JPS6028670A - Double face copying machine - Google Patents

Abstract

PURPOSE:To perform the double face copying where picture deviations on front and rear faces or the like are prevented, by providing a stacker which accumulates and supplies again forms accurately. CONSTITUTION:After a picture is formed on the first face, a form P is inverted in a device 21 by a path indicated by a dotted line and is fed into a stacker S from a carrying part 22. The other end-side part of a bottom plate 23 is connected to a pulley, which is driven by a motor 27, through a wire 25, and its angle is changed by rotation of the motor 27. The motor 27 is rotated counterclockwise by a copying start signal of the second face to turn the bottom plate 23 to the second approximately horizontal position (b), and the top of accumulated forms is fed out and is brought into contact with a roll 32, and the roll 32 is rotated to feed forms one by one through double feed preventing roll 33, and forms are fed to an image transfer part through a carrying roll 35. After all forms are supplied there and copying to the second faces of forms is completed, the motor 27 is rotated clockwise, and the bottom plate 23 falls and is returned to the first state to prepare for the next double face copying start.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a duplex copying machine that obtains a copy having images on both sides of a sheet of paper, and more specifically, it relates to a duplex copying machine that obtains a copy having images on both sides of a sheet of paper, and more specifically, The present invention relates to a double-sided copying machine having an improved temporarily accumulating refeeding force (hereinafter simply referred to as star, y force).

[Prior art]

Copy images are recorded on both sides of a single sheet of paper (in a so-called double-sided copying machine, the paper is fed from the first paper feed section, the image is transferred and fixed on the first side, and then Once the paper is stacked in the stacker section, the stacked sheets are sent out one by one during subsequent copying operations and the image is transferred to the second side.
Fix it to obtain the desired double-sided copy.

FIG. 1 is a schematic diagram showing an example of a paper feeding path in a double-sided copying machine as described above. ■ is a cassette that stores paper, and it is located at a designated location (first paper feed section) on the main body of the machine (not shown).
will be installed on the The cassette 1 in i1 paper feed fel+
The paper fed by the paper feed roller 2 has its leading edge aligned by the registration roller 3 which is in a stopped state, and then is sent to the transfer section T as the registration roller rotates and is transferred to the transfer electrode 13.
Visualization (toner imaging) by known methods under the action of
a photosensitive drum 4 having an electrostatic charge image on its surface;
After the toner image is transferred and separated by an appropriate separating means, the toner image is introduced to the fixing roller 6 by the first conveyor belt 5, and the toner image is fixed.

The part (8) indicated by the dashed line in the figure is the paper reversal and path switching section, where the paper sent from the fixing section is switched.
7 times, and then stacked on a stacker 9 with the image side facing up by the conveyance roller 7 and the second conveyance belt 8. When the transfer of the original to be recorded on the first side of the paper is completed and the copying of the original to be recorded on the second side of the paper is started, the papers accumulated in the stacker 9 are fed out one by one by the paper refeed roller 10. The image is transferred to the position of the registration roller 3 via the conveyance roller 11, and transferred and fixed in the same manner as on the first side. After the images have been transferred and fixed on both sides, the paper passes through a section (8) whose path is switched to paper ejection, and is ejected from the machine by an ejection roller 12.

In the above mechanism, the sheets loaded into the first paper feed section are well aligned in advance in the cassette and stored in the cassette, etc. However, in the stacker 9, the use of the cassette is longer than Ire L < . Since the sheets conveyed through the path must be fed one by one onto a plywood board, for example, it is difficult to stack the sheets with the leading edges of the sheets aligned in an accurate position. Irregular stacking of sheets in the stacker 9 can result in discrepancies between the front and back images due to misalignment of the image formed on the second side of the sheet, or in extreme cases, the sheets may be fed crookedly with respect to the transport path, resulting in the sheets being This was a major problem in the production of double-sided copying machines because clogging could cause malfunctions.

As a way to solve the above problem and align the front edges of the sheets fed into the stacker, the stacker is tilted, and the weight of the sheets themselves is used to push the sheets being transported against the lower end of the tilted stacker. This is disclosed in Japanese Patent Application Laid-open No. 57-70561 and Japanese Patent Application Laid-open No. 57-72525, but in all of these, the stacker is fixed and mounted at a fixed angle of inclination.

On the other hand, as a matter of course, a paper feeding means 10 is required near the stacker 9 to feed out the stored sheets one by one when refeeding, but such paper feeding means is only necessary when refeeding. However, when stacking sheets on the stacker 9, it becomes a hindrance and must be moved to a position where it does not come into contact with the sheets, resulting in a complicated structure. In addition, feeding sheets of paper placed at a steep angle one by one has the disadvantage that it is technically possible to feed the sheets in stacks that are separated from each other, which may easily cause paper jams. Furthermore, depending on the size of the paper, its basis weight, the state of curling, etc., it is often the case that the sheets are not properly aligned with a pre-fixed inclination angle.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a double-sided copying machine that is equipped with a stacker that accurately stacks and refeeds sheets, thereby preventing image misalignment between the front and back sides.

[Structure of the invention]

The purpose of the above is to reverse the paper with an image formed on the first side during its conveyance, and then stack it on the stacker, which is in the first state tilted forward and downward when viewed from the direction of paper movement, for the next copying operation. This has been achieved by a double-sided copying machine configured to bring the stacker to a second substantially horizontal state in response to a signal and then feed paper using a paper refeeding means.

The stacker used in the double-sided copying machine of the present invention has a rotatable bottom plate, and the set angle when stacking paper is changed so that stacking is performed correctly according to the size, nature, etc. of the paper to be used, In addition, when refeeding paper, it rotates to a nearly horizontal position suitable for paper feeding and refeeds the paper, thereby ensuring accurate stacking and feeding of paper. This is intended to prevent malfunctions such as misalignment of front and back images, bending, and paper jams.

The stacker used in the double-sided copying machine according to the present invention or its surroundings is provided with a drive means for rotating the stacker, a sensor for detecting the rotating position of the stacker, etc. The stacker mode is configured such that the mode of the stacker can be switched between a first tilted state for stacking sheets and a second substantially horizontal state for feeding sheets. As the driving means, an electrical/mechanical sensor such as a photo sensor in either forward or reverse direction or a microswitch can be used. In addition, the above-mentioned stacker is equipped with a paper aligning means for aligning both sides of the stacked sheets, such as a movable or fixed side plate, or a sensor for detecting the presence of sheets, etc., as necessary. Ancillary equipment may also be provided.

This will be specifically explained below using examples.

〔Example〕

FIG. 2 is a schematic diagram of the stacker and refeeding section of the double-sided copying machine according to the present invention. There is a photosensitive drum 4 (k) Processing means for achieving electrophotographic copying such as charging and exposure provided around the photosensitive drum 4, as well as a part of the paper conveyance path shown in FIG. 1 have been omitted for the sake of explanation. In addition, various mechanisms for switching the paper reversing path can be considered, and one example is shown in FIG. 1, but this is the feature of the present invention. For this reason, a detailed explanation will be omitted.

The paper P, such as plain paper, on which the image formation on the first side has been completed is reversed by the reversing device 21 along the path indicated by the dotted line, and is sent from the conveyance section 4 to the stacker section S.

It can be moved. The printer has a size that can accommodate the largest sheet of paper used on the bottom plate of the stacker, and is rotatably attached to the main body of the copying machine (not shown) by a pivot. The other end side of the bottom plate B is connected to a pulley 26 driven by a DC reversible motor n via a wire part.
The angle can be changed by rotating the DC reversible motor. 40 is the wire 5
This shows a pulley that is movably suspended. The figure shows the paper storage position of the stacker, that is, the first state,
The bottom plate of the stacker is installed so as to be inclined toward the front and lower side when viewed from the moving direction of the paper sent from the reversing device side.

The path is a side plate for aligning both sides of the paper, and in this embodiment, only one side plate is configured to reciprocate in a direction perpendicular to the direction of movement of the paper. The pad is an abutment plate for aligning the leading edges of the sheets being fed, and is shaped and positioned to allow rotation around the support shaft of the stacker bottom plate Z. What is important is to bring the paper to the second state without causing the paper to get caught in the relative sliding or relative movement between the leading end of the paper and the abutting plate. The paper discharged from the conveyance section n slides on the bottom plate or on the slope of the upper surface of the paper already accumulated on the bottom plate, and its leading edge hits the abutment plate and stops at °C. During this time, both sides of the paper are aligned by the reciprocating movement of the side plates Z, so the position of the paper is regulated to a predetermined position both in the front and back and left and right directions. Subsequent sheets are stacked in the same position through exactly the same process, and by repeating this process, the sheets are correctly stacked.

Meta when storing and accumulating paper 1. It is more desirable that the phantom angle of the bottom plate be adjustable depending on the size and physical properties of the paper. In other words, from the perspective of aligning the leading edge of the paper against the abutting plate by the inclination of the bottom plate, it is preferable that the inclination angle of the bottom plate is large, but if it is too large, depending on the paper, the leading edge of the paper may be affected by the weight of the paper itself. bend by,
This is because it is possible to prevent, as much as possible, the phenomenon that the difference in height between the paper conveying section and the paper stacking position becomes large and the disturbance in paper position due to paper floating increases as much as possible.

The angle of the stacker board depends on the environmental conditions and changes in the state of the paper, but it is difficult to determine the angle that is suitable for the device, by experimenting with different paper types, sizes, etc. It is possible to do so. In the experiment, 55
kg paper, approximately 11' for B5 size, approximately 15° for B4 size, A4. Good results have been obtained with an A3 size paper of about 300 mm. In particular, when using small paper (for example, B5 size), in order to avoid paper floating and to ensure accurate stacking, move the end of the conveyance section in the direction of the arrow in the figure, and make the slope of the stacker bottom plate shallower, for example. It is preferable to take the position a in the figure. In addition, if the paper tends to curl and its front and rear edges tend to lift up, the angle of inclination should be made slightly shallower, etc. The angle of the stacker bottom plate B when storing the paper should be set based on various conditions as described above. There is a need.

The position control of the stacker bottom plate based on the paper size can be automatically set based on the detection signal of the cassette size (substantially the paper size) obtained from the paper cassette device, for example, and the tilt angle can be adjusted according to the curl situation. The adjustment can be performed manually through the operation panel, or automatically by installing a sensor that detects curling of the paper during conveyance or on the stacker. The angle of the stacker bottom plate n is changed by rotating a DC reversible motor in either direction based on a signal from a control unit (not shown), and the position of the bottom plate is determined by a plurality of sensors 30 provided on the abutting plate 29. It is only necessary to detect the position and stop it when it matches the set position. The angle of the bottom plate may be detected by placing a detector on the shaft barrel and rotating the shaft nine times. 31 is a sensor for detecting the upper surface of the stacked sheets and determining the second state of the stacker bottom plate when feeding the sheets, and 34 is a sheet guide plate.

When a predetermined number of copies of the first side are completed and the button to start copying to the second side is pressed on the operation panel, the signal causes the DC reversible motor to rotate counterclockwise to move the bottom plate n to a nearly horizontal position. After rotating the stacked sheets to position 2 (b in the figure) and bringing the top surface of the stacked sheets into contact with the feed roller 32, the feed roller 32 is rotated and the sheets are fed out one by one through the double-feed prevention roller and conveyed through the conveyance roller 35 as shown in the figure. The image is fed to the image transfer section.

When all the stacked sheets are fed and copying to the second side of the paper is completed, the DC reversible motor rotates clockwise in response to the copy completion signal, and the stacker bottom plate 32 is lowered to return to the first state and copy the next double side. Prepare to start copying.

When we prototyped a duplex copying machine with a paper refeed stacker section with the above structure and conducted a continuous duplex copying test on multiple sheets of paper of various sizes, we found that the stacking and refeeding of paper in the paper refeed stacker section was extremely accurate. , image misalignment between the front and back sides of the copy,
Malfunctions due to paper accumulation such as bending, paper jams, and irregular paper re-feeding However, the present invention is not limited to this, and for example, the feed roller may be made movable.Also, with regard to holding the stacker bottom plate in the second position in particular, the weight of the stacked sheets and the feed roller may be made movable. It is desirable to use an appropriate locking mechanism to maintain a stable state when the rollers are driven.Furthermore, although the term "double-sided copying machine" is used in this specification, it is a device that forms toner images on both sides of paper. Therefore, it includes processing means in electrophotographic copying, that is, development, transfer, fixing, and if necessary, an electrostatic recording device that can be used as a charging means.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a paper conveyance path of a double-sided copying machine, and FIG. 2 is a schematic diagram of a paper refeed stacker section of a double-sided copying machine according to the present invention. n... Sheet refeed stacker bottom plate U... Support shaft °゛ wire... Houli 2'7° - DC Reno 9 - Shiple motor agent Yoshimi Kuwahara

Claims (1)

[Claims] (1) After the paper with an image formed on its first side is reversed during its conveyance, it is once stacked by 4J on the paper refeeding stand, which is in the first state tilted forward and downward when viewed from the direction of paper movement. , a double-sided copying machine characterized in that, in response to a next copying operation signal, the paper refeeding means feeds paper after the paper refeeding stacker is brought to a second substantially horizontal state. .