sheet is stopped. When the solenoid 45c is turned off, the driven roller 45b moves to a position where it contacts the drive roller 45a, and the sheet is conveyed.

A first sheet sensor SS1 is disposed between the registration roller 45 and the photosensitive drum 31 on the main transport path 4a. The first sheet sensor SS1 detects that the front end of each sheet has passed the registration rollers 45. The first sheet sensor SS1 can be used even during multiple processing in which a plurality of sheets are conveyed in an overlapping state.
It detects that the front end of each sheet has passed through the registration roller 45.

For example, when a reflection type optical sensor or a mechanical sensor is used as the first paper sensor SS1, a portion of the main transport path 4a upstream of the portion where the first paper sensor SS1 is disposed in the transport direction. The front end of the rear sheet of the two sheets overlapping each other is separated from the rear end of the front sheet when passing the position where the first sheet sensor SS1 is formed by forming a bent portion on the second sheet. It can be determined that the part where the detection value of the one sheet sensor SS1 greatly changes is the front end of the rear sheet. Therefore, in the configuration shown in FIG. 3, the first sheet sensor SSl of the reflection type optical sensor or the mechanical sensor is a driven roller at the time of the front end multiplexing processing in which the rear end of the front sheet is superimposed on the front end of the rear sheet. It should be arranged on the drive roller 45a side in the rear end multiplexing process in which the front end of the rear sheet is overlapped on the rear end of the front sheet.

When a transmission type optical sensor is used as the first sheet sensor SS1, the light source and the light receiving element are arranged at positions facing each other with the sheet being conveyed therebetween, and the light source transmits light through the sheet. The fact that the front end of the rear sheet has passed through the registration roller 45 is detected based on the decrease in the received light amount.

FIG. 4 is a diagram showing a configuration near the main transport path of the paper transport section in the digital copying machine. The image forming unit 3 in the paper transport unit 4 of the digital copying machine 1
Between the photosensitive drum 31 and the fixing roller 46
The sheet sensor SS2, the third sheet sensor SS3, and the variable speed belt 37 are arranged. The second paper sensor SS2 is
It is detected whether or not the rear end of the sheet has passed a transfer position where the photosensitive drum 31 in the image forming unit 3 and the transfer unit 35 face each other. The third sheet sensor SS3 detects that the rear end of the sheet reaches the upstream side of the variable speed belt 37 and the front end of the sheet
6 is reached. The second sheet sensor SS
As the second and third sheet sensors SS3, similarly to the above-described first sheet sensor SS1, a reflection type or transmission type optical sensor or a machine type sensor can be used. Variable speed belt 37
Is an endless belt stretched over a pair of pulleys 37a and 37b, and corresponds to the separation and conveyance means of the present invention.

The photosensitive drum 31 has a charging process, an exposure process,
It rotates at a predetermined rotation speed equal to the processing speed (process speed) of the image forming process including the development step and the transfer step. On the other hand, the fixing roller 46
It rotates at a higher speed than the peripheral speed of 1. This photosensitive drum 31
Speed belt 37 disposed between the fixing belt 46 and the fixing roller 46
During rotation of the developer image on the paper at the transfer position, the rotation of the paper rotating at the same peripheral speed as that of the photosensitive drum 31 and contacting the peripheral surface of the variable speed belt 37 is performed. After the rear end has passed the position of the second sheet sensor SS2 (after the transfer process for the sheet has been completed) to the point where the rear end has passed the position of the third sheet sensor SS3 (until the front end of the sheet reaches the fixing roller 46). During this time, the fixing roller 46 rotates at the same peripheral speed as the peripheral speed. In other words, the variable speed belt 37 moves the photosensitive drum 3 in accordance with the transport state of the sheet.
The fixing roller 46 rotates at either one of the peripheral speed of 1 and the peripheral speed of the fixing roller 46.

Therefore, the area from the paper feed cassette 41 to the third paper sensor SS3 in the paper transport path is the process speed area for transporting the paper at the process speed, and is the paper overlapping area where the paper is overlapped. .
Further, the portion where the variable speed belt 37 is disposed in the paper transport path is a speed variable region where the transport speed of the paper changes and a paper separation region where the superimposed state of the paper is released. Further, a portion between the downstream side of the variable speed belt 37 and the paper discharge roller 51 in the paper transport path is a high-speed area for transporting the paper at a speed higher than the process speed.

FIG. 5 is a flowchart showing a part of the processing procedure in the control unit of the digital copying machine. The control unit of the digital copier 1 receives an image forming request by operating a start button or the like after a document is set on the upper surface of the document table 21 and copying conditions such as the number of copies and paper size are set and input. (101) The image reading unit 2 is operated to read the image of the original on the original platen 21 to create one-page image data (102). Next, the control unit determines whether or not the number of sheets on which image formation is to be performed in the current copy processing is plural based on the set and input copy conditions (103), When the formation process is performed, the multiplex process is executed (1
04), when performing image forming processing on a single stamp, normal processing is performed (105).

FIG. 6 is a flowchart showing a processing procedure at the time of multiplex processing in the control section of the digital copying machine. At the time of multiplex processing in which a plurality of sheets are conveyed in a state of being overlapped with each other to form an image, the control unit first checks the sheet size in the copy conditions set and input (11).
1) A paper feed position is determined based on the set paper size (112). The determination of the paper feed position is, for example, a process of determining which paper is fed from the paper feed cassette 41 or the manual feed tray 42. The control unit is
At the same time, after performing predetermined image processing on the image data, multiplexed image data is created (113). Thereafter, the control unit performs a sheet feeding process (114) for continuously feeding a plurality of sheets from the determined sheet feeding position, an image forming process (115) based on the created multiplex image data, and image fixing. The process (116) is performed in parallel.

FIG. 7 is a flowchart showing the procedure of the multiplexed image data creation process included in the multiplexing process in the control unit. When performing the front end multiplexing process of forming an image in a state where the rear end of the front sheet is superimposed on the front end of the rear sheet, the control unit is configured to continuously perform image forming for a plurality of pages. Among them, for each of the image data of the second and subsequent pages, the length of the margin on the front end side in the paper transport direction is detected, and this detection result is temporarily stored in the memory (121). Next, the control unit deletes data corresponding to the length stored in the memory from the front end in each of the image data of the second and subsequent pages, and then sequentially connects the image data of all pages,
One piece of multiplexed image data is created (122).

In detecting the length of the front margin, each image data is compressed in the image processing unit or the control unit of the image reading unit 2, and the data of the margin is continuously "0". It is configured in a simple form. This makes it possible to easily extract a blank portion in the image data.

For example, when the leading edge multiplexing process is performed on image data of two pages, the image data of the first page is 000000BDCF13D8C... 12430.
B12370000000, and the image data of the second page is 000000000000CB0FF ... 8902
In the case of 31 ABCD090000, the blank space on the front side of the image data of the second page is deleted and the image date of the first page is joined, and the image data of the first page is 0000000BDCF13D.
8C ・ ・ ・ 12430B1237000000CB0F
F. Multiple image data of 890231 ABCD090000 is created.

In the image data for a plurality of pages to be continuously formed, all the front and rear margins in the image data of each page are deleted, so that the image data of each page necessary for image formation is deleted. A line feed code may be added only for the margin range.

FIG. 8 is a flowchart showing the procedure of the sheet feeding process included in the multiplexing process in the control unit. The control unit controls the pickup roller 43 every predetermined time.
Is repeatedly executed at predetermined time intervals for the number of sheets calculated in the processing of 103 shown in FIG.
21-123). As a result, the number of sheets required for the set copying process are sent out to the sheet feeding conveyance path 4b in a state where they are overlapped with each other by a certain amount of overlap.

FIG. 9 is a flowchart showing the procedure of the image forming process included in the multiplexing process in the control unit. FIG. 10 is a diagram illustrating a state of transporting a sheet in the image forming process. The front-end multiplexing process is performed using multiplexed image data formed by deleting a front-side margin from the second and subsequent image data among image data to be formed on each of a plurality of continuously fed sheets. When the image forming process is performed, the control unit drives the charger 32, the developing unit 34, and the charge remover 36, and supplies the multiplexed image data to the scan unit 33, and the photosensitive drum 31
Developer images based on the multiplex image data are formed sequentially. In this state, when the first sheet sensor SS1 detects the front end of the first sheet P1, the control unit controls the solenoid 45.
c is turned on to temporarily stop the conveyance of the sheets P1 to P3 (131, 132). Thereafter, the control unit turns off the solenoid 45c at a predetermined timing and drives the transfer unit 35 (133 to 135), and the developer carried on the photosensitive drum 31 at the transfer position at the front end of the first sheet P1 The conveyance of the sheets P1 to P3 is restarted at the timing coincident with the front end of the image. This state is shown in FIG. Thus, the developer image is transferred to the first sheet P1.

In the meantime, the control unit controls the first sheet sensor SS1
When the front end of the second sheet P2 is detected, the solenoid 4
5c is turned on (136, 137), and the conveyance of the sheets P2, P3 is temporarily stopped. This state is shown in FIG. Note that the interval of one rotation of the pickup roller 43 or 48 in the sheet feeding process is longer than the time during which the sheet is transported between the registration roller 45 and the transfer position. For this reason, the first sheet sensor SSl detects that the second sheet P
When the front edge of the first sheet P1 is detected, the front edge of the first sheet P1 has passed the transfer position, and the first sheet P1 remains in the main conveyance path even when the supply of the conveyance force from the registration rollers 45 is cut off. 4a, the developer image is continuously transferred to the first sheet P1.

When a predetermined time has elapsed from the timing at which the solenoid 45c was turned off in the process of 134, the control unit turns on the solenoid 45 turned on in the process of 137.
c is turned off (138, 139). This predetermined time is a time required to convey the sheet by a length excluding a margin on the front end side of the second sheet P2 from the total length of the sheet in the conveying direction. This state is shown in FIG. As a result, the conveyance force of the registration rollers 45 is supplied to the sheets P2 and P3, and the rear end of the first sheet Pl overlaps with the margin on the front end side of the second sheet P2 while maintaining the state. The second sheet P2 is conveyed to the transfer position, and the developer image based on the image data of the second page from which the margin on the front end side has been deleted is the same as the original image data on the front end side of the second sheet P2. The image is transferred with a margin portion of the range provided.

The control unit repeats the above processes 136 to 139 also for the third and subsequent sheets (140 → 136), so that all of the plurality of sheets required for the set copy process are set in the backward direction. The paper is passed through the transfer position in a state where the rear end of the front paper is overlaid on the margin on the front end side of the paper.

FIG. 11 is a flowchart showing the procedure of the image fixing process included in the multiplexing process in the control unit. FIG. 12 is a diagram showing a state of transporting a sheet in the image fixing process. As described above, the peripheral speed of the fixing roller 46 is set higher than the peripheral speed of the photosensitive drum 31 determined by the process speed. When the third sheet sensor SS3 detects the front end of the front sheet Pl, the control unit makes the peripheral speed of the variable speed belt 37 equal to the peripheral speed of the photosensitive drum 31 (141, 142). When the front end of the front sheet P1 reaches the position where the third sheet sensor SS3 is located, the rear end of the front sheet P1 has not yet passed the transfer position, and the front sheet P1 is exposed together with the rear sheet P2. The conveyance is continued at a process speed defined by the peripheral speed of the body drum 31. This state is shown in FIG.

Next, the control section controls the second sheet sensor SS2.
Detects the rear end of the preceding sheet P1, the peripheral speed of the variable speed belt 37 is made to match the peripheral speed of the fixing roller 46 (14).
3,144). This state is shown in FIG. As a result, the front sheet P1 that has passed the transfer position over the entire surface is conveyed toward the fixing roller 46 at a higher speed than the rear sheet P2 being conveyed at the process speed, and the front sheet P2 with respect to the front end of the rear sheet P2. The amount of superposition gradually decreases.

Thereafter, the control section controls the third sheet sensor SS3
Detects the front end of the rear sheet P2,
The peripheral speed of the photosensitive drum 31 (14).
5 → 141). When the front end of the rear sheet P2 reaches the position where the third sheet sensor SS3 is located, the front end of the front sheet P1 has reached the fixing roller 46, and the front sheet P1 is not affected by the peripheral speed of the variable speed belt 37. The paper is conveyed at the peripheral speed of the fixing roller 46. On the other hand, the rear sheet P2 is conveyed at a speed corresponding to the peripheral speed of the photosensitive drum 31 until the rear end passes the transfer position. This state is shown in FIG. Thereby, the overlapping amount of the front sheet Pl with respect to the front end of the rear sheet P2 further decreases, and before the front end of the rear sheet P2 reaches the position where the third sheet sensor SS3 is disposed, the front sheet Pl is overlapped. The rear end is separated from the front end of the rear sheet P2 so that the two sheets do not pass through the fixing roller 46 in a superimposed state.

After the control unit makes the peripheral speed of the conveyor belt 46 coincide with the peripheral speed of the photosensitive drum 31 in the processing of 145 → 141, the second paper sensor SS2 detects a part of the next paper. It is determined whether the second sheet sensor SS2
Until 141 is no longer able to detect part of the next sheet.
The processing of 145 is repeatedly executed (146). As a result, all of the plurality of sheets relating to the set copying operation can be fixed without overlapping with other sheets.
Can be passed through.

Further, the photosensitive drum 31 and the fixing roller 46
Must be longer than at least the total length of the sheet in the transport direction. If the interval is shorter than the entire length of the sheet, the front end of the sheet is transported at a higher speed than the rear end, and the sheet may be damaged.

As described above, in the digital copying machine 1 according to the present embodiment, the front end margin from the image data to be formed on the second and subsequent sheets out of the plurality of sheets fed continuously. One portion of the multiplexed image data is created by deleting the portion, an electrophotographic image is formed based on the multiplexed image data, and each of the portions passing through the transfer position is determined based on the length of the deleted margin portion in the transport direction. By controlling the amount of superposition of the sheets, a plurality of sheets are passed to the transfer position in a state where the rear end of the front sheet is superimposed on the margin on the front end side of the rear sheet.

As a result, in the digital copying machine 1 according to this embodiment, the length of the plurality of sheets in the transport direction can be minimized within a range in which the original image data can be faithfully reproduced on each sheet. In addition, the copying operation time can be significantly reduced. In addition, after deleting the front end margin from the image data to be formed on the second and subsequent sheets, all the image data are sequentially connected, whereby multiplexed image data can be easily created. Further, the conveying force is selectively supplied to each sheet from the registration rollers 45 based on the length of the blank portion removed from the image data when the multiplexed image data is created, so that the length of the blank portion in each sheet is adjusted. The superimposed state can be easily realized.

In the digital copying machine 1 according to this embodiment, the paper passing the transfer position is conveyed by the variable speed belt 37 and the fixing roller 46 at a speed higher than the conveyance speed of the rear paper, so that each paper is conveyed. Since it is made to pass through the fixing roller 46 while being separated from each other,
Heat and pressure are not applied by the fixing roller 46 in a state in which a plurality of sheets are overlapped, and there is no occurrence of close contact of the sheets which causes a discharge failure. Further, a variable speed belt 37 whose circumferential speed can be changed is arranged between the photosensitive drum 31 and the fixing roller 46, and the paper conveyance speed is switched via the variable speed belt 37. For this reason, after the front end of the front sheet reaches the fixing roller 46, the peripheral speed of the variable speed belt 37 is made to match the peripheral speed of the photosensitive drum 31 that is lower than the peripheral speed of the fixing roller 46, so that the variable speed belt 37 is moved. Even if there is a difference between the peripheral speed and the moving speed of the paper, the paper rubs on the upper surface of the variable speed belt 37, and the paper is not damaged unlike the case where a roller or the like is used.

However, when the amount of superposition between the respective sheets is large, that is, when the length of the blank portion in the image data in the transport direction is long, the arrangement interval between the photosensitive drum 31 and the fixing roller 46 is changed. In addition to making it sufficiently large, more preferably, the variable speed belt 37 is rotated at the same peripheral speed as the photosensitive drum 31, and a transport roller rotating at the same peripheral speed as the fixing roller 46 is provided on the upper surface of the variable speed belt 37. Should be placed face-to-face.

Further, in the digital copying machine 1, by controlling the rotation of the pickup roller 43 or 48, a plurality of sheets are overlapped with each other when sheets are fed from the sheet cassette 41 or the manual feed tray 42. Therefore, it is possible to easily realize a transport state in which the respective sheets are overlapped with each other. Further, in the sheet feeding cassette 41 or the manual feed tray 42, the paper is nipped by the elastic force between the arc portion on the peripheral surface of the partially arc-shaped pickup roller 43 or 48 and the rotating plate 41a. For this reason, even if a part of the uppermost sheet remains in the paper feed cassette 41 or the manual feed tray 42,
By rotating the pickup roller 43 or 48, the second and subsequent sheets can be sequentially fed via the frictional force between the sheets, and a transport state in which the sheets are superimposed on each other can be realized very easily.

In addition, in the digital copying machine 1, the conveying force for the sheet from the registration roller 45 is turned on based on the detection result of the first sheet sensor SS1 and the length of the blank portion deleted from each image data. By turning on / off, the overlap amount of each sheet fed from the sheet feed tray 41 or the manual feed tray 42 in a state of being overlapped with each other easily and accurately matches the length of the margin portion deleted from the image data. Can be done.

In the digital copying machine 1, the registration roller 45 is constituted by a pair of rollers, and the other driven roller 45b is freely movable toward and away from the one driving roller 45a. 4
5b is separated from the drive roller 45a. Therefore, by controlling the drive timing and drive time of the solenoid 45c, it is possible to easily adjust the conveying force to match the overlap amount of each sheet to the length of the blank portion deleted from the image data. Can be.

Further, it is preferable to provide a peeling member for peeling the sheet on which the developer image has been transferred from the circumferential surface of the photosensitive drum 31 on the side of the fixing roller 46 on the circumferential surface of the photosensitive drum 31. Then, the leading sheet is subjected to a peeling operation by a peeling member, so that the second and subsequent sheets are sequentially stacked together with the preceding sheet on the photosensitive drum 3.
1 from the peripheral surface. For this reason, at the time of the front end multiplexing process, the time for operating the peeling member can be shortened as compared with the time when a plurality of sheets pass through the transfer position, and the mechanical damage that the photosensitive drum 31 receives from the peeling member can be reduced. Can be reduced.

In the digital copying machine 1 according to the above-described embodiment, the front end multiplexing process is performed in which the rear end of the front sheet is superimposed on the front end of the rear sheet. The present invention can be similarly applied to the case of performing the rear end multiplexing process in which the front end of the rear sheet is overlapped on the end.

In order to reliably feed one sheet of paper by rotating the pickup rollers 43 and 48, the pickup rollers 43 and 48 need to be rotated at a relatively low speed. On the other hand, in order to overlap two sheets by a length corresponding to the range of the margin portion in the image data, it is necessary to rotate the pickup rollers 43 and 48 at a relatively high speed. Therefore, the big up roller 43,
48, the high-speed multi-stage pickup roller driven at a plurality of rotation speeds
2 can be used that is supported on the upper surface of the paper housed in the paper 2 so as to be able to freely contact and separate.

Further, either the front end multiplexing process or the rear end multiplexing process may be selectively executed in response to a selection input by the operator or based on a comparison result of the image forming processing time. In this case, as an example, as shown in FIG. 13, a front-side margin portion and a rear-end side margin portion of image data formed on each of a plurality of continuously conveyed sheets are extracted (151). If the operator has selected either the front end multiplex processing or the rear end multiplex processing, processing relating to the operator's selection is executed (152, 153).
If the operator has not selected the processing, the distance from the front end of the first sheet to the rear end of the last sheet in each of the front end multiplex processing and the rear end multiplex processing is calculated. (156), the process with the shorter calculated distance is selected (157 → 154,155).

Further, it is determined whether the margin portion of the image data to be formed on each sheet is formed at the front end side or the rear end side of the sheet, and based on the determination result, the front end multiplex processing or the rear end Multiple processing may be selectively executed for each sheet. For example, as shown in FIG. 14, if there is a margin on the rear end side in the image data G1 to G3 of three originals, the second and third sheets P2, P
A rear end multiplexing process is performed in which the rear end of No. 3 is superimposed on the front ends of the first and second sheets P1 and P2. FIG.
As shown in the figure, if there is a margin on the front end side in the image data G1 to G3 of the three originals, the first and second sheets P2 and P3 are placed on the front end of the second and third sheets P2 and P3. A front end multiplexing process is performed in which the rear ends of the sheets P1 and P2 are overlapped. Further, as shown in FIG. 16, there is a margin at the rear end of the first image data G1, and there is no sufficient margin at the front and rear ends of the second image data. If there is a margin on the front end side of the third image data G3, the rear end multiplexing process is performed on the first and second sheets P1 and P2, and the second and third sheets are processed. The leading edge multiplexing process is performed on the sheets P2 and P3.

As described above, when the front end multiplexing process or the rear end multiplexing process is selectively executed in accordance with the formation position of the margin portion in the image data, the front end of the rear sheet in the sheet feeding section is replaced with the front sheet. Switching means for selectively switching between a position below the rear end and a position above the rear end is required. The configuration of the paper supply unit for this purpose will be described below in the case where paper is supplied from a paper supply cassette.

FIG. 17 is a diagram showing a first configuration example of the paper feeding unit of the digital copying machine. In this example, a paper output sensor 61 is arranged at the exit of the paper feed cassette 41, and the paper output sensor 61 detects the rear end of the front paper or feeds the rear paper at the timing when it is not detected. Is started to selectively execute the front end multiplexing processing or the rear end multiplexing processing.

That is, in the front end multiplexing process in which the rear end side of the front sheet is overlapped on the front end side of the rear sheet, FIG.
As shown in FIG. 7A, the sheet feeding solenoid 43a is driven at the timing when the sheet output sensor 61 detects a predetermined position on the rear end side of the front sheet, and the pickup roller 43 is brought into contact with the upper surface by bringing the pickup roller 43 into contact with the upper surface. Start feeding paper.
In this case, the predetermined position of the front sheet to which the paper output sensor 61 should face at the timing of feeding the rear sheet is determined by the direction from the rear end of the front sheet to the conveyance direction of the front end margin in the image data for the rear sheet. Is the position on the front end side by the length y2. The timing Ta at which the paper output sensor faces this position is the timing T1 at which the paper output sensor 61 detects the front end of the paper, the length L of the peripheral paper in the transport direction, and the margin of the front end side in the image data for the rear paper. Ta = T1 + {(L−y2) / V1} can be calculated from the length y2 in the transport direction and the transport speed V1 after the front sheet is fed. After stopping the conveyance of the front sheet at this timing, the sheet feeding solenoid 43a is driven, and the pickup roller 43 is rotated until the sheet output sensor 61 detects the front end of the rear sheet.
An area where a margin is to be formed on the front end side of the rear sheet is overlapped below the rear end side of the front sheet.

Also, at the time of the rear end multiplexing process in which the rear end side of the rear sheet is superimposed on the front end side of the front sheet, FIG.
As shown in (B), the feeding of the rear sheet is started in a state where the front sheet is completely sent out of the sheet feeding cassette 41. For this reason, at the timing when the paper output sensor 61 detects that the rear end of the front paper has passed, the conveyance of the front paper is stopped, and the paper feed solenoid 43a is driven to bring the pickup roller 43 into contact with the upper surface. Start feeding the rear sheet. Then, the conveyance of the front sheet is restarted at the timing when the sheet output sensor 61 detects the predetermined position on the front end side of the rear sheet. In this case, at the timing when the conveyance of the front sheet is restarted, the predetermined position of the rear sheet to which the sheet output sensor 61 is to face is determined from the front end of the rear sheet to the rear margin of the image data for the front sheet. This position is on the rear end side by the length y1 in the transport direction. The timing Tb at which the paper output sensor 61 opposes this position is the timing T2 at which the paper output sensor 61 detects the front end of the paper, the length y1 in the transport direction of the margin on the rear end side in the image data for the paper in front, And Tb = T2 + (y1 / V2) using the paper feed speed V2 of the rear sheet. By restarting the front sheet at the same speed as the feeding speed of the rear sheet at this timing, the front end side of the rear sheet is superimposed on the rear end side of the front sheet above the area where the margin is to be formed. .

As described above, based on the detection signal of the paper output sensor 41 disposed in the vicinity of the exit of the paper feed cassette 41, the multiplex state of the paper according to the formation state of the margin portion in the image data can be simplified. And can be easily realized.

FIG. 18 is a diagram showing a second configuration example of the paper feeding unit of the digital copying machine. In this example, a paper output sensor 61 and a distribution guide 62 are arranged at the exit of the paper supply cassette 41, and the distribution guide 62 is selectively rocked counterclockwise or clockwise to output paper from the paper supply cassette 41. The conveyed paper is conveyed to the upper side or the lower side of the distribution guide 62,
The front end multiplex processing or the rear end multiplex processing is selectively executed.

That is, at the time of front end multiplexing processing, FIG.
As shown in the figure, the distribution guide 62 is swung in the counterclockwise direction, and the paper output from the paper feed cassette 41 is moved to the distribution guide 6.
Lead to the top of 2. Thereby, the front end of the rear sheet enters between the lower surface on the rear end side of the front sheet and the upper surface of the distribution guide 62, and the rear end of the front sheet is superimposed on the front end of the rear sheet. . On the other hand, at the time of the rear end multiplexing processing, as shown in FIG. 18B, the distribution guide 62 is swung clockwise to guide the sheet output from the sheet cassette 41 to the lower side of the distribution guide 62. As a result, the front end of the rear sheet enters between the upper surface on the rear end side of the front sheet and the lower surface of the sorting guide 62, and the front end of the rear sheet is superimposed on the rear end of the front sheet. You.

The detection signal of the paper output sensor 61, and
By determining the timing for stopping the conveyance of the front paper and the timing for resuming the conveyance based on the length of the margin in the image data in the conveyance direction, the front of the paper is determined according to the formation state of the margin in the image data. It is possible to make the overlapping amount of the sheet of paper and the rear sheet appropriate.

FIG. 19 is a diagram showing a third configuration example of the paper feeding section of the digital copying machine. In this example, instead of the distribution guide 62 in the second configuration example shown in FIG.
A guide 63 having a through hole formed therein is provided so as to be swingable up and down. The solenoid 63a is selectively driven according to whether the front end multiplex processing or the rear end multiplex processing is selected, and the sheet feeding cassette side of the guide 63 is moved to the sheet feeding cassette 4
Move to the upper or lower side of 1 outlet. In this manner, the front end multiplexing process or the rear end multiplexing process can be selectively executed in the same manner as in the configuration example shown in FIG.

FIG. 20 is a diagram showing a fourth configuration example of the paper feed unit of the digital copying machine. In this example, instead of the distribution guide 62 in the second configuration example shown in FIG.
Inlet fans 64a and 64b are provided above and below the paper transport path. The upper intake fan 64a or the lower intake fan 64b is selectively driven in accordance with whether the front end multiplex processing or the rear end multiplex processing is selected, and the rear end of the fed front sheet is supplied. The suction is performed above or below the outlet of the paper cassette 41. Also in this manner, the front end multiplexing process or the rear end multiplexing process can be selectively executed in the same manner as in the configuration example shown in FIG.

FIG. 21 is a diagram showing a fifth configuration example of the paper feeding section of the digital copying machine. In this example, instead of the distribution guide 62 in the second configuration example shown in FIG.
The friction roller 65 is rotatable in both the counterclockwise direction and the clockwise direction. The friction roller 6 depends on whether the front end multiplex processing or the rear end multiplex processing is selected.
5 is selectively rotated counterclockwise or clockwise through a motor 65a to guide the front end of the fed rear sheet to the upper side or lower side of the front side sheet. As a result, FIG.
In the same manner as in the configuration example shown in (1), the front end multiplex processing or the rear end multiplex processing can be selectively executed.

FIG. 22 is a diagram showing a sixth configuration example of the paper feeding section of the digital copying machine. In this example, instead of the distribution guide 62 in the second configuration example shown in FIG.
A lever 66 is provided that can swing up and down on the downstream side in the transport direction with the paper feed cassette 41 side as a fulcrum. The downstream end of the lever 66 is selectively swung downward or upward depending on whether the front end multiplex processing or the rear end multiplex processing is selected, and the front end of the fed rear sheet is moved forward. Guide to the top or bottom of the paper. Also in this manner, the front end multiplexing process or the rear end multiplexing process can be selectively executed in the same manner as in the configuration example shown in FIG.

As shown in FIG. 23, by controlling the operation of the sheet feeding unit at the time of sheet feeding for each sheet, the front end multiplexing processing or the rear end multiplexing processing is performed in accordance with the formation state of the margin in each image data. Optimal processing among the processing can be executed for each sheet. This is the same in other examples except the example using the distribution guide 62 shown in FIG.

FIGS. 24 to 27 are diagrams showing another configuration of the paper transport section of the digital copying machine. In this example,
Two separated conveyance paths 401a and 401b separated from each other are formed between the sheet cassette 41 and the image forming unit 3, and separation claws 403 are arranged between the sheet cassette 41 and the separation conveyance paths 401a and 401b. Between the registration roller 45 and the separation conveyance paths 401a and 401b.
a and 405b are arranged to form an overlapping portion 404.

As shown in FIG. 24, the separation claw 403 guides the sheet P fed via the pickup roller 43 and the sheet feeding roller 44 to the separation conveyance paths 401a and 401b alternately. The transport rollers 4 are provided in the separation transport paths 401a and 401b.
02a and 402b are provided, and the sheet P is conveyed to the overlapping unit 404 via the separation conveyance paths 401a and 401b.

As described above, the paper P fed from the paper feed cassette 41 is alternately guided to the respective separation conveyance paths 401a and 401b, so that the front paper P can completely reach the overlapping portion 404 before the paper P reaches the inside. The rear sheet P can be fed, and the feeding interval of a plurality of sheets can be shortened to shorten the entire image forming operation.

The upper surface of the separation claw 403 is formed by a curved surface having the same curvature as the conveyance surface of one separation conveyance path 401a, and the lower surface of the separation claw 403 is formed by the other separation conveyance path 40a.
1b is constituted by a curved surface having the same curvature as the transfer surface. As a result, the paper P fed from the paper feed cassette 41 comes into contact with the upper or lower surface of the separation claw 403, and is smoothly guided into the separation conveyance paths 401a and 401b.

Further, as shown in FIG.
Are the minimum sized paper width Pb1 and the maximum sized paper width Pb in the direction orthogonal to the paper conveyance direction.
In consideration of 2, the paper is divided and arranged at a plurality of positions in contact with both ends of the paper of each size. Thus, the paper P fed from the paper feed cassette 41 can be reliably guided to each of the separation transport paths 401a and 401b regardless of the size.

As shown in FIG. 26, the overlapping member 40
5a and 405b are disposed below and above the overlapping portion 404, respectively.
And is moved upward or downward through the overlapping portion 404 so as to be freely exposed. The vertical width of the overlapping section 404 is set so that the rear end of the front sheet and the front end of the rear sheet can be overlapped in the vertical direction.
01a and 401b are wider than the upper and lower widths.

FIG. 27 is a diagram showing the operation of the overlapping member. At the time of the rear end multiplexing process in which the front end of the rear sheet is overlapped on the upper surface of the rear end of the front sheet, the rear end of the front sheet P1 conveyed via one of the separation conveyance paths 401a is an overlapping member. After the sheet P2 reaches the position facing the sheet P 405a, 405b, the front end of the rear sheet P2 conveyed via the other separation conveyance path 401b is overlapped with the overlapping member 405a, 405b.
Before reaching the position facing the 405b, the upper overlapping member 405b is moved downward to be exposed in the overlapping portion 404. As a result, the rear end of the front sheet P1 is pushed down below the opening of the other separation conveyance path 401b, and the front end of the rear sheet P2 is moved forward.
Is guided above the rear end.

On the other hand, at the time of the front end multiplexing process in which the rear end of the front sheet is overlapped with the upper surface of the front end of the rear sheet, the front sheet P1 conveyed via one of the separation conveyance paths 401a. The rear ends are overlapped members 405a, 40
5b, the other separation conveyance path 401
Before the front end of the rear sheet P2 conveyed via the “b” reaches the position facing the overlapping members 405a and 405b, the lower overlapping member 405a is moved upward to be exposed in the overlapping portion 404. Let it. As a result, the rear end of the front sheet P1 is pushed up above the opening of the other separation conveyance path 401b, and the front end of the rear sheet P2 is guided below the rear end of the front sheet P1. I will

Note that the overlapping members 405a and 405b
Similarly to the separation claw 403, in the direction orthogonal to the paper transport direction, the paper is divided and arranged at a plurality of positions in consideration of the transportable paper size. Two sheets can be accurately overlapped.

The amount of superposition of the two sheets is adjusted by the timing at which the registration roller 45 starts rotating after the front end of the rear peripheral sheet P2 reaches the rear end of the front sheet P1. Can be.

[0125]

According to the present invention, the following effects can be obtained.

(1) In each image data to be formed on a plurality of sheets of paper conveyed continuously, a margin at the front end side or the rear end side in the paper conveyance direction is deleted, and the deleted margin is conveyed. By transporting a plurality of sheets in a state of being overlapped in the length in the direction, a plurality of sheets are stacked in a state where the respective sheets are overlapped by the overlap amount determined based on the image range in the sheet transport direction in the image data. A plurality of sheets pass through the image forming unit in a state where the sheets can be transported and do not disturb the image forming state of each sheet, that is, in a state where the original image data can be faithfully reproduced on each sheet. The time to do this can be minimized.

(2) A margin on the rear end side of the image data to be formed on the front paper is deleted, and the margin on the rear end of the front paper is removed by the length of the paper conveyance direction. By transporting a plurality of sheets to the image forming unit with the front end of the rear sheet overlapped, a range in which the rear sheet overlaps the front sheet, that is, a range in which the rear sheet does not face the image forming unit. The margins can be deleted from the image data so that the image data can be formed on the front end of each sheet with the image data as it is, and the margins included in the image data can be rearranged on the rear end of each sheet. Can be masked by the same sheet of paper, and the contents of image data formed on each sheet can be kept unchanged.

(3) The front margin of the image data to be formed on the rear paper is deleted, and the margin removed on the front edge of the rear paper is moved forward by the length of the paper in the paper transport direction. By transporting a plurality of sheets to the image forming unit with the rear ends of the sheets overlapped, a margin corresponding to a range where the front sheet overlaps with the rear sheet, that is, a range that does not face the image forming unit. Parts can be deleted from the image data so that the image data can be formed on the rear end side of each sheet with the image data as it is, and at the front end side of each sheet, the margin included in the image data is removed from the rear side. Masking can be performed using paper, so that the content of image data formed on each paper does not change.

(4) By performing the rear end multiplexing processing or the front end multiplexing processing in accordance with the selection operation by the operator, the state in which the operator has selected according to the desired paper discharge state, the configuration of the paper transport path, and the like. A plurality of sheets can be superimposed on each other, and the fastest image forming operation can be performed according to the discharge state desired by the operator and the configuration of the sheet conveyance path.

(5) A plurality of sheets are automatically superimposed on each other in a state corresponding to the formation state of a margin portion in image data to be formed on each of a plurality of sheets of paper, and the fastest image formation according to the image data is performed. Work is performed.

(6) Each sheet fed from the sheet feeding section in a state of being overlapped by a fixed amount in the sheet feeding direction until the image forming section reaches the image forming section. By adjusting the overlap amount according to the length, each sheet fed from the paper feed unit is overlapped with the overlap amount according to the length of the margin part deleted from the image data, and the image is Can be led to the forming part.

(7) An appropriate amount of overlap between the front sheet and the rear sheet according to the image data can be easily realized when feeding the rear sheet from the sheet storage position.

(8) Each of a plurality of sheets passing through the transfer position in an overlapping state is guided to a fixing position while being separated from each other, so that heating and pressing can be performed while the respective sheets are separated from each other. Thus, it is possible to prevent the paper from coming into close contact with other paper and to reliably discharge the paper.

(9) Each sheet is conveyed at a speed higher than the conveyance speed at the transfer position from the time when the rear end passes through the transfer position to the time when the front end reaches the fixing position. When the trailing edge passes through the transfer position, the front paper that has passed through the transfer position in a state where it overlaps the previous paper is transported at a higher speed than the rear paper that is passing through the transfer position, and is reliably separated from the rear paper. can do.

(10) In the period from the time when the rear end passes through the transfer position to the time when the front end reaches the fixing position, each sheet is set at a higher speed than the sheet transport speed at the fixing position in accordance with the amount of overlap with the rear sheet. By transporting at high speed, each paper is
The sheet can be reliably separated from the following sheet from when the sheet passes through the transfer position to when the sheet reaches the fixing position.

(11) By controlling the vertical paper feed position from the paper storage position according to whether the rear end multiplex processing or the front end multiplex processing is selected,
The sheet is fed downward or upward according to the processing selected from the rear end multiplexing processing or the front end multiplexing processing, and the front end of the rear sheet is guided above or below the rear end of the front sheet. A power space is formed.

(12) Depending on whether the rear end multiplexing processing or the front end multiplexing processing is selected, the front end of the rear sheet fed from the sheet storage position is changed to the rear end of the front sheet. By guiding the sheet upward or downward, the rear end of the front sheet and the front end of the rear sheet are reliably overlapped with each other in a state suitable for the selected processing.

(13) Depending on whether the rear end multiplexing processing or the front end multiplexing processing is selected, the rear end of the front sheet when feeding the rear sheet from the sheet storage position is set to the lower side. By displacing to the position or the upper position, to form a space in which the front end of the rear sheet is guided above or below the rear end of the front sheet according to the selected process,
Both are superimposed in a state suitable for the selected processing.

(14) Depending on whether the rear end multiplexing processing or the front end multiplexing processing is selected, the front end of the rear sheet fed from the sheet storage position is moved to the upper position or the lower position. , The front end of the rear sheet can be reliably guided above or below the rear end of the front sheet according to the selected process.

(15) A plurality of sheets continuously fed from the sheet storage position are sequentially guided to a plurality of separation conveyance paths, respectively.
After being conveyed through each separation conveyance path, by superimposing according to the selection state of the rear end multiplex processing or the front end multiplex processing in front of the image forming unit, a plurality of sheets can be subjected to the rear end multiplex processing or the front end multiplex processing. In addition to being able to be conveyed to the image forming unit while being superimposed in a suitable state, the time interval for sequentially feeding a plurality of sheets can be sufficiently shortened, and the image forming operation time can be shortened. .

(16) The rear end of the front sheet is moved rearward through the superposition member disposed between the separation conveyance path and the image forming section, depending on the selection state of the rear end multiplexing processing or the front end multiplexing processing. By moving the sheet below or above the front end of the sheet, the sheets before and after being conveyed via each separation conveyance path are accurately overlapped in a state suitable for the rear end multiplex processing or the front end multiplex processing to form an image. Can be led to the department.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a digital copying machine that is an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a view for explaining a sheet conveyance state in the digital copying machine.

FIG. 3 is a diagram showing a configuration near a paper feed path of a paper feed unit in the digital copying machine.

FIG. 4 is a diagram showing a configuration near a main transport path of a paper transport unit in the digital copying machine.

FIG. 5 is a flowchart showing a part of a processing procedure in a control unit of the digital copying machine.

FIG. 6 is a flowchart showing a processing procedure at the time of multiplex processing in a control unit of the digital copying machine.

FIG. 7 is a flowchart showing a processing procedure of multiplexed image data creation processing included in the multiplexing processing in the control unit.

FIG. 8 is a flowchart illustrating a processing procedure of a sheet feeding process included in the multiplexing process in the control unit.

FIG. 9 is a flowchart illustrating a processing procedure of an image forming process included in the multiplexing process in the control unit.

FIG. 10 is a diagram illustrating a sheet conveyance state in the image forming process.

FIG. 11 is a flowchart illustrating a processing procedure of an image fixing process included in the multiplexing process in the control unit.

FIG. 12 is a diagram illustrating a sheet conveyance state in the image fixing process.

FIG. 13 is a flowchart showing a processing procedure of a control unit of a digital copying machine according to another embodiment of the present invention.

FIG. 14 is a diagram illustrating image data and a sheet conveyance state during rear-end multiplex processing in the digital copying machine according to the embodiment of the present invention.

FIG. 15 is a diagram illustrating image data and a sheet conveyance state during the front-end multiplexing process.

FIG. 16 is a diagram illustrating image data and a sheet conveyance state during a mixing process of the rear end multiplexing process and the front end multiplexing process.

FIG. 17 is a diagram illustrating a first example of a paper feeding unit of the digital copying machine according to the present invention.
FIG. 3 is a diagram showing an example of the configuration.

FIG. 18 is a diagram illustrating a second example of a paper feeding unit of the digital copying machine according to the present invention.
FIG. 3 is a diagram showing an example of the configuration.

FIG. 19 is a diagram illustrating a third example of the paper feeding unit of the digital copying machine according to the present invention.
FIG. 3 is a diagram showing an example of the configuration.

FIG. 20 is a diagram illustrating a fourth portion of the paper feeding unit of the digital copying machine according to the present invention.
FIG. 3 is a diagram showing an example of the configuration.

FIG. 21 is a diagram illustrating a fifth example of the paper feeding unit of the digital copying machine according to the present invention.
FIG. 3 is a diagram showing an example of the configuration.

FIG. 22 is a sixth section of the paper feeding section of the digital copying machine according to the present invention;
FIG. 3 is a diagram showing an example of the configuration.

FIG. 23 is a diagram illustrating a first example of a paper feeding unit of the digital copying machine according to the present invention.
FIG. 7 is a diagram illustrating a paper feed state during the mixing process in the configuration example of FIG.

FIG. 24 is a diagram showing a configuration of a paper feed cassette (paper storage position) side in another example of the paper transport unit of the digital copying machine of the present invention.

FIG. 25 is a plan view showing an arrangement state of separation claws in the paper transport unit.

FIG. 26 is a diagram illustrating a configuration of an image forming unit side of the paper transport unit.

FIG. 27 is a diagram illustrating an operation of a superimposing claw in the sheet transport unit.

[Explanation of symbols]

 1-Digital Copier (Image Forming Apparatus) 2-Image Reading Section 3-Image Forming Section 4-Circumferential Sheet Conveying Section 31-Photosensitive Drum 35-Transfer Unit 37-Variable Speed Belt (Separating / Conveying Means) 41-Paper Cassette (Sheet feeding unit) 43 -Pickup roller (Sheet feeding unit) 44 -Sheet feeding roller (Sheet feeding unit) 45 -Regist roller (Adjusting unit) 46 -Fixing roller

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 21/14 H04N 1/00 E 5C062 15/36 108M 5C076 H04N 1/00 1/38 108 G03G 21/00 372 1/38 382 (72) Inventor Yoshifumi Yoneya 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (72) Inventor Hideki Sekino 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka Sharp Corporation (72) Inventor Masayuki Gomi 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Inside (72) Inventor Masahiro Kitashiri 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Inc. (72 Inventor Takehiro Kato 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Noriyuki Nakajima Osaka Prefecture Univ. (22) Inventor Hiroki Kinoshita, 22-22 Nagaikecho, Abeno-ku, Osaka, Japan Inside Sharp Co., Ltd. (72) Inventor Yoshio Nishimoto, Chief of Abeno-ku, Osaka, Osaka 22-22 Ikemachi Sharp Co., Ltd. (72) Inventor Yoya Sato 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka F-term (reference) 2H027 DC07 DC10 DE02 DE03 DE07 ED16 EE02 EE03 EE06 FA11 FD01 FD08 ZA07 2H072 AA07 AA16 AA24 AB07 3F053 EA05 EC02 EC06 ED29 3F101 LA07 LB03 3F343 FA02 FB02 GA01 GB01 GC01 GD01 JA01 KA04 KA13 MB04 MB13 MC06 5C062 AB22 AB30 AB32 AC12 AC15 A24 BA04 5076

Claims (16)

[Claims] An image forming apparatus according to claim 1, wherein a blank portion at a front end side or a rear end side in a paper transport direction in each of a plurality of image data to be continuously formed is deleted and supplied to an image forming unit, and the deleted blank portion of paper is removed. An image forming apparatus, comprising: a control unit that operates a sheet conveying unit so as to convey a plurality of sheets to an image forming unit in a multiplexed state that overlaps over a length in a conveying direction. 2. The image forming apparatus according to claim 1, wherein the control unit supplies a plurality of image data to the image forming unit by deleting a margin on a rear end side of the front image data of the image data formed before and after each other. A rear end multiplex process for conveying a plurality of sheets in a state where a front end of a rear sheet is overlapped on a rear end of a front sheet among sheets conveyed before and after each other. 2. The image forming apparatus according to 1. 3. The control section supplies a plurality of image data to the image forming section by deleting a margin on the front end side of the rear image data of the image data formed before and after each other. 2. A front end multiplexing process for conveying a plurality of sheets in a state in which a rear end of a front sheet is overlapped on a front end of a rear sheet among sheets conveyed before and after is performed. The image forming apparatus as described in the above. 4. The control unit according to claim 2, wherein the control unit executes one of the rear-end multiplexing processing and the front-end multiplexing processing according to claim 3. 2. The image forming apparatus according to 1. 5. The control unit selects one of a rear end multiplexing process according to claim 2 and a front end multiplexing process according to claim 3, according to a formation state of a margin portion in name image data. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured to execute the processing. 6. A sheet feeding means for feeding a plurality of sheets from a sheet feeding section by overlapping a predetermined amount in a feeding direction, and each sheet between a sheet feeding section and an image forming section. And an adjusting means for adjusting the overlapping amount of the image data, wherein the control unit operates the adjusting means in accordance with the length of the blank portion deleted from the image data in the paper transport direction. 6. The image forming apparatus according to any one of claims 1 to 5, 7. The paper feeding roller, wherein the adjusting means is configured to be able to freely contact and separate from the upper surface of the peripheral paper stored in the paper storage position and to feed paper at any one of a plurality of paper feeding speeds. The image forming apparatus according to claim 6, wherein: 8. A separation and conveyance device for separating and conveying paper sheets that are adjacent to each other between a transfer position where an image is transferred onto a paper sheet in the image forming unit and a fixing position where the paper sheet that has passed the transfer position is heated and pressed. The image forming apparatus according to claim 1, further comprising a unit. 9. The separation / conveyance means conveys a sheet at a speed higher than the sheet conveyance speed at the transfer position from the time when the rear end of each sheet passes the transfer position to the time when the front end of the name sheet reaches the fixing position. The image forming apparatus according to claim 8, wherein: 10. A paper sheet in a blank portion in which a sheet conveying speed from a time when a rear end of each sheet passes a transfer position to a time when a front end of each sheet reaches a fixing position is deleted from image data. 9. The image forming apparatus according to claim 8, wherein the number increases or decreases according to the length in the transport direction. 11. The paper transport unit according to claim 2, wherein a vertical position of the paper stored in the paper storage position is determined according to a selection state of the rear end multiplexing processing according to claim 2 or the front end multiplexing processing according to claim 3. The image forming apparatus according to claim 5, further comprising a sheet feeding position control member that controls a sheet feeding position. 12. The paper feed position control member according to claim 2, wherein the rear end multi-processing or the front multi-processing according to claim 3 selects the rear end of the sheet output from the sheet storage position. The image forming apparatus according to claim 11, wherein the front end is selectively guided to an upper side or a lower side of a rear end of a front sheet. 13. The paper feed position control member according to claim 2, wherein the rear end multi-processing or the front multi-processing according to claim 3 selects the rear end of the paper from the paper storage position. 13. The image forming apparatus according to claim 12, wherein a rear end portion of a front sheet is sometimes moved downward or upward. 14. The paper feed position control member according to claim 2, wherein the rear end multiplexing processing or the front end multiplexing processing according to claim 3 outputs a paper sheet from a paper storage position according to a selection state. 13. The image forming apparatus according to claim 12, wherein the front end of the rear sheet is sometimes moved upward or downward. 15. The paper transport section comprises at least two separate transport paths separated from each other between a paper storage position and an image forming section, and separates paper between the separation transport path and the paper storage position. A separation claw that is alternately guided to the conveyance path, and between the separation conveyance path and the image forming unit.
According to the selection status of the rear end multiplexing processing described in (1) or the front end multiplexing processing described in (3), the sheet that has passed through one separation conveyance path passes above or below the rear end of the other separation conveyance path. The image forming apparatus according to claim 11, further comprising an overlapping member that guides a front end of the sheet. 16. The superposing member, when the rear end multiplexing processing according to claim 2 is selected, sets the rear end of the front sheet conveyed through one separation conveyance path to the other end. A front sheet conveyed via one of the separation conveyance paths when the front end multiplex processing according to claim 3 is selected, wherein the front sheet is pushed down below a front end of the rear sheet conveyed via the separation conveyance path. 16. The image forming apparatus according to claim 15, wherein a rear end of the sheet is lifted above a front end of a rear sheet conveyed through the other separation conveyance path.