JP2001287849A - Sheet material conveyer roller and method of manufacturing the same and method of conveying sheet material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a good accuracy and a high image quality in a sheet material conveyance by setting an encoder not requiring a large set-up space. SOLUTION: A magnetic pattern is provided on a sheet material conveyer roller itself and is read by a magnetic resistance element arranged adjacent to the conveyer roller. Accordingly, the conveyer roller is stopped accurately and a small set-up space is required to miniaturize an image forming device such as a printer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a sheet material transport roll for transporting a sheet material such as paper or plastic in an image forming apparatus.

[0002]

2. Description of the Related Art In image forming apparatuses such as various printers, electronic copiers, facsimile machines, and XY plotters, cassettes or the like are used to record various information including characters and figures on sheet materials such as paper and plastic. A transport device is provided which separates a large number of sheet materials stored in a stacked state one by one and feeds them into the apparatus main body, and transports the sheet materials to a recording area.

As a recording means system adopted for the image recording means of the image forming apparatus, there are an ink jet system, a wire dot system, a thermal system, a laser beam system and the like. As an example of these recording methods, an image forming apparatus of an ink jet method will be described with reference to FIGS. The ink jet head 11 mounted on the carriage 10 discharges ink and performs printing on the sheet material s according to image information. The carriage 10 is reciprocated by a driving device (not shown) in a direction perpendicular to the feeding direction of the sheet material s using the carriage shaft 12 as a guide. By driving the energy generating means of the ink jet head 11 along with the movement of the carriage 10, ink is ejected onto the sheet material s to perform recording. The ejection of ink from the inkjet head 11 is performed while the sheet material s is stopped, and when the recording is completed, the sheet material s is conveyed for a fixed distance. The material s moves in the direction perpendicular to the feed direction and ejects ink according to image information. The means for conveying the sheet material s is a sheet material s
And a pinch roller 14 for pressing the sheet conveying roller 13 disposed on the back side of the sheet conveying roller 13. The sheet conveying roller 13 is rotationally driven by transmitting power from a driving source (various motors or the like) 15 to apply a conveying force to the sheet material s. The pinch roller 14 has a plate spring 1 at both ends of the rotation shaft.
6 and presses against the sheet conveying roller 13. An encoder 17 for detecting the rotational position of the sheet conveying roller 13 is attached to the shaft of the sheet conveying roller 13. The axis of the sheet conveying roller 13 is
It is connected to the drive source 15 via the intermediate transmission device 18.

[0004] Here, the encoder is attached to accurately convey the sheet material over a predetermined distance.
In order to obtain more accurate image quality, it is used to control the rotation speed and stop position of a transport roller, a motor of a driving source, and the like. In Japanese Patent Application Laid-Open No. Hei 8-225239, a sensor and an encoder calculate the roller rotation speed from the number of rotations and the rotation angle of the roller, and use the result to control the motor voltage value or current value so as to obtain a target paper conveyance speed. Used. In Japanese Patent Application Laid-Open No. H11-254776, the position of a drive shaft is controlled by closed loop feedback by an encoder in order to accurately perform a predetermined line feed of a sheet. However, the encoders used for these components use a shaft of a sheet conveying roll to attach another component. For this reason, a separate installation space was absolutely necessary.

[0005]

In recent years, in particular, in recent years, downsizing and high performance of personal computers have required printers connected to these devices to be downsized and have high image quality. The demand for printers is also emerging. As one of the measures to meet such demands, the appearance of a space-saving encoder for performing accurate detection is desired. That is, an encoder that is highly accurate and minimizes the installation space leads to downsizing of the printer. An object of the present invention is to provide a high-precision sheet material conveying roll which has an encoder function and can be installed in a small space.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and the encoder can be easily manufactured by adding a magnetic encoder function to the transport roll itself. This is a roll for conveying a sheet material having an encoder function that can contribute to high precision and miniaturization. Rolls for transporting sheet materials are required to have abrasion resistance. For this purpose, Ni plating is performed on a metal cylindrical base. Normally, Ni—P plating is applied, but the higher the content of P in the plating layer, the higher the wear resistance. In order to obtain high wear resistance,
Those containing 15% by mass are preferred. If the content of P is small, the wear resistance is reduced. If the content of P is too large, the coating becomes brittle.
About 5 to 90% by mass and about 10 to 15% by mass of P are preferable. However, if the plating remains as it is, the hardness becomes Hv450-55.
0 and still insufficient as abrasion resistance, 250-500 ° C
By performing the heat treatment described above, a hardness of Hv 600 or more can be obtained. Preferably, a heat treatment temperature of 300 to 450 ° C is good. At the same time, the plating layer, which was non-magnetic,
It is magnetic.

[0007] The first invention of the present application is to provide a non-magnetic electroless Ni plating layer on a surface of a roll substrate by applying a heat treatment after applying a non-magnetic electroless Ni plating layer to the surface of the roll base.
A method of manufacturing a roll for conveying a sheet material, which imparts hardness and magnetism and thereafter forms a magnetized pattern with a constant period on a circumference of at least a part of the roll.

In the present invention, a cylindrical base made of a metal material is used as a material of a roll for transporting a sheet material, and a nonmagnetic electroless Ni plating layer is formed on a surface of the cylindrical base at a required thickness of 1 μm.
By applying a heat treatment at 500 ° C. or less, preferably 250 to 450 ° C. on the cylindrical substrate having the plating layer, the nonmagnetic plating layer is formed at 4.5 kA.
A magnetic layer having a coercive force of at least / m and a saturation magnetization of at least 0.2T can be converted into a magnetic layer having a surface hardness of at least Hv600. Next, a magnetized pattern having a constant period (for example, a pitch of 10 μm or more) is formed in a part of the roll in the circumferential direction.

In a second aspect of the present invention, a magnetic layer made of a magnetic recording material such as γ-iron oxide is provided on the surface of a roll base, and thereafter, at least a part of the circumference of the roll is magnetized at a constant period. This is a method for manufacturing a roll for conveying a sheet material on which a pattern is formed.

In the present invention, a cylindrical base made of a metal material is used as a material of a roll for conveying a sheet material, and a magnetic recording material powder such as γ-iron oxide, CrO ₂ , FeCo or the like is formed in the circumferential direction of the surface. A magnetic layer dispersed in a resin binder is applied in a thickness of 20 μm or more by coating and baking. This magnetic layer is formed outside the area where the roll and the sheet material are in contact. It is desirable that the magnetic properties of the magnetic layer have a coercive force of 4.5 kA / m or more and a saturation magnetic flux density of 0.1 T or more. Next, a magnetized pattern having a constant period (for example, a pitch of about 10 μm) is formed in a part of the roll in the circumferential direction. The cylindrical substrate may be hollow or solid. The hollow roll is light in weight and has good responsiveness in sheet material conveyance control. Since the solid roll has high rigidity, it is advantageous to increase the roundness of the roll and to reduce the warpage during conveyance.

Further, the inventor of the present invention has the greatest influence on the paper feeding accuracy and image quality when the concentricity of the magnetic encoder and the sheet conveying portion is increased. It has been found that it is advantageous to be integrally integrated. In order to obtain a high concentricity, it is desirable to form the magnetic encoder section and the sheet conveying portion in one member, or to form the members separately from each other, and to perform the outer peripheral processing in one step after integrating them.

Therefore, a third invention of the present application is to form a magnetic layer portion in a circumferential direction of a roll material having a sheet conveying portion,
This is a method for manufacturing a roll for transporting a sheet material in which the sheet transport portion and the magnetic layer portion are substantially concentric.

[0013] Therefore, the fourth invention of the present application is that the roll material having the sheet conveying portion and the encoder material having the magnetic layer portion in the circumferential direction are coaxially integrated, and then the sheet conveying portion and the magnetic layer portion are integrated. Is a method for producing a roll for transporting a sheet material which is substantially concentric.

The fifth invention of the present application is a roll for conveying a sheet material having a magnetic layer composed of an electroless Ni plating layer provided with a magnetized pattern in a circumferential direction on the surface.

A sixth invention of the present application is a roll for conveying a sheet material having a magnetic layer made of a magnetic recording material such as γ-iron oxide having a magnetized pattern in the circumferential direction of the surface.

According to a seventh aspect of the present invention, there is provided a sheet conveying portion and a magnetic layer portion provided with a magnetized pattern in a circumferential direction, and the sheet conveying portion and the magnetic layer portion are substantially concentric. Roll for conveying the sheet material.

In the present invention, a fixed magnetizing pattern can be formed in the circumferential direction of at least a part of the magnetic layer by magnetizing means. It is desirable that the magnetized pattern is formed at a position where the transport roll does not contact the sheet material. As a sensor for detecting this magnetization pattern,
Generally, an MR sensor or a GMR sensor, which is a magnetoresistive element, is used.

In the present invention, it is preferable that at least a part of the surface of the roll other than the magnetized pattern has a rough surface of 3 μm or more in Rz. To make the surface rough,
This is for imparting a grip force when the transport roll sandwiches and transports the sheet material between the pinch roll and the sheet material.

In the present invention, the means for imparting a predetermined surface roughness to the roll substrate includes a blasting or etching treatment, a dulling method for roughening by local heating of a laser, a thermal spraying method, a ceramic coating method, and a machine. A processing method, a grindstone roll, a rubber roll, and the like are preferable. When the surface of the roll substrate is covered with a rubber layer, it is coated thinly to maintain the coefficient of friction while suppressing deformation. Since the magnetized pattern is preferably formed on a smooth surface, the surface roughening treatment is preferably performed by masking the portion where the magnetized pattern is formed. After this surface roughening treatment, the roll base is subjected to electroless Ni-P plating. However, when sufficient gripping force and abrasion resistance can be obtained only by roughening the roll substrate, the N
The i-P plating may be applied only to the portion where the magnetized pattern is formed or to a slightly wider range including the portion. There are various blasting methods, but generally sand blast is often used. The etching is performed by screen-printing a resist resin in the form of dots on the surface of a roll base, and then immersing the roll base in an etchant (hydrochloric acid, sulfuric acid, nitric acid, etc.) to form a rough surface (which may be electrolytic etching). You. A stable roughened surface can also be formed by a dulling method using a heating mark formed by local heating by irradiation with a YAG laser or CO ₂ laser spot.

In the present invention, the conveying roll is rotated while the sheet is pressed against the conveying roll of the sheet material having the magnetized pattern of a fixed period on at least a part of the circumference of the roll, and the conveying pattern is rotated. The magnetizing pattern formed on the transporting roll is counted as a repetitive waveform signal by the magnetoresistive element installed close to or in contact with it, and the read signal stops the motor of the drive source, and thus the transporting roll. Can be accurately controlled and stopped.

In the present invention, the thickness of the nonmagnetic electroless Ni plating is preferably 1 μm or more. This is to make the coercive force 4.5 kA / m or more and the saturation magnetization 0.2T or more when magnetized by heat treatment. This is because if the coercive force and the saturation magnetization are weak, reading with a magnetoresistive element may be difficult. Heat treatment temperature is 250-50
Although 0 degreeC may be sufficient, 300-450 degreeC is more preferable. If the temperature is lower than 200 ° C., the heat treatment time is too long, and the surface hardness is Hv450 to 550 as plated.
Out of the area. At a temperature of 200 ° C. or less, the nonmagnetic Ni plating layer does not change to a magnetic material. The hardness reaches the maximum of about Hv1000 at a heat treatment temperature of about 400 ° C., but if the heat treatment is performed at a temperature exceeding this, the hardness gradually decreases or the roll deforms.
There is not much point in performing a heat treatment at a temperature exceeding 500 ° C.

Here, a method of imparting a magnetized pattern with a constant period in the circumferential direction of at least a part of the transporting roll is a method of imparting magnetism and hardness by applying non-magnetic Ni plating and performing heat treatment. As described above, the method and the transport roll of the present invention are not limited to this. For example, gamma iron oxide, CrO ₂ , FeC
The magnetic layer may be formed by applying and baking a magnetic layer dispersed in a resin binder made of a magnetic recording material powder such as o. The magnetic layer can also be formed by press-fitting or inserting a ring of a ferromagnetic material into a desired location of the roll. The roll base is made of high carbon steel such as SUS431, quenched and tempered to give magnetism,
There is also a method such as performing a nitriding treatment to increase the surface hardness. In these cases, it is desirable to use a roll substrate having a high surface hardness.

In the present invention, it has been disclosed that the entire roll is heat-treated to change the non-magnetic plating layer into a magnetic layer. However, the present invention is not limited to this. Alternatively, it is also possible to apply flame quenching or the like to convert only a portion necessary for forming a magnetization pattern into a magnetic layer.

When a magnetized pattern having a constant period is provided on the circumference of the roll, the pitch can be changed according to the diameter of the roll and the required stopping accuracy. This pitch is
When the roll diameter is small, for example, 7 mm, it is naturally preferable that the roll diameter is small, and the pitch is about 10 μm. However, if the diameter is smaller than 10 μm, detection by the magnetoresistive element may be erroneous.
μm or more pitch, more preferably 40 μm
It is more preferably 80 μm or more.

[0025]

(Embodiment 1) An embodiment of the present invention will be described below. FIG. 1 is a schematic perspective view showing a use state of a main portion of a roll for conveying a sheet material according to an embodiment of the present invention, which is installed in a printer. In this embodiment,
Although the drive unit is not shown in the drawings, a drive means and a roll connecting means that is substantially the same as the conventional method shown in FIG. 4 is used. Reference numeral 1 denotes a roll for conveying the sheet material according to the present invention, which is an aluminum cylinder having a diameter of 13 mm.
A coercive force of about 11 kA / m and a saturation magnetization of 0.08 T are given by a heat treatment at 1 ° C. × 1 h, and the surface hardness is Hv75.
It is about 0. The surface of the sheet material s transport portion of the transport roll 1 has a rough surface 3 of about 7 μm in Rz by sandblasting so that a grip force can be exerted when the sheet material s is transported. Reference numeral 2 denotes a magnetized pattern provided near the end of the transporting roll 1.
(B). Reference numeral 4 denotes an MR magnetoresistive element that detects and counts the magnetization pattern 2 and is disposed close to or in contact with the magnetization pattern 2 at a distance of several μm. Reference numeral 5 denotes a rotation transmission gear which is fitted on the rotation shaft 6 of the transport roll 1. The rotation transmission gear 5 is connected to a drive source via an intermediate transmission device (not shown). Reference numeral 7 denotes a pinch roll, which serves to press the sheet s so that the sheet s is in close contact with the transport roll 1 when the sheet s is transported by the transport roll 1. Although not shown, the pinch roll 7 may be biased by a spring or the like at the shaft end of the pinch roll 7 in order to bring the sheet material s closer to the transport roll 1.

FIG. 2 (a) shows the transport roll 1 of the present invention.
FIG. 4 is an enlarged view of a main part of a magnetized pattern 2 and a magnetoresistive element 4 having a constant period of FIG. (B) is an example of magnetization of a magnetization pattern,
N and S are repeatedly magnetized. In this embodiment, an example is shown in which 18 poles of N and S are respectively magnetized, but it is also possible to magnetize at a finer pitch as described above.

This transport roll 1 was incorporated into an ink jet printer at 12 sheets per minute and printing was evaluated. As a result, both paper feeding accuracy and printing quality were good.

FIG. 5 is a diagram showing a control system of a roll for conveying a sheet material. Arrows indicate the action of information or force, and indicate that they flow in the direction of the arrows. It indicates that the encoder is attached to the transport roll. Based on the image information, the printer interface exchanges information with control means of a driving source of the printer. The control means moves or stops the drive source according to the image information received from the printer interface. The conveyance of the sheet material is stopped according to the image information, and recording is performed during this time. When the recording is completed, the control means moves the driving source. The sheet conveying roller connected to the driving source rotates, and as shown in FIG. 1, the magnetized pattern applied to the surface of the sheet conveying roll is counted by a magnetoresistive element, and the count information is obtained. Feedback to the control means. The control means stops the driving source at a count number set in advance based on the count information. In this way, accurate conveyance of the sheet material is performed.

Example 2 A sheet conveying roll having the same dimensions as in Example 1 was prepared by the following method. One end of a SUS304 pipe having an outer diameter of 13.05 mm and an inner diameter of 10 mm has a width of 6 mm,
After forming a wide groove with a depth of 0.2 mm and applying / baking γ-iron oxide for magnetic tape, the SUS304 pipe part and γ-iron oxide baked coating part are simultaneously centerless polished to finish to an outer diameter of 13.00 mm. Was. The magnetic characteristics of the γ-iron oxide baked coated portion are as follows: coercive force 24 kA / m, saturation magnetic flux density 0.
It was 1T. SUS304 that comes into contact with the sheet material
Surface roughness Rz = 22μ by sandblasting
After the surface was roughened to m, the same magnetization as in Example 1 was performed on the γ-iron oxide portion. The same evaluation as in Example 1 was performed using this transport roll, and as a result, both the paper feeding accuracy and the print quality were good.

Example 3 A γ-iron oxide baking application portion (encoder portion) and a SUS304 sheet conveyance portion were separately manufactured, and the encoder portion was press-fitted and bonded to the sheet conveyance portion to be integrated. Next, both parts were simultaneously subjected to centerless polishing, and sandblasting and magnetization were performed. The outer diameter, magnetic properties, and surface roughness of the produced transport roll were almost the same as those in Example 2. The same evaluation as in Example 1 was performed using this transport roll, and as a result, both the paper feeding accuracy and the print quality were good.

(Comparative Example 1) Each part was produced in the same manner as in Example 2 except that the γ-iron oxide baking coating part (encoder part) and the SUS304 sheet conveying part were separately produced. The magnetized encoder section was press-fitted and bonded to the sheet conveying section to be integrated. When this was subjected to a print test evaluation in the same manner as in Example 1, the paper feeding accuracy was reduced, and moire-like print image quality was obtained.

Comparative Example 2 The magnetization of γ iron oxide was SUS30.
A sheet conveying roll was produced in the same manner as in Comparative Example 1, except that the adhesive was fixed to the four main body portions and then carried out on the basis of the SUS304 outer diameter. The same evaluation as in Example 1 was performed using this transport roll. As a result, the paper feeding accuracy was reduced, and moire-like print image quality was obtained.

(Comparative Example 3) The outer diameter of the encoder was 13.0.
A sheet conveying roll was produced in the same manner as in Comparative Example 1, except that a ferromagnetic ring of a Fe—Cr—Co alloy finished to 0 mm was used. The same evaluation as in Example 1 was performed using this transport roll. As a result, the paper feeding accuracy was reduced, and moire-like print image quality was obtained.

Examples and comparative examples are shown in the following table. It is the concentricity of the magnetic encoder section and the sheet conveying section that most affects the paper feeding accuracy and the image quality. To ensure a high concentricity, the encoder section and the sheet conveying section are simultaneously processed and substantially integrated. It turns out that it is necessary.

[0035]

[Table 1]

The definition and measurement method of concentricity are as follows. When the sheet transport rolls are set on the printer body, both ends are supported by bearings, so each becomes a rotation reference. Generally, the concentricity is defined as a half value (μm) of the total deflection on the outer peripheral surface of the encoder unit when both outer ends of the sheet conveying unit are supported and rotated by a V block or the like.

[0037]

According to the present invention, a magnetized pattern having a fixed period can be directly applied to a sheet material conveying roll, and this can be detected by a magnetoresistive element, so that the sheet material conveying roll can be stopped accurately. At the same time, the installation space can be made compact, which can contribute to downsizing of an image forming apparatus such as a printer.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part in which a sheet conveying roll according to an embodiment of the present invention is used.

FIGS. 2A and 2B are diagrams showing details of a magnetization pattern of a roll for conveying a sheet material of the present invention, wherein FIG. 2A is an enlarged view of an end portion of the roll 1 and FIG. is there.

FIG. 3 is a sectional view schematically showing a conventional ink jet printer.

FIG. 4 is a plan view schematically showing a conventional ink jet printer.

FIG. 5 is a diagram showing a control system of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conveyance roll of sheet material 2 Magnetization pattern 3 Rough surface 4 MR magnetoresistive element 5 Rotation transmission gear 6 Rotation axis 7 Pinch roll 10 Carriage 11 Inkjet head 12 Carriage shaft 13 Sheet conveyance roller 14 Pinch roller 15 Drive source 16 Plate spring 17 Encoder 18 Intermediate transmission device s Sheet material

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C059 CC08 CC15 CC18 2H072 AA08 AA16 CA01 CB05 JA02 JB03 JB05 3F048 AA01 AB01 BA21 CC01 CC17 DC06 DC19 3F049 AA10 CA01 CA14 DA12 EA24 LA01 LB03

Claims (14)

[Claims] 1. A non-magnetic non-electrolytic N
After applying the i-plated layer, heat treatment is performed to impart hardness and magnetism to the non-magnetic electroless Ni-plated layer, and thereafter, magnetized at a fixed period on at least a part of the circumference of the roll. A method for manufacturing a sheet material conveying roll, comprising forming a pattern. 2. The method according to claim 1, wherein the heat treatment temperature of the sheet material conveying roll is 500 ° C. or less. 3. The method for producing a sheet material transport roll according to claim 1, wherein the hardness of the plating layer after heat treatment of the sheet material transport roll is Hv600 or more. 4. A method for forming a magnetic layer comprising a magnetic recording material on a surface of a roll substrate,
Forming a magnetized pattern having a constant period on the circumference of the portion. 5. The sheet material conveying roll according to claim 1, wherein the coercive force of the magnetic layer of the sheet material conveying roll is 4.5 kA / m or more. Production method. 6. A sheet material transporting method, wherein a magnetic layer portion is formed in a circumferential direction of a roll material having a sheet transporting portion, and the sheet transporting portion and the magnetic layer portion are substantially concentric. Roll manufacturing method. 7. After the roll material having the sheet transport portion and the encoder material having the magnetic layer portion in the circumferential direction are coaxially integrated, the sheet transport portion and the magnetic layer portion are made substantially concentric. A method for manufacturing a roll for transporting a sheet material. 8. A sheet material conveying roll having a magnetic layer comprising an electroless Ni plating layer provided with a magnetized pattern in a circumferential direction on the surface. 9. A sheet material conveying roll having a magnetic layer made of a magnetic recording material having a surface provided with a magnetization pattern in a circumferential direction. 10. A sheet comprising: a sheet conveying portion; and a magnetic layer portion provided with a magnetized pattern in a circumferential direction, wherein the sheet conveying portion and the magnetic layer portion are substantially concentric. Rolls for transporting materials. 11. At least one portion other than the portion where the magnetization pattern of the sheet material conveying roll is applied is Rz3μ.
2. A surface having a rough surface of not less than m.
A roll for conveying a sheet material according to any one of the above items. 12. The sheet material according to claim 11, wherein the rough surface of the sheet material conveying roll is formed by one of a blasting process, a dulling process by laser local heating, and an etching process. Transport roll. 13. The sheet material conveying roll according to claim 8 is rotated while being pressed against the sheet material, and a magnetization pattern of the sheet material conveying roll is detected by a magnetic sensor. A method of conveying a sheet material, wherein the rotation is controlled by a signal from a magnetic sensor. 14. The sheet conveying method according to claim 13, wherein the signal from the magnetic sensor has a repetitive waveform, the number of repetitions is counted, and rotation is controlled at a predetermined count.