JPH0683133A - Both-side copying device - Google Patents

Abstract

PURPOSE:To perform optimum both-side copying without causing the missing of an image even when the size and the longitudinal and lateral feeding directions of an original are different. CONSTITUTION:This device is provided with a driving device 43 enabling an intermediate tray 4d to rotate by 90 deg. or 180 deg., a position detecting sensor 45 detecting the rotating position of the tray 4d, an original detecting sensor detecting the size and the longitudinal and lateral feeding directions of the original, a sheet detecting sensor 44 detecting the size and the longitudinal and lateral feeding directions of a sheet, a setting means setting optimum copying magnification based on the sizes of the sheet and the original, a decision means deciding the longitudinal and lateral feeding directions of the sheet and the original, and a controller for controlling to rotate the tray 4d by 90 deg. in the case the longitudinal and lateral feeding directions of the sheet and the original are not the same, and rotate the tray 4d by 180 deg. in the case the longitudinal and lateral feeding directions of the sheet and the original in back side copying are the same.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-sided copying machine for forming a copied image on both sides of a sheet.

[0002]

2. Description of the Related Art In a copying machine, a charge corotron, an exposure device, a developing device, a transfer corotron, a cleaning device, a charge eliminating lamp, etc. are arranged around the image carrier. After being uniformly charged, an electrostatic latent image corresponding to the original image is formed on the image carrier by the exposure device, this electrostatic latent image is developed into a toner image by the developing device, and then this toner image is conveyed. After transferring with a transfer corotron to the incoming sheet, fix the transferred image,
On the other hand, in the image carrier, after the residual toner on the image carrier is removed by the cleaning device, the charge is removed from the image carrier by the charge eliminating lamp to form an image.

In the copying apparatus, when a copy image is formed on both sides of a sheet, an image corresponding to the first original image is formed on the surface of the sheet, and the sheet is guided to the reverse sheet feeding path to convey the sheet. After reversing the direction and accommodating in the intermediate tray, the sheet is fed again to the transfer portion, and an image corresponding to the second original image is formed on the back surface of the sheet.

By the way, in general, the first original size and the second original size
The original size is not necessarily the same as the original size, and if the second original is larger than the first original, the second
The original document image does not fill and the image is cut off. Therefore, in Japanese Examined Patent Publication No. 4-10069, when the first document size and the second document size are different, the optimum magnification of the second document size is automatically set so that the sheet of which the front side is copied enters the sheet. Is set to double-sided copying.

[0005]

However, in the method disclosed in the above Japanese Patent Publication No. 4-10069, it is established under the condition that the vertical and horizontal feed directions of the original are set to be the same in the vertical and horizontal directions. As shown in the drawing, when the originals A and B in the vertical and horizontal feeding directions are mixed, even if the front side copy image A'is normal, the back side copy image B'has an image defect as shown by the dotted line. It has the problem of missing information.

The present invention solves the above problem and provides a double-sided copying apparatus capable of performing optimum double-sided copying without image loss even when the document size and the vertical and horizontal feeding directions are different. With the goal.

[0007]

In order to achieve the above object, the double-sided copying apparatus of the present invention forms an image of a first original on the surface of a sheet in an image forming unit and reverses the front and back of the sheet. In a double-sided copying apparatus in which the image of the second original is formed on the back surface of the sheet in the image forming unit again by 90 ° or 180 °.
◦ A drive device that allows rotation, a position detection sensor for detecting the rotation position of the intermediate tray, a document detection sensor for detecting the size of the document and the vertical and horizontal feed directions, and a sheet size and vertical and horizontal feed directions. When the sheet detection sensor for detecting, the setting means for setting the optimum copy magnification from the size of the sheet and the original, the determination means for determining the vertical and horizontal feeding directions of the sheet and the original, and the vertical and horizontal feeding directions of the sheet and the original are not the same And a control device for rotating the intermediate tray by 90 ° and rotating the intermediate tray by 180 ° when the vertical and horizontal feeding directions of the sheet and the original are the same in back side copying.

[0008]

In the present invention, the intermediate tray driving device is arranged so as to be rotatable by 90 ° or 180 °, and by rotating the intermediate tray by 90 °, the sheet fed in the lateral direction to the intermediate tray is vertically moved. Alternatively, it is possible to prevent the image loss by feeding the sheet fed in the vertical direction in the horizontal direction, and by rotating the intermediate tray 180 °, the conveying direction of the reversed sheet is returned to the original direction. It is possible to return the sheet, and thus the top and bottom (upper and lower sides) of the copied image can be made the same on the front and back sides of the sheet.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a double-sided copying apparatus of the present invention. The present invention is not limited to such a color electrophotographic copying machine, but can be applied to a copying machine of a single color or other various types.

Referring to FIG. 1, the image forming apparatus includes an automatic document feeder 1, an image input unit 2, an image forming unit 3, sheet feeding trays 4a to 4c, and a sheet feeding unit 4 having an intermediate tray 4d.
Consists of. The color original document is placed on the platen glass 5 by the automatic original document feeder 1.

The image input unit 2 is composed of an imaging unit 6, a wire 7 for driving the unit, a drive pulley 9 and the like, and a CCD line sensor and a color filter in the imaging unit 6 are used for a case of four colors full color. Color originals are B (blue), G which are the primary colors of light.
After reading each (green) and R (red) and converting into a digital image signal, this reflectance information is converted into density information, and further, in order to improve reproducibility such as color, gradation and definition After performing the data processing of the above, it is converted into pixel signals of Y (yellow), C (cyan), M (magenta), and K (black) which are the primary colors of the toner, and the laser is turned on for each pixel according to this signal. The time is determined and output to the image forming unit 3.

The image forming section 3 has an electrostatic latent image carrier such as a laser scanner unit 10 and a photosensitive drum 11.
Around the photoconductor drum 11, a charger 12 for uniformly charging the photoconductor drum 11, a developing device 13 for developing an electrostatic latent image into a toner image, and a toner image for transferring the toner image to a sheet. A transfer device 15 and a cleaning device 16 for collecting the untransferred residual toner are arranged, and the photosensitive drum 11 is rotationally driven by an electric motor as shown by an arrow.

Output unit 1 of laser scanner unit 10
At 0a, for example, a yellow image signal from the image input unit 2 is converted into an optical signal, and the polygon mirror 10b,
A latent image corresponding to the original image is formed on the photosensitive drum 11 via the f / θ lens 10c and the reflecting lens 10d. When the yellow latent image is transferred to the sheet through development, the photoconductor drum 11 is charged by the charger 12 after the residual toner is removed by the cleaner 16, and the laser output unit 10a outputs the cyan image signal. Output. Less than,
Latent images of magenta and black image signals are sequentially formed.

The developing device 13 is a yellow developing device 13.
Y, cyan developing device 13C, magenta developing device 13M,
It has a black developing device 13K, and each developing device is arranged around the rotation shaft. When, for example, a yellow toner image is formed, the yellow developing device 13 is placed at the position shown in the figure.
When developing with Y to form a cyan toner image, the developing device 13 is rotated and the cyan developing device 13C is disposed at a position in contact with the photosensitive drum 11. The magenta and black developments are similarly operated.

A sheet carrier made of a dielectric film is stretched around the outer periphery of the transfer drum 15 constituting the sheet holder, and the transfer drum 15 is connected to a dedicated electric motor or the photosensitive drum 11 by a gear. , Is driven to rotate as indicated by an arrow. Around the transfer drum 15, a transfer charger 17, a toner charge control static eliminator 19, and a peeling claw 2 are provided.
0, a static eliminator 21, a cleaner 22, a suction roll 23, and a suction charger 25 are arranged. And the sheet is
From the paper feed trays 4a to 4c, a pickup roll 31 for taking in sheets, a feed roll 3 for feeding sheets,
2, the retarding roll 33 for separating, the transporting roll 34, the pre-registration roll 35 for forming a loop, and the registration roll 36 for synchronizing the transfer portion, and then the transporting drum 15, and the dielectric film by the corona discharge of the charging device 25 for adsorption. Is adsorbed on.

The transfer drum 15 rotates in synchronism with the photoconductor drum 11. For example, a toner image developed by yellow is transferred onto a sheet by a transfer charger 17, and the transfer drum 15 is rotated to sequentially transfer other toner images. Is transferred. When the transfer drum 15 is rotated four times and the transfer of four colors is completed, the discharging is performed by the separating discharger 19 provided inside and outside the transfer drum 15, the sheet is separated by the peeling claw 20, and the fixing belt is fixed by the conveyor belt 27. Then, the toner image is sent to the heat transfer roller 29 and the toner image is fused and fixed by the heat and pressure roller 30, and the copy cycle ends.

Next, the structure for double-sided copying according to the present invention will be described. In case of double-sided copying, the fixing device 29
By the switching of the switching plate 37 provided on the downstream side of the sheet, the sheet on which the image is formed is conveyed by the transport rollers 38, 39.
Is transported to the re-feeding path 41 by the
When the sheet is fed to the reversing paper feed path 42 by 0, and the trailing edge of the sheet reaches just before the forward / reverse roll 40, the forward / reverse roll 40 is reversed to convey the sheet in the intermediate tray 4d. It When the copy signal for the back surface of the sheet is output, the sheet in the intermediate tray 4d is fed to the transfer drum 15 by the pickup roll 31, the feed roll 32, and the retard roll 33, and an image is formed on the back surface of the sheet.

The intermediate tray 4d is moved to 9 by the drive device 43.
It is arranged to be rotatable by 0 ° or 180 °. By rotating the intermediate tray 4d by 90 °, it becomes possible to feed the sheet fed in the horizontal direction to the intermediate tray in the vertical direction or the sheet fed in the vertical direction in the horizontal direction.
Further, by rotating the intermediate tray 4d by 180 °, it becomes possible to return the conveyance direction reversed in the reversal paper feed path 42 to the original direction, whereby the top and bottom (up and down) of the copy image on the front and back of the sheet. Can be the same.

Each of the paper feed trays 4a to 4c is provided with a sheet detection sensor group 44 for detecting the size of the sheet and the vertical and horizontal feeding directions. The intermediate tray 4d has an intermediate tray position detection sensor 45 for detecting the rotational position thereof.
Is provided. Further, in the automatic document feeder 1, a document detection sensor group 46 for detecting the size of the document and the vertical and horizontal feeding directions is provided.

FIG. 2 is a block diagram of the control system of the double-sided copying machine according to the present invention. The original detection sensor 46 detects the size of the original and the vertical and horizontal feeding directions, and the sheet that detects the size of the sheet and the vertical and horizontal feeding directions. The signal of the detection sensor 44 is
The optimum copying magnification is sent to the optimum copying magnification setting means 47, and the optimal copying magnification is set from the size of the sheet and the original. Further, the feeding direction judging means 48 of the sheet and the original judges the longitudinal and lateral feeding directions of the sheet and the original, and the control device. In 49, if the vertical and horizontal feeding directions of the sheet and the original are not the same, the intermediate tray is rotated by 90 °, and if the vertical and horizontal feeding directions of the sheet and the original are the same in back side copying, the intermediate tray is set to 180. The output signal is output from the drive device 43 so that
Output to.

FIGS. 3 and 4 are diagrams showing a control flow of the double-sided copying apparatus of the present invention. FIG. 3 shows a flow of front surface copying of the first original onto a sheet. In step S1, the size and vertical and horizontal feeding directions of the first original are detected by the original detection sensor group 46, and in step S2, optimum feeding is performed. When the paper tray is selected, the copy magnification is automatically set in step S3.
The copy magnification may be set and the paper feed tray may be automatically selected. The position of the intermediate tray is detected by the intermediate tray position detection sensor 45 in step S4, and it is determined in step S5 whether or not the original and the sheet are fed in the same direction. If they are the same, copying is performed on the sheet surface in step S7. If the feeding directions are not the same, the intermediate tray is rotated by 90 °, then copying is performed on the sheet surface in step S7, and 1 is added to N in step S8.

FIG. 4 shows the back and front surfaces of the second and subsequent originals.
The flow of copying to ... Is shown. In step S9, the size of the Nth (even-numbered) document and the vertical and horizontal feed directions are detected by the document detection sensor group 46, and the copy magnification is automatically set in step S10. In step S11, it is determined whether or not the feeding directions of the original and the sheet are the same. If the feeding directions are not the same, the intermediate tray is rotated 90 ° in step S12, and if the feeding directions are the same, in step S13. After rotating the intermediate tray by 180 °, copying is performed on the back surface of the sheet in step S14, the size of the N + 1th (or odd number) original and the vertical and horizontal feeding directions are detected in step S15, and the copy magnification is determined in step S16. Is automatically set. In step S17, it is determined whether or not the original and the sheet are fed in the same direction.
When the intermediate tray is rotated by 90 ° in step 18 and the feeding direction is the same, copying is performed on the sheet surface in step S19 as it is, and 2 is added to N in step S20. repeat.

FIG. 5 shows a specific example of double-sided copying according to the present invention, in which the size of the original and the vertical and horizontal feed directions are A3 horizontal and A
If the A4 paper feed tray is selected for the copy sheet in the case where 4 vertical, B4 horizontal, and A4 horizontal are mixed, the first A
The original of 3 landscape is copied on the surface of the first A4 landscape sheet with a magnification of 70%. The second A4 portrait original has a magnification of 100% and the feed direction is different, so the intermediate tray is rotated 90 ° and copied on the surface of the A4 portrait sheet, and the third B4 portrait is printed. The original document has a magnification of 81% and the feeding direction is different, so the intermediate tray is rotated to return 90 ° and copied on the surface of the A4 horizontal sheet.
Of course, the original A4 landscape original has 100% magnification,
In order to make the top and bottom (upper and lower) of the copied image the same on the front and back sides of the sheet, the intermediate tray is rotated 180 ° and a copy is made on the surface of the A4 horizontal sheet.

[0024]

As is apparent from the above description, according to the present invention, by making the intermediate tray rotatable by 90 ° by the driving device, the image defect is caused even when the document size and the vertical and horizontal feeding directions are different. There is no optimum double-sided copying. In addition, the drive device drives the intermediate tray 180
By making it rotatable, the top and bottom (upper and lower) of the copied image can be made the same on the front and back of the sheet.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a double-sided copying apparatus of the present invention.

FIG. 2 is a block diagram of a control system of the double-sided copying apparatus of the present invention.

FIG. 3 is a diagram showing a control flow of the double-sided copying apparatus of the present invention.

FIG. 4 is a diagram showing a control flow of the double-sided copying apparatus of the present invention.

FIG. 5 is a diagram for explaining a specific example of double-sided copying in the present invention.

FIG. 6 is a diagram for explaining problems of a conventional double-sided copying machine.

[Explanation of symbols]

3 ... Image forming unit, 4a to 4c ... Paper feed tray, 4d ... Intermediate tray 43 ... Drive device, 44 ... Sheet detection sensor, 45 ... Intermediate tray position detection sensor 46 ... Original detection sensor

Claims (1)

[Claims] 1. An image of a first original is formed on a front surface of a sheet in an image forming unit, the front and back of the sheet are reversed and stored in an intermediate tray, and a second original is again formed on the back surface of the sheet in the image forming unit. In a double-sided copying machine that forms images of
A drive device that allows the intermediate tray to rotate 90 ° or 180 °, a position detection sensor that detects the rotational position of the intermediate tray, a document detection sensor that detects the size of the document and the vertical and horizontal feed directions, and a sheet. Sheet detection sensor for detecting the size and the horizontal and vertical feed direction, setting means for setting the optimum copying magnification from the size of the sheet and the original, determination means for determining the vertical and horizontal feed direction of the sheet and the original, When the vertical and horizontal feeding directions are not the same, the intermediate tray is rotated by 90 °, and when the vertical and horizontal feeding directions of the sheet and the original are the same in back side copying, the intermediate tray is rotated by 180 °. A double-sided copying machine characterized by comprising.