JPS63202529A - Cut sheet feeder - Google Patents

Abstract

PURPOSE:To enable both the distance between a paper feed roller and a separating claw and the pressure contacting force between said paper feed roller and a sheet to be simultaneously varied by forming said paper feed roller to be movable obliquely upward in a paper feeding direction with respect to a stacking board. CONSTITUTION:When a lever 19 is rotated around a shaft 13a, the projection 20a of a claw 20 is engaged with a recessed part 18a provided in the appropriate position of a claw fixing part 18, moving a roller shaft 7 in a condition that a gear 13 is engaged with a paper feed gear 14. Here, as the paper feeding shaft 7 is moved in three, I, II, and III positions, a paper feed roller 9 takes three positions and the distance l1I between a separating claw 11 and the roller shaft and the height (h) of the roller shaft with respect to a chassis 3 are, l1I<l1II<l1III, hI>hII>hIII, respectively. The pressure contacting force of the paper feed roller is given by a spring 10 for energizing a stacking board 2 and, as the (h) becomes larger, the deflecting quantity of the spring becomes smaller, lowering the pressure contacting force. That is, the pressure contacting force F is, FI<FII<FIII.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a cut sheet feeder that automatically feeds cut sheets in a recording device such as a printer, and more particularly to a cut sheet feeder that separates cut sheets using separation claws.

[Conventional technology]

A cut sheet feeder is a device that loads a stack of sheets (recording media such as paper or blank sheets) that have been cut to a predetermined size, and automatically feeds these sheets one by one to a recording unit, etc. Widely used in various recording devices such as copying machines.

FIG. 7 shows the appearance of a cut sheet feeder suitable for applying the present invention.

In FIG. 7, cover 1. A stacking plate 2 is swingably supported on a chassis (body frame) 3 having a main body frame 1, and a hopper H for storing and holding a layer of cut sheets is formed on the upper surface of the stacking plate. A seat support 5.5 is provided at the tip of this hopper H.

Further, a discharge roller 4 for discharging the sheets coming out of the recording device is pivotally supported at the front lower part of the sheet palm 3, and a stacker S for storing the discharged cut sheets is provided above the discharge roller. ing.

A pair of left and right sheet guides 6.6 are slidably engaged with the stacking plate 2 and are movable in the middle direction of the sheet.

A paper feed roller shaft 7 extending left and right is supported on the chassis 3, and a paper feed roller unit 9, in which a pair of left and right paper feed rollers are fitted into bushings, is located at a position of the drive shaft facing the hopper H. It is installed.

The left and right paper feed roller units 9.9 rotate integrally with respect to the paper feed roller shaft 7, but are mounted so as to move together with the left and right sheet guides 6.6 in the axial direction.

The layers of cut sheets are guided and regulated on both sides by the sheet guides 6.6 and stacked in the hopper H.

FIG. 8 shows a cross section of a main part of the cut sheet feeder shown in FIG. 7.

In FIG. 8, torsion coil springs 10 are attached to the left and right seat guides 6, and the tips of each torsion coil spring 10 are in pressure contact (press contact) with the inner surface of the lower part of the chassis 3 with a predetermined spring force, and this pressure reaction force Each sheet guide 6.
6 and the stacking plate 2 are pushed upward, so that the stacked layers of cut sheets 8 are transferred to each paper feed roller unit 9,
9 with a predetermined force F.

In FIG. 8, reference numeral 11 denotes a separation claw arm that is swingably supported by each of the left and right sheet guides 6.6 via a bin 12, and each separation claw arm 11. Separation claws 11A and IIA are formed at the leading end of the sheet 8 to engage with both sides of the upper front end of the layer of the sheet 8, respectively.

As shown in FIG. 9, the paper feeding roller unit 9 is formed by fitting a bushing 9b onto a paper feeding roller shaft, and fitting a paper feeding roller 9a into the bushing 9b.

The left and right paper feed roller units 9 rotate integrally with respect to the paper feed roller shaft 7, but are positioned relative to the sheet guide 6 in the axial direction by plungers 9d and 9e provided on the bushing 9b. It is designed to move together with 6.

In the above configuration, when the paper feed roller shaft 7 is rotated and the paper feed roller units 9, 9 are rotated in the direction of arrow A, thrust is applied to the uppermost layer of sheets 8 in the sheet hopper H, After forming a loop R at the leading end, the sheet passes over the separation claws +1A and IIA and is fed in the direction of arrow B.

Here, the likelihood of the loop R occurring is determined by the distance 11 from the tangent between the paper feed roller 9a and the sheet 8 to the leading edge of the sheet shown in FIG. 10, and the distance I! from the end of the paper feed roller 9a to the end of the sheet! 2 and the pressure contact force between the paper feed roller and the sheet, and when l, , 12 is small, a loop R is generated ((a large thrust force by the paper feed roller 9a is required.
! . . , 12 is large, loop R is likely to occur (no large thrust by the paper feed roller 9a is required.

Therefore, generally when the sheet is thick, l 1 +1!
2. Increase the pressure force (11°12 for thin sheets)
It is known that paper feeding performance is improved by reducing the pressure contact force.

[Problems to be Solved by the Invention] However, in this type of conventional cut sheet feeder, the thrust force and the distance 2. ．． 22 is constant, if the quality or thickness of the sheet changes, or if the environment changes, the likelihood of the loop R occurring changes, and the paper feed roller 9a will move against the sheet 8 due to insufficient thrust. There has been a problem in that the usable sheets and the sheet thicknesses that can be used must be limited because the thrust force is too large and causes double feeding.

[Means for solving problems]

According to the present invention, in a cut sheet feeder in which a stacking plate on which sheets are stacked is urged toward a paper feed roller by a spring, and the stacked sheets are fed one by one by the paper feed roller, the paper feed roller is loaded. By being configured to be movable obliquely upward in the sheet feeding direction with respect to the plate, it is possible to simultaneously change the distance between the sheet feeding roller and the separating claw and the pressure contact force between the sheet feeding roller and the sheet.

〔Example〕

FIG. 1 shows an embodiment of a cut sheet feeder according to the invention.

In FIG. 1, the paper feed roller 9a is movable obliquely upward relative to the stacking plate 2 in the paper feeding direction.

FIG. 2 shows a structure for moving the paper feed roller 9a shown in FIG. The driving force is obtained through the

A lever 19 is rotatably supported on the side plate 16 on the same shaft 13a as the gear 13.
is rotatably supported. Pawl 20 on lever 19
The side plate 16 is provided with a pawl fixing member 18 that engages with the pawl 20. Figure 3 is A-A of Figure 2.
It is a cross-sectional view, in which a protrusion 20a provided on the pawl 20 engages with four parts 18a provided on the pawl fixing member 18, thereby positioning and fixing the lever 19.

Next, the effect will be explained. When the lever 19 is rotated around the shaft 3a, the protrusion 20a of the pawl 20 engages with the recess 18a provided at an appropriate position on the pawl fixing member 18, and the roller shaft 7 is moved into the gear as shown in FIG. 13 and the paper feed gear 14 can be moved while still being engaged with each other. 17 is a roller shaft hole provided in the side plate. Here, when the paper feed shaft 7 is moved in three positions, I, n, and Ill, the paper feed roller 9 is moved to I, n, and Ill positions as shown in FIG.
, Take the three positions of LLT and determine the distance between the separation claw 11 and the roller shaft! , and the height h of the roller shaft relative to the chassis 3 is I! ll<I! lrl<ji'1lll, hl>
hn > hui.

Since the pressing force of the paper feed roller is given by the spring IO that biases the stacking plate 2, as h increases, the amount of deflection of the spring decreases and the pressing force decreases. That is, the pressure contact force F satisfies F+<Fn<Fm.

As shown in the conventional example, with thin (weak) sheets,
Compared to thicker (stronger back) sheets, I! The paper feeding performance is better when +(I!2) is small and the pressure contact force is weak (the spring force is weak when h is large), and the opposite is true for thick sheets. For example, in Figure 1, state H is 7
0g/rr? (Suitable for feeding leprosy sheets!!,, h
(pressing force), a thinner sheet can be fed in state I, and a thicker sheet can be fed in state (3).

Further, as shown in FIG. 5, if the bushing 9b and the second bushing 9C are engaged by the claw 9f and the hole 9g, the distance i between the paper guide 6 and paper feed roller 9a! 2 can also be adjusted depending on the thickness of the sheet.

[Other Embodiments] In addition to the above embodiments, as a means for moving the roller shaft, a pulley 14a is provided on the roller shaft 7 as shown in FIG. It's okay.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to simultaneously change the distance between the paper feed roller and the separation claw and the pressure contact force between the paper feed roller and the sheet, thereby stably feeding sheets of different thicknesses and hardnesses. .

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, FIGS. 2 to 5 are diagrams showing the main parts thereof, and FIG. 6 is a diagram showing the main parts of another embodiment. FIG. 7 to FIG. 10 are diagrams showing a conventional cut sheet feeder. ■...Cover, 2...Loading plate, 3...Chassis,
4... Discharge roller, 5... Sheet support 1., 6.
... Sheet guide, 7... Paper feed roller shaft, 8... Sheet, 9... Paper feed roller unit, 9a... Paper feed roller, 9b... Bush, 10... Torsion coil spring, DESCRIPTION OF SYMBOLS 11... Separation claw, 12... Pin, 13... Drive side gear, 14... Paper feed gear, 15... Paper feed roller unit, 15a... Paper feed roller.

Claims (2)

[Claims] (1) In a cut sheet feeder in which a stacking plate on which sheets are stacked is urged toward a paper feed roller by a spring, and the stacked sheets are fed one by one by the paper feed roller, the paper feed roller is moved against the stacking plate. A cut sheet feeder characterized in that it is configured to be movable diagonally upward in a paper feeding direction. (2) The cut sheet feeder according to claim 1, wherein the paper feed roller is provided so that its position on the roller axis can be changed.