JPS63147772A - Printing device - Google Patents

Abstract

PURPOSE:To prevent erroneous feeding such as skew to serve enhancement of locational accuracy in two-side printing by moving one of a pair of width direction restrictive members selectively in the width direction, wherein said restrictive members are furnished in the width direction of an intermediate tray which once receives the printed sheet. CONSTITUTION:A stationary guide 24b and a movable guide 24a are furnished in the width direction of an intermediate tray 23. when a sensor installed upstream said intermediate tray 23 senses the leading edge of a sheet, the movable guide 24a is widened for a distance S with respect to a specified width A. When a certain period of time has passed and loading of sheets on the tray 23 is finished, the movable guide 24a is returned for the distance S for alignment of the stacked sheets. Movement of said movable guide 24a is controlled with a solenoid installed at the rear of the intermediate tray 23. This prevents the sheet from improper feeding such as skewing, which should enhance the locational accuracy in two-side printing.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a printing apparatus, and more specifically, to a sheet material conveying mechanism of a double-sided printing apparatus such as a double-sided printing machine.

(B) Prior Art FIG. 1 is a diagram illustrating the configuration of a typical double-sided printing apparatus to which the present invention is applied. The image forming section 1 prints an image signal sent from the image processing device 2 onto a sheet material S. The image forming section 1 is provided with an upper cassette 3a and a lower cassette 3b. Each cassette 3a, 3b has a sheet material S.
is loaded.

A large capacity feeding deck (hereinafter referred to as deck) 5 is connected to the duplex unit 6. The vertical transport section 7 is connected to the image forming section 1
Sort the sheet materials output from. The face-up tray 9 is loaded with output sheets and materials.
7. Among the sheet materials S in the upper cassette 3a, the lower cassette 3b, and the deck 5, one set of sheet materials S is selected by the control signal from the image processing value W2, and the respective pickup Rollers 10a, 10b, 11 rotate and are fed. The fed sheet material S reaches the registration roller 12 and once stops, and the image signal sent from the image processing value M2 is processed as a latent image on the photosensitive drum 13 by a known laser and laser scanning optical system. formed and visualized by known electrophotographic techniques.

The sheet material reaches a fixing roller 15 and is fixed thereon by a belt-shaped sheet material transport mechanism 14, and is transported to a deflector 17 by a transport roller 16.

The deflector 1f deflects the sheet material S to the vertical conveyance section 7 or the duplex unit 6. For example, deflector 17
When the sheet material S moves upward, the sheet material S is conveyed to the duplex unit 6. The sheet material S that has entered the duplex unit 6 is transported by the transport roller 18, the leading edge of the sheet material is detected by the sensor 19, and the sheet material S is transferred to the intermediate tray 2 at a timing based on the leading edge of the sheet material S.
Sent to 3.

The sheet material S is transported by a belt-shaped transport section 20 until it is sent to the intermediate tray 23, and the leading edge of the sheet material S is detected by a sensor 21, and delays and accumulations are confirmed according to the timing based on the sensor 19. It will be done. The sheet material S that has passed the sensor 19 is sent to an intermediate tray 23 by a conveyance roller 22.

The intermediate tray 23 temporarily stores the printed sheet material S on the first side. The guides 24 are for regulating the width direction of the sheet material S, and are provided parallel to both sides of the intermediate tray 23. The guide 24 is supported so as to be movable in the width direction of the sheet material S, and aligns the sheet material S loaded on the intermediate tray 23 to a reference position.

In order to refeed the sheet material S loaded on the intermediate tray 23, first, the sheet material presser 25 presses down the sheet material S,
The auxiliary rollers 26 and 27 rotate to convey the sheet material S from below, and the refeed roller 28 and separation roller 28' separate the sheet materials S in the intermediate tray 23 one by one and refeed them.

The sheet material after being re-fed passes through the conveyance roller 29 and is sent to the sensor 3.
reaches 0. The sensor 30 detects the tip of the sheet material S,
Based on this, the sheet material S is conveyed to the sensor 33. 3
1.32 is a conveyance roller therebetween.

Next, the sheet material S is fed in the same manner as the sheet material S in the deck 5 described above, passes through the conveyance roller 34, the sensor 35,
Printed on the second side (back side). The sheet material S that has passed through the fixing device 15 is conveyed upward by a deflector 17. The sheet material is delivered to the face-up tray 9 by transport rollers 36 and 37.

→ Problems to be Solved by the Invention In the conventional double-sided printing apparatus, in order to align the sheet materials S stored in the intermediate tray 23 to the reference position, the intermediate tray 2
A guide 24 movably provided within the interior of the vehicle is utilized. However, the guide 24 did not take into account the width variations during sheet material manufacturing or the width changes of the sheet material that occur during the image forming process. For example, it is well known that in a heat fixing step during an image forming process, moisture in a sheet material evaporates due to rapid heating, causing shrinkage.

As a result, the sheet materials S in the intermediate tray 23 may not be aligned with the reference position or may be stacked diagonally with respect to the direction of travel, resulting in skewed feeding or defective reference position during re-feeding, and the second surface There was a drawback that the printing position accuracy during printing deteriorated.

B) Means for solving RWI The printing apparatus of the present invention receives a printed sheet material on a -H intermediate tray, and then prints on the sheet material again. By providing a pair of width regulation guides, a member for moving at least one of the width regulation guides in the width direction of the intermediate tray, and a member for selectively controlling the movement position of the width regulation guide, It solves the problem.

(e) Effects In the printing apparatus of the present invention, the movement position of the width regulation guide is controlled as follows.

■When receiving the sheet material into the intermediate tray S>C-A ■When aligning the sheet material to the reference position in the intermediate tray A≦B ■When refeeding the sheet material from the intermediate tray S>k≧C
-A However, A: Distance between a pair of guides when the width regulation guide is not aligned with the reference position in the intermediate tray B: Minimum width of the sheet material C: Maximum width of the sheet material S, To: Spread distance of the width regulation guide (F) Embodiments Next, embodiments of the present invention will be described with reference to the drawings.

2 to 4 show an embodiment of a pair of width regulating guides 24a and 24b according to the present invention.

The guide 24a is movable in the width direction of the intermediate tray 23, and the guide 24b is fixed to the intermediate tray 23 and serves as a reference for the sheet material S in the width direction.

The guide 24a has a width A (A is the regulation guide interval, When the minimum width of the sheet material S sent to 23 is B, there is a relationship of A2B.)
Distance s'r! (When the maximum width of the sheet material S sent to the intermediate tray 23 is C, the relationship S>C-A exists.) The sheet material S moves in the spreading direction, and the sheet material S
This makes loading easier.

Next, when the leading edge of the sheet material S is detected by the sensor 21 and a predetermined period of time has elapsed and the sheet material has been loaded in the intermediate tray 23, the movable width regulating guide 24a moves in a direction to narrow the width by S. , the interval between the width regulation guides 24a and 24b is returned to A, and the sheet material S is reliably moved to the reference position.

As shown in FIG. 4, a contact piece 43 made of felt or a Teflon sheet is adhered to the back surface of the movable width regulating guide 24a, contacts the intermediate tray 23, and slides. When the solenoid 44 is energized, the iron core 45 is attracted, and a link 47 rotatably attached to a pin 46 press-fitted into the iron core 45 is moved by a distance S.

The link 47 passes through the slit e of the intermediate tray 23 and is fixed to the regulation guide 24a from below with a screw, and also connects two pins 49 caulked to the intermediate tray 23 with a width slightly larger than the shaft diameter. It passes through the slit f, is prevented from being removed by a retaining ring 48, and is supported so as to be slidable in the direction of the arrow.

When the solenoid 44 starts to be energized, the link 47 is attracted and the width regulating guide 24a is moved to the width A. At this time, the stopper 52, which is rotatably supported by the solenoid 51 with the notch 6 as a fulcrum, is pulled by the spring 53 attached to the solenoid 51, and the bent part of the stopper 52 comes into contact with the h part of the solenoid 51. Its rotation stops. When the solenoid 44 is de-energized, the link 47
The width regulating guide 24m moves in the direction of expanding. link 47 i
and the claw part J of the stopper 52 come into contact with each other, and the regulation guide 2
4a spreads only over the distance and stops.

Next, when the sheet material S is carried into the intermediate tray 23, the solenoid 51 starts to be energized, the stopper 52 is pulled, the claw part J of the stopper 52 is released from the i part of the link 47, and the spring 50 The regulation guide 24a moves in the expanding direction. One end of slit e and width regulation guide 24
a comes into contact with a, moves by a distance II (S-k) and stops.

FIG. 5 is a perspective view showing the mechanism of the sheet presser 25.

The sheet presser 25 is rotatably supported around a central shaft 25'. The electromagnetic solenoid 38 moves the sheet presser 25 up and down. The electromagnetic solenoid 38 is a solenoid core 38
' and is fixed to the machine frame by an angle 39. The pin 40 is press-fitted and caulked into the solenoid core 38'. The link 41 is rotatably attached to the pin 40 and is fitted with a pin 42 which is caulked to the sheet material presser 25.

When the iron core 38' is pulled upward, the sheet material presser 25 is pressed until the pin 40 hits the upper side of the notch a of the angle 39.
is lifted upwards into the position shown in FIG.・
When the solenoid 38 is de-energized, the solenoid core 38
' is lowered by the weight of the sheet material presser 25, and presses the sheet material S stacked on the intermediate tray 23 as shown in FIG.

At this time, the width regulating guide 24a is at g (A+k). When the intermediate tray 23 is released downward,
The pin 40 of the sheet material presser 25 hits the lower part of the notch a of the angle 39, and the sheet material presser 25 does not move downward any further.

Note that it is of course possible to move both of the restriction guides. Furthermore, two types of images may be formed on one side (multiple copy).

As another embodiment of the present invention, when the sheet material S is sent to the intermediate tray 23, the interval between the width regulating guides 24a and 24b is set to A+S, and after the sheet material S is loaded on the intermediate tray 23, the width regulating guide 24a is moved in the direction to narrow it by the distance laS, the guide interval is set to A, and the sheet materials are aligned at the reference position. At the same time, the sheet material presser 25 is lowered, a pressing force is applied to the sheet material, and the auxiliary rollers 26 and 27 are operated to perform re-feeding. Even in such a simple configuration,
For sheets other than particularly stiff sheet materials such as thick sheet materials, skew, feeding failure, and reference position failure are prevented, and the printing position accuracy on the second side can be sufficiently improved.

As explained above, according to the embodiment of the present invention, when the interval between the width regulating guides is A1, the minimum width of the sheet material sent to the intermediate tray is 81, and the maximum width is C, when the sheet material is carried into the intermediate tray, Width regulation guide spacing is A+S>C, A≦B
When the sheet material is expanded by an amount S that satisfies the relationship G, any predetermined sheet material can be easily stacked on the intermediate tray.

After loading is completed, narrow the regulation guide by S and set the regulation guide spacing to A, and see! - It is possible to align the sheet materials in the intermediate tray to the reference position without being affected by variations in the width of the materials themselves or changes in sheet width that occur during image formation.

After that, set the regulation guide to kf that satisfies the relationship S>k≧C−A! At the same time, the sheet material can be kept aligned at the reference position by operating the sheet material presser and applying a pressing force to the sheets stacked on the intermediate tray.

Furthermore, by setting the regulation guide width to A+k during refeeding, it is possible to prevent the end face of a stiff sheet material such as a thick sheet material from hitting the regulation guide and causing a feeding failure during refeeding. can.

(G) Effects of the Invention As described above, sheet materials can be easily aligned to the reference position within the intermediate tray, skew feeding, feeding errors, and reference position errors can be prevented, and printing position accuracy can be improved.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a typical double-sided printing device to which the present invention is applied, FIG. 2 is a plan view of an intermediate tray section according to the present invention, and FIG. 3 is a view of a width regulating guide section according to the present invention. FIG. 4 is a perspective view of the rear side of the width regulating guide section, FIG. 5 is a perspective view of the sheet material presser according to the present invention, and FIG. 6 is a side view showing the operating state of the sheet material presser. 23... Intermediate tray, 24a... Movable width tll
lli guide 24b...Fixed width regulation guide,
25... Sheet material presser, 38, 44, 51...
・Solenoid, 47...link.

Claims (1)

[Claims] (1) In a printing device that once receives a printed sheet material on an intermediate tray and then prints on the sheet material again, a pair of width regulation guides provided on both sides of the intermediate tray; A printing device comprising: a member that moves at least one of the intermediate trays in the width direction of the intermediate tray; and a member that selectively controls the movement position of the width regulation guide.