JP2789344B2 - Liquid jet recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid jet recording apparatus, and more particularly, to recording by causing ink droplets to fly and adhere to a recording medium in accordance with recording information. The present invention relates to a liquid jet recording apparatus provided with a conveying and holding means.

[Conventional technology]

Recording devices such as printers and facsimile machines can be classified into a thermal type, a wire dot type, a liquid jet type, and the like according to the recording method.

Of these, the liquid jet method (ink jet recording method)
Has at least one fine orifice (or nozzle)
Supplies ink to a recording head having an orifice, drives an energy generator provided in the orifice based on print data, applies pressure to the ink in the orifice, and causes the ink droplet to fly from the tip of the orifice. Is attached to a recording medium such as a plain paper or a plastic thin plate to form a dot pattern.

FIG. 8 is a perspective view of a recording section of a conventional liquid jet recording apparatus, and FIG. 9 is a schematic side view of the apparatus of FIG.

8 and 9, reference numeral 1 denotes a liquid jet head, 2
Is an urging member for urging the recording medium (plain paper, plastic thin plate, etc.) to the platen 3, 3 is a platen, 4 is a discharge roller for transporting the recorded recording medium, 5 is a discharge roller 4.
, A carriage on which the liquid ejecting head 1 is mounted, 7 a timing belt for reciprocating the carriage 6, 8 a sliding shaft for slidably holding the carriage 6, and 9 a feed roller 11. Driving motor, 10
Denotes a discharge recovery device; 11, a feed roller for supplying a recording medium to the platen 3; 12, a pinch roller for pressing the recording medium against the feed roller 11; 13, a paper pan disposed below the feed roller 11; , A paper guide for accommodating the discharged recording medium, 15 a recording medium, and 16 a motor serving as a drive source for moving the carriage 6.

In the above-described configuration, when recording is performed, the leading end of the recording medium 15 is inserted between the feed roller 11 and the paper pan 13, and the feed roller 11 is rotated to be sent to the recording start position. In this state, a print command is output and the liquid jet head 1
In addition to recording by flying ink droplets, the motor 16
Is driven to rotate the timing belt 7 to move the carriage 6. Each time one row of recording is completed, the feed roller 11 rotates and conveys the recording medium 15 by the row interval. At this time, the urging member 2 regulates the movement of the recording medium 15 so that the recording medium 15 does not rise from the platen 3.

Normally, the urging member 2 is in contact with the surface of the recording medium 15.

When printing is completed, the carriage 6 is returned to the home position, and the recording medium 15 is conveyed while being nipped between the discharge roller 4 and the bail roller 5.
It is sent up on 14.

Printing accuracy and printing quality in the liquid jet recording device
The closer the distance between the recording head and the recording medium, the better. Further, the more uniform the interval, the more uniform the printing result. This interval is about 0.3 mm to 2.5 mm, but advanced technology is required to stably maintain this interval at a small value. For this reason, conventionally, the urging member 2 is arranged close to the printing position and is arranged so that the recording medium does not float.

[Problems to be solved by the invention]

However, such a conventional liquid jet recording apparatus requires a certain time until the recording liquid (ink) absorbed on the recording medium is fixed. This time is not constant, but is limited by the time until the recording liquid evaporates, or varies depending on the time until the recording liquid is absorbed into the recording medium by capillary action. For this reason, when a back feed command is issued, the unfixed portion is sent between the platen and the urging member, and the unfixed ink is rubbed by the urging member, causing bleeding and flow, thereby deteriorating print quality. . This tendency increases as the humidity increases.

For this reason, conventionally, for the backfeed instruction,
The firmware on the recording device side has taken measures to prevent the function corresponding to the instruction from being executed, or to incorporate an alternative function. However, in this case, the printing result is different when using the conventional application software, and there is a problem that it takes a great deal of time to create a firmware for operating the recording device, which is inconvenient and inefficient. .

As one means for solving this problem, there is a method in which the position of the urging member is kept away from the printing position to provide a time margin for a slight back feed. However, in this case, the paper path becomes longer, and it is necessary to separately provide a means for uniformly pressing the recording medium against the platen, which causes an increase in the size and complexity of the apparatus.
High prices are inevitable.

The present invention has been made in view of such a conventional technique, and an object of the present invention is to prevent contamination due to rubbing of an unfixed recording liquid at the time of a back feed, and to achieve a high level not only at a front feed but also at a back feed. An object of the present invention is to provide a liquid ejecting recording apparatus that can obtain conveyance accuracy and can realize high-precision paper feeding at the time of next recording after back feed.

[Means for solving the problem]

According to a first aspect of the present invention, in order to achieve the above object, an image to be formed on an object to be recorded by ejecting recording droplets from an orifice of a recording head toward an object to be recorded disposed on a platen in accordance with recording information. In a liquid jet recording apparatus that performs droplet recording on the recording medium while performing recording and front feed or back feed of the recording medium, the recording droplets adhere to an upstream side of the recording head in a recording medium transport direction. An urging member arranged to press the surface of the recording medium to be pressed, and urging the recording medium against the platen;
A feed roller that is arranged rotatably forward and backward on the upstream side in the recording medium transport direction of the recording head and that front-feeds or back-feeds the recording medium according to the forward / reverse rotation; A pinch roller disposed upstream of the recording medium transport direction to press the recording medium against the feed roller during front feed and back feed of the recording medium, and the back feed of the recording medium by the feed roller The urging member is moved away from the surface of the recording medium in conjunction with the recording medium, and after the recording medium stops and the back feed ends, the surface of the recording medium is not changed until the next recording starts. And a driving unit for returning the urging member to a position where the urging member can be pressed.

According to a second aspect of the present invention, in addition to the first aspect, the driving unit separates the urging member from the surface of the recording medium when the back feed is performed within a set time. Accordingly, it is possible to provide a liquid jet recording apparatus which can prevent unnecessary movement of the urging member, prevent wear, and reduce occurrence of troubles and the like.

[Action]

With this configuration, the urging member is separated from the surface of the recording medium during back feed, and a certain space is formed between the urging member and the recording medium. The recording liquid does not adhere to or be rubbed against the urging surface of the urging member, and therefore does not lower the print quality.

Furthermore, since the urging member and the pinch roller cooperate,
High conveyance accuracy is obtained not only in the front feed but also in the back feed, and high-precision paper feeding at the time of the next recording after the back field can be realized.

Further, only when the back feed is performed before the completion of the fixing, the urging members are separated from each other, so that useless operation of the driving means can be eliminated.

With this configuration, even after recording, the urging member can be separated only when the back feed is performed before the elapse of the set time. By setting the set time to a time sufficient for the recording liquid to complete fixing, the urging member can be driven only when necessary.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to FIGS.

FIG. 1 is a schematic side view showing one embodiment of a liquid jet recording apparatus according to the present invention. In this embodiment, the same components as those of the conventional device shown in FIG. 9 are denoted by the same reference numerals, and the description thereof will not be repeated below.

In FIG. 1, reference numeral 17 denotes a release arm for separating the upper portion of the urging member 2 from the surface of the recording medium 15, reference numeral 18 denotes a regulating pin fixed to a chassis or the like to regulate the rotation of the arm 17, and
Is a one-way clutch mounted coaxially with the axis of the feed roller 11. One end of the arm 17 has the urging member 2
The other end is eccentrically mounted on a part of the one-way clutch 19 and is rotatably supported. The one-way clutch 19 does not become a load on the feed roller 11 when the feed roller 11 rotates clockwise, and rotates as a load when the feed roller 11 rotates counterclockwise, and rotates integrally with the feed roller 11. The arm 17 is driven.

In the above configuration, when the recording medium 15 is inserted onto the paper pan 13, the recording medium 15 is pressed by the pinch roller 12 and closely contacts the feed roller 11 according to the clockwise rotation of the feed roller 11. While being fed front.

At this time, even if the feed roller 11 rotates, the one-way clutch 19 does not rotate, so that the arm 17 is not driven and remains stopped. Since the arm 17 is stopped,
The urging member 2 urges the recording medium 15 toward the peripheral surface of the feed roller 11 to prevent the paper from rising.

Next, when the feed roller 11 rotates counterclockwise for back feed, the one-way clutch 19
(Clutch-on), and both rotate integrally. In this process, the arm 17 moves in the length direction according to the amount of rotation of the one-way clutch 19, and separates the urging member 2 from the surface of the recording medium to create a space between the arm 17 and the surface of the urging member 2. . The lower end surface of the arm 17 contacts the regulating pin 18 at a certain amount of rotation, and this state is maintained, and the separating operation of the urging member 2 is stopped. If the back feed has not been completed at this point, the feed roller 11 further rotates counterclockwise, but the one-way clutch 19 has a friction structure, so it slips with respect to the feed roller 11 and only the feed roller 11 Keeps spinning.

By forming a space between the recording medium 15 and the urging member 2, even if the recording liquid (ink) attached to the recording surface is not fixed, the recording liquid is rubbed by the urging member 2. The print quality is maintained.

FIG. 3 shows another embodiment of the present invention, which is characterized in that a plunger 20 is used in place of the one-way clutch 17. The plunger 20 is provided so that an urging force in a direction opposite to the urging force of the elastic body 27 for urging the urging member 2 toward the recording medium can be applied to the urging member 2. Further, since the movable range of the armature of the plunger 20 is determined, the regulating pin 18 is unnecessary.

Normally, the plunger 20 is demagnetized, and the urging member 2 is in contact with the recording medium 15 by the urging force of the elastic body 27. At the time of back feed, the plunger 20 is excited,
The urging member 2 is urged in a direction away from the feed roller 11, and separates from the normal position. Thereby, the recording medium 15
The contact between the printing surface and the urging member 2 can be avoided, and the printing quality can be maintained. When the back feed ends,
The plunger 20 is demagnetized, and the biasing member 2 is pulled by the elastic body 27 and pivots to a position where it contacts the recording medium 15.

FIG. 4 shows a modification of the embodiment of FIG.
A detection gear 21 is mounted on the side surface of 11 and a detection member 22 is fixedly installed on the chassis side so as to face the detection gear 21.

In this configuration, when the back feed is performed, the rotation of the feed roller 11 at that time is detected from the movement of the detection gear 21. With such a configuration, even when the feed roller 11 reversely rotates due to an external force and the back feed is performed, the rotation can be detected and the plunger 20 can be controlled.

In addition to the configuration example shown in FIG. 3, for example, there are configurations shown in FIGS. 5, 6, and 7. In either case, the movement of the recording medium 15 can be detected with high accuracy.
FIG. 5 shows a gear mechanism 23 for providing a rack 24 at the base of the urging member 2 so as to be movable on the chassis S and for driving the rack 24 forward and backward in the longitudinal direction according to the rotation of the feed roller 11.
Is provided.

In this configuration, when the feed roller 11 rotates in the backward direction, the rack 24 moves to the left in the figure by rotation of the gear mechanism 23, and operates so as to separate the urging member 2 from the surface of the recording medium.

FIG. 6 shows a ratchet mechanism 25 provided integrally and coaxially with the feed roller 11, and an arm 26 having a pin engageable with the ratchet mechanism 25 is provided on the biasing member 2. . When the feed roller 11 rotates clockwise, the ratchet mechanism 25 and the arm 26 are not engaged, and no pressing force is applied to the urging member 2. On the other hand, when the feed roller 11 rotates counterclockwise, the teeth of the ratchet mechanism 25 are engaged with the arm 26, and the biasing member 2 is separated from the surface of the feed roller 11 against the biasing force of the elastic body 27. Move to.

FIG. 7 shows a housing 28 of a one-way clutch.
The cam-shaped part 29 is provided on the
29 rotates counterclockwise together with the feed roller 11 so that the urging member 2 can be pressed. The cam-shaped portion 29 is fixed at the position when the cam-shaped portion 29 abuts on the regulating pin 18, and is returned to the normal position by rotating the feed roller 11 clockwise, and the urging member 2 can also perform the urging operation.

The movement of the urging member 2 is necessary because the recording liquid on the surface of the recording medium 2 is not dried, and when the back feed is performed after fixing of the recording liquid (after drying). Need not move the urging member 2. Therefore, the sequence in which the urging member 2 is not operated for the back feed after a lapse of a fixed time (a time equal to or longer than the time until the completion of fixing) after printing is performed can be achieved.

Furthermore, since the fixing time is greatly affected by the surrounding environment, these environmental conditions are detected to determine the optimum fixing time, and the operation is not performed at a longer interval, or whether or not the fixing is performed. It is possible to use a means for providing a sensor for determining, for example, preventing the urging member from operating when fixing is determined by the sensor.

In addition, during the back feed, if the operation of moving the urging member in the same direction as the recording medium feeding direction to prevent the printing stain is performed, the back feed is completed and the recording is performed. When the operation is performed again, the urging member may return to the initial set position and urge the recording medium again.

〔The invention's effect〕

As is apparent from the above description, according to the first aspect of the present invention, the recording medium is ejected from the orifice of the recording head toward the recording medium disposed on the platen in accordance with the recording information. In a liquid jet recording apparatus that performs droplet recording on the recording medium while performing image recording performed on the recording medium and front feed or back feed of the recording medium, the recording liquid is disposed upstream of the recording head in the recording medium transport direction. An urging member arranged to press the surface of the recording medium to which the droplets adhere, and urging the recording medium against the platen; A feed roller that is rotatably disposed to front-feed or back-feed the recording medium in accordance with the forward / reverse rotation; and a feed roller that is disposed upstream of the urging member in the recording medium transport direction, and A pinch roller for pressing the recording medium against the feed roller at the time of front feed and back feed of the recording medium, and the urging member for recording the recording medium in conjunction with the back feed of the recording medium by the feed roller; After the recording medium stops and the back feed ends, the urging member is returned to a position where the surface of the recording medium can be pressed before the next recording starts, while separating the recording medium from the surface of the recording medium. And a driving unit for performing the front feed and the back feed, while preventing contamination due to the rubbing of the unfixed recording liquid droplets, and by the cooperation of the urging member and the pinch roller,
High conveyance accuracy can be obtained not only in front feed but also in back feed, and high-precision paper feed can be realized for the next recording after back feed, and therefore high-speed image recording even after back feed The present invention provides a liquid jet recording apparatus which can be performed with high accuracy and quietly.

According to the invention of claim 2, in addition to the configuration of claim 1,
Since the driving unit is configured to separate the urging member from the surface of the recording medium when the back feed is performed within a set time, the driving unit may further move the urging member unnecessarily. Therefore, it is possible to obtain an effect that wear can be prevented and occurrence of a failure or the like can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing one embodiment of a liquid jet recording apparatus according to the present invention, FIG. 2 is a schematic side view showing a back feed mode of the embodiment of FIG. 1, and FIG. FIG. 4 is a schematic side view showing another embodiment of the invention, FIG. 4 is a schematic side view showing a modification of FIG. 3, and FIGS. 5, 6, and 7 are three examples of other embodiments. FIG. 8 is a perspective view showing a conventional liquid jet recording apparatus, and FIG. 9 is a schematic side view of the apparatus shown in FIG. DESCRIPTION OF SYMBOLS 1 ... Recording head (liquid ejecting head), 2 ... Urging member, 3 ... Platen, 6 ... Carriage, 11 ... Feed roller, 15 ... Recording medium, 17 ... Release arm, 18 ...
... Regulatory pin, 19 ... One-way clutch, 20 ... Plunger, 21 ... Detection gear, 22 ... Detection member, 23 ... Gear mechanism, 24 ... Rack, 25 ... Ratchet mechanism, 26 ...
Arm, 27 ... elastic body.

Claims (2)

(57) [Claims] An image recording performed on a recording medium by ejecting a recording liquid droplet from an orifice of a recording head toward a recording medium disposed on a platen in accordance with recording information, and a front feed of the recording medium. Alternatively, in a liquid jet recording apparatus that performs droplet recording on the recording medium while performing back feed, the surface of the recording medium to which the recording liquid droplets adhere is pressed upstream of the recording head in the recording medium transport direction. And an urging member for urging the recording medium against the platen, and disposed so as to be rotatable forward / reversely on the upstream side of the recording head in the direction of conveyance of the recording medium. A feed roller for front-feeding or back-feeding the recording medium in response to the recording medium; A pinch roller for pressing the recording medium against the feed roller at the time of feeding, and separating the urging member from the surface of the recording medium in conjunction with the back feed of the recording medium by the feed roller. And a driving unit for returning the biasing member to a position where the surface of the recording medium can be pressed before the next recording starts after the recording medium stops and the back feed ends. A liquid jet recording apparatus characterized by the above-mentioned. 2. The liquid according to claim 1, wherein the drive unit separates the urging member from the surface of the recording medium when the back feed is performed within a set time. Injection recording device.