JPH09300761A - Paper feed device of ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the contamination of paper with undried ink by smoothly guiding the paper to a spur roller part. SOLUTION: A paper discharge guide 38 is provided so as to protrude toward the upstream area in a paper feed direction from the outermost periphery of a spur roller 18. The length L3 of the paper discharge guide 38 is set to the min. blank length of the leading end of paper or less and, even if the leading end of the printed paper impinges against the paper discharge guide 38, an ink bonded part does not come into contact with the paper discharge guide 38. When the paper reaches the spur roller 18 along the paper discharge guide 38, it is pressed to the spur roller 18 to generate a gap between the paper and the paper discharge guide 38 and fed without being brought into contact with the paper discharge guide 38.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying device for an ink jet printer.

[0002]

2. Description of the Related Art Conventionally, as a sheet conveying device mounted on an ink jet printer, a spur roller that comes into contact with the printing surface of the sheet with contact teeth radially provided on the outer periphery has been provided, and the spur roller is used to convey the sheet. It is known that a printed sheet is discharged while being pressed.

In this type of paper transporting device, the paper is normally ejected while the paper is nipped between the ejection roller and the spur roller as the ejection roller disposed downstream of the recording head in the paper conveyance direction rotates. The printed paper is ejected to the outside of the device by the frictional force between the roller and the paper. By using such a paper transport device, even if the ink adhering to the printing surface is not sufficiently dried, the contact teeth of the spur roller only come into contact with the printing surface with a very thin tip, so that the printing surface is not polluted. I was able to eject the paper.

[0004]

However, the prior art has the following problems. That is,
The above-described sheet transporting device is generally provided with another delivery mechanism upstream of the spur roller in the sheet transport direction, and the delivery mechanism transports the printed sheet to a position where the spur roller is present. Depending on the thickness, hardness, curl, etc. of the paper, the leading edge of the paper may not come to the position where the spur roller is pressed, and the spur roller may not start discharging the paper, and the upstream side However, there is a problem that the paper is jammed in the vicinity of the spur roller.

The present invention has been made in order to solve such a problem, and an object thereof is to smoothly start the introduction of a sheet into a spur roller portion and cause a paper jam in the vicinity of the spur roller. An object of the present invention is to provide a paper transporting device for an inkjet printer that does not have such a device.

[0006]

Means for Solving the Problems and Effects of the Invention In order to achieve the above-mentioned object, according to the present invention, as described in claim 1, a feeding means for feeding a sheet to a position facing a recording head, and a sheet feeding means. Sending-out control means for controlling the operation of the sending-out means so as to convey a sheet to a printing start position where printing is started with a margin of a minimum margin length or more at the leading end, and contact teeth radially projected on the outer periphery. In the paper transporting device of the ink jet printer, which has a spur roller that comes into contact with the printing surface of the paper and discharges the printed paper while pressing the paper with the spur roller, It is provided so as to project to the upstream side of the outermost periphery in the paper transport direction, and the front end of the printed paper sent from the upstream side is brought into contact with the front end of the paper to the spur roller along the contact portion. Induce A paper ejection guide is provided, and a contact portion of the paper ejection guide with the paper printing surface is set to have a length equal to or shorter than the minimum margin length, and the paper is pressed by the spur roller. It is characterized in that it is arranged at a position where a gap is formed between the printed surface and the printed surface.

According to the paper transporting apparatus of the present invention, the paper discharge guide is provided so as to project upstream of the outermost periphery of the spur roller in the paper transporting direction, and the leading end of the paper comes into contact with the paper discharge guide to guide the paper. Therefore, the paper is smoothly introduced into the spur roller. In particular, in this paper ejection guide, the contact portion with the paper printing surface has a length equal to or shorter than the minimum margin length of the paper, and therefore the paper is printed until the leading edge of the paper reaches the outermost circumference of the spur roller. It does not come into contact with the ink-attached area on the surface. Moreover, the contact portion with the printing surface of the paper is arranged at a position where a gap is created between the printing surface of the paper and the printing surface of the paper as the paper is pressed by the spur roller. After reaching the outermost circumference of the roller, the paper is pressed in the rotational direction as the spur roller rotates and separates from the paper ejection guide. Never come into contact with. Therefore, with such a paper discharge guide, the ink does not come into contact with any ink-adhered portion on the printing surface of the paper, so that the ink does not stain the paper even if the ink-jet printer is hard to dry.

The sheet discharge guide as described above may have a structure in which a dedicated separate part is attached near the spur roller. However, as described in claim 2, the sheet discharge guide has the spur roller. If it is integrally molded so that it projects from the supporting holder member, the position of the paper ejection guide will not vary with respect to the spur roller, and the position will be ensured without any adjustment of the position. The effect of the period can be obtained. Moreover, since the number of parts is reduced and the number of assembling steps can be reduced accordingly, it also contributes to the reduction of manufacturing cost.

By the way, in the sheet conveying apparatus of the present invention, since the sheet is guided to the spur roller portion by using the margin portion of the sheet, it is important to surely provide a margin of the minimum margin length or more at the tip of the sheet. . For example, claim 3
As described above, the delivery means has a pair of delivery rollers for nipping the sheets at the contact positions with each other as they are rotationally driven and delivering the sheets to the downstream side in the transport direction, and the delivery control means includes: It is preferable to control the rotation amount of the delivery roller from the state where the leading edge of the paper has abutted the contact position of the delivery roller to convey the paper to the printing start position.

According to such a sheet conveying apparatus, the sheet can be conveyed to the desired print start position only by controlling the amount of rotation of the sheet feeding roller provided in the sheet feeding means. It is not necessary to use a detection unit such as a sensor that detects that the print has reached the print start position.

When a detecting means such as a sensor is provided, the detecting means for detecting the leading edge of the sheet sent by the sending means is provided, and the sending control means has the detecting means. From the time point when the leading edge of the sheet is detected, the operation amount of the sending unit may be controlled to convey the sheet to the print start position.

According to such a sheet transporting device, the delivery control means controls the rotation amount of the delivery roller provided in the delivery means from the time when the detection means detects the leading edge of the paper.
Since the paper can be conveyed to the desired print start position, even if for some reason the paper is not delivered from the delivery roller as planned, make sure that the paper reaches the proper print start position. You can

Further, when the paper discharge guides are provided so as to project at positions on both sides of the spur roller, the paper is guided near the spur rollers by the paper discharge guides. While the desired effect can be obtained, at a position away from the spur roller, there is nothing that comes into contact with the paper, and frictional resistance against the paper can be suppressed to a minimum.

[0014]

Next, embodiments of the present invention will be described with reference to the drawings. The specific devices described below are merely examples of the embodiments of the present invention, and the embodiments of the present invention are not limited to the specific devices illustrated below.

The ink jet type printer 1 (hereinafter referred to as printer 1) is a paper feeding mechanism, which is rotationally driven by a motor (not shown) as shown in FIG. 1, and accommodates a large number of paper sheets in a stacked state. A paper feed roller 11 that feeds paper one by one from the cassette 8 to the downstream side, and a paper feed roller 11 that is also rotationally driven by a motor (not shown).
The conveying roller 12 that further conveys the sheet sent to the downstream side, and the arm 13 is rotatably provided at the tip of the arm 13 and applies a pressing force to the conveying roller 12 to sandwich the sheet between the conveying roller 12 and the conveying roller 12. Pressure roller 14
And a discharge roller 16 that is rotationally driven by a motor (not shown) and that further sends out the paper sent by the transport roller 12 to the downstream side, and a spur holder 17 that are rotatably provided and apply a pressing force to the discharge roller 16. In addition, it is provided with a spur roller 18 that holds the paper between the discharge roller 16.

In addition to the above-mentioned paper transport mechanism, a carriage 22 is provided which is reciprocally movable with respect to a main shaft 21 provided in the width direction of the apparatus main body, and is mounted on the carriage 22 and is transported by the paper transport mechanism. The recording head 26 is provided with a recording head 26 that performs recording by ejecting ink droplets onto the incoming paper, and a replaceable ink cartridge 28 that contains the ink to be supplied to the recording head 26.

Among these structures, the spur roller 18
As shown in FIG. 2, the metal base contact teeth 32 are provided on the outer periphery of the resin base 30 in a radially protruding manner, and the flexible spring shaft 34 is arranged at the center of rotation. . The spring shaft 34 is the rotating shaft of the spur roller 18 and at the same time,
It functions so that the contact teeth 32 are pressed against the discharge roller 16 with a slight elastic deformation.

The spur holder 17 is made of resin, and has a bearing portion 36 that rotatably supports the spring shaft 34 of the spur roller 18 and both sides of the spur roller 18 that is rotatably supported by the bearing portion 36. The paper discharge guide 38 protruding at the position is integrally formed with the base portion 40.

As shown in FIG. 3, the paper discharge guide 38 is provided so as to project more upstream than the outermost periphery of the spur roller 18 in the paper transport direction, and particularly, the contact portion 38a with the paper printing surface.
Is less than or equal to a predetermined minimum margin length L3. Moreover, the sheet is arranged at a position slightly deviated from the tangential plane that passes through the contact point between the spur roller 18 and the discharge roller 16 and the sheet is pressed by the spur roller 18 and moves downward. Along with this, a gap is formed between the paper and the printing surface.
It should be noted that the minimum margin length L3 is a length that is determined according to the rotation amount of the transport roller 12 at the time of initial introduction of a sheet, and in the printer 1, the minimum margin length L3 is set to 3 mm.
That is, at the time of printing, a margin having a length of at least 3 mm is provided at the leading end of the paper.

By the way, in FIG. 2, three spur rollers 1 are provided.
8 is illustrated, but in reality, 10 spur rollers 18 having a similar structure are arranged at appropriate intervals in the longitudinal direction of the spur holder 17, and the spur holder 17 side also has the above-mentioned structure. Ten sets of the bearing portion 36 and the discharge guide 38 are formed.

The printer 1 is equipped with other various devices similar to a normal printer, but the details thereof are not directly related to the embodiment of the present invention, and therefore illustration and description thereof are omitted. . In the printer 1 configured as described above, the operation of each unit is controlled by a control device (not shown) mainly composed of a well-known CPU and the like, and the paper transport process shown in the flowchart of FIG. 4 is executed.

In this paper carrying process, first, the paper feeding roller 11 is rotated in the forward direction and the carrying roller 12 is rotated in the reverse direction until the paper P is fed by the predetermined length L1 (S).
102, S104). In order to send out the paper P by a predetermined length L1, the paper feed roller 11 may be rotated by a predetermined amount. In the case of the printer 1, a stepping motor that drives the paper feed roller 11 is provided with a predetermined number of pulse signals. The rotation amount of the paper feed roller 11 is controlled. As a result, the paper feed roller 11 moves from the paper feed cassette 8 to the paper P as the paper feed roller 11 rotates.
1 sheet is fed out, and the leading edge of the sheet P is conveyed by the conveying roller 12 and the pressure roller 1 as shown by the chain double-dashed line in FIG.
It comes into contact with the contact position with 4.

At this time, as indicated by the arrow in FIG. 1, since the conveying roller 12 is rotating in the reverse direction, the sheet P does not enter between the conveying roller 12 and the pressure roller 14, and the sheet P slightly moves. It is pressed against the transport roller 12 and the pressure roller 14 in a bent state. Then, the paper P has a predetermined length L.
When only 1 is fed (S104: YES), the transport roller 12 is rotated in the forward direction until the paper P is fed by the predetermined length L2 (S106, S108). As a result, the paper P is sent out by a predetermined length L2 from the contact position between the transport roller 12 and the pressure roller 14, as shown by the chain double-dashed line in FIG. The predetermined length L2 usually differs depending on the designation of the margin length included in the print data or the like received from the external device, but is a length such that printing is started with at least the minimum margin length L3.

In this way, when the paper P is sent out by the predetermined length L2 (S108: YES), thereafter, a normal printing operation is repeated in which printing and line feed are repeated up to near the end of the paper according to the print data (S110). As the printing operation progresses, the paper P is further sent to the downstream side. here,
Even if the paper P is slightly warped upward, the leading end of the paper P contacts the paper ejection guide 38, and therefore, in most cases, the paper P is below the paper ejection guide 38 as indicated by the chain double-dashed line in FIG. Be guided to. At this time, the printing surface side of the paper P comes into contact with the contact portion 38a on the discharge guide 38 side, but since this length is the same as the minimum margin length L3, the contact portion The ink adhered portion of the paper P does not come into contact with 38a.

When the printing operation is further advanced, the paper P is further sent to the downstream side. At that time, the paper P is
Since the leading end of the sheet P has reached the position where it is caught by the spur roller 18, the sheet P is pressed downward by the spur roller 18, and accordingly, the sheet P is separated from the sheet ejection guide 38, and a gap is formed between them. Occurs. Therefore, even after this, the ink-attached portion of the paper P does not come into contact with the contact portion 38a.

When the printing operation further progresses and the paper P is further sent to the downstream side, finally, as shown by the chain double-dashed line in FIG. The sheet is sandwiched between the sheet and the sheet 18, and is sent out toward a sheet discharge port (not shown). Since the conveying speed of the discharging roller 16 is set to be slightly higher than the conveying speed of the conveying roller 12, the paper P is slightly pulled by the discharging roller 16 and the spur roller 18, and as a result, the conveying is performed. In the paper conveyance path from the roller 12 to the discharge roller 16, the paper P is always held at an appropriate position without sagging. Therefore, even in this state, the paper ejection guide 38
The ink adhering portion of the paper P does not come into contact with the abutting portion 38a.

As described above, according to the printer 1, since the paper discharge guide 38 adjusted to the characteristic arrangement position and shape as described above is provided, the paper P can be introduced into the spur roller 18 portion. Even if it starts smoothly and the paper P is slightly warped or it is hard to bend like thick paper,
No paper jam near the spur roller 18 is caused.

Next, another embodiment will be described. In the following description, points different from the above-described embodiment will be described in detail, and the same configurations as those described above will be denoted by the same reference numerals and description thereof will be omitted. The present embodiment differs from the above-described embodiment in that a paper sensor 50 is provided in the vicinity of the transport roller 12 as shown in FIG. The paper sensor 50 is a reflective optical sensor including a pair of a projector and a light receiver, and the on / off state is switched depending on the presence or absence of paper.

Then, the operation of each unit is controlled by the control device (not shown), and the paper carrying process shown in the flowchart of FIG. 8 is executed. In this paper conveyance process, first, the paper feed roller 11 is rotated in the normal direction and the conveyance roller 12 is rotated in the reverse direction until the paper P is fed by the predetermined length L1 (S202, S204). As a result, similarly to the above-described embodiment, the leading edge of the sheet P contacts the contact position between the transport roller 12 and the pressure roller 14.

Subsequently, when the paper P is fed by the predetermined length L1 (S204: YES), the carry roller 12 is rotated forward (S206), and it is checked whether or not the paper sensor 50 detects the paper (S208). ). At first, the paper has not reached the position of the paper sensor 50, so
The sheet is not detected (S208: NO), and moreover, it means that the sheet has not been fed by the predetermined length L4 from the position of the sheet sensor 50 (S210: NO), and the processing from S206 is repeated. The predetermined length L4 usually differs according to the designation of the margin length included in the print data or the like received from the external device, but is a length such that printing is started with at least the minimum margin length L3. is there.

When the sheet reaches the position of the sheet sensor 50 by repeating the processing from S206, the sheet is detected from that point (S208: Y).
ES), still a predetermined length L4 from the position of the paper sensor 50
Since it has not been sent out (S220: NO), the processing from S206 is repeated.

In this way, when the paper is sent out by the predetermined length L4 (S220: YES), the normal printing operation is repeated after which printing and line feed are repeated up to near the end of the paper according to the print data (S222). It should be noted that although no paper is detected in the processing of S208 (S208:
NO), when the conveyance roller 12 is rotated by an amount equivalent to sending out the paper by the predetermined length L4 (S210:
If the answer is YES, there is a possibility that there is no paper in the paper feed cassette 8 or a paper jam has occurred in the middle of the paper path. Therefore, error processing such as notifying an error by a display or an alarm sound is performed (S212). ).

Even if the above-described processing is performed, a margin having an appropriate length can be provided at the leading end of the paper. Therefore, by providing the characteristic paper discharge guide 38 of the present invention, the spur roller 18 portion can be provided. The introduction of paper P into the
Even if the paper P is slightly warped or is hard to bend such as thick paper, it does not cause paper jam near the spur roller 18. In particular, when the paper sensor 50 detects the paper and determines the print start position, the rotation amount of the carry roller 12 is determined after the delivery of the paper by the carry roller 12 is reliably started. The paper can be more accurately delivered to the print start position.

Although the embodiments of the present invention have been described with reference to the specific examples, various concrete configurations of the present invention are possible other than the specific examples described above. For example, in the above-described embodiment, an example in which the paper ejection guides 38 are provided on both sides of the spur roller 18 is shown. However, a paper ejection guide is also provided on a portion without the spur roller 18, On the contrary, some of the spur rollers 18 may not be provided with a paper discharge guide on one side or both sides, or may be a paper discharge guide between the two spur rollers as a whole. However, in the embodiment described above, the paper is guided by the paper discharge guide 38 in the vicinity of the spur roller 18, and the desired effect is obtained, while at the position away from the spur roller 18, the paper is contacted. This is desirable in that there is nothing to do and the frictional resistance against the paper can be minimized.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an internal structure of an inkjet printer.

FIG. 2 is a partial plan view showing a structure in the vicinity of a discharge guide.

FIG. 3 is a partial cross-sectional view showing a structure from a transport roller to a discharge roller.

FIG. 4 is a flowchart showing a sheet conveyance process.

FIG. 5 is a partial cross-sectional view showing a state in which the paper is guided to the spur roller along the paper discharge guide.

FIG. 6 is a partial cross-sectional view showing a state where a sheet is sandwiched between a discharge roller and a spur roller.

FIG. 7 is a partial cross-sectional view showing a structure of a main part of an ink jet printer according to another embodiment.

FIG. 8 is a flowchart showing a sheet conveyance process in another embodiment.

[Explanation of symbols]

1 ... Inkjet printer, 8 ... Paper feeding cassette, 11 ... Paper feeding roller, 12 ... Conveying roller,
13 ... Arm, 14 ... Pressure roller, 16
... Ejection roller, 17 ... Spur holder, 18 ...
Spur roller, 21 ... spindle, 22 ... carriage,
26 ... Recording head, 28 ... Ink cartridge, 30 ... Base part, 32 ... Contact teeth, 34 ... Spring shaft, 36 ... Bearing part, 38 ... Paper ejection guide, 38
a ... abutting portion, 40 ... base portion, 50 ... paper sensor.

Claims (5)

[Claims] 1. A delivery unit for delivering a sheet to a position facing a recording head, and a sheet to be conveyed to a print start position where printing is started with a margin of a minimum margin length or more at the leading end of the sheet. A delivery control unit that controls the operation of the delivery unit and a spur roller that comes into contact with the printing surface of the sheet with contact teeth that are radially provided on the outer periphery are provided, and the printed sheet is pressed while pressing the sheet with the spur roller. In a paper carrying device of an ink jet printer provided with a paper ejecting means for ejecting, a printed paper sent out from the upstream side is provided so as to project more upstream than the outermost circumference of the spur roller in the paper carrying direction. A paper ejection guide is provided that abuts the tip and guides the tip of the paper to the spur roller along the corresponding contact portion, and the contact portion of the paper ejection guide with the paper printing surface is the minimum margin length or less. The length of , Moreover, as the paper is pressed against the spur roller, the sheet conveying apparatus characterized by being arranged at a position where the gap is formed between the printing surface of the sheet. 2. The sheet conveying device for an ink jet printer according to claim 1, wherein the sheet ejection guide is integrally formed so as to project from a holder member that supports the spur roller. Paper transport device. 3. The paper transporting device for an ink jet printer according to claim 1, wherein the delivery means is downstream driven in the transport direction while nipping the paper at a mutual contact position as the delivery means is rotationally driven. A pair of delivery rollers for delivering to the side, and the delivery control means controls the rotation amount of the delivery roller from a state where the leading edge of the sheet abuts the contact position of the delivery roller to reach the print start position. A paper transporting device for transporting a sheet. 4. The sheet conveying device for an ink jet printer according to claim 1, further comprising a detecting unit that detects a leading edge of the sheet sent by the sending unit, and the sending control unit. A sheet conveying device, wherein the sheet is conveyed to the printing start position by controlling the operation amount of the sending unit from the time when the detecting unit detects the leading edge of the sheet. 5. The paper transporting device for an ink jet printer according to claim 1, wherein the paper ejection guides are provided at positions on both sides of the spur roller. Paper transport device.