JP2876748B2 - Printer's recording paper transport device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a recording paper transport device for a printer.

[Related Art] A recording paper transporting device of a conventional printer will be described below by taking an ink jet printer as an example.

In an ink-jet printer, various inconveniences occur when a recording paper or other recording medium rises on a platen arranged at a predetermined interval facing a recording head.
For example, printing smear due to contact between the recording head and the recording paper, damage to the recording head, deterioration of the printing quality due to a change in the interval between the recording head and the recording paper, and the like occur.

Therefore, in a conventional ink jet printer, in order to bring the recording paper into close contact with the platen, a first transport unit that transports the recording paper at a predetermined speed and a second transport unit that is separated in the traveling direction of the recording paper are provided. The feeding force of the recording paper in the second conveying unit is made smaller than the feeding force of the recording paper in the first conveying unit, and the conveying speed in the second conveying unit is set to be higher than the conveying speed in the first conveying unit. ing. With this configuration, the transport speed of the recording paper is determined by the first transport unit, and a constant tension is applied to the paper between the first transport unit and the second transport unit. The recording section is disposed between the first transport section and the second transport section to prevent the recording paper from rising in the recording section.

As shown in FIG. 6, a first example of a conventional second transport unit for satisfying the above-described transport conditions is a drive roller having a peripheral speed greater than the transport speed of the first transport unit and having a predetermined friction coefficient. Ten
1 and a press roller 10 for pressing the recording paper against the drive roller 101
It consists of two. The press roller 102 is rotatably held by a press lever 103 and is urged by a spring member 105 onto the recording paper.

In addition, as a second example, there is a mechanism that also drives the pressing roller 102. As shown in FIG. 7, this mechanism holds both ends of a pressing roller driving shaft 114 to which a plurality of pressing rollers 112 are fixed so as to be rotatable by a pressing roller shaft lever 113, and holds the pressing roller 112 on a recording paper by a spring member 115. I was energizing.

[Problems to be Solved by the Invention] However, the above-described conventional technology has the following problems.

First, in the first example, since the pressing roller 102 shown in FIG. 6 is a driven roller, a rotation defect is caused by abrasion or the like, and printing stains are generated. Further, the number of components of the mechanism is large, which has contributed to an increase in cost.

In the case of using the method of driving the pressing roller 112 shown in FIG. 7 as in the second example, the number of components increases compared to the first example, which further increases the cost. In addition, it is difficult to press the plurality of press rollers 112 with the same force, and it is not possible to convey the recording paper straight with high precision, so accurate output can be obtained when printing graphics on cut paper. Absent. Presser roller 112
Is a pressing roller or the like having a knurl on the peripheral surface, the printing surface is damaged. Further, both the first and second examples have a problem that the ink is transferred from the jaws to the rollers 101 and 111 on the other side and the back surface of the recording paper becomes dirty.

Therefore, the present invention solves such a problem, and an object of the present invention is to make it possible to convey a recording sheet straight and obtain high-precision printing at a low cost, and furthermore, to record an image in an ink jet printer or the like. It is an object of the present invention to provide a recording paper transport device of a new printer for preventing the contamination of the value paper.

[Means for Solving the Problems] In a recording paper transport device of a printer according to the present invention, a thin bowl-shaped thin material made of a pair of materials is provided on one of a pair of roller shafts disposed substantially parallel to each other across a recording transport path. The rollers are arranged with their openings facing each other and spaced apart from each other in the axial direction. On the other hand, a disk-shaped roller is disposed radially inward of the outer periphery of the thin bowl-shaped roller. And, it is arranged so as to be located between the thin bowl-shaped rollers in the axial direction.

Further, the disk-shaped roller is formed as a thin roller provided with a knurl on the circumference.

[Operation] According to the above configuration of the present invention, when the recording medium is conveyed while being nipped, the thin bowl-shaped elastic member is bent and the outer periphery of the elastic member is pressed against the recording medium. As a result of the rotation, a constant conveying force is applied to the recording medium, and the pressing force in the direction perpendicular to the traveling direction of the recording medium becomes uniform, so that the recording medium can move straight forward accurately. In addition, since the elastic member is attached at a position slightly apart in the axial direction of the roller having a knurl in the circumference, the ink adhered to the roller does not transfer to the thin bowl-shaped elastic member, thereby preventing the recording medium from being stained. .

Example An example illustrated below will be described.

FIG. 1 is a diagram showing the entire configuration of a recording paper transport processing apparatus of an ink jet printer according to an embodiment of the present invention.

This recording paper transport device is roughly divided into a paper feed unit 10 having a fanfold paper feed path and a cut sheet feed path,
It comprises a paper transport unit 20 provided in the recording and writing unit, and a discharge unit 60 for discharging the recording paper S while drying it.

A gate roller 21 coupled to a driving force transmission mechanism (not shown) is disposed on the upper side of the paper transport unit 20 so as to sandwich the traveling path of the carriage 80. In addition, the driven roller 22 is provided at a position immediately below the platen 46 on the lower side. The driven roller is configured to rotate at the same peripheral speed as the gate roller 21 via a paper feed belt 23 suspended between the driven roller and the gate roller 21.

Reference numeral 29 denotes a paper pressing roller lever that is pivotally supported above the gate roller 21 with a fulcrum 31 as a fulcrum. This paper press roller lever 29 is used when the recording paper S fed here is a cut sheet or an envelope mainly fed by the frictional force between the paper feed belt 23 forming the outer periphery of the gate roller 21 and the paper press roller 32. The contact pressure of the paper pressing roller 32 with respect to the paper feed belt 23 can be changed depending on whether the paper is fanfold paper mainly fed by a tractor (not shown). In this embodiment, the first transport unit is constituted by the gate roller 21, the paper feed belt 23, and the paper pressing roller 32.

37 is a paper bail which comes into contact with and separates from the paper feed belt 23 on the driven roller 22. The paper bail 37 is configured such that a plurality of disk-shaped knurled rollers provided with knurls on the periphery are fixed to the shaft 36 at intervals. Paper bail lever 38 that supports this paper bail 37 at one end
The base end is fixed to a support shaft 39 supported on the lower side of the driven roller 22. The trailing edge of the recording paper S is a gate roller.
Immediately before passing over the paper 21, the paper bail 37 is pressed against the paper feed belt 23 to feed the recording paper S.

In the discharge section 60, an intermediate discharge roller shaft 62 and a rotating shaft 65 are provided on the lower side adjacent to the driven roller 22. An intermediate discharge roller shaft 62 disposed below the discharge guide plate 61 has a thin cylindrical elastic member as shown in FIG.
63 are fixed at intervals. Also the rotating shaft 65
A thin plate-shaped roller 66 having a knurl is rotatably attached to the elastic member 63 so as to be slightly displaced in the axial direction with respect to the elastic member 63 and slightly overlap in the radial direction.
The second transport section is fixed by the elastic member 63 and the roller 66 so that the recording sheet S can be sandwiched and discharged without applying excessive force to the wet recording sheet S.
Incidentally, the intermediate discharge roller shaft 62 is a drive shaft.

Reference numerals 68 and 71 denote a pair of paper discharge roller shafts disposed on the lower side of the hot air drying unit 90. One of the paper discharge roller shafts 68 disposed below the paper discharge guide plate 61 has a structure shown in FIG. As shown in
A plurality of paper discharge rollers 69 made of an elastic material having thin wrappers 70 provided only at both ends are fixed. Further, a thin plate-shaped knurled roller 72 is rotatably fixed to the other discharge roller shaft 71 so as to be slightly displaced in the axial direction with respect to the thin wrapper portion 70 and slightly overlap in the radial direction. ing.
Then, a large wave is formed on the dried recording paper S in the transport direction, and the recording paper S is protruded flat by the stiffness strengthened by the stiffness, and is sent to the paper discharge tray 14.

Next, the operation of the recording paper transport device of the present embodiment will be described with reference to FIGS.

FIG. 2 is a detailed configuration diagram of the second transport unit, FIG. 3 is a diagram illustrating the second transport unit in a recording paper transport state, and FIG. 4 is a diagram illustrating a speed relationship in the second transport unit. As described above, the second transport unit disposed immediately after the driven roller 22 includes the thin cylindrical elastic member 63 and the thin plate-shaped roller 66 having a knurl, and thus the transport of the recording paper S. In this state, the elastic member 63 is deformed as shown in FIG. 3 and presses the recording paper S with the same force. Therefore, the recording paper S can be conveyed with a uniform force over the entire width of the recording paper S. Also, by slightly separating the elastic member 63 from the roller 66 in the axial direction, it is possible to prevent ink remaining on the recording surface undried and adhering to the roller 66 from being transferred to the elastic member 63 and soiling the back surface of the recording paper. doing.

As shown in FIG. 4, the transport speed Vs of the recording paper S is determined by the peripheral speed of the paper feed belt 23. The peripheral speed of the elastic member 63 is
In order to prevent the recording paper S from being lifted from above the platen and rubbing against the recording head due to absorption and expansion of the ink, the peripheral speed of the paper feeding belt 23 is slightly higher. In this embodiment, it is set to about 1.1 times. Since the roller 66 is rotatably attached to the rotating shaft 65, the roller 66 rotates at an angular velocity w2 such that the outer circumference becomes Vs by the contact pressure with the recording surface of the recording paper S. Here, if the roller 66 is fixed non-rotatably with respect to the rotating shaft 65,
If the 65 does not rotate, the roller may be worn due to wear due to durability, and a decrease in the contact pressure from the recording paper in the case of high density printing.
66 rotation failures occur. Therefore, in the present embodiment, the roller 66 is rotatably mounted on the
Is rotated at a speed w3 slightly higher than w2, whereby the relative speed between the roller 66 and the rotating shaft 65 is reduced to improve the durability.

In this way, the recording paper S that has been wet by the writing process with the ink is in a state of being loosely sandwiched between the elastic member 63 and the roller 66, and is written on the surface by the roller 66 having the knurls. Discharge guide plate without disturbing the image
It is guided to 61 and sent into the hot air drying unit 90, where it undergoes a required drying process with hot air, and the paper discharge rollers 69,
The paper is discharged to a paper discharge tray 74 by 72.

Immediately before the trailing end of the recording paper S passes over the gate roller 21, a paper end detection sensor (not shown) disposed here detects this state, and lowers the paper bail lever 38 based on the detection output. The paper bale 37 at the end thereof is brought into contact with the paper feed belt 23, and the recording paper S, which has been conveyed by the gate roller 21, is adversely affected by the driven roller 22 and the thin jagged roller of the paper bail 37. It is sent out to the hot-air drying unit 90 without any change.

The present invention can be applied not only to the ink jet printer described in the present embodiment, but also to an impact printer or the like that conveys high-precision recording paper.

[Effect of the Invention] According to the present invention, when a recording medium is conveyed while being pinched, the thin bowl-shaped elastic member is bent, and the elastic member rotates while being pressed against the recording medium. result,
Since a constant conveying force is applied to the recording medium and the pressing force in the direction perpendicular to the direction of travel of the recording medium becomes uniform, the recording medium can be moved straight forward accurately.

In addition, since the elastic member is attached at a position slightly apart in the axial direction of the roller having a knurl on the circumference, the ink attached to the roller is not transferred to the thin bowl-shaped elastic member,
It is possible to prevent the recording medium from being stained.

[Brief description of the drawings]

FIG. 1 is a diagram showing the entirety of a recording paper transport device of an ink jet printer according to an embodiment of the present invention. FIG. 2 is a detailed configuration diagram of a second transport unit. FIG. 3 is a diagram showing a second transport unit in a recording paper transport state. FIG. 4 is a diagram showing a speed relationship in a second transport unit. FIG. 5 is a detailed configuration diagram around a discharge roller. FIG. 6 is a diagram showing a first example of the prior art. FIG. 7 is a diagram showing a second example of the prior art. 10 paper feed unit, 20 paper transport unit 60 discharge unit, S recording paper 14 discharge tray 21 gate roller 22 driven roller 23 paper feed belt 29 Paper press roller lever 32 Paper feed roller 37 Paper bail 38 Paper bail lever 46 Platen 61 Discharge guide plate 62 Intermediate discharge roller shaft 63 Elastic member 65 Rotary shaft 66: Roller with knurls 68: Discharge roller shaft 69: Discharge roller 71: Discharge roller shaft 72: Ridge roller 80: Carriage 90: Hot air drying unit

Claims (2)

(57) [Claims] 1. A pair of thin-walled rollers made of an elastic material are opposed to one of a pair of roller shafts disposed substantially parallel to each other across a recording / conveying path, with their opening portions facing each other, and in the axial direction. On the other hand, a disc-shaped roller is provided on the other side, and the pair of thin bowl-shaped rollers are disposed radially inward of the outer periphery of the thin bowl-shaped roller and axially. A recording paper transport device for a printer, wherein the recording paper transport device is disposed so as to be located between the recording paper transport devices. 2. A recording paper transport device for a printer according to claim 1, wherein said disk-shaped roller is formed as a thin roller provided with a knurled circumference.