JPH02287565A - Image forming device - Google Patents

Abstract

PURPOSE:To precisely match the position of the first face of the paper with that of the second face and to prevent dislocation in front and back faces print ing by providing a positioning means by means where a regulating means and a lateral registration adjusting means directly and mutually perform positioning without using a device main body. CONSTITUTION:The flapper 11 is positioned upward and the paper P is inserted into lateral registration boards 24a and 24b by a conveying roll 10 and guides 12a and 12b and the roll 10 is stopped. At the next stage, a semicircular roll 13 is counterclockwise rotated and stopped when the trailing edge of the paper P passes through the flapper 11. At this time, a pulse motor 27 is already clockwise rotated, enlarges the lateral registration boards 24a and 24b and waits for the paper so that the board 24a is made to abut on the base edge of a lateral registration regulating tip 19. Therefore, simultaneously with the stop of the roll 13, the motor 27 is counterclockwise rotated by the prescribed number of pulses, moves the boards 24a and 24b inwardly by prescribed lateral width and is precisely made the position of the paper P in a free condition coincident with the position of the paper P of a cassette 2.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a printer, and more particularly to an image forming apparatus capable of double-sided printing.

(b) Conventional technology Conventionally, in printers with automatic duplex printing function, the 11th
As shown in the figure, paper P loaded in a cassette 51 is fed by a paper feed roller 52, passes under a photoreceptor drum 53, an image is transferred, is fixed by a fixing device 54, and is corrected by a reversing unit 55. The paper P is sent backwards by the reversing roller 56, transferred to the second surface again under the photosensitive drum 53 via the conveyance rollers 57 and 58, and after passing through the fixing device 54, is discharged to the tray 60 via the paper discharge roller 59 and stacked. be done. In this way, with automatic duplex printers, the paper transport distance between printing the first side and printing the second side is long, and when printing the second side,
There is a problem in that the printing position in the direction perpendicular to the paper conveyance direction, so-called lateral registration (hereinafter abbreviated as lateral registration), tends to be distorted.

Therefore, in the case of an automatic double-sided printer as shown in FIG. 11, an automatic lateral registration adjustment device is provided in a portion 61 in the figure as shown in FIG. 12.

Paper P is conveyed in the six directions of arrows, and a diagonal feed roller 62 is provided here, and by applying force in the direction of arrow B with this roller 62, the left edge of paper P is moved in horizontal registration. It is brought into contact with the plate 63. The horizontal resist plate 63 is the first
It is theoretically provided at the same position as the left side edge of the paper P during double-sided printing, and by sending the paper to the transfer unit again by the conveyance roller 64 while keeping the paper P in contact with the horizontal registration plate 63,
The printing positions on the first and second sides can be aligned.

(About Problems to be Solved by the Invention) However, in such a configuration, when printing on the first side, the paper width regulating plate in the cassette 51 and the horizontal resist plate 63
Although it is necessary to minimize the positional misalignment, in reality, relative positional misalignment occurs due to accumulation of dimensional tolerances of individual members, etc., and the printing positions on the first and second sides of the paper P do not match accurately. There was a problem.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image forming apparatus that prevents printing misalignment between the front and back sides during double-sided printing.

(d) Means for solving the problem The present invention has been made in view of the above circumstances, and includes:
For example, referring to FIGS. 1 and 4, the loading means (2
, 3), a paper feeding unit (18) which feeds the paper P stacked in the interior while regulating the width direction by a regulating means (23), and means (11, 12a, 13) for reversing the sheet material (P). and horizontal registration adjustment means (24a, 24b,
27); a lateral registration adjustment unit (17);
In the automatic double-sided printing image forming apparatus (1), in which the regulating means (23) and the lateral registration adjusting means (24a, 24b, 27) are each independently and removably attached,
It is characterized by having positioning means (19, 21) for directly positioning each other without going through the device main body.

(E) Function Based on the above configuration, the paper feed unit (18) and the lateral registration adjustment unit (17) are detachably attached to the image forming apparatus (1). At this time, the positioning means (19,
21) for direct positioning.

It should be noted that the numbers in parentheses are for illustration purposes only, and do not limit equivalent configurations.

(F) Examples Examples of the present invention will be described below with reference to the drawings.

FIG. 1 shows a printer 1 according to a first embodiment of the present invention. A cassette 2.3 loaded with paper P is set on the right side plate of the device 1, and the paper P fed by each paper feed roller 4 is conveyed by registration rollers 5 in synchronization with the photosensitive drum 6, and the paper P is The image is transferred to the first side of the paper and fixed by the fixing section 7. Then, in a state where the flapper 8 is also facing upward than shown in the figure, it is conveyed downward and further conveyed by conveyance rollers 9 and 10.

Then, with the flapper 11 facing upwards as shown, it is conveyed into the guides 12a and 12b, and sent to the right by normal rotation (left rotation) of the reversing roller (half-moon roller) 13. Thereafter, by reversing, the paper P is conveyed in the opposite direction to the previous direction, conveyed upward again to the photosensitive drum 6 by the upper conveyance roller 14, and then conveyed upward to the photosensitive drum 6 by the paper ejection roller 15 to the paper ejection tray provided on the top surface of the apparatus 1. 16, are printed on both sides, are ejected, and are stacked.

Next, the lateral registration adjustment unit 17 and paper feeding unit 18, which are comprised of the flapper 11, guides 12a, 12b, rollers 13, etc., will be described in detail with reference to FIGS. 2 to 5.

As shown in FIG. 2, the lateral registration adjustment unit 17 is detachably fitted to the bottom of the printer 1, and the paper feed unit 18 is connected to the lateral registration adjustment unit 1.
It is designed to be inserted into the printer 1 on the upper right side of the printer 7. As shown in FIG. 3, a horizontal registration regulating piece 19 is provided upright on the front right side of the unit 17, and as shown in FIG. 4, a cassette rail 20 is attached to the bottom of the unit 18. ing. This cassette rail 20
is provided with a downwardly directed groove 21, and both units 17.1
8 is fitted into the printer 1, the horizontal registration regulating piece 1
9 is fitted into the groove 21. A plurality of grooves 22 are provided on the side upper surface of the cassette rail 20, and a paper regulating plate 23 of the cassette 2 protrudes downward from the bottom plate of the cassette 2. It is adapted to be fitted into any of the grooves 22 of.

Further, as shown in FIGS. 4 and 5, the guide plate 12a
, 12b, horizontally movable horizontal resist plates 24a and 24b having a U-shaped cross section are provided so as to sandwich both sides of the conveyed paper P. These horizontal resist plates 24a, 24
Levers 25a and 25b are provided at right angles to b, and racks 28a and 28b are provided at opposite positions.
8 are engaged.

Next, the functions of both units 17 and 18 of this embodiment will be explained.

In FIG. 2, when the paper feed unit 18 is set in the printer 1 and the horizontal registration adjustment unit 17 is inserted and set from the left side, the horizontal registration regulating piece 19 is fitted into the groove 21 of the cassette rail 20 of the paper feed unit 18, and the horizontal registration adjustment unit 17 is inserted and set from the left side. As shown in Figure 4, the horizontal resist plate 24a is connected to the horizontal resist regulating piece 19.
When the sheet P comes into contact with the sheet P, both sides of the sheet P in the cassette are positioned so that there is a gap between the inner surfaces of the horizontal registration plates 24a and 24b by a width a. (In this case, the paper size (width)
In the case of a small paper regulating plate 23, the paper regulating plate 23 is fitted into one of the inner grooves 22. ) The flapper 11 is positioned upward from the attitude shown in the first figure, the paper P is inserted by the transport roller 10 into the guides 12a, 12b, and therefore the horizontal registration plates 24a, 24b, and the transport roller 10 stops. Next, the semicircular roller 13, which had been stopped with the notch facing downward, rotates to the left, and when the rear end of the paper P passes the flapper 11, the roller 13 stops with the notch facing downward. At this point, as shown in FIGS. 4 and 5, the pulse motor 27 is already rotating clockwise, and the lateral resist plates 24a, 24b are
The horizontal resist plate 24a is brought into contact with the base end of the horizontal resist regulating piece 19 and is on standby. Therefore, roller 13
Simultaneously with, immediately before, or immediately after stopping, the pulse motor 27 rotates counterclockwise for a predetermined number of pulses, moves the horizontal resist plates 24a and 24b inward by a predetermined width a, and transfers the free paper P to the cassette 2. The position of the paper P within the

Thereafter, the half-moon roller 13 is reversed, and the flapper 11 relays the paper P, which has undergone lateral registration adjustment, to the transport roller 14 in the posture shown in the first figure. Next, the horizontal registration plates 24a and 24b move to a position where they come into contact with the horizontal registration regulating piece 19, and then stop.

In the above, when the paper size P is different, the pulse motor 27 generates a corresponding number of pulses on the horizontal resist plate 24a.
, 24b inwardly.

In this embodiment, by fitting the lateral registration regulating piece 19 to the cassette rail 20, the lateral registration of the units 17 and 18 can be directly and accurately and easily adjusted, thereby improving serviceability.

Next, a second embodiment will be described with reference to FIG. below,
Members with the same configuration and function are given the same reference numerals, and their explanations will be omitted.

In the figure, reference numeral 29 denotes a cassette rail, in which the cassette rail 20 and the lateral registration regulating piece 19 in the first embodiment are integrated to determine the position (home position) at which the lateral registration plate 24a abuts.

Next, a third embodiment will be described with reference to FIGS. 7 to 10.

The inner surface of the protrusion of the cassette rail 30 is at the same position in the width direction as the inner surface of the paper regulating plate 23 of the cassette 2. A diagonal feed roller 31 is provided, and a conveyance roller 32 is provided near the downstream of the flapper 11.

Therefore, the rear end of the paper P passes through the flapper 11 by the transport roller 32, and the transport is stopped.

Thereafter, the left end of the paper P is slid on the inner surface of the protruding portion of the cassette rail 30 by the diagonal feed roller 31 and relayed to the transport roller 14 . Note that the oblique feed roller 31 is a half-moon-shaped roller, and when it is stopped, the notch portion is located downward, so that the sheet P can be conveyed.

The cassette rail 30 is limited to one type of paper P size, but as shown in FIG. 10, the cassette rail 33
A hole 34 is provided in the vertical direction, and a plurality of regulating plates 35a, 35b, 35c which are urged upward are inserted into this hole 34, and are pressed downward by the end of the paper regulating plate 23. One of the regulating plates projects downward.

In FIG. 10, the regulating plate 35b protrudes downward to regulate the left end of the paper P.

In all of the above embodiments, the lateral registration adjustment unit 17 is provided at the bottom of the paper feed unit 18, but the same effect can be obtained even if it is provided at the top.

In addition, it is not necessary to use a cassette, but a deck type or the like can be used in place of the cassette. Although the case of double-sided printing has been described, a multiplexing case is also possible.

(G) As described in detail, according to the present invention, the regulating means (23) and the lateral registration adjusting means (24a, 24b) for the sheet material (P) in the cassette (2) are connected to the positioning means (19). ,21
), the dimensional tolerances of individual members do not accumulate, unlike when positioning is performed through the main body of the device (1), and the first and second surfaces of the paper P Since the positions of the images are aligned accurately, it is possible to prevent printing misalignment between the front and back sides.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional side view of a printer showing the entire first embodiment of the present invention, FIG. 2 is a cross-sectional side view showing a state in which a paper feed unit and a lateral registration adjustment unit are attached and removed, and FIG. FIG. 4 is a vertically cross-sectional rear view of the paper feeding unit and the horizontal registration adjustment unit, FIG. 5 is a plan view of the horizontal registration adjustment means, FIG. 6 shows the second embodiment, and FIG. 7 shows the third embodiment, a rear view similar to FIG. 6, FIG. 8 a longitudinal side view of FIG. 7, and FIG. 9 a planar view similar to FIG. 5. 10 is a rear view similar to FIG. 7, FIG. 11 is a sectional side view of a conventional printer, and FIG. 12 is a plan view of its lateral registration adjusting means. Fig. 4 1... Image forming device (printer) 2.3... Loading means (cassette) 11.12a, 13... Reversing means (flapper, guide, half-moon roller), 17... Horizontal resist Adjustment unit 18...Paper feed unit 19.21-...Positioning means (horizontal registration regulating piece, cassette rail groove) 23...Regulating means (paper regulating plate) 24a, 24b, 27... Lateral registration adjustment Means (horizontal resist plate, pulse motor) P...
・Sheet material (paper) Fig. 5 Fig. 6 Fig. 10 Fig. 1 5b Fig. 8 Fig. 9

Claims (1)

[Claims] 1. A paper feeding unit that feeds the sheet material stacked in the stacking means while regulating the width direction by a regulating means, a means for reversing the sheet material, and a lateral registration during printing on the second side. In an image forming apparatus in which a lateral registration adjustment unit having an adjustment means is independently and removably mounted, the regulation means and the lateral registration adjustment means can be directly positioned relative to each other without intervening the apparatus main body. An image forming apparatus characterized by having a positioning means that performs the following operations.