JPH0543621B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sheet cueing method for a printing device such as a printer or a typewriter, which sets a sheet such as printing paper at the printing position of the printing device.

[Prior Art] Generally, when a printing device such as a printer or a typewriter is used to print continuously on a plurality of sheets of paper, a paper feed unit that automatically feeds the paper is attached to the paper feed port of the printing unit.

Some of these paper feed units are equipped with a drive source, but recently, in order to reduce costs, some paper feed units do not have a drive source and instead use the drive force from the printing unit to rotate the paper feed roller and feed the paper into the printing unit. Some are supplied individually.

Further, the printing unit grips the supplied paper between a platen and a pressure roller, supplies it to a printing position, and prints with a head that reciprocates along the platen.

Printing devices that obtain the driving force for the paper feed unit from the printing unit include, for example, the
There is one in Publication No. 6633.

In order to register the leading edge of the paper sent out by the paper feed roller, this printing device abuts the leading edge of the paper against the pressure contact between the platen and the pressure roller, bends the paper, and registers using the stiffness of the paper. ing.

However, since the paper feeding unit receives driving force from the printing unit, when the paper feeding roller is rotating, the platen must also rotate. On the other hand, in order to register the leading edge of the paper sent out by the paper feed roller, if the platen is rotated in the conveyance direction of the paper, the leading edge of the paper cannot be registered. For this reason, the platen is rotated in a direction opposite to the paper conveyance direction.

That is, the paper sent out by the paper feed roller is brought into contact with the pressure contact between the platen and the pressure roller, which rotate in the opposite direction to the conveyance direction, and the paper is deflected to register the leading edge of the paper, and then the platen is rotated in the normal direction. The paper is set in the print position.

However, since the paper is brought into contact with the pressure contact between the platen and the pressure roller, which rotate in the opposite direction to the conveyance direction, the leading edge of the paper is not only bounced off and not accurately registered, but also tends to break.

Further, when the platen is reversed (rotated in the transport direction) after registration to feed the paper to the printing position, it is difficult to hold the paper that was flipped during registration, and the printing position is likely to shift.

On the other hand, as a method for accurately registering and preventing folding of the leading edge of paper during registration,
Publication No. 189951 discloses that after the paper sent out by the feeding means is held between the first conveyance means and the second conveyance means, the paper is once retreated and discharged to perform registration, and then Disclosed is a method of driving a first conveying means and a second conveying means to hold and feed a sheet between the first conveying means and the second conveying means (at this time, the feeding means is driven). ing.

[Problems to be Solved by the Invention] However, the method disclosed in JP-A-57-189951 has the following problems.

Even if the paper sent out by the feeding means is sent in a skewed state to the pressure contact part of the first conveying means and the second conveying means, the paper will be bent due to the reversal of both conveying means, and the leading edge of the paper will be bent. Skew is removed (resisted).

However, when the paper is fed in a skewed manner, the degree of sagging formed at both left and right ends of the paper, for example, differs. Therefore, the pressure force of the leading edge of the paper against the pressure contact portion also differs between the left and right ends of the leading edge of the paper.

When the degree of skew is large, the pressure contact force on the other left and right ends becomes very small compared to the pressure contact force on the left and right ends.

Therefore, when the sheet is gripped again by the conveying means after registration, the gripping timing may be shifted at both left and right ends of the sheet, and there is a problem in that the skew cannot be completely corrected.

An object of the present invention is to provide a method for registering a sheet by retracting the sheet after it is gripped by the pressure contact portions of first and second conveyance means, in which the degree of skew is large when the sheet is fed out, and when the sheet is registered. When the degree of sagging of the paper is different on the left and right sides, and the pressing force of the paper against the conveyance means is different on the left and right sides, this function prevents left and right deviations in the timing of the sheet gripping of the conveyance means and corrects the skew. It is an object of the present invention to provide a method for reliably locating the beginning of a sheet in a printing device.

[Means for Solving the Problems] In order to achieve the above object, the present invention transfers sheets sent out by a feeding means such as a paper feeding roller to a first conveying means such as a platen and a second conveying means such as a pressure roller. After the sheet is held in the pressure contact portion with the means, the sheet is once retracted by the first and second conveyance means with the feeding means stopped and discharged from the pressure contact portion, and then the sheet is held in the pressure contact portion again. While driving the feeding means to send out the sheet, the first and second conveying means are driven to hold the sheet in the pressure contact part, and the sheet is conveyed by a predetermined amount downstream from the pressure contact part in the sheet conveyance direction. After that, the sheet is conveyed to the printing position by stopping the feeding means and continuing to drive the first and second conveying means.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

The printing apparatus of this embodiment includes a printing unit 3 as shown in FIGS. 1 and 2 and a paper feeding unit 101 as shown in FIG.

First, the printing unit 3 has a structure as shown in FIGS. 1 to 4.

As shown in FIG. 1, a frame 9 is provided within the cover 7 of the printing unit 3, and a platen shaft 13 is rotatably supported on both sides 9L, 9R of the frame 9 via bearings 11L, 11R. A platen knob 15L and a gear 17 are attached to the left side of this platen shaft 13, a platen 19 is attached to the center, and a gear 21 and a platen knob 15R are attached to the right side.
is installed.

Further, a motor 23 for driving the platen 19 is attached to the side portion 9R of the frame 9.
The driving force is transmitted to gear 21 via gears 24 and 25.

Further, as shown in FIG. 2, guide rods 26 and 28 are provided parallel to the platen 19. A head carriage 27 is attached to these guide rods 26, 28 so as to be reciprocally movable, and the head carriage 27 is driven laterally along the guide rods 26, 28 by a drive device (not shown).

As shown in FIG. 4, a printing head 29 and a leading edge guide 30 are attached to the head carriage 27, and a ribbon cassette 34 is detachably attached thereto.

Further, as shown in FIGS. 2 and 3, around the platen 19 are a platen guide 31, pressure rollers 33 and 35 arranged in two rows, and a paper bail roller 3 that presses the paper against the platen 19.
7. A platen cover 39 and the like are provided.

The pressure rollers 33, 35 have a pressure lever 43 shown in FIGS. 1 and 3 on a shaft 42.
By rotating around the shaft 4, the roller 44
By rotating the arm 46 attached to the platen 5, the guide 31 is rotated about the shaft 45, and the guide 31 is brought into pressure contact with the platen 19 or released from the pressure contact. Note that the arm 46 is urged against the roller 44 by a spring 48.

Further, by rotating the paper bail lever 47, the arm 51 of the paper bail roller 37 rotates around the shaft 49, and the paper bail roller 37 is brought into pressure contact with the platen 19 or released from pressure contact.

Note that the cover 5 is located above the head carriage 27.
3 can be opened and closed, and the ribbon cassette 34 can be replaced in the open state.

For example, a paper feed unit 101 as shown in FIGS. 5 to 10 is attached to the paper feed/discharge port 5 of the printing unit 3 configured as described above.

This paper feed unit 101 includes a paper feed stacker 54 that accommodates stacked sheets P as shown in FIG.
As shown in FIG. 8, a pair of left and right side plates 56L, 5
6R and feeds the paper P to the platen 19 side using a paper feed roller 58.

As shown in FIG.
5 and the like.

Further, as shown in FIG. 9, the housing portion 57 includes a shaft hole 69 that supports a rotating shaft 67 to which a paper feed roller 58 is attached, and a support shaft that supports a manual feed guide 71 provided in front of the paper feed roller 58 from above and below. Shaft holes 77 and 79 for holding the shafts 73 and 75 are provided. Although not shown, the drive transmission mechanism 5 for the paper feed roller 58
A confirmation window is provided to confirm the home position of item 5.

A drive transmission mechanism 55 is housed in the housing portion 57, as shown in FIGS. 9 and 10.

First, a gear 107 that meshes with the gear 17 of the printing unit 3 is attached to the support shaft 81. Further, a gear 109 that meshes with the gear 107 is attached to the rotary shaft 108 on which the paper discharge roller 241 is attached, and a gear 111 that meshes with the gear 109 and a gear 113 smaller than the gear 111 are attached to the support shaft 85. Furthermore, a gear 115 that meshes with the gear 113 is attached to the support shaft 87, and a gear 119 that meshes with the gear 115 is attached to the support shaft 89.

A ratchet pawl 123 rotating about a shaft 121 and a leaf spring 125 biasing the ratchet pawl 123 toward the support shaft 89 are attached to the inside of the gear 119. And the ratchet claw 123
The cam 127 that regulates the operation of the pins 91, 93,
It is attached to 95. Note that a color indicating the home position is displayed at one location on the outside of the gear 119 at a position corresponding to the confirmation window.

Furthermore, the support shaft 89 has a gear 129 shown in FIG.
is installed. Gear 11 of this gear 129
A ratchet 131 shown in FIG. 9 is attached to the 9 side. A gear 133 that meshes with the gear 129 via the support shaft 67 is provided in the shaft hole 69 .

The drive transmission mechanism 55 configured in this way is covered with a cover plate 147 as shown in FIG.

A chucking part 99 is attached below the housing part 57 that houses the drive transmission mechanism 55, as shown in FIG. This chucking portion 99 includes a fitting portion 135 that fits into the bearing 11L shown in FIG.

On the other hand, the side plate 56R is attached to the flange 1 as shown in FIG.
65, support parts 169, 171, 173, and a chucking part (not shown) similar to the chucking part 99 that fits into the bearing 11R of FIG. 1.

Support shafts 65, 73, 75 and a conveyance guide 134 are attached between the side plates 56L, 56R configured as above to provide rigidity, and rotating shafts 67, 108 are rotatably attached. .

A bottom plate 195 having an N-shaped side surface is attached to the support shafts 65 and 75 via support plates 197 and 199.

This bottom plate 195 is a rear part 195 located at the rear.
A and a stopper section 195B that holds the leading edge of the paper.
and a guide section 195C that guides the paper forward.
The support portion 195D shown in FIG. 6 is provided. A paper feed frame 201 that supports the rear of the paper on the paper feed stacker 54 is removably attached to the rear surface portion 195A.

Further, a set lever 202 that moves the paper feed stacker 54 up and down is rotatably attached to the support portion 195D via a shaft 204. This set lever 202 integrally includes a lever portion 202A and a cam portion 202B. A click spring 206 is provided between the support portion 195D and the cam portion 202B.
is installed.

A paper feed stacker 54 is rotatably attached to the support shaft 65. This paper feed stacker 54 is
As shown in the figure, it is divided into a left stacker 54L having a side plate 203L and a right stacker 54R having a side plate 203R. The left stacker 54L is fixed in the axial direction, and the right stacker 54
R is movable in the axial direction.

Attached to the rear surface of the left stacker 54L is an arm 213L to which a pin 211 that engages with the cam portion 202B of the set lever 202 is attached as shown in FIG. 6, and a frame 213 having a spring attachment portion 213R as shown in FIG. ing. A spring 215 is attached between the spring attachment portion 213R and the back surface portion 195A, and always urges the paper feed stacker 54 toward the paper feed roller 58 side.

A support shaft 217 is provided on the outside of the side plates 203L and 203R, and a separation lever 219
L, 219R are attached through attachment holes 221.

The separation levers 219L and 219R include a separation claw 223 that separates the paper P sent out by the paper feed roller 58 into one sheet, and a stopper 225 that restricts the amount of downward rotation.

The rotating shaft 67 to which the paper feed roller 58 is attached has sponge rollers 22 on both sides of the paper feed roller 58.
7L and 227R are installed.

The manual feed guide 71 supported by the support shafts 73 and 75 has arms 229L and 229R on both lower sides that engage with the support shaft 75, and a paper ejection frame 233 is attached to the upper part via a pair of support parts 231. There is. Note that this paper ejection frame 233 constitutes a paper ejection stacker together with the recessed portion of the conveyance guide 134 and the manual feed guide 71.

The support part 231 has a slit 235 that engages with a notch provided in the upper part of the manual feed guide 71, and also has a stopper 237.
7 and the back surface of the upper part of the manual feed guide 71.
39, the support portion 231 is fixed to the manual guide 71, and the manual guide 71 is held on the support shaft 73.

A plurality of paper discharge rollers 241 are provided on the rotating shaft 108 as shown in FIGS. 5 and 8.

Further, the conveyance guide 134 forms a manual feed port 243 between it and the manual feed guide 71, and is formed in an N-shape so as to support the rear end of the paper P discharged by the paper discharge roller 241. In addition, on the front side of the conveyance guide 134, there is a static eliminating brush 2 as shown in FIG.
45 is installed.

The paper ejection guide 141 guides the paper P ejected from the printing unit 3 toward the paper ejection roller 241 side, and has support plates 246L, as shown in FIG. 8, at both ends.
246R, and the shaft 14 is attached to the side plates 56L, 56R.
It is rotatably supported around 3 and 189.

The printing device configured as described above operates as follows.

First, the lever part 2 of the set lever 202 in FIG.
Rotate 02A and attach the pin 211 with the cam part 202B.
Press down to move the paper feed stacker 54 to the paper feed roller 58.
keep away from Then, the paper P is placed on this paper feed stacker 54 at the stopper portion 19 whose leading end is the bottom plate 195.
Laminate them in contact with 5B. At this time, the right stacker 54R is moved according to the width of the paper P.

Next, turn the platen knob 15L by hand while looking through the confirmation window provided on the side plate 56L, stop when the color indicating the home position is visible, and set the platen to the home position.

By rotating the lever portion 202A clockwise, the cam portion 202B is rotated as shown in FIG.
is removed from the pin 211. As a result, the return force of the spring 215 causes the paper feed stacker 5 to
4 is urged upward, and the paper P is pressed against the paper feed roller 58.

In this state, when a print command is issued, the head carriage 27 shown in FIG. 4 moves from its leftmost home position to the center and waits for paper to be supplied.

Further, the motor 23 in FIG. 1 is driven to rotate as shown in FIG. 11, and the platen shaft 13 rotates clockwise in FIGS. 9 and 10. For this reason, gear 1
Gear 119 rotates to the left via gears 7, 107, 109, 111, 113, and 115. At this time, the ratchet pawl 123 is in contact with the inner circumferential surface of the cam 127, so it is not connected to the ratchet 131.
Therefore, the gear 129 does not rotate and the drive is not transmitted to the rotating shaft 67, so the paper feed roller 58 does not rotate.

As the gear 119 rotates and the ratchet 123 disengages from the cam 127, it engages with the ratchet 131. Therefore, the driving force of gear 119 is
9, the paper feed roller 58 and the sponge rollers 227L, 227R rotate as shown in FIG. 11 via the gear 133 and the rotating shaft 67, and both front ends of the paper P are lightly pressed by the sponge rollers 227L, 227R. Then, the paper P is fed by the paper feed roller 58.
is pushed out.

At that time, both front ends of the paper P are separated by the separation claws 223 and 2.
23 and begins to bend. Then, the sponge rollers 227L and 227R are deformed by the force caused by the deflection of the paper. When the deflection of the paper exceeds the elastic limit, both front ends of the paper P bounce and
The sheet is separated into sheets, passed between the guide portion 195C and the manual feed guide 71, and then supplied between the platen 19 and the pressure roller 33.

When the motor 23 starts rotating and rotates a predetermined amount M1 as shown in FIG. 11, that is, when the platen 19 and the press roller 33 grip the paper as shown in FIG. 12, the rotation of the motor 23 is stopped.

Then, the motor 23 is reversely rotated by a predetermined amount M2.
As a result, the platen 19 rotates in reverse and discharges the paper P.

By the way, due to the reverse rotation of the platen shaft 13, the gear 1
19 is also reversed, but since the ratchet 131 idles relative to the ratchet pawl 123, the gear 129
No drive is transmitted to the paper feed roller 58 and the sponge rollers 227L, 227R, which are stopped.

As a result, the paper P is bent between the platen 19 and the paper feed roller 58, and the leading edge of the paper is registered between the platen 19 and the pressure roller 33 due to the stiffness of the paper P.

Then, when the platen 19 rotates normally again, the paper P
The sheet is gripped by the platen 19 and the pressure roller 33, and the rear side of the sheet is backed up and fed by the sheet feed roller 58.

The gear 119 rotates further and the ratchet pawl 12
3 comes into contact with the inner peripheral surface of the cam 127,
The ratchet pawl 123 comes off the ratchet 131, and the drive is no longer transmitted to the gear 129.

However, since the paper P is held between the platen 19 and the pressure rollers 33 and 35, the paper P is pulled by the rotation of the platen 19.

Therefore, after the deflection of the paper P is absorbed, the paper feed roller 58 and the sponge rollers 227L, 22
7R rotates following the paper P.

When the motor 23 has rotated a predetermined amount M3, that is, at the printing start position of the paper P, the motor 23 is temporarily stopped, and the print head 29, which was located on the center side, is rotated.
is returned to the home position on the left side by moving the carriage 27, and printing is started. The motor 23 rotates one line each time printing for each line is completed.

The printed paper P is guided along the guide surface of the paper ejection guide 141 and is ejected by the paper ejection roller 241. The leading edge of the discharged paper is in contact with the manual feed guide 71 and the paper discharge frame 233, and the trailing edge is supported by the recessed portion of the conveyance guide 134.

In the case of continuous paper feeding, the above operation is repeated, and the paper P is sent out in a constant cycle regardless of the length.

According to the above embodiment, the following effects can be obtained.

(1) After the paper fed by the paper feed roller 58 is gripped between the platen and the presser roller 33, the paper is moved backward to form a sag and register, so that when the paper is gripped, , platen 1 rotating in the transport direction
The paper is fed between the pressure roller 9 and the pressure roller 33, so that the paper is smoothly gripped and the leading edge of the paper is not easily bent.

Furthermore, since the registration is performed by spitting out the paper held in the mouth to form a sag in the paper, the registration can be performed reliably.

(2) Drive the paper feed roller 58 to transfer the registered paper to the platen 19 and pressure roller 33.
Since the paper is fed between the two, the leading edge of the paper can be forcibly inserted into the pressure contact portion between the platen 19 and the pressure roller 33.

Therefore, if the degree of skew during sheet feeding is large, the degree of deflection of the paper during registration is different on the left and right sides, and the pressure force of the paper against the conveyance means is different on the left and right sides, it is difficult to grip the sheet again to the conveyance means. It is possible to prevent left and right deviations in timing and thereby ensure skew correction.

(3) After the motor 23 has rotated a predetermined amount M1 after the motor 23 starts rotating, the motor 23 is rotated in the opposite direction to register the paper P, so that the paper can be ejected without the need for a paper edge detection means such as a sensor; Can be resisted.

Therefore, this cueing method can be applied even to a printing device in which the printing unit 3 is not provided with a sensor for detecting the leading edge of the sheet held between the platen 19 and the pressure roller 33.

That is, cueing can be performed regardless of the format of the printing unit 3.

The present invention is not limited to the above-mentioned embodiment, and for example, the following modifications are possible.

(1) In the above embodiment, a printing device is shown in which the printing unit and the paper feeding unit are detachable, but the printing unit and the paper feeding unit may be integrated.

(2) In the embodiment described above, after the platen rotates and feeds the paper by the paper feed roller 58, the motor 23 is rotated by a predetermined amount M2 after rotating by a predetermined amount M1 to discharge the paper held between the presser roller 33 and the platen 19. However, a sensor may be provided at the tip of the pressure roller 33, and when this sensor detects the leading edge of the paper, the platen 19 may be reversed.

(3) As shown in FIG. 13, the paper conveyed along the guide 301 is moved to the platen 309 by two or more pressure rollers 303, 305, 307.
It may be pressed against.

In this case, once the paper has been held up to the pressure roller 305, it may be retreated and discharged, or once it has been held up to the pressure roller 307, it may be discharged.

(4) In the embodiment described above, the platen 19 is driven and the pressure rollers 33 and 35 are driven.
Pressure rollers 303, 3 as shown in FIG.
05, 307 may be driven, and the platen 309 may be driven.

Also, the platen 309 and pressure roller 30
3, 305, and 307.

(5) This invention is based on the platen 311 as shown in FIG.
is fixed, and the present invention can also be applied to a printing device in which paper guided by a guide 313 is fed to a printing position by rollers 315, 317, 319, and 321.

(6) This invention has a guide 323 as shown in FIG.
The paper guided by the roller 325
Platen 3 by 7,329,331,333
It can also be applied to a printing device that supplies data to 35 printing positions.

[Effects of the Invention] As explained above, according to the present invention, after the sheet sent out by the feeding means is held in the pressure contact portion of the first conveying means and the second conveying means, the sheet is fed. While the feeding means is stopped, the sheet is once retreated by the first and second conveying means and discharged from the pressure contact portion, and then the sheet is sent out again by driving the feeding means, The first and second conveying means are driven to hold the sheet in the pressure contact part, and after the sheet is conveyed a predetermined amount downstream from the pressure contact part in the sheet conveyance direction, the feeding means is stopped, and the sheet is stopped. 1. Since the sheet is sent to the printing position by continuing to drive the second conveyance means, the portion of the leading edge of the paper where the pressure contact force against the pressure contact portion of the conveyance means is weak is forced into contact with the pressure contact portion. It can be embedded.

Therefore, if the degree of skew during sheet feeding is large, the degree of sagging of the paper during registration is different between the left and right sides, and the pressing force of the paper against the transport means is different between the left and right sides, the gripping of the sheet by the transport means may occur. It is possible to prevent left and right deviations in timing and thereby ensure skew correction.

[Brief explanation of the drawing]

Figures 1 to 4 are diagrams showing the configuration of the printing unit, where Figure 1 is a cross-sectional view of the printing unit, Figure 2 is a longitudinal sectional view of the printing unit, and Figure 3 is a cross-section showing the pressure contact mechanism of the pressure roller. 4 are diagrams showing the structure around the print head. Figures 5 to 10 are diagrams showing the configuration of the paper feed unit. Figure 5 is a longitudinal sectional view showing the overall configuration of the paper feed unit, Figure 6 is a left side view of the area around the paper feed stacker, and Figure 7 is a diagram showing the structure of the paper feed unit. 8 is a right side view of the vicinity of the paper feed stacker, FIG. 8 is a partially cutaway plan view of the paper feed unit, and FIGS. 9 and 10 are diagrams showing the structure of the drive transmission mechanism. FIG. 11 is a timing chart for explaining the operation, and FIG. 12 is an explanatory diagram of the operation. FIGS. 13 to 15 are diagrams showing modifications of the present invention. 3... Printing unit, 19... Platen, 29
... Print head, 33, 35 ... Pressure roller, 101 ... Paper feed unit, 58 ... Paper feed roller, 241 ... Paper discharge roller.

Claims (1)

[Scope of Claims] 1. Printing is performed by feeding stacked sheets one by one by a feeding means, and placing the fed sheets between a first conveying means and a second conveying means that are pressed together. In a printing device that performs printing work by feeding the sheet to a position, the sheet fed by the feeding means is held in a pressure contact portion between the first conveying means and the second conveying means, and then the feeding means is moved. In the stopped state, this sheet is once retreated by the first and second conveyance means and discharged from the pressure contact part, and then the sheet is again driven by the feeding means and fed out, while the sheet is - Driving the second conveying means to grip the sheet in the pressure contact part, and stopping the feeding means after the sheet has been conveyed a predetermined amount downstream from the pressure contact part in the sheet conveyance direction; A sheet cueing method for a printing device, characterized in that the sheet is fed to the printing position by continuing to drive the second conveyance means. 2. In the sheet head finding method for a printing device according to claim 1, the first conveyance means is a platen, and the second conveyance means is a pressure roller. How to put it out. 3. The method for positioning a sheet in a printing apparatus according to claim 1, wherein the first conveyance means and the second conveyance means are rollers pressed against each other. How to put it out. 4. In the sheet cueing method for a printing device according to claim 1, the first conveyance means is driven by a drive source, and the second conveyance means follows the operation of the first conveyance means. A sheet cueing method for a printing device characterized by the following. 5. In the sheet cueing method for a printing device according to claim 1, the second conveyance means is driven by a drive source, and the first conveyance means follows the operation of the second conveyance means. A sheet cueing method for a printing device, characterized in that: