JPS63306145A - Positioning device for sheet - Google Patents

Abstract

PURPOSE:To simultaneously carry out the correction of skewing and the correction of shifting by controlling the movement of a skew correction mechanism based on a control signal from a shifting quantity control means. CONSTITUTION:As a sheet 9 is conveyed, skew detecting sensors 11a, 11b are shielded from light due to the sheet 9. At this time, the quantity of skewing is operated by a skewing quantity detecting means 19 from the difference in detecting time between both skew detecting sensors. On the other hand, the relation between the pressure contacting time of pressure contact rollers 2a, 2b and a skewing quantity is kept stored in the pressure contacting time operating means 20 of a controlling computer, and a pressure contacting time is obtained by the pressure contacting time operating means 20 from the data of the skewing quantity from the skewing quantity detecting means 19. This result is transmitted to a pressure contacting time control means 24 to operate pressure-contact roller pressure contacting means 25, 26. And, based on a signal from a shift detecting sensor 17, the correction of shifting is carried out by a shifting quantity control means 22 prior to the correction of skewing. After that, the quantity resulting from the correction of skewing is operated by a corrected shifting quantity operating means 23 to simultaneously carry out the correction of shifting and the correction of skewing.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to sheet feeding used in printers, etc.
In particular, the present invention relates to a sheet positioning device suitable for high-speed printers that support high print quality.

[Conventional technology]

As described in Japanese Patent Application Laid-open No. 58-167340, this type of conventional device drives and controls a DC motor for rotating a conveyance roller, which is arranged independently on the sheet surface side.
It was a mechanism to correct diagonal feed such as skew.

Furthermore, as described in Japanese Patent Application Laid-Open No. 58-212541, the driving roller and the pressure roller of the paper feeding device are both made of an elastic member such as rubber to form a contact surface, and this contact area is changed. It was a mechanism that controlled the amount of paper feed.

(Problems to be Solved by the Invention) The above-mentioned conventional technology does not take into consideration the shift amount (parallel movement amount) caused by skew correction.
There is a problem in that a shift detection element must be separately arranged downstream of the skew correction mechanism to correct the shift. As a result, a large space is required for positioning the seat, which poses a problem in terms of miniaturization and cost reduction.

An object of the present invention is to provide a seat positioning device that can perform skew correction and shift correction simultaneously.

[Means for solving problems]

The above purpose is to detect the amount of skew of the sheet using a skew detection means installed in front of the contact area between the drive roller for skew correction and the pressure roller, and calculate the amount of skew correction and the shift amount caused by this skew correction using a calculation means. After the sheet is pinched by the contact portion, the skew correction mechanism is once shifted by a predetermined amount based on the signal from the shift detection means with respect to one end surface of the sheet, and after this operation is completed, the skew correction is performed. This is achieved by simultaneously performing a shift correction corresponding to the shift amount caused by this skew correction.

[For production]

A drive roller and a pressure roller covered with an elastic material such as rubber are placed on either side of the sheet. The pressing roller can be independently pressed against the driving roller, and the pressing force is adjusted equally on the left and right sides by a spring. Therefore, if skew correction is not performed, there is no change in the posture of the sheet before and after the sheet passes through the pressure roller.

When performing skew correction, the pressure force of either the left or right pressure roller is increased, the amount of deformation of the drive roller is increased, and the sheet feeding speed is increased based on the calculation result. For example, a solenoid is used to increase the pressing force, and the amount of skew correction is controlled by the operating time of this solenoid.

The shift amount caused by the skew correction is a value that can be calculated using the skew correction amount. Therefore, while performing skew correction, shift correction can also be performed at the same time.

This shift correction is performed integrally with the sheet by making the skew correction mechanism movable in a direction perpendicular to the paper feeding direction.

This makes it possible to position the seat in a small amount of space and in a short time.

〔Example〕

Hereinafter, the present invention will be described in detail based on the drawings.

First, with reference to FIG. 6, it will be explained how the actual conveyance amount changes with respect to the ideal conveyance amount calculated from the radius of the rubber roller before deformation with respect to the deformation of the rubber roller.

In FIG. 6, the horizontal axis represents the amount of rubber roller deformation [m 2 ], and the vertical axis represents the conveying speed change ratio [%].

Then, when the conveyance speed of the sheet is 424 ma+/s, the rotation speed of the rubber roller is 30 Orpm, the roller diameter of the rubber roller is 27 am, and the material of the rubber roller is CRHs30, the relationship between the amount of deformation of the rubber roller and the conveyance speed change ratio is The wall thickness t is 2 mm and 3 m+a as shown in FIG. 6.

How the actual conveyance amount changes with respect to the deformation amount of the rubber roller with respect to the ideal conveyance amount calculated from the radius of the rubber roller before deformation will be explained. It can be seen from FIG. 6 that as the amount of deformation of the rubber roller increases, the conveyance speed increases with a tendency to be almost proportional.

As a result, the conveyance amount of the sheet can be controlled by the amount of deformation of the rubber roller.

For example, if the deformation amount of two rubber rollers that share the same drive shaft is controlled to 0.2 m at point a and 0.4 mm at point b, the sheet conveyance amount change ΔL will be ΔL=fΔ■・d
It becomes t.

That is, the skew of the sheet is corrected by this ΔL.

Next, specific embodiments of the present invention will be described using FIGS. 1 to 5.

FIG. 1 is a schematic diagram of the main parts of the skew correction mechanism in this embodiment. Drive rollers la, lb covered with an elastic material such as rubber are arranged on both sides of the sheet 9 on a drive shaft 3 which is rotatably supported on a side plate (not shown). This drive shaft 3 is connected to a drive motor 10 for driving.

Pressure rollers 2a and 2b, which are driven rollers, are respectively attached to driven shafts 4a and 4b that are rotatably supported by pressure roller supports 5a and 5b, facing the drive rollers la and lb. The pressure rollers 2a and 2b have a characteristic that the contact portion between the two rollers is less deformed than the drive rollers la and lb. For example, the pressure roller 2a.

2b may be made of a metallic material. The pressure roller supports 5a, 5b are pressed down by pressure links 7a, 7b connected to suction type solenoids 8a, 8b. The crimp links 7a, 7b are independently rotatably attached to a crimp ring support shaft 6 supported by a side plate (not shown).

The conveyance direction of the sheet 9 is the illustrated arrow F1 direction. Skew detection sensors 11a and llb, which are skew detection means, detect that the sheet 9 is connected to drive rollers la and lb.
The rollers 2a and 2b are arranged in front of the contact portion of the pressure rollers 2a and 2b. The amount of skew of the sheet 9 is calculated from the time difference when the front end of the sheet 9 blocks light from the skew detection sensors 11a and 11b, and the conveyance speed of the sheet 9.

FIG. 2 shows an example of the skew correction operation of the skew correction mechanism in FIG. 1 when the sheet 9 is skewed to the left with respect to the conveyance direction.

The suction type solenoid 8b operates, and the pressure roller 2b
is pressed onto the drive roller 1b by the rotation of the pressing link 7b. As a result, the contact length of the drive roller 1b becomes longer than the contact length of the drive roller 1a, and as a result, the conveyance speed of the sheet 9 by the drive roller 1b increases.
The conveyance speed of the sheet 9 is faster than the conveyance speed of the sheet 9 according to b. As a result, the sheet 9 is sent obliquely in the direction of arrow F2 shown in the figure.

FIG. 3 is a schematic diagram of the entire configuration of this embodiment.

The skew correction mechanism shown in FIG.
4. It is attached to a case consisting of a bottom plate 13. A slide bearing 16 is fixed to the bottom plate 13 of the case, and is movable in a direction perpendicular to the conveying direction of the sheet 9, that is, in the direction of the arrow shown. This movement is performed by rotation of the lead screw 15.

The lead screw 15 is rotated by a drive source (not shown).

The amount of movement of the skew correction mechanism is determined by a shift detection sensor 17 which is a shift detection means. When the shift detection sensor 17 does not detect the sheet 9, the skew correction mechanism is moved in the X direction and stopped when one end of the sheet 9 blocks the shift detection sensor 17 from light. On the other hand, if the shift detection sensor 17 has already detected the seat 9, the skew correction mechanism is moved in the -X direction to once overrun the shift detection sensor 17. Then, the skew correction mechanism is moved in the X direction again, so that one end of the sheet 9 is aligned with the shift detection sensor 1.
7. Stop at a place where the light is blocked.

FIG. 4 shows control blocks for skew correction and shift correction.

When the sheet 9 is conveyed in the direction of the illustrated arrow, the skew detection sensors 11a and llb are shielded from light by the sheet 9. Both skew detection sensors 11a, l at this time
Skew amount detection means 1 detects the skew amount based on the detection time difference of lb.
Calculate using 9.

On the other hand, the relationship between the crimping time and the skew amount of the crimping rollers 2a and 2b is stored in the crimping time calculation means 20 of the control computer, and the crimping time calculation means 20 uses the skew amount data from the skew amount detection means 19. Find the crimping time. This result is transmitted to the pressure bonding time control means 24, and the pressure roller pressure bonding means 25, 26 are operated.

In the shift correction, based on the signal from the shift detection sensor 17, before the skew correction, that is, the sheet 9
The shift amount control means 22 performs shift correction in a state where the shift amount is skewed. Thereafter, the skew correction is started, and the shift amount caused by the skew correction is calculated by the corrected shift amount voice means 23, and the shift correction is performed simultaneously with the skew correction.

According to the present invention, it is possible to position the sheet 9 in a short time and with high precision.

FIG. 5 shows how to determine the amount of shift caused by skew correction.

It is assumed that the sheet 9 is conveyed in the illustrated posture and the skew angle is θ. Here, the pressure on the drive roller 1a is increased and the conveyance speed is changed from vo to V. Then, when the pressure bonding time is Δt, R is the radius of rotation of the sheet 9. Q is the distance between the drive rollers. On the other hand, the speed ratio when the suction solenoid is operated and when it is not operated is a known quantity, and a=□...(2)■ From equations (1) and (2), the following can be determined. R is a characteristic value of the skew correction mechanism.

Also, the pressing time Δt to the drive roller 1a is R・θ Δt=□　　　　　　　　　　 （4）■ It is determined by

After correcting the skew, each drive roller la, lb moves from point A to point A.
' point, move from point B to point B'. Therefore, with respect to point C, which is the distance from the reference plane at which shift positioning was performed before the skew correction, the distance C' between the 01 point and the O point becomes the distance from the reference plane of the sheet 9 after the skew correction. As a result, it is necessary to perform shift correction again, and the shift correction amount c'-c is C'-C=bsino+C(CO8θ-1)
-...It is found by (5). b indicates the shift detection sensor 17 and drive rollers la, l, which are determined at the time of designing the mechanism section.
This is the distance between b. The skew amount θ is detected by the skew detection sensor 11, the skew is corrected by pressing either one of the pressure rollers 2, and the calculation of the above equation (5) is performed by the correction shift amount calculation means 23 to control the shift amount. The means 22 rotates the lead screw 15 by C'-0 to correct the shift.

〔Effect of the invention〕

According to the present invention, since skew correction and shift correction can be performed simultaneously, the sheet can be positioned in a short time and with a short conveyance path length, and the skew correction and shift correction can be performed while reliably holding the sheet. This has the effect of allowing highly reliable positioning of both thin and thick sheets.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a schematic configuration of main parts of a skew correction mechanism in an embodiment of the present invention, FIG. 2 is a perspective view of a schematic configuration explaining the operating state of FIG. 1, and FIG. 3 is a schematic diagram of a shift correction mechanism. A perspective view of the configuration, FIG. 4 is a control block diagram in the present invention,
FIG. 5 is a diagram showing the relationship between the skew correction amount and the shift amount caused by the skew correction, and FIG. 6 is a diagram illustrating the relationship between the rubber roller deformation amount and the conveying speed change ratio. DESCRIPTION OF SYMBOLS 1... Drive roller, 2... Pressure roller, 5... Pressure roller support part, 7... Pressure link, 8... Solenoid, 9... Sheet, 10... Drive motor, 11・
... Skew detection sensor, 15... Lead screw 1 country j-, large motion roller 2--, pressure 10-ra 5-, sword-like loaf multi-31 anzu-ya-lI-...masaku knee degree 5th recess 1--JLR Corolla 9-Rate

Claims (1)

[Scope of Claims] 1. A sheet positioning device comprising a skew correction mechanism that detects the skew amount of the sheet by a skew amount detection means and corrects the skew of the sheet based on this detection signal, the skew correction mechanism The mechanism includes at least two rubber rollers that share a drive shaft, and at least two driven rollers that are opposed to the rubber roller and can be pressed against the rubber roller for a predetermined period of time and with a predetermined pressing force based on a signal from the skew amount detection means. The skew correction mechanism supports the rubber roller and the driven roller integrally so as to be movable in a direction perpendicular to the paper feeding direction, and detects the sheet shift amount from the shift amount detection means by a signal from the skew correction means. A seat comprising: a shift amount control means for predicting and correcting a shift amount caused by skew correction of the sheet based on the above, and controlling movement of the skew correction mechanism based on a control signal from the shift amount control means. positioning device. 2. Two pairs of conveyance rollers each consisting of a drive roller with a large amount of deformation and a slave roller with a small amount of deformation compared to the drive roller are provided at a predetermined interval on a drive shaft perpendicular to the sheet conveyance direction; The sheet positioning device according to claim 1, characterized by a skew correction mechanism that corrects the skew by changing the pressing force of the pair of conveyance rollers.