JPH0653537B2 - Copying device - Google Patents

Description

The present invention relates to a copying apparatus provided with an intermediate tray for double-sided copying and composite copying.

[Conventional technology]

Conventionally, in a copying apparatus, a pair of adjoining conveying rollers in a sheet conveying path are used, the conveying roller on the downstream side is stopped to serve as a so-called registration roller, and the conveying roller on the upstream side conveys the sheet. It is generally practiced to press the front end of the paper against the registration roller to correct the paper skew feed, that is, to correct the paper inclination with respect to the transport direction, and to control the paper supply timing by the registration roller. .

In such a case, in a copying machine equipped with an intermediate tray and capable of performing double-sided copying and composite copying, conventionally, the registration time, that is, the time for pressing the paper against the registration rollers, is set to be the same between double-sided copying and composite copying. It had been.

[Problems to be solved by the invention]

However, the paper discharged to the above-mentioned intermediate tray has its front side and back side reversed during double-sided copying and composite copying, which allows the front surface of the paper, that is, the top surface, to be printed during double-sided copying and composite copying. Since there is a difference between the presence or absence of the fixing oil and toner, and the curl direction of the paper is different between double-sided copying and composite copying, the paper feeding from the intermediate tray is required. The paper transportability by the paper roller is different between double-sided copying and composite copying. In this case, if the registration time is equalized between the double-sided copy and the composite copy as described above, there is a problem that paper jams due to paper slip, and paper jams and paper breaks due to excess resist are likely to occur. Was.

[Means for solving problems]

In order to solve the above problems, the copying apparatus according to the present invention is capable of performing double-sided copying and composite copying by connecting a paper return conveyance path from an intermediate tray to a paper conveyance path from a paper cassette to a photoconductor. In addition, in the copying machine in which the transport rollers are provided on the downstream side and the upstream side in the sheet return transport path, the upstream transport roller is driven while the downstream transport roller is stopped. By causing the paper to have its tip pressed against the downstream-side transport roller, the paper is temporarily bent, and then the upstream-side transport roller is stopped and the downstream-side transport roller is activated, so that the paper is transferred to the photosensitive member. A control means is provided for controlling both the transport rollers so that the upstream transport rollers are stopped when the downstream transport rollers are stopped. So different from each other in that during synthesis copying is characterized in that for driving the conveying rollers of the upstream side.

[Action]

According to the above configuration, during double-sided copying and composite copying,
In the paper return transport path from the intermediate tray, the paper is pressed against the downstream transport roller in the stopped state, and the paper is bent. Then, the drive time of the upstream-side conveyance roller when the flexure is generated is changed between the double-sided copying and the composite copying. In other words, since the front and back sides of the paper are reversed between the double-sided copy and the composite copy, the transportability of the paper from the intermediate tray is different between the double-sided copy and the composite copy, as described above. According to such a difference,
As described above, by changing the drive time of the upstream-side transport roller between the double-sided copying and the composite copying, the bending amount of the paper can be made substantially equal. As a result, it is possible to reduce the above-mentioned problems such as paper jam caused by slipping of the paper and paper jam and paper folding caused by excessively pressing the paper against the downstream transport roller.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

As shown in FIG. 1, the copying apparatus 1 according to the present invention has a transparent original placing table 2, and below the original placing table 2, an optical means 3 including a light source, a mirror, a lens and the like is arranged. ing. The original document (not shown) placed on the original document table 2 is illuminated by the light source in the optical means 3, and as a result,
The reflected light from the document is exposed on the photoconductor 4 via the optical means 3. Since the photoconductor 4 is charged to a predetermined potential by the charger 5 prior to the exposure, the reflected light from the document is exposed to expose the photoconductor 4 with an electrostatic latent image corresponding to the image of the document. Is formed.

When an electrostatic latent image is formed on the photoconductor 4, toner is continuously supplied from the developing device 6 to the photoconductor 4, and the electrostatic latent image is developed by this toner to form a toner image on the photoconductor 4. It is formed. Subsequently, the paper for copying is fed from the manual paper feeding unit 7 or any of the paper feeding cassettes 8 and 9 to the registration roller 18 by the paper feeding rollers 11 to 13 and the conveying rollers 14 to 17, and the above paper is registered. It is supplied from the roller 18 to the photoconductor 4 at a predetermined timing.

Then, the toner image on the photoconductor 4 is transferred to the above-mentioned paper by the transfer charger 20. After that, the paper is stripper 21
Then, it is separated from the photoconductor 4 and is conveyed to the fixing unit 23 by the conveyor belt 22. The toner remaining on the photoconductor 4 after the transfer of the toner image is removed by the cleaning device 24, and the photoconductor 4 is uniformly discharged by the charge removing means 25 such as a charge removing lamp prior to the next copying.

After the toner image is fixed here, the sheet sent to the fixing unit 23 is discharged to the discharge tray 27 via the switching gate 26 in the case of one-sided copying. On the other hand, in the case of performing double-sided copying, the above-mentioned paper is guided to the paper transport path 28 as the switching gate 26 is reversed, and is sent to the reversing mechanism 31 via the switching gate 30, where the front and back are reversed. Then, the sheet is discharged to the intermediate tray 32.

Further, in the case of performing composite copying, the paper is directly discharged from the paper transport path 28 to the intermediate tray 32 via the switching gate 30.

Paper 33 is stored in the intermediate tray 32 with the image forming surface facing upward in the case of double-sided copying, and downward with the image forming surface facing in the case of composite copying. These sheets 33 are a feed roller 3 and one of a feeding roller 34 and a conveying roller arranged to face the intermediate tray 32.
5, the uppermost one is sequentially carried out from the intermediate tray 32.

The paper feed roller 35 is provided in a paper return transport path connected to a paper transport path from the paper feed cassettes 8 and 9 to the photoconductor 4, and the paper delivered by the paper feed roller 35 is further , And is conveyed to the registration roller 36 which is one of the conveying rollers. Then, the paper 33 is further conveyed to the registration rollers 18 via the conveyance rollers 17 and 15, and is re-supplied to the photoconductor 4 from here, so that double-sided copying or composite copying is performed. A paper passage detection sensor 37 is arranged between the paper feed roller 35 and the registration roller 36.

As shown in FIG. 2, the copying apparatus 1 includes a microcomputer 38.
Is configured to control each part in the copying apparatus 1 according to a control program stored in a ROM (Read Only Memory) 40 in advance. A RAM (Random Access Memory) 41 connected to the microcomputer 38 is used as a buffer memory, a flag necessary for copy control, and used as a calculation area.

Further, the signal input device 42 inputs a detection signal from a key switch, a paper passage detection sensor 37, etc., which is operated by operating various keys provided in the copying machine 1 and a detection signal of the rotational position of the photoconductor 4 to the microcomputer 38. The above-mentioned detection signals and the like are transferred to the microcomputer 38 via the interface circuit 43.

On the other hand, the driver array 44 has an interface circuit 45.
Various display elements 4 for displaying the copy magnification and the like based on a signal supplied from the microcomputer 38 via
6 and 46 and various loads 47 and 47 of the copying apparatus 1, specifically, for example, the drive unit of the conveyor belt 22 and the reversing mechanism 3.
It is designed to drive and control one drive unit and the like.

As will be described below, the microcomputer 38 presses the paper 33 against the registration roller 36 by the intake roller 34 and the paper feed roller 35 to correct the skew feed of the paper 33, during double-sided copying and during composite copying. The resist amount when pressed against the resist roller 36 with,
It also has a role as a control unit for controlling the registration time, that is, the time for pressing the paper 33 against the registration roller 36 so that the bending amounts of the paper 33 are almost equal.

Next, the feeding of the sheet 33 from the intermediate tray 32 will be described.

When performing double-sided copying or composite copying, as described above, the paper 33 on which one-sided copying has been completed or a part of which has been completed is temporarily discharged to the intermediate tray 32. The paper 33 is sequentially carried out from the intermediate tray 32 from the uppermost one by the intake roller 34 and the paper feed roller 35, and is conveyed to the registration roller 36 side via the paper passage detection sensor 37.

At this time, the registration roller 36 is stopped and the paper 3
The paper 33 is sent to the registration roller 36 side by the intake roller 34 and the paper feed roller 35 in a state in which the leading end of the sheet 3 abuts the registration roller 36, so that the inclined feeding of the paper 33 is corrected. The conveyance of the paper 33 by the take-in roller 34 and the paper feed roller 35 is stopped after a lapse of a fixed time after the paper 33 has passed the paper passage detection sensor 37, whereby the correction of the inclined feeding of the paper 33 is completed. After that, the registration roller 36 is activated at a predetermined time, and the paper 33 is supplied to the registration roller 18 side.

The above-mentioned fixed time from when the sheet 33 passes through the sheet passage detection sensor 37 to when the feeding roller 34 and the sheet feeding roller 35 terminate the conveyance of the sheet 33 is pressed against the registration roller 36 during the double-sided copying and the composite copying. Paper 33
Is controlled by the microcomputer 38 so that the amount of flexure is almost the same during double-sided copying and during composite copying. As a result, the paper 33 is prevented from being jammed or broken, and the stability of conveyance of the paper 33 is ensured.

In the above-described embodiment, the microcomputer 38 controls the drive of the paper transport system including the drive control of the intake roller 34, the paper feed roller 35, and the registration roller 36. A similar control unit may be provided, a signal may be transmitted between the control unit and the microcomputer 38, and the drive control of the paper transport system may be separately performed by the control unit.

〔The invention's effect〕

As described above, the copying apparatus according to the present invention is connected to the paper return conveyance path from the intermediate tray to the paper conveyance path from the paper cassette to the photoconductor, and enables double-sided copying and composite copying. In a copying machine in which a transport roller is provided on each of the downstream side and the upstream side in the sheet return transport path, the upstream transport roller is driven to transport the sheet while the downstream transport roller is stopped. Due to
After causing the paper whose tip is pressed against the downstream side transport roller to bend once, stop the upstream side transport roller and activate the downstream side transport roller to feed the sheet to the photoconductor. A control means for controlling the roller is provided, and the control means makes the stop timing of the upstream-side transport roller, which is driven when the downstream-side transport roller is stopped, different between double-sided copying and composite copying. It is configured to drive the side transport roller.

As a result, it is possible to make the amount of bending of the paper pressed against the downstream transport roller in the stopped state substantially the same between the double-sided copy and the composite copy. It is possible to reduce problems such as paper jam due to slip of paper and paper jam due to excessive pressing and paper breakage.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention. FIG. 1 is an explanatory diagram showing the overall configuration, and FIG. 2 is a block diagram showing a control system. Reference numeral 4 is a photoconductor, 8 and 9 are paper feed cassettes, 35 is a paper feed roller (conveyance roller), 36 is a registration roller (conveyance roller), and 38 is a microcomputer (control means).

Claims (1)

[Claims] 1. A paper return path from an intermediate tray is connected to a paper path from a paper cassette to a photoconductor for double-sided copying and composite copying, and a downstream side of the paper return path. In a copying machine in which a transport roller is provided on each of the upstream side and the upstream side, by driving the upstream transport roller while the downstream transport roller is stopped to transport the paper, the leading end portion of the downstream transport roller is obtained. After causing the sheet to be pressed against the sheet to bend, the control means for controlling both the transport rollers to feed the sheet to the photoconductor by stopping the upstream transport roller and activating the downstream transport roller. The control means is provided so that the stop timing of the upstream-side transport roller that is driven when the downstream-side transport roller is stopped is different between double-sided copying and composite copying. A copying machine characterized in that it drives the conveying roller.