JP3943842B2 - Double-sided image recording device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile capable of double-sided recording by an interleaf method. More specifically, the present invention stores a plurality of original image data obtained by reading by a scanner and the like. The present invention relates to a digital duplex image recording apparatus capable of duplex recording.
[0002]
[Prior art]
In recent years, with the rapid spread of digital copying machines and laser printers, “higher productivity of double-sided copying” has been raised as a market need. As a double-sided recording method using a digital machine, a so-called interleaf control method disclosed in Japanese Patent Application Laid-Open No. 63-313172 having high printing efficiency is becoming the mainstream in recent years.
[0003]
In addition, in an image recording apparatus of a digital copying machine, it is necessary to read image information by automatic document feeding using an automatic document feeder (ADF) or the like. Although it is also referred to as memory printing, image information is temporarily stored in a memory or the like, and the information is read out as necessary for printing.
[0004]
The flow of paper when performing double-sided copying with a conventional digital image recording apparatus will be briefly described.
[0005]
In the double-sided recording, the paper on which the image has been recorded on the front surface (first surface) is reversed by the double-sided unit and returned to the recording position to record the image on the back surface (second surface). Recently, so-called stackless duplex recording, in which sheets are not stacked in a duplex unit, is becoming mainstream. The simplest double-sided copying method is a method in which an image is recorded on the front side of a sheet, and after waiting for the sheet to return to the recording position, an image is recorded on the back side of the sheet. In this case, since the front and back images are recorded for each sheet, the efficiency is very low, and the productivity decreases as the double-sided conveyance path becomes longer. That is,
"First sheet → → → First sheet → Second sheet → → → Second sheet → Third sheet → → → Third sheet ...”
In this order, image recording is performed alternately on the front and back of each sheet. Therefore, after receiving the image recording on the front surface, the paper is reversed and then fed again to the recording means until receiving the image recording on the back surface. The time required for this, that is, the period indicated by “→→→” becomes longer. Therefore, an interleaf control method has been proposed in order to avoid such a problem of productivity reduction.
[0006]
In the interleaf control method, images are continuously recorded on the surface of two or more sheets at first, sequentially conveyed into an intermediate conveyance path, and the first sheet (the first sheet) among the plurality of sheets. ) To the recording means and image recording on the back side is performed. Immediately after starting the image recording on the first sheet, one new sheet (white sheet) is fed from the sheet feeding unit to the recording unit, and the image is recorded on the surface thereof. Thereafter, control is performed so that a new paper feed (front) from the paper feed unit and a paper feed (back) from the duplex unit are alternately performed to record an image. In this manner, the interleaf control method is a control in which a new sheet is alternately interrupted after re-feeding a sheet on which an image has been recorded on the front surface. By this interleaf control, a plurality of sheets always exist in the in-machine conveyance path, and productivity is improved. For reference, the image recording order is as follows.
[0007]
<Example of image recording order: Two-leaf interleaf control>
Front side of the first page → Front side of the second page (recorded two consecutively at first) → Back side of the first page → Front side of the third page → Back side of the second page → Front side of the fourth page ... ...
<Example of image recording order: Three-sheet interleaf control>
1st sheet → 2nd sheet → 3rd sheet (first 3 consecutive records) → 1st sheet → 4th sheet → 2nd sheet ... ...
Next, conventional interleaf control will be further described with reference to FIG.
[0008]
FIG. 9 is a diagram for explaining the flow of conventional interleaf control. The top of FIG. 9 shows the timing of reading image information using an ADF (automatic document feeder). Ten single-sided originals are read sequentially. As shown in the figure, image information (original) is read in page order at a fixed timing by ADF (reading of image information). The image recording timing of this system is assumed to be an image recording system in which image information can be written on the photoreceptor in synchronization with the ADF reading timing. Therefore, at the time of single-sided recording shown in FIG. 9A (at the time of single-sided recording from a single-sided original), the reading speed for reading the original and the writing speed for writing on the photoconductor are substantially the same. Note that the timing at which the corresponding image is written on the photoconductor slightly deviates from the timing at which each page of the document is read because the operation of reading the image once stored in the memory is performed. . In addition, a toner image obtained by developing the electrostatic latent image formed on the photoconductor is transferred (recorded) to the paper at the timing of writing image information on the photoconductor to form an electrostatic latent image. This timing is usually constant.
[0009]
Next, FIG. 9B shows an example of a conventional interleaf control method in which the number n of interleafs is three. This is an example of recording two copies of 10 single-sided originals in the sort mode. In this example, face-up paper discharge (paper discharge in which odd-numbered pages 1, 3, 5,... Are sequentially stacked downward) is assumed, and as shown in FIG. Image reading is performed, and writing to the photoconductor is performed at almost the same time. Also, the image information sequentially read into the ADF is temporarily stored in a memory or HDD (hard disk) in order to record a large number of copies. In addition, the numbers with circles (▲ 1, ▼, ▲ 3) are page numbers. The shaded area corresponds to the back side, and the thick line frame corresponds to the second copy. The horizontal axis (right direction) is the time axis.
[0010]
First, since the number of interleafs n is 3 in this example, the surface image is recorded on the three sheets in the order of (1) → (3) → (5) in accordance with the reading order of odd pages. Then, the first sheet (page (1)) is reversed and fed again through the double-sided path (double-sided loop) to the recording position (transfer position), and image recording is performed on the back side (page (2)). Is done. Next, a new fourth sheet (page 7 is a white sheet scheduled to be recorded) is fed after the first sheet. Next, following the fourth sheet, this time, the second sheet (page (3)) is re-feeded from the double-sided loop, and the image is recorded on the back surface (page (4)). (Alternate conveyance) is started. That is,
1st sheet (Page 1) → 2nd sheet (Page 3) → 3rd sheet (Page 5) → Back 1 (Page 2) → 4th sheet (▲ Page 7 ▼ →→
Thus, the paper is fed.
[0011]
The point to be noted here is that, as shown in FIG. 9B, even page (information on the back side) cannot be written on the photoconductor in the initial stage of reading the document. In the meantime, there is a loss of n-1 sheets as compared with FIG. 9 (a) showing the timing of single-sided recording. In this example, since the number of interleaf n is 3 (n = 3), a loss of 2 sheets occurs at the position indicated by the dotted line in the figure. Further, after the alternate paper feed is started, data is read from the memory or HDD and written as needed.
[0012]
In the final stage of FIG. 9B, in the recording process of the second copy, after recording on the back of page (6), new paper is not fed by interleaf control. A loss of (n-1) sheets (2 sheets) occurs. This is a disadvantage of the interleaf control, which causes a decrease in productivity. As described above, in the control method of FIG. 9B, compared with the image recording performance at the time of single-sided shown in FIG. 9A, (n−1) sheets (two sheets) indicated by a dotted blank in the initial stage. ) And (n-1) (2) losses occur in the final stage.
[0013]
The loss that occurs in the early stages is
1) Depending on the reading speed of image information by ADF or the like (whether there is information that can be immediately written to the photoconductor in response to an image recording request)
2) Due to the double-sided conveyance path length of paper required for double-sided image recording
The two causes are as follows.
[0014]
That is, in 1), the image reading by the ADF or the like is continuously performed on pages (1), (2), (3), (4),..., But the image information on pages (2) and (4) is In the example, even page information), information on the back side of the paper cannot be written on the photoconductor immediately. Therefore, the image information of even pages is temporarily stored in a memory or the like, so that the writing order in the initial stage becomes the front surface (1), (3), (5), and so on. The image recording operation will continue. Then, when reading a large number of single-sided originals by ADF or the like, the first loss that occurs when reading (2) (4) (even pages) is inevitable as shown in FIG. 9 (a).
[0015]
In 2), even if images are continuously recorded on the first three sheets (1), (3), and (5), before the leading sheet (1) goes round the double-sided conveyance path, Since a loss of (n-1) sheets occurs, it is clear that the double-sided conveyance path length is affected.
[0016]
[Problems to be solved by the invention]
On the other hand, FIG. 9C is a diagram for explaining an interleaf control system according to the invention (Japanese Patent Application No. 2000-309717) proposed by the present inventor last time. According to the present invention, at the final stage of a series of writing and recording operations by the interleaf control, the front surface image is recorded on (2n-1) sheets (5 sheets) and the last back surface image recording operation is continuously performed. Thus, the invention eliminates the loss at the final stage. That is, in the recording process of the second copy, recording is performed on five sheets of odd-numbered pages from (1) page table to (9) page table and sent into the duplex unit, and thereafter the five sheets The image is continuously recorded on the back surface of the image. However, this proposal cannot eliminate the loss that occurs in the initial stage.
[0017]
An invention disclosed in Japanese Patent Laid-Open No. 8-20147 is also known. The present invention has a conveyance path length capable of accommodating n (n ≧ 2) sheets, and is a circulation type sheet conveyance in which a sheet having a copy image formed on one side is turned upside down and re-fed to a copy position. When double-sided copying using the mechanism and n or more sheets is performed, copying of the original image of the (2n-1) th page can be started in order to set the number of first sheet circulation by the sheet transport mechanism to n sheets. The first sheet feeding timing is set so that the nth sheet reaches the copy position after the time point. In the present invention, the required time in the interleaf control method is shortened, but the loss occurring in the initial stage cannot be eliminated as in the above example.
[0018]
The present invention has been made in view of the actual state of the related art, and its purpose is not only in the final stage but also in the initial stage when performing double-sided recording of a plurality of copies from a plurality of single-sided originals by the conventional interleaf control method. An object of the present invention is to provide a double-sided image recording apparatus that eliminates the loss that occurs and can realize double-sided productivity of 100% as “required time for single-sided image recording = required time for double-sided image recording”.
[0019]
[Means for Solving the Problems]
In order to achieve the above object, the present invention stores image information for each page of a document in page order, and reads out each image information as necessary.
Recording means for recording two pages of image information on the first surface and the second surface of the recording medium, respectively, among the image information stored in the storage means;
Control means for controlling the storage means and the recording means;
Reversing means for reversing the front and back in order to record image information on the second surface of the recording medium;
A double-sided intermediate conveyance path that guides the recording medium that has been turned upside down to the recording means;
The second surface of the recording medium that has recorded on the first surface after recording on the first surface of the plurality of recording media continuously at the beginning of recording and sequentially introducing them into the double-sided intermediate conveyance path In the double-sided image recording apparatus of the interleaf control system that alternately records on the first surface and records on the first surface of the unrecorded recording medium,
An interleaf in which a recording medium on which an image is formed on the first surface is present in the conveyance path when alternately fed In the case where the number of sheets is n, at least (2n-1) recording media can be stored in a double-sided conveyance path through which the recording medium passes during double-sided recording, and the interleaf control is performed. In the first stage until it starts,
n <x ≦ 2n−1
Recording continuously on the first surface of x recording media represented by
y = x-n + 1
Then, after continuously recording on the second surface of the y recording media represented by
[0020]
In this case, continuously at the end of the final stage of the recording operation.
n <x ≦ 2n−1
Of the x number of recording media represented by 2 surface Recorded in It is recommended to record.
[0021]
Moreover, in the said invention, the said double-sided intermediate conveyance On the road It is necessary to set the length so that (n-1) sheets of recording medium can be retained.
[0022]
Further, the reversing means comprises a switchback conveyance path provided on the upstream side of the double-sided intermediate conveyance path, and in the switchback conveyance path, one succeeding sheet is reversed with respect to the preceding reversed sheet. It is preferable to set the operation so that the paper can be reversed while passing each other.
[0023]
In this interleaf control, the storage operation in the storage means can be applied to a storage operation that is performed before the start of recording on the recording medium, that is, when a document is read at an early timing. Further, it is suitable for the case where both sides of a document whose storage operation is performed at a substantially early timing are stored simultaneously, or when the storage operation in the storage unit is performed at a speed twice or more the recording speed.
[0024]
In the interleaf control, preferably , When the number of interleaf sheets is n, it has a configuration that can store at least (2n-1) recording media in a double-sided conveyance path through which a recording medium passes during double-sided recording, and interleaf control. In the first stage until the start of the recording, recording is continuously performed on the first surface of (2n-1) recording media, and then recording is continuously performed on the second surface of n recording media. The final stage of the recording operation so( 2n-1) sheets of paper of Recording on the second surface may be performed continuously.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0026]
FIG. 1 is a schematic configuration diagram of a double-sided image recording apparatus according to an embodiment of the present invention. In FIG. 1, the image forming apparatus includes a main body 100, a paper discharge device (hereinafter referred to as “finisher”) 200, and an automatic document feeder (hereinafter referred to as “ADF”) 300. The main body 100 further includes an image forming unit 1, a transport unit 2, a paper feed unit 3, a reading unit 50, and a writing unit 57.
[0027]
The reading unit 50 is a unit for scanning a document placed on the contact lens 6. The reading unit 50 includes a contact glass 6 on which an original is placed and an optical scanning system. The optical scanning system includes an exposure lamp 51, first to third mirrors 52, 55, and 56, a lens 53, and a CCD image. It is composed of a sensor 54 and the like.
[0028]
The exposure lamp 51 and the first mirror 52 are fixed on a first carriage (not shown), and the second mirror 55 and the third mirror 56 are fixed on a second carriage (not shown). When reading a document image, the first carriage and the second carriage are mechanically scanned and moved at a relative speed of 2: 1 so that the optical path length does not change. This optical scanning system is driven by a scanner drive motor (not shown). The document image is read by the CCD image sensor 54, converted into an electrical signal, and processed.
[0029]
The ADF 300 automatically feeds a sheet document onto the contact glass 6, and a plurality of documents placed with the surface (first surface) facing upward on the document table 301 are fed one by one by a feed roller 302. Then, it is sent to the position of the document reading sensor 305. The original passes through the original reading sensor 305 at a constant speed as it is, and the image on the front side of the original is read by the sensor 305 in this process. The read image data is subjected to image processing such as MTF correction, filter processing, and compression, and is sequentially stored in an image memory 66 described later. As the image reading sensor 305, for example, a close contact type equal magnification CCD device is used. The ADF 300 includes a back side document reading sensor 306 for simultaneous reading on both sides. The back side document reading sensor 306 is provided upstream of the front side document reading sensor 305 in the document feeding direction and downstream of the feeding roller 302 so as to face the back side of the document. Then, one or both sides of the document are read by sheet through.
[0030]
The writing unit (writing means) 57 includes a laser output unit 58, an imaging lens 59, and a mirror 60. Inside the laser output unit 58, a laser diode that is a laser light source and a motor that rotates at a constant speed at a high speed. A square mirror (polygon mirror) is provided. Laser light output from the writing unit 57 is applied to the image forming photoconductor 15 to form an electrostatic latent image (writing of image information).
[0031]
An outline of the procedure for visualizing the electrostatic latent image formed on the photoreceptor 15 and recording the image on a recording medium such as recording paper will be described below.
[0032]
The sheets (recording media) of each size stacked on the first tray 8, the second tray 9, and the third tray 10 are respectively fed by the first sheet feeder 11, the second sheet feeder 12, and the third sheet feeder 13. The paper is fed and transported by the vertical transport unit 14 to a position (main body transport path 124) that contacts the photoconductor 15. The image data on the image memory 66 (FIG. 4) is written on the photoconductor 15 by the laser from the writing unit 57 to become an electrostatic latent image, and toner adheres when the electrostatic latent image passes through the developing unit 27. Development is performed to form a toner image. Then, the toner image on the photosensitive member 15 is transferred by the transfer means 16 such as a transfer roller while the sheet is conveyed by the conveying belt 16a at the same speed as the rotation of the photosensitive member 15. Thereafter, the image is fixed by the fixing unit 17 and is discharged to the paper discharge tray 19 by the paper discharge unit 18. In this embodiment, the photoconductor 15, the developing unit 17, the transfer unit 16, and the fixing unit 17 constitute an image recording unit.
[0033]
Next, an outline of a procedure for recording an image on both sides of a sheet will be described.
[0034]
FIG. 2 is an explanatory diagram schematically showing the operation of the sheet reversing unit 112. A sheet fed from one of the sheet feed trays 8, 9, and 10 and having an image recorded on the front surface (first surface) by the image recording means is switched to the sheet discharge tray 19 side by switching the reverse path switching claw 115. Without being guided, it is transported to the reversing unit 112 by the reversing inlet transporting means 125 via the double-sided entrance transporting path 113 and temporarily stored in the switchback transporting path 119. Next, after both sides are aligned by the sheet alignment jogger 117, the sheet is fed out in the reverse direction (refeeding direction) by the vertically movable return conveying means 122 and guided downward by the reverse sheet discharge switching claw 123. Then, the paper is reversed and sent to the double-sided intermediate transport path 121 provided below the unit by the reverse exit transport means 126. Then, the intermediate conveyance unit 118 and the double-sided exit conveyance unit 120 connected to a drive source (motor) (not shown) are sent to the vertical conveyance unit 14 again, and an image is recorded on the back surface by the image recording unit while passing through the main body conveyance path 124. Are recorded and discharged outside the main body 100. Each of the conveying means 118 and 120 is provided with a drive cutoff means such as an electromagnetic clutch (not shown) so that one or more sheets can be temporarily held in the double-sided intermediate conveying path 121. Further, the return conveying means 122 provided in the switchback conveying path 119 is configured to be retractable upward, and the two sheets can be present in the conveying roller switchback conveying path 119 so as to pass each other. At this time, the preceding sheet is completely gripped by the reverse exit transport roller 126 and the jogger fence 117 is retracted, and the subsequent sheet is fed into the switchback transport path 119 by the reverse entrance transport roller 125. In addition, when the paper is reversed on the switchback conveyance path 119 and discharged outside the apparatus, the paper that has been switched back by the reversing unit 112 is not sent to the double-sided intermediate conveyance 121 by the paper discharge reversal switching claw 123, but is reversed and discharged. The paper is discharged out of the main body 100 via the paper conveyance path 114. A sheet discharged from the apparatus main body 100 is discharged to either the discharge tray 19 or the finisher 200 of the main body by a discharge destination switching claw 116. The paper discharged to the finisher 200 is once stacked on the stack tray 201 for stapling. After all the sheets are collected in the stack tray 201, the sheet bundle is bound by the stapler unit 202 and discharged to the discharge tray 203.
[0035]
Here, the double-sided conveyance path is a concept indicating a series of loop paths including the main body conveyance path 124, the double-side entrance conveyance path 113, the switchback conveyance path 119, and the double-sided intermediate conveyance path 121.
[0036]
FIG. 3 is a block diagram showing the main part of the control unit.
[0037]
The control unit includes a main CPU (control means) 20 and an operation unit 30. A key input device 32 and a liquid crystal display 31 are connected to the operation unit 30, and a finisher 200 and an ADF 300 are connected to the main CPU 20. Then, the main CPU 20 inputs information by the key input device 32 of the operation unit 30, display output by the liquid crystal display 31, control of the ADF 300, main motor 25, SOL 115, 116, 123, clutch 118, 120, double-sided conveyance drive motor, alignment. Various load controls such as a jogger drive motor, communication control with the finisher unit 200, etc. are performed. The main CPU 20 is connected to the memory controller of the image processing unit shown in FIG. ) And recording means. The storage means is means for storing the recorded information for each page of the read document in page order, and can read each recorded information as necessary. The recording means is recorded information stored in the storage means. Among these, the recording information for two pages is recorded on the first surface and the second surface of the recording medium.
[0038]
FIG. 4 is a block diagram showing the configuration of the image processing unit.
[0039]
The image processing unit includes a memory unit including a memory controller 65, an image memory 66, a secondary compression unit 67, and a hard disk device (hereinafter referred to as “HDD”) 68, a document reading sensor (CCD) 303, an A / D converter. 61, an image data processing unit including a shading correction unit 62, an MTF / γ correction unit 63, and a scaling processing unit 72, and a writing unit including a writing γ correction unit 71 and a writing unit 57. The memory controller 65 includes a CPU 20 Are connected, and the CPU 20 is connected to a ROM 69 and a RAM 70. The ROM 69 stores static data including a program of the CPU 20, and the RAM 70 functions as a work area of the CPU 20 and stores dynamic data such as data used for the control of the CPU 20.
[0040]
An image signal obtained by reading an original image by the CCD image sensor 305 (and 306—both sides simultaneous reading) in the ADF 300 is converted into a digital signal by the A / D converter 61. The image signal converted into the digital signal is subjected to shading correction 62 and then subjected to MTF correction, γ correction and the like in the image processing unit 63. The image signal that has been subjected to MTF correction, γ correction, etc. is enlarged / reduced in accordance with the designated scaling factor via the scaling unit 72 and flows to the memory controller 65. The image data that has entered the memory controller 65 is subjected to primary compression processing and then written into the image memory 66. The operations up to this point are processed without stopping until all the page information is written in the memory when the document reading is started while feeding a plurality of documents one by one.
[0041]
Next, the image data written in the image memory (storage means) 66 is further subjected to the secondary compression processing by the secondary compression processing 67 as necessary to further reduce the data amount, and then the HDD 68 (hard disk drive = storage). And so on). Once the image data is stored in the HDD 68, the original can be read only once even when a plurality of copies are made. When an image written in the image memory 66 is recorded, image data is sent from the image memory 66 to the memory controller 65, and from there to the writing unit 57 (writing means) via the writing γ correction unit 71. Sent.
[0042]
Further, in order to perform the sort image recording operation, the original image is read and accumulated in the HDD 68. The important point at this time is that when the first copy is recorded while the original is being written. This means that access to the HDD 68 is always only an operation for accumulating images, and an operation for expanding image data from the HDD 68 to the image memory 66 is not performed. Since access to the HDD 68 can only be performed in one direction, productivity cannot be increased unless the batting of storage in the HDD 68 and expansion from the HDD 68 is avoided as much as possible. Therefore, the image memory 66 is not released until another image is written until transfer of the read document image to the writing unit 57 and the HDD 68 is completed and becomes unnecessary.
[0043]
Next, a characteristic configuration and operation of the present embodiment will be described with reference to FIGS.
[0044]
FIG. 5 is a diagram for explaining the interleaf control method when all image information is ready to be written by pre-scanning or the like (flow schematic diagram showing the timing of reading and writing image information), and FIG. It is a figure which shows the flow of the paper at the time of implementing the control system of this invention shown to b).
[0045]
Prior to the description of the present embodiment shown in FIG. 5B, first, when all the image information is ready to be written by pre-scanning or the like on the document, the above-described loss at the initial stage and the final stage occurs. Whether or not can be eliminated will be described with reference to FIG.
[0046]
FIG. 5A shows the reading order of image information when memory image recording is performed. In this case, the image information is previously stored in the image memory 65, the HDD 66, or the like by a continuous document image reading operation by pre-scanning or the like. It is stored and can be read and written as needed.
[0047]
FIG. 5A shows a case where the conventional control method is used to control the write timing at the initial stage to be the fastest. That is, in this case, each image information to be recorded on the surface of each sheet (1) (3) (5) from the initial stage is continuously written on the photosensitive member with the same performance as the image recording timing at the time of single-sided recording. Is assumed to be performed. In this interleaf control, since the surface is continuously image-recorded by the number of interleaf sheets (here, n = 3 sheets) at the first stage and then the operation shifts to an alternate sheet feeding operation, the first sheet (1) is selected. A certain time Td (double-sided loop one-round time) is required to go back around the double-sided conveyance path for recording the back image. Therefore, as shown in the figure, even if images are continuously recorded on the surface of the first three sheets (1), (3), and (5), by the time the leading sheet (1) goes around the double-sided conveyance path and returns, A loss of (n-1) sheets occurs. Thus, it has been difficult in the past to avoid the initial loss due to the length of the duplex conveyance path. Similarly, a loss of (n-1) sheets at the final stage was also generated, and the productivity was reduced.
[0048]
FIG. 5 (2) shows the reading timing when the image information reading speed using the ADF 300 or the like is high, for example, when reading can be performed at a speed more than twice the writing speed. FIG. The read timing in the case of performing is shown. In either case, the even page read timing does not affect the odd page write order, and the odd pages can be written continuously from the initial stage. However, in any of the reading modes of FIGS. 5 (2) and (3), as long as the conventional control method shown in FIG. 5 (a) is adopted, loss in the initial stage and the final stage can be avoided. Can not. In other words, it is clear that the loss in the initial stage and the final stage and the decrease in productivity caused by the loss cannot be solved by using any of the reading methods of FIGS. 5 (1), (2), and (3). . Regarding the loss at the final stage, according to the previously proposed invention (the control method described in FIG. 9C), the maximum number of interleafs at the final stage is (2n-1). By doing so, the loss in the final stage can be eliminated.
[0049]
Next, the embodiment of the present invention shown in FIG.
[0050]
The embodiment of the present invention shown in FIG. 5B is an example in the case where 10 single-sided originals are image-recorded (sort mode) by 10-sheet interleaf control as in the case of FIG. The present embodiment can be applied when there is image information that can be written immediately in advance. That is, the present invention is applied when the reading methods shown in FIGS. 5 (1), (2), (3) and the like are employed.
[0051]
As described above, when three initial surface image recordings are continuously performed by the conventional interleaf control method shown in FIG. 5A, as shown in the drawing, the first sheet (▲ 1) A certain double-sided loop round time TG is required in order for (頁) to go round the double-sided loop. Therefore, while the first sheet returns to record an image on the back surface (page (2)), a loss of (n-1) sheets is generated. Therefore, in order to eliminate the loss in the initial stage, as shown in FIG. 5B, in this embodiment, (2n-1) sheets (page No. 1) 3) are continuously provided in the initial stage. (5) (7) (9) (5 sheets) of surface images are written (and recorded). Thereafter, at time t1, writing (and image recording) of the back side image information corresponding to n sheets (page No. (2) (4) (6)) from the first sheet is performed). Start continuously. In this embodiment, since n = 3 sheets, first, the front side image is continuously recorded on five sheets, and then the back side image recording is performed by ejecting the three sheets from the duplex conveyance path. After that, at time t2, alternate sheet feeding is started by normal three-sheet interleaf control. That is, the idea of the present invention is to shift to the target (normal) interleaf control after inserting a large amount of sheets at the initial stage and discharging excess.
[0052]
According to this control method, the loss in the initial stage can be surely eliminated regardless of the number of interleaf sheets n and the number of recording copies.
[0053]
Further, in the present invention, with respect to the loss that occurs in the final stage, the surface image recording of (2n-1) sheets (5 sheets) is performed at the final stage of a series of writing and image recording operations by the interleaf control. At the same time, the last backside image recording is continuously performed so that the loss at the final stage is eliminated. That is, in the recording process of the second copy, at the timing of t2, recording is performed on five sheets of the odd page (1) page table to (9) page table and sent into the duplex unit. Continuously records images on the back side of the five sheets. This eliminates the loss of (n−1) sheets as shown in FIG. 5A, shortens the time required for all processes, and increases productivity. Note that this embodiment is based on the premise that reading of image information corresponding to each page has already been completed at the time of writing, as shown in FIGS. 5 (1), (2), and (3).
[0054]
6 and 7 are explanatory diagrams showing the flow of paper when the control method according to the embodiment of the present invention shown in FIG. 5B is adopted. Hereinafter, the flow of the control method according to the present embodiment will be described with reference to FIG.
[0055]
When two image recording is performed in the sort mode using ten single-sided originals by this image recording apparatus, initially (2n-1) unrecorded sheets as shown in FIG. Are continuously fed from the paper feed unit with a constant paper interval δ. Then, as shown in FIG. 6B, at the initial stage, (2n-1) sheets, that is, a total of five sheets are put into the duplex conveyance path. Next, as shown in FIGS. 6C, 6D, and 6E, the three sheets (first sheet to third sheet) that have been sequentially guided into the double-sided intermediate conveyance path 121 from the beginning. The paper is continuously fed again toward the recording means, and image recording is performed on the back ((2), (4), (6)) pages. Then, as shown in FIG. 6E, the fourth sheet (7) moved to the double-sided intermediate conveyance path 121 stands by at the double-sided exit, and the sixth sheet (1) 'is newly added from the sheet feeding unit. Waiting for the paper to be fed, the fourth sheet (7) is then fed again. After FIG. 6F (t2 in FIG. 6B), normal three-sheet interleaf control (alternate paper feeding) is started. Here, (1), (2), (3) ... are page numbers. The symbol “′” represents the second part. As described above, in this embodiment, when there is image information that can be written in advance, the initial loss can be eliminated very effectively.
[0056]
Furthermore, in this embodiment, as shown in FIGS. 7 (i) to (l), 2n-1 sheets (5 sheets from the 6th sheet to the 10th sheet in this example) were again recorded at the final stage. Then, these sheets are sequentially stored in the double-sided conveyance path, and finally, the five sheets (6th to 10th sheets) are continuously fed again to record the back side image (FIGS. 7 (m) to (p)). ) To complete the image recording process. As a result, the loss at the final stage can be surely eliminated. That is, by alternately feeding paper to (l), (j), and (k) in FIG. 7, the sixth and seventh sheets are stopped in the double-sided intermediate conveyance path 121, and a new tenth sheet is obtained. After the paper feeding is completed, the remaining five sheets are fed again as shown in FIGS. 7L to 7P, so that the loss at the final stage is eliminated.
[0057]
In order to realize such interleaf control, at least (2n-1) sheets in the double-sided conveyance path (main body conveyance path 124, double-sided inlet conveyance path 113, switchback conveyance path 119, double-sided intermediate conveyance path 121). It is important to configure so that the sheets can be stored simultaneously. That is, in order to eliminate the loss at the final stage, it is necessary to secure a conveyance path length that can substantially store at least (2n-1) sheets of paper in the double-side conveyance path.
[0058]
Temporarily increasing the transport speed in the double-sided transport path is necessary to eliminate the initial stage loss by the conventional interleaf control method. In addition to unavoidably increasing costs in terms of control and control, it is inevitable that the transport reliability will be greatly reduced. In addition, in order to shorten the time until the first sheet fed from the paper feeding unit to the main body conveyance path 124 returns to the recording position via the duplex intermediate conveyance path 121, the conveyance path is shortened, and the double-side conveyance path When the number of stored sheets is n, it becomes impossible to insert (2n-1) sheets into the double-sided conveyance path to eliminate the loss at the final stage. Therefore, in order to eliminate the loss at the final stage, it is necessary to configure so that at least (2n-1) sheets can be simultaneously stored in the double-sided conveyance path.
[0059]
As described above, in the present embodiment, at least (n−1) sheets can be retained in a path other than the main body transport path 124 (double-side inlet transport path 113, switchback transport path 119, double-sided intermediate transport path 121). Thus, (2n-1) sheets can be reliably stored in the double-sided conveyance path at the final stage. That is, as shown in FIG. 7 (k), two sheets (sixth sheet (1) ', seventh sheet) on the double-sided intermediate conveyance path 121 and near the exit of the double-sided conveyance unit 111 at the final stage. 3 ▼ ') is retained in the front-rear position relationship. Then, the subsequent three sheets (the eighth sheet {circle over (5)}, the ninth sheet {circle over (7)}, the tenth sheet {circle over (9)}) that are continuously conveyed with an interval of one sheet catch up. Then, the insertion of (2n-1) sheets into the double-sided conveyance path is completed, and at the same time, the discharge of the sheet (reverse image recording) at the final stage is started. This state is shown in FIG. Note that the paper stopped near the exit of the duplex conveying unit 111 is in a state where the leading edge of the sheet is sandwiched between the duplex exit conveying means 120 (roller pair) to some extent and stopped.
[0060]
In the present embodiment, since the sheets are continuously inserted from the initial stage while maintaining the sheet interval δ, the sheet can be conveyed in the switchback conveying path 119. That is, a switchback conveyance path 119 that reverses the front and back of the sheet that has been recorded on the first surface is provided on the upstream side of the double-sided intermediate conveyance path 121, and one preceding reversed sheet in the switchback conveyance path 119 is provided. The sheet is inverted while passing the other sheet while passing the other sheet. In the passing inversion, the succeeding one sheet may be conveyed while the preceding inverted sheet is stopped, or the following sheet may be inverted while moving the preceding sheet. . Specifically, as described above, in order to enable the passing reversal, the preceding sheet is completely gripped by the reversing exit conveying roller 126 and the subsequent sheet is conveyed at the reversing entrance while the jogger fence 117 is retracted. The roller 125 is fed into the switchback conveyance path 119.
[0061]
If a configuration that cannot be reversed in the switchback conveyance path 119 as in the present embodiment and that cannot be reversed in the switchback conveyance path 119 is used, a preceding sheet is required to reverse a certain sheet. Therefore, it is necessary to leave an interval for one sheet, and continuous feeding (continuous image recording), which is the point of the present invention, becomes impossible. For example, in order to reverse without interfering during continuous image recording in a device that cannot pass, it is necessary to increase the transport distance and greatly accelerate the unit, which reduces transport reliability and increases costs. Invitation and control are also complicated.
[0062]
In the above embodiment, the number of interleaf sheets n is 3 (n = 3). However, the number of interleaf sheets varies depending on the apparatus size according to the paper size and the conveyance path length. So, like the present invention , When the number of interleaf sheets is n, in the first stage until the start of interleaf control, continuous recording is performed on the first surface of x recording media represented by n <x ≦ 2n−1. In the case where the process proceeds to n interleaf control after continuously recording on the second surface of y recording media represented by y = x−n + 1, as shown in FIG. Become.
[0063]
That is, FIG. 8 shows an example in which the number of interleafs n is 3, 4, and 5 in the present invention, and corresponds to the control shown in FIG. As you can see from this figure, it becomes the maximum
x = 2n-1
When
y = x−n + 1 = n
It becomes. this is , When the number of interleafs is n, in the first stage until the start of interleaf control, recording is continuously performed on the first surface of (2n-1) recording media, and then n sheets are continuously recorded. After continuous recording on the second surface of the recording medium, the control proceeds to n interleaf control, and at the final stage of the recording operation , This shows that double-sided recording can be performed most efficiently if the recording on the second side is continuously performed. Specifically, when the number of interleaf sheets to be continuously recorded on the first surface at the beginning of recording is n = 5, (2n−1) = at the first stage until the start of interleaf control. Recording is continuously performed on the first surface of nine recording media, and then recording is continuously performed on the second surface of n = 5 recording media, and then n = 5 interleaf control is performed. In the final stage of the recording operation, (2n-1) = 9 sheets On the second Continuous recording on two sides To control It will be.
[0064]
【The invention's effect】
As above Book According to the invention , If image information that can be recorded in advance is stored in a memory, etc., and can be read out at any time (image recording is possible), the loss at the initial stage caused by conventional interleaf control can be eliminated, and double-sided image recording is possible. The same performance as the maximum single-sided image recording speed can be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of a double-sided image recording apparatus according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram schematically showing the operation of a sheet reversing unit of the double-sided image recording apparatus shown in FIG.
FIG. 3 is a block diagram illustrating a main part of a control unit of the double-sided image recording apparatus according to the embodiment.
FIG. 4 is a block diagram illustrating a configuration of an image processing unit of the double-sided image recording apparatus according to the embodiment.
FIG. 5 is an explanatory diagram showing an interleaf control method when all image information is ready to be written by pre-scanning or the like in the double-sided image recording apparatus according to the embodiment.
FIG. 6 is an explanatory diagram showing the flow of paper when the control method of the present invention is implemented.
FIG. 7 is an explanatory diagram showing the flow of paper when the control method of the present invention is implemented.
FIG. 8 is an explanatory diagram showing a control example of an interleaf control method in the double-sided image recording apparatus of the present invention.
FIG. 9 is an explanatory diagram showing an interleaf control method according to a conventional example.
[Explanation of symbols]
6 Contact glass
14 Vertical transport unit
15 photoconductor
16 Transfer means
17 Fixing unit
18 Paper discharge unit
19 Output tray
27 Development unit
50 reading unit
57 Writing unit (writing means)
58 Laser output unit
100 body
111 Double-sided transport unit
112 Inversion unit
113 Double-sided entrance conveyance path
114 Reverse paper delivery path
119 Switchback transport path
121 Double-sided intermediate transport path
124 Main body conveyance path
200 Automatic document feeder
300 Document platen

Claims (7)

Storage means for storing image information for each page of the document in page order, and reading each image information as necessary;
Recording means for recording two pages of image information on the first surface and the second surface of the recording medium, respectively, among the image information stored in the storage means;
Control means for controlling the storage means and the recording means;
Reversing means for reversing the front and back in order to record image information on the second surface of the recording medium;
A double-sided intermediate conveyance path that guides the recording medium that has been turned upside down to the recording means;
The second surface of the recording medium that has recorded on the first surface after recording on the first surface of the plurality of recording media continuously at the beginning of recording and sequentially introducing them into the double-sided intermediate conveyance path In the double-sided image recording apparatus of the interleaf control system that alternately records on the first surface and records on the first surface of the unrecorded recording medium,
A double-sided conveyance path through which the recording medium passes during double-sided recording when the number of interleaf sheets existing in the conveyance path of the recording medium on which the image is formed on the first surface when alternately fed is n In the first stage until the interleaf control is started, and a configuration in which at least (2n-1) recording media can be stored therein,
n <x ≦ 2n−1
Recording continuously on the first surface of x recording media represented by
y = x-n + 1
The double-sided image recording apparatus is characterized in that after the continuous recording on the second surface of the y number of recording media represented by Continuously at the end of the final stage of the recording operation, n <x ≦ 2n−1.
In double-sided image recording apparatus according to claim 1, wherein the intends rows record on the second surface of the x pieces of recording media represented. 3. The double-sided image recording apparatus according to claim 1, wherein the double-sided image recording apparatus is set so that (n-1) recording media can stay in the double-sided intermediate conveyance path .   The reversing means comprises a switchback conveyance path provided on the upstream side of the double-sided intermediate conveyance path. The double-sided image recording apparatus according to any one of claims 1 to 3, wherein an operation of reversing while passing is set to be possible.   The double-sided image recording apparatus according to claim 1, wherein the storage operation in the storage unit is performed before the recording on the recording medium is started.   6. The double-sided image recording apparatus according to claim 1, wherein the storing operation in the storage unit is performed by simultaneously storing both sides of the document.   2. The double-sided image recording apparatus according to claim 1, wherein the storage operation in the storage means is performed at a speed twice or more the recording speed.

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