JPH04105969A - Apparatus feeding sheet material - Google Patents

Abstract

PURPOSE:To set a leading end blank to the min. by arranging a paper pressing plate on the downstream side of a platen to perform printing in such a state that the levitation of the leading end of paper is prevented. CONSTITUTION:A carriage 18 loaded with a head 19 stands by on the lateral side of a platen 11. The sheet material 2 fed to the platen 11 becomes a state curled on the leading end side thereof to be levitated as shown by a two-dot broken line in many cases. Then, when it is judged that the sheet material 2 is fed to a position where the leading end of the sheet material 2 is pressed at the almost central part thereof in the lateral direction of a paper pressing plate 21 by counting the number of pulses of the pulse feed of a feed roller 7 by a count means D, a current is supplied to a solenoid and a gear lever 22 is rotated by attraction force and the paper pressing plate 21 is rotated through a gear 20a to press the leading end of the sheet material 2 to the platen 11. Since the carriage 18 loaded with the head 19 moves along a rail 17 in this state and the printing of one line can be carried out, the blank at the leading end part of the sheet material can be set to the min.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sheet material conveying device in, for example, an inkjet printer.

[Conventional technology]

Conventionally, sheet material conveying devices installed in inkjet printers and the like include a pick-up roller that feeds out the sheet materials loaded in a cassette one by one, and a pair of conveyors that sandwich the fed sheet materials and send them onto a platen. Some printers generally include a roller and a pair of discharge rollers for transporting the printed sheet material from the platen.

In this sheet material conveyance device, a sheet material sent out by a pickup roller is held between a conveyance roller and a paper ejection roller before and after a platen, and a carriage equipped with a head scans and prints.

At this time, the sheet material is fed by a fixed amount by each roller and printed in sequence, and when printing is completed, it is discharged by a paper discharge roller.

[Problem that the invention is trying to solve]

However, in this type of sheet conveyance device, printing starts after the sheet paper is sandwiched between the conveyance rollers and paper ejection rollers arranged before and after the platen, so there are many blank areas on the leading edge of the sheet material that cannot be printed. There was a problem that this occurred.

Therefore, some printers start printing before the leading edge of the sheet paper is pinched by the paper ejection rollers, but with these types, the leading edge of the sheet material may curl depending on the environment such as ambient temperature and humidity, or the recording condition. If the sheet floats above the platen and comes into contact with the head, contaminating the sheet material, or if it is curled and fed over the platen, it can ride on the ejection roller.
Problems such as folded corners of sheet paper may occur.

Additionally, in order to prevent the leading edge of the sheet paper from floating, some platens are equipped with electrostatic suction devices or suction devices using pumps, but these suction/suction devices have problems such as increased costs and increased device size. was there.

[Means to solve the problem]

The sheet material conveying device of the present invention is characterized in that a paper presser plate is disposed downstream of the platen and is displaced to push the sheet material toward the platen.

Further, the paper pressing plate may be rotated to press the sheet material against the platen.

[Effect]

The sheet material conveyed onto the platen is pressed against the platen by a paper pressing plate provided on the downstream side of the platen to prevent it from lifting up, thereby making it ready for printing and reducing the margin area that cannot be printed.

〔Example〕

FIGS. 1 and 2 show embodiments of the present invention, and are a sectional view and a perspective view, respectively. A pickup roller 5 separates the topmost sheet of paper 2 loaded in the cassette 1, feeds it, and sends it out between the upper guide 3 and the lower guide 4.
is provided. When the pickup roller 5 rotates once, it stops in the state shown in the figure and loses its conveying force, but before that, the leading edge of the sheet paper is clamped between the upper conveying roller 6 and the lower conveying roller 7, and from then on, this conveying roller 6.7. The upper conveyance roller 6 is pressurized by a spring 10 via a pressure plate 9 having a shaft 8 as a fulcrum, and the lower conveyance roller 7
It is designed to rotate passively with the rotation of. When the sensor S determines that the sheet material 2 has been sent, the lower conveyance roller 7 starts rotating and feeds the sheet material 2 by pulse feeding.

An upper paper discharge roller I2 and a lower paper discharge roller 13 are disposed downstream of the platen 11, and sandwich the sheet paper 2 being fed on the platen 11. The paper ejection upper roller 12 is the shaft 1
It is pressurized by a spring 16 via a pressure plate 15 with 4 as a fulcrum, and is configured to rotate passively as the lower paper discharge roller 13 rotates. Furthermore, since the circumferential speed of the lower paper ejection roller 13 is set to be increased by several percent compared to the circumferential speed of the lower transport roller 7, the sheet paper 2 on the platen 11 is always given appropriate tension. It is designed so that it does not sag.

A carriage 18 is provided above the platen 11 and is movable along a rail 17 provided in a direction intersecting the conveyance direction of the sheet paper 2. A head 19 as a recording means is mounted on the carriage 18. There is.

Next, the paper presser section 20, which is the main part of the present invention, will be explained.

A gear 20a is rotatably provided coaxially with the upper paper discharge roller 12, and a paper press plate 21 that can come into contact with the upper surface of the platen 11 is fixed to the gear 20a. A rotatably provided gear lever 22 meshes with the gear 20a.

A return spring 23 and a solenoid 24 are attached to the gear lever 22 from opposite sides, and when the solenoid 24 is not powered, the return spring 23 causes the paper press plate 21 to stand by at a position away from the platen 11. When power is supplied to the solenoid 24, the gear lever 22 rotates to rotate the gear 20a and press the paper pressing plate 21 against the platen 11.

The operation related to the above configuration will be explained.

The topmost sheet of the sheet material 2 loaded in the cassette 1 is sent out by a pickup roller 5.

The sent-out sheet material 2 is guided between the upper kite 3 and the lower guide 4, is held between the upper conveyance roller 6 and the lower conveyance roller 7, and is further conveyed onto the platen 11.

At this time, the carriage 18 carrying the head 19 is waiting on the side of the platen 11. The sheet paper 2 fed onto the platen 11 is often curled and raised at its leading edge, as shown by the two-dot chain line in FIG. Therefore, it is determined by counting the number of pulses of the conveying roller 7 to determine when the sheet material 2 has been fed to a position where the leading edge of the sheet material is pressed at approximately the center in the width direction of the paper presser plate 21. Then, power is supplied to the solenoid, and the attraction force rotates the gear lever 22, and the gear 20a is rotated.
The paper press plate 21 rotates through the platen 11 to press the leading end side of the sheet material 2 onto the platen 11.

In this state, the carriage 18 carrying the head 19 can scan along the rail 17 and print one line, so the margin at the leading edge of the paper can be set to the minimum. After one line of printing is completed, the sheet material 2 is fed a fixed amount to print the next line. The paper can be smoothly caught between the upper paper roller I2 and the lower paper discharge roller 13. In other words, if the paper presser plate 21 is opened, the leading edge of the sheet material will rise again, and if it is conveyed as it is, it may get stuck on the paper ejection upper roller I2, or problems such as the paper corner folding may occur. This can be prevented by the holding plate 21.

After it is determined by counting the number of pulses of the conveying lower roller 7 that the sheet paper 2 has been pinched between the upper sheet discharging roller 12 and the lower sheet discharging roller 13, the paper presser plate is no longer necessary, so the head 19 when the solenoid 2 returns to the standby position.
4 is released, and the paper press plate 21 is released by the return spring 23.
is retracted and held at a position where it does not interfere with the scanning of the carriage 18.

When the printing of the entire area of the paper is completed by repeating the fixed amount of feeding of the paper and the printing of one line by the head 19, the paper ejection roller 12.1
3, the sheet material 2 is discharged onto the tray 25, and the series of printing operations is completed.

Note that when using a plastic sheet or the like on which ink dries slowly as recording paper, by selecting a mode that does not pull the solenoid 24 from the beginning, the paper presser plate 21 will not be contaminated with undry ink. . In addition, the upper paper ejection roller is configured to be divided in the axial direction as proposed in Japanese Patent Application No. 1-114531, and a part of the upper ejection roller is rotated only in the printing area so that it comes into contact with the lower paper ejection roller. You can respond by canceling the .

Setting of this mode is performed as follows.

The switch a is operated according to the material of the sheet material 2, and the control device solenoid 2 is operated based on the operation signal from the switch.
Control 4. That is, in the case of a plastic sheet, no power is supplied to the solenoid 24 and the paper press plate 21 is released.

Alternatively, the sensor C determines whether or not light passes through the material of the sheet material 2, and the control device controls the solenoid 24 based on the determination signal.

3 to 5 show other embodiments of the present invention, and since only the structure of the paper presser 26 differs from the embodiment shown in FIG. 1, only that portion will be described in detail.

A shaft 27 is rotatably provided coaxially with the upper paper discharge roller 12, and a paper pressing plate 28 is fixed to the shaft 27.

Further, the shaft 27 is provided with a torsion coil spring 29, which always urges the paper press plate 28 in the direction of arrow A in FIG. A gear 30 is provided at the end of the shaft 27,
Gear 30 meshes with gear 31. A pin 32 is provided on the side surface of the gear 31. A lever 33 is provided on the outside of the gear 32, and when the lever 33 engages with the pin 3 of the gear 32, the gear 30 and the paper press plate 28 are removed.
is held at a predetermined position, and in this position, the paper presser plate 28 is open to the platen 11, and furthermore, the paper presser plate 28 is rotatable only in the direction of arrow B in FIG.

The carriage 18 has a roller 3 as a suppressing means for riding on the upper surface of the paper press plate 28 and pressing the paper press plate 28 against the platen 11 when the carriage 18 moves onto the platen 11.
4 are provided. Also, a roller 3 is provided on the paper press plate 28.
A sloping portion 35 is formed at the longitudinal end so that 4 can easily climb up.

The operation related to the second configuration will be explained below.

As shown in FIG. 4, the sheet material 2 sent onto the platen 1 can slip under the paper press plate 28 because the paper press plate 28 is in an open state even if the leading end side is curled. . Then, as in the previous embodiment, when the sheet material 2 is fed to a predetermined position, the carriage 18 that was waiting on the side of the platen 11 moves along the rail 17.
Accordingly, the roller 34 rides on the paper pressing plate 28 and rolls. As a result, as shown in FIG. 5, the sheet material 2 is pressed onto the platen 11 by the roller 34, and the leading end side of the sheet material 2 is pressed down to ensure a good printing condition. Then, printing is sequentially performed on the sheet material 2.

Furthermore, when using a plastic sheet or the like on which ink dries slowly as the recording paper, by operating the lever 33 in the direction of arrow C in FIG.
9, the sheet material 2 is evacuated to the position indicated by the two-dot chain line in FIG.
You can avoid contact with.

In the above embodiment, the paper presser plate is rotated, but it may be moved vertically in parallel.

Further, the sheet material conveyance device of the present invention is preferably combined with an inkjet recording type recording means.

The inkjet recording method includes a liquid ejection port for ejecting recording ink liquid as flying droplets, a liquid flow path communicating with the ejection port, and a part of this liquid flow path. and ejection energy generating means for providing ejection energy for causing the ink liquid to fly. The ejection energy generating means is then driven in accordance with the image signal to eject ink droplets and record an image.

As the ejection energy generation means, for example, a method using a pressure energy generation means such as an electromechanical transducer such as a piezo element, a method in which electromagnetic waves such as a laser are irradiated and absorbed by the ink liquid to generate heat, and the ink is ejected by the action of the heat generation. There is a method using an electromagnetic energy generating means that causes the ink to flow, or a method using a thermal energy generating means that heats the ink liquid using an electrothermal converter and ejects the ink. Among these methods, the method of ejecting ink using a thermal energy generating means such as an electrothermal converter is capable of high-resolution printing because liquid ejection ports can be arranged in a high density, and the print head is compact. It is suitable because it can also be

Here, the serial bubble jet recording method will be briefly explained.

FIG. 8 is an explanatory diagram of an exploded configuration of the recording head (2) constituting the recording means, and FIGS. 9(a) to (g) are explanatory diagrams of the bubble jet recording principle.

In Fig. 8, ■a is a heater board, and an electrothermal converter (discharge heater) ■b and an electrode ■C made of aluminum or the like that supplies power to this are formed and arranged on a silicon substrate. has been done. It is constructed by adhering to this heater board (a) a dot plate (e) having a partition wall for partitioning a recording liquid path (nozzle) (d). Furthermore, an ink cartridge for supplying ink to the recording head (2) is replaceably attached to a predetermined position of the apparatus.

The ink supplied from the ink cartridge through the conduit is filled into the common liquid chamber (g) in the recording head (■) through the supply port (f) provided on the top plate (e), and is supplied to each nozzle from this common liquid chamber (g). ■ Guided into d. These nozzles (d) are formed with ink ejection ports (h), and the ink ejection ports (■) are formed in these nozzles (d).
h are formed at a predetermined pitch in the sheet conveying direction, facing the recording sheet of the recording head (2).

The recording head (2) having this configuration is mounted on a reciprocally movable carriage, and recording is performed by ejecting and flying ink from the recording head (2) in synchronization with the movement of the carriage.

Here, the principle of ink flying in the bubble jet recording method will be explained with reference to FIGS. 9(a) and 9(b).

In a steady state, as shown in FIG. 9(a), the surface tension and external pressure of the ink (2) filled in the nozzle (2) are balanced on the ejection port surface. When the ink (2) is to be ejected in this state, the electrothermal converter (2) in the nozzle (2) is energized to cause the ink in the nozzle (2) to rapidly rise in temperature beyond nucleate boiling. Then, as shown in FIG. 9(b), the ink adjacent to the electrothermal transducer (b) is heated to produce microbubbles, and the ink in the heated area is vaporized to cause film boiling, resulting in As shown in FIG. 9(c), the bubble (2) grows rapidly.

When the bubble (2) grows to its maximum size as shown in FIG. 9(d), an ink droplet is pushed out from the ejection opening in the nozzle (2). Then, when the energization to the electrothermal converter b is finished, the ninth
As shown in Figure (e), the grown bubbles ■ are cooled and contracted by the ink ■ in the nozzle ■d.
The contraction causes ink droplets to fly from the ejection port. Furthermore, as shown in FIG. 9(f), the ink comes into contact with the surface of the electrothermal converter 05 and is rapidly cooled, so that the bubbles (2) disappear or shrink to an almost negligible volume. When the bubble (2) contracts, ink is supplied from the common liquid chamber (2) g by capillary action into the nozzle (2), as shown in FIG. 9(g), in preparation for the next energization.

Therefore, an ink image is recorded on the recording sheet by reciprocating the carriage and energizing the electrothermal transducer (b) in accordance with the image signal in synchronization with this movement.

〔Effect of the invention〕

As described above, by arranging the paper press plate on the downstream side of the platen and performing printing while preventing the leading edge of the paper from floating, it is possible to set the leading edge margin to a minimum.

Furthermore, since there is no need to provide an electrostatic adsorption device or a suction device using a pump on the platen, there is no need to increase costs or increase the size of the device.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing one embodiment of the present invention, and FIG. 2 is a perspective view showing one embodiment of the present invention.
3 is a perspective view of another embodiment of the present invention, FIGS. 4 and 5 are partial sectional views showing the operating state of the paper press plate, and FIGS. FIG. 7 is a block diagram of mode setting, FIG. 8 is an exploded perspective view of the recording head, and FIGS. 9(a) to (g) are illustrations of the bubble jet recording principle. 2... Sheet material 6.7... Conveyance roller 11... Platen 12.13... Paper ejection roller 18... Carriage 19... Head 21.28... Paper press plate 34... Roller (pressing means)

Claims (6)

[Claims] (1) In a sheet material conveying device for transporting sheet material onto and from a platen for printing by a recording means, a paper presser plate that is displaced and presses the sheet material against the platen is disposed on the downstream side of the platen. A sheet material conveying device characterized by the following. (2) The recording apparatus according to claim 1, wherein the recording means includes an inkjet head that performs recording by ejecting ink in response to a signal. (3) the recording means energizes the electrothermal transducer according to the signal;
The recording apparatus according to claim 2, further comprising an inkjet head that performs recording by ejecting ink using thermal energy generated by the electrothermal converter. (4) the recording means energizes the electrothermal transducer according to the signal;
4. The recording apparatus according to claim 3, further comprising a bubble jet head that performs recording by ejecting ink from an ejection port by the growth of bubbles generated by heating exceeding film boiling by the electrothermal converter. (5) The sheet material conveying device according to claim (1), wherein the paper pressing plate is rotatably provided and rotates to press the sheet material against the platen. (6) In a sheet material conveying device for transporting sheet material onto and from a platen for printing by scanning a carriage equipped with a head, a rotatable paper press plate is disposed on the downstream side of the platen, and the carriage 1. A sheet material conveying device comprising a pressing means for rotating a paper pressing plate and pressing the sheet material against a platen by movement of the sheet material conveying device.