JPH04116056A - Printer paper conveyance device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field 1 The present invention relates to a recording paper conveying device for a printer.

[Prior Art 1] A recording paper conveyance device of a conventional printer will be described below, particularly taking an inkjet printer as an example.

In an inkjet printer, a number of problems occur when recording paper or other recording media floats on a platen that is disposed at a predetermined distance opposite a recording head. For example, print stains due to contact between the recording head and the recording paper, damage to the recording head, and deterioration of print quality due to variations in the distance between the recording head and the recording paper occur.

Therefore, in conventional inkjet printers, in order to bring the recording paper into close contact with the platen, a first conveyance section that conveys the recording paper at a predetermined speed and a second conveyance section that is separated in the traveling direction of the recording paper are used. to make the recording paper feeding force in the second conveying section smaller than the recording paper feeding force in the first conveying section,
Furthermore, the conveyance speed in the second conveyance section is set to be higher than the conveyance speed in the first conveyance section. In this way, the conveyance speed of the recording paper is determined by the first conveyance section, and a constant tension is applied to the paper between the first conveyance section and the second conveyance section. The recording section is arranged between the first conveyance section and the second conveyance section to prevent the recording paper from floating up in the recording section.

A first example of a conventional second conveyance section for satisfying the above-mentioned conveyance conditions is a drive having a circumferential speed greater than the conveyance speed of the first conveyance section and a predetermined Wi friction coefficient, as shown in FIG. roller 1
01, and a presser roller 102 that presses the recording paper onto the drive roller 101. and presser roller 10
2 is rotatably held by a presser lever 103 and urged onto the recording paper by a spring member 105.

Further, as a second example, there is a mechanism in which the presser roller 102 is also driven. As shown in FIG. 7, this mechanism consists of a presser roller drive shaft 11 to which a plurality of presser rollers 112 are fixed.
Both ends of the roller 4 are rotatably held by a presser roller shaft lever 113, and the presser roller 112 is urged onto the recording paper by a spring member 115.

[Problem B that the invention attempts to solve] However, the above-mentioned conventional technology has the following problems.

First, in the first example, since the presser roller 102 shown in FIG. 6 is a driven roller, it may cause rotation failure due to wear or the like, and print stains may occur. In addition, the large number of component parts of the mechanism caused an increase in cost.

When the method of driving the presser roller 112 shown in FIG. 7 is used as in the second example, the number of components increases compared to the first example, which further increases costs. In addition, it is difficult to press down the multiple presser rollers 112 with the same force, and it is not possible to convey the recording paper in a straight line with high precision. I can't. Furthermore, if the presser roller 112 is a presser roller with serrations on the circumferential surface, the printed surface will be damaged. In addition, in both the first and second examples, there was a problem in which ink was transferred from the serrations to the opposing rollers 101 and 111, staining the back side of the recording paper.The present invention therefore solves this problem. The purpose of this is to create a new printer paper transport device that allows recording paper to be conveyed in a straight line to achieve high-precision printing at low cost, and to prevent stains on the recording paper in inkjet printers, etc. It is in a place where we provide.

[Means for Solving the Problems] A first aspect of the present invention provides a printer having a first conveyance section that conveys a recording medium at a predetermined speed, and a second conveyance section that is IIILB in the traveling direction of the recording medium. The second conveyance section is configured by a thin cylindrical elastic member that rotates with its peripheral surface in contact with the recording medium, and a roller that is disposed facing the elastic member and sandwiching the recording medium. shall be.

A second invention is characterized in that the roller is rotatably attached to a rotating shaft that rotates at an angular velocity that is slightly faster than the angular velocity that is the conveying speed of the first conveying section.

A third aspect of the invention is that the roller is a plate-shaped roller having serrations on the circumferential surface in contact with the recording surface of the recording medium, and the elastic member is disposed at a position a predetermined distance away from the roller in the axial direction. Features.

1 Effect 1 According to the above configuration of the present invention, the thin cylindrical elastic member is bent and rotates with the outer periphery pressed against the recording medium, so that a constant conveying force is applied to the recording medium. It will be done. Therefore, the feeding force in the direction perpendicular to the traveling direction of the recording paper can be made uniform, and highly accurate printing with less paper feeding skew can be obtained. Further, according to the second invention, since the relative angular velocity difference between the roller and the rotating shaft of the roller is small, durability is dramatically improved. Furthermore, according to the third invention, since the roller having the serrations and the elastic member are separated in the axial direction, the ink on the recording medium is not transferred to the elastic member due to the serrations, thereby eliminating stains on the recording medium. .

[Example] The illustrated embodiment will be described below.

FIG. 1 is a diagram showing the entire structure of a recording paper conveyance processing device for an inkjet printer, which is an embodiment of the present invention.

This recording paper conveyance device is roughly divided into a paper feeding section 10 having a fanfold paper feeding path and a cut paper feeding path;
It is constituted by a paper conveyance section 20 disposed in the record writing section and a discharge section 60 that discharges the recording paper S while drying it.

A gate roller 21 connected to a driving force transmission mechanism (not shown) is disposed in the paper conveyance section 20 on the upper side thereof so as to sandwich the travel path of the carriage 80 . Further, a driven roller 22 is disposed at a position immediately behind the platen 46 on the lower side. The driven roller includes a gate roller 2.
It is configured to rotate at the same circumferential speed as the gate roller 21 via a paper feed belt 23 suspended between the gate roller 21 and the gate roller 21.

Reference numeral 29 denotes a paper presser roller lever that is pivotably supported above the gate roller 21 with a fulcrum 31 as a fulcrum. This paper presser roller lever 29 is used when the recording paper S fed here is a cut sheet or an envelope that is mainly fed by the frictional force between the paper feed belt 23 forming the outer periphery of the gate roller 21 and the paper presser 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 a fan-fold paper that is mainly fed by a tractor (not shown). In this embodiment, the gate roller 21, paper feed belt 23
, and the paper pressing roller 32 constitute a first conveying section.

37 is a vapor pail that comes into contact with and separates from the paper feed belt 23 on the driven roller 22. This vapor pale 37 is
A plurality of disc-shaped jagged rollers having jagged edges are fixed to a shaft 36 at intervals.

The vapor pail lever 38 that supports the vapor pail 37 at one end has its base end fixed to a support shaft 39 supported on the lower side of the driven roller 22. Immediately before the rear end of the recording paper S- passes over the gate roller 21, the paper pail 37 is pressed against the paper feed belt 23 to feed the recording paper S.

In the discharge section 60, an intermediate paper discharge roller shaft 62 and a rotating shaft 65 are disposed on the downstream side adjacent to the driven roller 22. As shown in FIG. 2, a plurality of thin-walled cylindrical elastic members 63 are fixed to an intermediate paper discharge roller shaft 62 disposed below the paper discharge guide plate 61 at intervals.

Further, a thin plate-shaped roller 66 with serrations is rotatably attached to the rotating shaft 65 so as to be slightly shifted in the axial direction with respect to the elastic member 63 and slightly matched in the radial direction. . The second conveying section is fixed by these elastic members 63 and rollers 66, and can sandwich the recording paper S and discharge the wet recording paper S without applying excessive force.

Note that the intermediate paper ejection roller shaft 62 serves as a drive shaft.

Reference numerals 68 and 71 denote a pair of paper ejection roller shafts disposed on the downstream side of the hot air drying unit 90, and one of the paper ejection roller shafts 68 disposed below the paper ejection guide plate 61 has a As shown in FIG. 2, a plurality of paper ejection rollers 69 made of an elastic material are fixed with thin wrapper portions 70 provided only at both ends. Also,
A thin plate-shaped jagged roller 72 is rotatably fixed to the other paper ejection roller shaft 71 so as to be slightly shifted in the axial direction with respect to the thin wrapper portion 70 and slightly matched in the radial direction. ing. Then, the dried recording paper S is configured to form a large wave in the conveyance direction, and is made to protrude flat due to the stiffness thereof and is sent to the paper discharge tray 14.

Next, the operation of the recording sheet conveying device of this embodiment will be explained based on FIGS. 2 to 4.

FIG. 2 is a detailed configuration diagram of the second conveyance section, FIG. 3 is a diagram showing the second conveyance section in a recording paper conveyance state, and FIG. 4 is a diagram showing the speed relationship in the second conveyance section. As described above, the second conveyance section disposed immediately after the driven roller 22 is composed of a thin cylindrical elastic member 63 and a thin plate-like roller 66 with serrations, so that the recording paper S cannot be conveyed easily. In this state, the elastic member 63 deforms as shown in FIG. 3 and presses down the recording paper S with the same force. Therefore, the recording paper S can be conveyed with uniform force over the entire width of the recording paper S. In addition, the elastic member 6
3 is slightly layered in the axial direction from the roller 66 to prevent ink remaining undried on the recording surface and attached to the roller 66 from being transferred to the elastic member 63 and staining the back surface of the recording paper.

As shown in FIG. 4, the conveying speed Vs of the recording paper S is determined by the circumferential speed of the paper feeding belt 23. The circumferential speed of the elastic member 63 is set to be slightly faster than the circumferential speed of the paper feeding belt 23 in order to prevent the recording paper S from lifting off the platen and rubbing against the recording head due to the recording paper S absorbing ink and stretching. There is. 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 due to the contact pressure with the recording surface of the recording paper S.

Here, if the roller 66 is fixed to the rotating shaft 65 so that it cannot rotate, or if the shaft 65 does not rotate, due to wear due to durability, decrease in contact pressure from the recording paper in the case of high-density printing, etc. A rotation failure of the roller 66 occurs. Therefore, in this embodiment, the roller 66 is rotatably attached to the rotating shaft 65, and the rotating shaft 65 is rotated at a speed W3 slightly faster than W2, thereby reducing the relative speed between the roller 66 and the rotating shaft 65. This improves durability.

In this way, the recording paper S, which has been wetted by the writing process with the ink, is loosely sandwiched between the elastic member 63 and the roller 66, and the dots written on the surface by the roller 66, which has serrations, can be seen on the recording paper S. The paper is guided by the paper discharge guide plate 61 without disturbing the image and sent into the hot air drying unit 90, where it undergoes the necessary drying process with hot air and is discharged to the paper discharge tray 74 by the paper discharge rollers 69 and 72. be done.

It should be noted that just before the trailing edge of the recording paper S passes over the gate roller 21, a paper edge detection sensor (not shown) disposed here detects this state, and uses the detection output to lower the paper pail lever 38. , paper pail 3 at the tip
7 in contact with the paper feed belt 23, and the gate roller 2
The recording paper S whose conveyance by 1 is cut off is sent out toward a hot air drying unit 90 by a driven roller 22 and a thin jagged roller of a paper pail 37 without adversely affecting the recorded image.

Note that the present invention is not limited to the inkjet printer described in this embodiment, but can be similarly applied to impact printers that transport recording paper with high precision.

[Effect of the invention 1 According to the first invention, the thin cylindrical elastic member is bent and rotates with the outer periphery pressed against the recording medium, so that a constant conveying force is applied to the recording medium. As a result, the feeding force in the direction perpendicular to the traveling direction of the recording medium becomes uniform. Therefore, the recording medium can be fed straight, which is particularly effective for page printers that require highly accurate printing.

According to the second aspect of the invention, since the relative angular velocity difference between the roller and its rotating shaft is small, durability is dramatically improved, and defective rotation of the roller can be prevented.

According to the third invention, since the elastic member is attached to a position slightly layered in the axial direction of the roller having serrations, ink attached to the roller is not transferred to the elastic member, thereby preventing staining of the recording medium. can.

Further, in any of the inventions, the second
Since the conveyance section is configured, the spring member 10, which was conventionally required, is
5.115 or lever 103.113 (see Figure 6.7)
This eliminates the need for cost reduction.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the entire structure of a recording paper conveyance device of an inkjet printer which is an embodiment of the present invention. FIG. 2 is a detailed configuration diagram of the second conveyance section. FIG. 3 is a diagram showing the second conveyance section in a recording paper conveyance state. FIG. 4 is a diagram showing the speed relationship in the second conveyance section. FIG. 5 is a detailed configuration diagram of the area around the paper ejection 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. 1.・Paper feed section 20・ ・Discharge section S... Paper ejection tray, gate roller, driven roller, paper feed belt, paper presser roller lever, paper presser roller, paper pail, paper pail lever, platen, paper ejection Guide plate... Intermediate paper ejection roller shaft... Elastic member - Rotating shaft... Roller with knurling, Paper ejection roller shaft... Paper ejection roller, Paper transport section, Recording paper, Paper ejection roller shaft, Jagged roller, Carriage... Applicant for hot air drying units and above Seiko Epson Co., Ltd. Agent Patent attorney Kizobe Suzuki (and 1 other person) Figure 2 63-j Rumor wholesale a 6 Low key y□? Tori 110-La No. 4N

Claims (1)

[Scope of Claims] 1) A printer having a first conveyance section that conveys a recording medium at a predetermined speed and a second conveyance section that is separated in the traveling direction of the recording medium, in which a circumferential surface is attached to the recording medium. Recording paper conveyance for a printer, characterized in that the second conveyance section is constituted by a thin cylindrical elastic member that rotates in contact with the elastic member, and a roller that is disposed facing the elastic member and sandwiching the recording medium therebetween. Device. 2) The roller is rotatably attached to a rotating shaft that rotates at an angular velocity slightly higher than an angular velocity at which the outer circumferential velocity of the roller is equal to the conveying speed of the first conveying section. A recording paper conveying device for a printer according to claim 1. 3) A claim characterized in that the roller is a plate-shaped roller having serrations on the circumferential surface that contacts the recording surface of the recording medium, and the elastic member is disposed at a position a predetermined distance away from the roller in the axial direction. Item 2. A recording paper conveying device for the printer according to item 1 or 2.