JP2009109693A - Belt for image forming apparatus, belt stretching device, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a belt for an image forming apparatus, which prevents crack or tear of the belt even when a large number of sheets are printed, and to provide a belt stretching device or an image forming apparatus which forms an image without any defect due to meandering of the belt. <P>SOLUTION: The belt for the image forming apparatus is provided with a belt body, a guiding member which is adhered to the belt body along a side edge on at least one side of the belt body and a notch provided to the surface of the guide member along the peripheral direction of the belt body. A belt stretching device is provided with the belt and a plurality of rolls for supporting the belt from inside. The image forming apparatus is provided with the belt or the belt stretching device. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a belt for an image forming apparatus, a belt stretching apparatus, and an image forming apparatus.

  As an image forming apparatus using an electrophotographic system, for example, there is an intermediate transfer type color image forming apparatus using an intermediate transfer belt. This is because an intermediate transfer belt that rotates in contact with a transfer portion of an image carrier (for example, a photosensitive drum) on which a toner image is formed by an electrophotographic process is stretched between a plurality of belt support rolls. The plurality of toner images formed on the image carrier are primarily transferred so as to overlap each other at the same position on the intermediate transfer belt, and then the toner image transferred onto the intermediate transfer belt is transferred to a sheet of paper. Secondary transfer is performed collectively. The multicolor toner image secondarily transferred onto the paper is then fixed by a fixing device to form a color image.

  In addition, as an image forming apparatus provided with a belt, there is a so-called tandem type color image forming apparatus that uses a sheet conveying belt that carries a sheet and conveys it through a transfer portion of a plurality of image forming units. . This is because a plurality of image forming units are arranged side by side in order to individually form toner images of each color component, and the sheet conveying belt is placed between a plurality of belt support rolls so as to rotate in contact with the transfer portion of each image forming unit. Each toner formed in each image forming unit by being stretched and transporting the paper adsorbed and supported by the paper transport belt so as to pass through the transfer portion of each image forming unit The image is transferred onto the same sheet in order to be superimposed, and finally fixed to form a color image.

  By the way, in a color image forming apparatus using a belt for an image forming apparatus such as an intermediate transfer belt or a sheet conveying belt, the parallelism of the rotation axis or the outside of the roll is used in a plurality of belt rolls that stretch and support the belt. The belt does not travel straight but travels in the axial direction of the roll due to variations in diameter or uneven tension due to changes in the circumference of the belt itself. Running or meandering may occur. For this reason, the position of each toner image transferred to the belt directly or sequentially onto the paper carried on the belt may be shifted. In this case, the color image finally formed on the paper may be changed. There is a problem that color misregistration or hue change occurs.

In order to prevent such a shift, it has been proposed that a groove is provided on the outer periphery of the roll, and a guide that fits into the groove is provided on the inner peripheral surface of the belt main body of the belt for the image forming apparatus (patent). Literatures 1-3).
However, the belt runs meandering due to the straightness of the guide when the guide is bonded. When the guide cross-sectional shape and the groove shape are the same as described in Patent Document 3, the straightness of the guide is the meandering amount (registration deviation amount). Also, when the side of the groove on the outer periphery of the roll is vertical, the straightness of the guide becomes the meandering amount, the guide does not enter the groove at the straightness change point, the guide rides on the roll, and the belt cracks or breaks. Cause.

Japanese Patent Laid-Open No. 11-338175 JP 2000-304102 A JP 2002-145429 A

  One problem to be solved by the present invention is to provide a belt for an image forming apparatus which is less likely to crack or break even when a large number of sheets are printed. It is an object of the present invention to provide a belt stretching device or an image forming apparatus capable of forming an image free from image defects due to meandering.

The above-described problems of the present invention have been solved by the following means (1), (5) and (7). It is listed together with (2) to (4) and (6) which are preferred embodiments.
(1) A belt body, a guide member bonded to the belt body along a side edge on at least one side of the belt body, and a cut provided on the surface of the guide member along the circumferential direction of the belt body. A belt for an image forming apparatus, comprising:
(2) The entire cross-section of the guide member is polygonal, and the cross-sectional shape of the notch is one type selected from the group consisting of a rectangle, a triangle, and a trapezoid, or a combination thereof. A belt for an image forming apparatus according to claim 1,
(3) For the image forming apparatus according to (1) or (2), the maximum depth of the notch in the cross-sectional shape of the notch is not more than two-thirds of the maximum thickness of the guide member. belt,
(4) The image forming apparatus according to any one of (1) to (3), wherein a maximum width of the notch in the cross-sectional shape of the notch is equal to or less than a half of a width of the guide member. belt,
(5) The image forming apparatus belt according to any one of (1) to (4), and a plurality of rolls that support the image forming apparatus belt by stretching the belt from the inside. Belt tension device,
(6) The guide member provided on the inner surface side of the belt for the image forming apparatus is guided by guide grooves provided on the outer periphery of the roll, and the inclination provided on the side surfaces on both sides of the guide groove is 20 ° or more and 50 °. The belt stretching device according to (5),
(7) An image forming apparatus comprising the belt for an image forming apparatus according to any one of (1) to (4) or the belt stretching apparatus according to (5) or (6). .

  According to the belt of the present invention, even when a large number of sheets are printed, a belt for an image forming apparatus in which the belt is hardly cracked or broken can be obtained. Moreover, according to the belt stretching apparatus or the image forming apparatus of the present invention, an image free from image defects due to meandering of the belt for the image forming apparatus can be formed.

A belt for an image forming apparatus according to the present invention includes a belt main body, a guide member bonded to the belt main body along a side edge on at least one side of the belt main body, and a surface of the guide member. And a notch provided along the circumferential direction of the belt.
Hereinafter, a belt for an image forming apparatus of the present invention and embodiments thereof will be described with reference to the drawings as appropriate.

<Belt for image forming apparatus>
The belt for the image forming apparatus of the present invention (hereinafter sometimes simply referred to as “belt”) is, for example, a paper carrying surface on which a toner image is transferred or a toner image on which a toner image is formed. The belt main body functions as a carrying surface, and a belt-shaped guide member is fixed to the belt main body along at least one side edge of the belt main body. This guide member acts to prevent meandering of the belt body.

Here, the belt of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a belt of the present invention provided with a guide member (partially shown in cross section), and FIG. 2 is an endless belt body viewed from the direction of arrow A in FIG. It is sectional drawing of a guide member.
As shown in FIG. 1, the belt 1 of the present invention is such that a guide member 3 is provided on the surface of a belt body 2 along the side edge. Here, “side edge” means to include an end portion. As shown in FIG. 2, the guide member 3 is preferably provided on the belt body via an adhesive portion 4. However, the mode in which the guide member is directly bonded to the surface of the belt body is not excluded. In FIG. 1, the guide member 3 is preferably provided on the inner side surface of the belt body 2, but may be provided on the outer side surface of the belt body 2 depending on the application to which the belt 1 is applied.

  As shown in FIG. 2, in the belt 1 of the present invention, the guide member 3 is bonded and fixed to the belt main body 2 via a sheet-shaped heat-sensitive adhesive (heat-sensitive adhesive sheet) as an adhesive portion 4. It is preferable. It is also preferable that the guide member 3 is bonded and fixed to the belt body 2 through a layer made of an elastic adhesive.

  The belt 1 of the present invention can be provided in an image forming apparatus, which will be described later, so as to be rotatably supported by a plurality of rolls, and the outer peripheral surface of the belt body 2 carries a sheet carrying surface on which a toner image is transferred. This is a resin belt that can function as an intermediate transfer surface for transferring a toner image, a photosensitive surface for forming a latent image, a charging surface for charging a contacted member, a developer holding surface for holding a developer, and the like. It is preferably used for a photosensitive device, an intermediate transfer device, a transfer separation device, a transport device, a charging device, a developing device, etc. in an electrophotographic copying machine, a laser printer or the like. Here, the material, shape, size, and the like of the belt main body constituting the belt of the present invention can be appropriately set according to the use and function of the belt.

FIG. 3 is a view for explaining a cross-sectional shape of the notch of the guide member.
The entire cross section of the guide member used in the present invention is preferably polygonal. Here, the “whole cross section” refers to the cross sectional shape of the entire guide member before the cutout is provided, and the polygon is preferably a rectangle or a trapezoid, and more preferably a rectangle.
The cross-sectional shape of the notch portion provided on the surface of the guide member can be selected as appropriate, and may be one type selected from the group consisting of a semicircle, an ellipse, a rectangle, a triangle (wedge shape), and a trapezoid. preferable. The cut-out cross-sectional shape of the guide member includes a rectangle shown in FIG. 3A, a triangle shown in FIG. 3B (a wedge shape), and a trapezoid shown in FIG. 3D or FIG. It is more preferable that In the illustrated shapes, the guide member when the guide member is regulated to prevent meandering is not easily deformed by stress, and it is easy to form or process a notch in the guide member.

In the cross-sectional shape of the notch, the maximum depth of the notch is preferably 2/3 or less of the thickness of the guide member, and more preferably 1/3 or more and 2/3 or less. preferable. In the cross-sectional shape of the notch, the maximum width of the notch is preferably less than or equal to one half of the width of the guide member, and more preferably between one quarter and one half. preferable.
When the cross-sectional shape of the notch has the maximum depth and the maximum width within the above ranges, the guide member can absorb the change in straightness of the guide member satisfactorily. As a result, the amount of displacement in the vertical direction of the belt is reduced, and cracks and breaks of the belt body can be almost completely eliminated.

-Belt body-
As the material of the belt body, a resin material having a Young's modulus of 2,000 MPa or more is preferably used. By using a resin material having a Young's modulus of 2,000 MPa or more, deformation due to stress applied to the guide member during belt running can be suppressed. The Young's modulus of the belt body is preferably as large as possible, but is practically 8,000 MPa or less, preferably 6,000 MPa or less. The Young's modulus of the belt body can be controlled within the above range by selecting the chemical structure of the resin material to be used, and the Young's modulus can be increased as the belt includes an aromatic ring structure.
The Young's modulus is obtained by performing a tensile test in accordance with JIS K7127, drawing a tangent line to the curve in the initial strain region of the obtained stress / strain curve, and determining the slope.
Examples of the material of the belt body 2 include polyimide resins, polyamideimide resins, polyester resins, polyamide resins, and fluorine resins. The belt body may or may not have a joint as long as it is annular. The thickness of the belt body is usually preferably about 0.02 to 0.2 mm.
When the belt of the present invention is used particularly as an intermediate transfer belt or a paper transport belt, the belt body is a semiconductive belt using a polyimide resin containing a conductive agent or a polyamideimide resin containing a conductive agent. Preferably used. Here, “semiconductive” means that the ranges of surface resistivity and volume resistivity described later are satisfied.

  For example, a belt body using a polyimide resin or a polyamideimide resin containing a conductive agent is prepared by, for example, applying a polyamideimide solution containing a conductive agent to the outer surface of a cylindrical body, drying and heating, and then a polyamideimide resin. It can be carried out by a known method such as peeling the film from the cylindrical body.

When the belt of the present invention is used as an intermediate transfer belt or a paper conveying belt, the surface resistivity is in the range of 1 × 10 ⁹ Ω / □ to 1 × 10 ¹⁴ Ω / □, and 1 × 10 ⁸ to 1 × 10 ¹³ Ωcm. It is preferable to control the volume resistivity within the range, and for that purpose, a conductive agent (conductive filler) can be added as necessary. Such conductive agents include carbon blacks such as ketjen black, acetylene black, metals or alloys such as graphite, aluminum, nickel, copper alloys, tin oxide, zinc oxide, potassium titanate, tin oxide-indium oxide or tin oxide. -Metal oxides such as antimony oxide composite oxides or conductive polymers such as polyaniline, polypyrrole, polysulfone, polyacetylene, and the like can be suitably used. These conductive fillers may be used alone or in combination of two or more. Among these, carbon black is preferable as the conductive filler in terms of cost. Moreover, processing aids, such as a dispersing agent and a lubricant, can be added as needed.
Here, the surface resistivity is measured in an environment of 22 ° C. and 55% RH using a Hiresta UPMCP-450 UR probe manufactured by Dia Instruments Co., Ltd., and is measured according to JIS K 6911. 24 points of the belt (3 places in the width direction × 8 places in the circumferential direction) are measured, and the average value is defined as the surface resistivity of the belt.

As described above, the belt body needs to be made of a flexible material, and an elastic thermoplastic resin or synthetic rubber is preferably used. Further, from the viewpoint of durability of the belt main body, it is preferable that a main component is a polyimide resin or a polyamideimide resin which is hardly deteriorated or deteriorated.
A manufacturing example of the belt main body is illustrated below. 15 to 35 weights per 100 parts by weight of a resin component of a solvent-soluble polyamideimide resin (Toyobo Co., Ltd .: Viromax HR16NN, etc.) or polyimide resin (Ube Industries Euvanis S, etc.) A coating liquid obtained by adding a part and dispersing the mixture is applied to the outer surface of an aluminum pipe, and then fired to produce a belt body of polyamideimide resin or polyimide resin. Next, with this belt body inserted into a cylindrical pipe and wound, or once removed from the forming pipe and stretched on another biaxial roll, a pair of blades set to a predetermined width are inserted. A belt body having a desired width can be manufactured by rotating the belt once.

(Eliminating the belt width difference)
When a pair of blades set to a predetermined width are inserted into the belt body and rotated once as described above, a normal step is generated at the start point and end point of the cut. This stepped portion is preferably removed by an arc shape. For example, when a step with a width of 0.8 mm occurs at the cut start point and end point position with a belt width of 365 mm, this step can be removed by using a punch with an arc shape having a depth of 2 mm and a chord length of 20 mm. . A portion having a step in the width is a starting point for breaking the belt main body as it is, so that the breaking strength of the belt main body can be improved by removing the step by an arc shape. The belt main body from which the step is removed by the circular arc shape can be rotated at a high speed over a long period without causing cracks or breakage.
Note that such a step difference may be eliminated before the guide member is bonded to the belt body, or may be performed after the guide member is bonded to the belt body.

-Guide member-
When the belt body is stretched around the roll and a shifting force is generated to move in the roll axis direction, a reaction force (stress) of the same strength generated against the shifting force is directly applied to the guide member. . From the viewpoint that this stress can be dispersed and absorbed to some extent by the guide member itself, the guide member is preferably an elastic member having a durometer hardness in a range of A60 to A90, and a durometer hardness in a range of A70 to A90. The inner elastic member is particularly preferable. When the durometer hardness is within the above range, the guide member does not ride on the support roll, and the belt body does not follow the belt support roll. The durometer hardness is measured using a type A durometer at a portion having no notch, with the guide member having a thickness of 6 mm, in accordance with JIS K6253 (1997).

  As the material of the elastic member having the durometer hardness as described above, an elastic body having an appropriate hardness such as polyurethane resin, neoprene rubber, polyurethane rubber, silicon rubber, polyester elastomer, chloroprene rubber, nitrile rubber, or the like can be used. Among these, polyurethane rubber and silicon rubber are particularly preferably used in consideration of electrical insulation, moisture resistance, solvent resistance, ozone resistance, heat resistance, and wear resistance.

  The cross-sectional shape of the guide member can be appropriately determined depending on the use conditions of the belt and the like, but in order to sufficiently obtain the meandering prevention effect, it is preferable that the cross-sectional shape before providing the notch is substantially rectangular. The width of the guide member is usually preferably from 1 to 10 mm, particularly preferably from 4 to 7 mm, from the viewpoints of the effect of preventing meandering and durability. Although thickness in particular is not restrict | limited, From viewpoints of a meandering prevention effect, durability, etc., 0.5-5 mm is preferable normally, and 1-2 mm is especially preferable.

  The guide member having a notch opened on the surface facing the adhesive surface can be molded by injecting urethane rubber or silicon rubber into a mold having a convex portion corresponding to the notch. In addition, after the guide member having no notch is first formed, the part corresponding to the notch can be removed mechanically or by a carbon dioxide laser.

-Production of belt for image forming apparatus-
The belt may be manufactured by bonding the sheet-shaped belt main body and the guide member, and then bonding the end portions of the belt main body to form an annular belt, or after forming the belt main body in an annular shape, the guide member May be bonded to produce a belt. The guide member may be provided only along one side edge of the belt body. However, in the case of a wide belt body, in particular, both side edges of the belt body from the viewpoint of further meandering prevention effect, durability and reinforcement effect. It is more preferable to provide along. The adhesion position (distance from the side edge) of the guide member to the belt body is appropriately set according to the use and function of the belt, the apparatus using the belt, and the like. The guide member may be adhered along the end portion of the belt main body, or may be fixed at a position appropriately entered from the end portion to the center side of the belt main body.

  In FIG. 1, the guide member 3 is bonded to the inner surface of the belt main body 2 in FIG. 1, but the bonding surface of the guide member 3 is on the outer surface of the belt main body 2 depending on the application to which the belt 1 is applied. It may be adhered. The guide member 3 is preferably provided on the entire circumference from the viewpoint of the reinforcing effect of the belt 1, but may have a gap of about 1 to 10 mm at the joint of the guide member.

(Adhesive part)
The guide member is fixed to the belt body in the circumferential direction along at least one side edge of the belt body. The outer periphery of the cross section perpendicular to the circumferential direction of the guide member is a rectangle or a trapezoid in a state before the cutout is provided, and is preferably a rectangle. When the cross-sectional shape of the guide member is rectangular or trapezoidal, one of the two opposing sides is fixed to the belt body, and the remaining one side is provided with an open notch. That is, the guide member has a notch opened on the surface of the guide member along the circumferential direction of the belt body, that is, in the same direction as the rotation direction.

  The belt body and the guide member are fixed to the belt body in the circumferential direction along at least one side edge of the belt body. For this fixing, the belt main body and the guide member are preferably fixed by an adhesive portion, and more preferably bonded by a heat-sensitive adhesive sheet containing an elastic adhesive.

(Elastic adhesive)
The elastic adhesive (elastic adhesive) used in the present invention refers to an adhesive having a durometer hardness in the range of A30 to A50 after the curing reaction, and is a one-component elastic adhesive from the viewpoint of workability and the like. Is preferably used. Further, from the viewpoint of good elasticity and adhesive strength, an elastic adhesive containing a silicon polymer is preferable.
Specific examples of such elastic adhesives include Super X No 8008 mainly composed of acrylic modified silicone polymer manufactured by Cemedine Co., Ltd., Bond MOS7 mainly composed of special modified silicon polymer manufactured by Konishi Co., Ltd. Super XNo 8008 mainly composed of an acrylic-modified silicone polymer manufactured by Cemedine Co., Ltd. is preferably used because of its adhesive strength with the belt body.

When only a silicone polymer-containing elastic adhesive such as Super XNo8008 made of Cemedine Co., Ltd., which is mainly composed of acrylic modified silicone polymer, is used alone as an adhesive part, generally a curing time of 2 hours or more is required at room temperature. Yes, workability is poor. After applying the adhesive to the guide member, the curing time can be shortened by heating at 60 ° C. to 140 ° C.
In the present invention, a heat-sensitive adhesive sheet can be used instead of the one-component elastic adhesive. The heat-sensitive adhesive sheet is particularly preferably a sheet in which an elastic adhesive is blended with a nonwoven fabric. Since the adhesive is held in the nonwoven fabric during the bonding operation, it can be prevented from protruding from the guide member. Further, the heat-sensitive adhesive sheet in which an elastic adhesive is blended with this nonwoven fabric is useful for preventing a failure in which the guide member is displaced or peeled off even when the belt is driven for a long time.

  In addition, it is important that the bonding is performed without bubbles, and usually a method such as bonding with a hand roll, rubber roll, or press, bonding under reduced pressure, or bonding under pressure is used. It is preferable. Further, the surface of the guide member or the belt body may be subjected to corona treatment, blast treatment, primer treatment, aging, or the like to improve the adhesive force.

<Tensioning device, guide member guide method>
Another aspect of the present invention relates to a belt stretching device, and includes the belt and a plurality of rolls that stretch and support the belt from the inside.
That is, the belt of the present invention can be used in a belt stretching device including a plurality of rolls that stretch and support the belt from the inside. The number of rolls is 2 or more, and preferably 2 to 4.
FIG. 4 is a perspective view or a partial cross-sectional view for explaining a guide groove for a guide member provided on the roll.

  In the image forming apparatus described later, the belt of the present invention is preferably stretched by a roll 21 provided with a guide groove 20 for guiding (regulating) the guide member 3 as shown in FIG. In this case, the guide groove 20 may be provided directly on the roll 21, or may be provided on a ring (pulley) 22 that can be freely rotated with the same diameter as the roll provided adjacent to the roll. . In any case, the guide member 3 in the belt 1 of the present invention is regulated along the inclined surface of at least one of the side surfaces of the guide groove 20 to prevent the belt 1 from running or meandering. Can do. 4A is a perspective view for showing the roll 21 provided with the guide groove 20, and FIG. 4B is provided with the guide groove 20 of FIG. 3 is an enlarged cross-sectional view of a main part when the roll 21 is cut along the surface of the roll 21. FIG. In the embodiment shown in FIG. 4, the guide groove 20 is provided in a free rotation ring (pulley) 22 that is coaxial and has the same diameter as the central portion of the roll 21.

An inclination is provided on the side surface of the guide groove 20 to prevent the guide member from climbing, and the inclination angle is indicated by α in FIG.
The present inventors examined the influence of the inclination angle of the guide groove using a guide member without a notch. As a result, when the inclination angle α is small (less than 20 °), the riding-up preventing effect is small and the meandering suppressing effect is also small. When the inclination angle is large (20 ° or more and 50 ° or less), the guide member is not completely contained in the groove, and the belt rotates with the guide member slightly riding on the side surface. In this case, the amount of riding changes according to the change in straightness, so that meandering is eliminated. However, the guide member is always on the side, and belt deformation always occurs. The deformation of the belt increases and the belt cracks and breaks. Further, when the inclination angle is large (greater than 50 °), the effect of preventing leaning is reduced.
When using a belt in which a guide member having a notch is bonded to the belt body, the inclination angle α of both wall surfaces of the guide groove provided on the roll of the belt stretching device is preferably 20 ° or more and 50 ° or less. . Even when the guide member rides on the side surface, the belt notch facilitates the deformation of the guide member, so that the belt can be prevented from running or meandering.
Further, as shown in FIG. 4C, the belt 1 is preferably stretched so that the guide member 3 abuts against an inclined portion on one side surface of the guide groove 20. As described above, the guide member 3 is restricted by the side surface of the belt guide groove 20, so that the belt 1 can be prevented from running or meandering, and the belt can be prevented from cracking or breaking.

As already described with reference to FIG. 4, this belt stretching device is configured to guide the belt meander or roll by guiding the guide member provided on the inner peripheral surface of the belt with a guide groove provided on the outer periphery of the roll or pulley. Can be prevented from getting on. More specifically, meandering of the belt body can be prevented by fitting a guide member adhered to the inner peripheral surface of the belt body into a guide groove provided on the side edge of the roll. In this case, the guide groove may be provided directly on the roll at the side edge of the roll, and the outer surface of the pulley has a rotation shaft and an outer diameter common to the roll and freely rotates adjacent to the roll. May be provided.
In any case, by restricting the guide member from the guide groove, the belt body can be conveyed without being affected by the straightness of the guide member, and the guide member can be prevented from riding on the roll or the pulley, A highly reliable belt without breakage can be obtained.

FIG. 5 is a cross-sectional view of a main part showing another embodiment of the belt stretching device, and a portion showing a mode in which guide members provided on both side edges of the belt main body are regulated by inclined portions at both ends of the support roll. It is sectional drawing.
The guide members provided on both side edges of the belt main body as shown in FIG. 5 can be particularly preferably applied to a wide belt main body. As shown in FIG. 5, the belt 1 is preferably stretched so as to come into contact with inclined surfaces provided on both sides of the roll 21. In this case, the guide member 3 can be prevented from running or meandering by the belt 1 by being restricted by being in contact with any one of the inclined surfaces provided on both sides of the end of the roll. In this case, the angle of inclination provided on both sides of the roll is preferably 20 ° to 50 °.
As yet another embodiment, guide grooves as shown in FIG. 4 may be provided at both ends of the roll to guide the guide members adhered to both side edges of the belt body.

<Image forming apparatus>
The image forming apparatus of the present invention is not particularly limited as long as it is an image forming apparatus using the belt of the present invention, and the belt is used as, for example, a sheet conveying belt or an intermediate transfer belt. As an aspect of the image forming apparatus, a normal monocolor image forming apparatus containing only a single color toner in the developing device, or a toner image carried on an image carrier such as a photosensitive drum is sequentially applied to an intermediate transfer member. Examples thereof include a color image forming apparatus that repeats primary transfer, and a tandem type color image forming apparatus in which a plurality of image carriers including developing devices for respective colors are arranged in series on an intermediate transfer body.

A color image forming apparatus that repeats primary transfer will be described below as an example of the image forming apparatus of the present invention. FIG. 6 is a schematic view showing an image forming apparatus provided with the belt of the present invention as an intermediate transfer belt.
An image forming apparatus shown in FIG. 6 includes a photosensitive drum 101 as an image carrier, an intermediate transfer belt 102 as an intermediate transfer member, a bias roll 103 as a transfer electrode, a tray 104 for supplying paper as a transfer target, BK (Black) toner developing device 105, Y (yellow) toner developing device 106, M (magenta) toner developing device 107, C (cyan) toner developing device 108, belt cleaner 109, peeling claw 113, belt support roll 121, 123 and 124, a backup roll 122, a conductive roll 125, an electrode roll 126, a cleaning blade 131, a paper 141, a pickup roll 142, and a feed roll 143, and the belt of the present invention is used as the intermediate transfer belt 102. It is done.
Since the guide member provided on the inner surface of the intermediate transfer belt 102 is positioned so as to contact the side edge portions of the belt support rolls 121, 123, and 124, the intermediate transfer belt 102 is guided by the belt member during belt running. The intermediate transfer belt 102 does not meander during belt running.

  In the image forming apparatus shown in FIG. 6, the photosensitive drum 101 rotates in the direction of arrow F, and its surface is uniformly charged by a charging device (not shown). An electrostatic latent image of the first color (for example, BK) is formed on the charged photosensitive drum 101 by image writing means such as a laser writing device. The electrostatic latent image is developed with toner by the developing device 105 to form a visualized toner image T. The toner image T reaches the primary transfer portion where the conductive roll 125 is disposed by the rotation of the photosensitive drum 101, and the toner image T is statically moved by applying an electric field having a reverse polarity from the conductive roll 125 to the toner image T. Primary transfer is performed by rotating the intermediate transfer belt 102 in the direction of arrow G while being electrically attracted to the intermediate transfer belt 102. As shown in FIG. 6, the conductive roll 125 may be disposed immediately below the photosensitive drum 101 or may be disposed at a position shifted from directly below the photosensitive drum 101.

  Thereafter, similarly, a second color toner image, a third color toner image, and a fourth color toner image are sequentially formed and superimposed on the intermediate transfer belt 102 to form a multiple toner image. The toner at this time may be a one-component toner or a two-component toner.

  The multiple toner images transferred to the intermediate transfer belt 102 reach the secondary transfer portion where the bias roll 103 is installed by the rotation of the intermediate transfer belt 102. The secondary transfer unit includes a bias roll 103 installed on the surface side on which the toner image of the intermediate transfer belt 102 is carried, a backup roll 122 arranged so as to face the bias roll 103 from the back side of the intermediate transfer belt 102, and this It comprises an electrode roll 126 that rotates in pressure contact with the backup roll 122.

  The paper 141 is picked up one by one from the paper bundle accommodated in the paper tray 104 by the pickup roll 142, and is fed by the feed roll 143 between the intermediate transfer belt 102 and the bias roll 103 of the secondary transfer portion at a predetermined timing. Sent. The toner image carried on the intermediate transfer belt 102 is transferred to the fed paper 141 by the pressure contact conveyance by the bias roll 103 and the backup roll 122 and the rotation of the intermediate transfer belt 102.

  The sheet onto which the toner image has been transferred is peeled from the intermediate transfer belt 102 by operating the peeling claw 113 in the retracted position until the primary transfer of the final toner image is completed, conveyed to a fixing device (not shown), and subjected to pressure / heating processing. The toner image is fixed to make a permanent image. The intermediate transfer belt 102 after the transfer of the multiple toner image to the paper is removed for residual toner by a belt cleaner 109 provided downstream of the secondary transfer portion, and is prepared for the next transfer. The bias roll 103 is attached so that a cleaning blade 131 made of polyurethane or the like is always in contact with it, and foreign particles such as toner particles and paper dust adhering to the transfer are removed.

In the case of transfer of a single color image, the toner image T that has been primarily transferred is immediately secondary transferred and the paper 141 is conveyed to the fixing device. In the case of transfer of a multicolor image by superimposing a plurality of colors, the toner image of each color is transferred. The rotations of the intermediate transfer belt 102 and the photosensitive drum 101 are synchronized so that the primary transfer portions accurately match each other so that the toner images of the respective colors do not shift. In the secondary transfer section, an output pressure (transfer voltage) having the same polarity as the polarity of the toner image is applied to an electrode roll 126 that is in pressure contact with a backup roll 122 disposed opposite to the bias roll 103 via the intermediate transfer belt 102. The toner image is transferred to a sheet by electrostatic repulsion.
As described above, an image can be formed.

Next, another example of the image forming apparatus of the present invention is shown. FIG. 7 is a schematic view showing an image forming apparatus provided with the belt of the present invention as a paper conveying belt.
The image forming apparatus shown in FIG. 7 includes units Y, M, C, and BK, a paper transport belt 206, transfer rolls 207Y, 207M, 207C, and 207BK, a paper transport roll 208, and a fixing device 209. The belt of the present invention is used as the paper transport belt 206.
A guide member (not shown) provided on the inner peripheral side of the paper transport belt 206 is positioned so as to contact the side edges of the belt support rolls 210, 211, 212, and 213. 206 is guided by a belt member. The sheet conveying belt 206 does not cause a problem of meandering when the belt travels because the guide member fits into a guide groove formed in the support roll 210 or the like and travels.

  The units Y, M, C, and BK are respectively provided with photosensitive drums 201Y, 201M, 201C, and 201BK so as to be rotatable at a predetermined peripheral speed (process speed) in the clockwise direction of an arrow. Around the photosensitive drums 201Y, 201M, 201C, and 201BK, there are charging rollers 202Y, 202M, 202C, and 202BK, exposure units 203Y, 203M, 203C, and 203BK, and color developing devices (yellow developing device 204Y and magenta developing device 204M). , Cyan developing device 204C, black developing device 204BK) and photosensitive drum cleaners 205Y, 205M, 205C, 205BK, respectively.

  The four units Y, M, C, and BK are arranged in the order of the units BK, C, M, and Y in parallel with the paper transport belt 206, but the order of the units BK, Y, C, and M, etc. An appropriate order can be set according to the image forming method.

  The sheet conveying belt 206 can be rotated by the belt support rolls 210, 211, 212, and 213 in the counterclockwise direction indicated by the arrow at the same peripheral speed as the photosensitive drums 201 </ b> Y, 201 </ b> M, 201 </ b> C, and 201 </ b> BK. 213 is arranged so that a part thereof located in the middle of 213 is in contact with the photosensitive drums 201Y, 201M, 201C, and 201BK, respectively. The sheet conveying belt 206 is provided with a belt cleaning device 214.

  The transfer rolls 207Y, 207M, 207C, and 207BK are disposed inside the paper transport belt 206 and at positions facing the portions where the paper transport belt 206 is in contact with the photosensitive drums 201Y, 201M, 201C, and 201BK, respectively. The transfer area (nip portion) for transferring the toner image onto the paper (transfer object) 216 via the photosensitive drums 201Y, 201M, 201C, 201BK and the paper transport belt 206 is formed. The transfer rolls 207Y, 207M, 207C, and 207BK may be arranged directly below the photosensitive drums 201Y, 201M, 201C, and 201BK as shown in FIG.

  The fixing device 209 is arranged so that it can be conveyed after passing through the respective transfer areas (nip portions) of the paper conveyance belt 206 and the photosensitive drums 201Y, 201M, 201C, and 201BK.

  The paper 216 is transported to the paper transport belt 206 by the paper transport roll 208.

  In the image forming apparatus shown in FIG. 7, in the unit BK, the photosensitive drum 201BK is rotationally driven. In conjunction with this, the charging roll 202BK is driven to uniformly charge the surface of the photosensitive drum 201BK to a predetermined polarity and potential. Next, the photosensitive drum 201BK whose surface is uniformly charged is exposed imagewise by the exposure device 203BK, and an electrostatic latent image is formed on the surface.

  Subsequently, the electrostatic latent image is developed by the black developing device 204BK. As a result, a toner image is formed on the surface of the photosensitive drum 201BK. The toner at this time may be a one-component toner or a two-component toner.

  The toner image passes through the transfer region (nip portion) between the photosensitive drum 201BK and the paper transport belt 206, and at the same time, the paper 216 is electrostatically attracted to the paper transport belt 206 and transported to the transfer region (nip portion). Then, the image is sequentially transferred onto the surface of the paper 216 by the electric field formed by the transfer bias applied from the transfer roll 207BK.

  Thereafter, the toner remaining on the photosensitive drum 201BK is cleaned and removed by the photosensitive drum cleaner 205BK. Then, the photosensitive drum 201BK is subjected to the next transfer cycle.

  The above transfer cycle is similarly performed in the units C, M, and Y.

The paper 216 onto which the toner image is transferred by the transfer rolls 207BK, 207C, 207M, and 207Y is further conveyed to the fixing device 209 and fixed.
Thus, a desired image is formed on the paper.

Furthermore, another example of the image forming apparatus of the present invention is shown. FIG. 8 is a schematic diagram for explaining a main part of a tandem type image forming apparatus provided with the belt of the present invention as an intermediate transfer belt.
Specifically, a charging roll 83 (charging device) that uniformly charges the surface of the photoreceptor 79, a laser generator 78 (exposure device) that exposes the surface of the photoreceptor 79 to form an electrostatic latent image, and the surface of the photoreceptor 79 are exposed. The formed latent image is developed using a developer, and is attached to a developing device 85 (developing device) that forms a toner image, a primary transfer roll 80 that transfers the developed toner image to an intermediate transfer belt 86, and a photoreceptor 79. A photoreceptor cleaner 84 (cleaning device) for removing the toner and dust and the like, a fixing roll 72 for fixing the toner image on the transfer material, and the like can be optionally provided by a known method as necessary. The photoconductor 79 and the primary transfer roll 80 may be arranged immediately above the photoconductor as shown in FIG. 8, or may be arranged at a position shifted from just above the photoconductor. By providing the belt of the present invention as the intermediate transfer belt 86, high-quality transfer image quality can be stably obtained even in the tandem image forming apparatus having the above-described configuration.

  Further, the configuration of the image forming apparatus shown in FIG. 8 will be described in detail. The image forming apparatus shown in FIG. 8 includes four toner cartridges 71, a pair of fixing rolls 72, a backup roll 73, a tension roll 74, a secondary transfer roll 75, a paper path 76, a paper tray 77, laser generators 78, 4. It includes four photosensitive members 79, four primary transfer rolls 80, a drive roll 81, a transfer cleaner 82, four charging rolls 83, a photosensitive member cleaner 84, a developing device 85, an intermediate transfer belt 86, and the like as main components. .

  First, around the photoconductor 79, a primary transfer roll 80 and a photoconductor cleaner 84 arranged via a charging roll 83, a developing device 85, and an intermediate transfer belt 86 are arranged counterclockwise. However, a developing unit corresponding to one color is formed. Each developing unit is provided with a toner cartridge 71 for replenishing the developer in the developing unit 85. The photosensitive member 79 of each developing unit is exposed to a photosensitive member between the charging roll 83 and the developing unit 85. A laser generator 78 capable of irradiating the surface of the body 79 with laser light corresponding to image information is provided.

  Four developing units corresponding to four colors (for example, cyan, magenta, yellow, and black) are arranged in series in a substantially horizontal direction in the image forming apparatus, and the primary transfer with the photoconductor 79 of the four developing units. An intermediate transfer belt 86 is provided so as to pass through the nip portion with the roll 80. The intermediate transfer belt 86 is stretched by a backup roll 73, a tension roll 74, and a drive roll 81 provided on the inner peripheral side thereof in the following order in the counterclockwise direction. The four primary transfer rolls are located between the backup roll 73 and the tension roll 74. A transfer cleaner 82 for cleaning the outer peripheral surface of the intermediate transfer belt 86 is provided on the opposite side of the drive roll 81 with the intermediate transfer belt 86 in contact with the drive roll 81.

  A toner image formed on the outer peripheral surface of the intermediate transfer belt 86 on the surface of the recording paper conveyed from the paper tray 77 via the paper path 76 to the opposite side of the backup roll 73 via the intermediate transfer belt 86. A secondary transfer roll 75 for transferring the ink is provided so as to be in pressure contact with the backup roll 73.

  Further, a paper tray 77 for stocking recording paper is provided at the bottom of the image forming apparatus, and a backup roll 73 and a secondary transfer roll 75 that constitute a secondary transfer unit from the paper tray 77 via a paper path 76 are provided. The sheet can be supplied so as to pass through the press contact portion. The recording paper that has passed through the pressure contact portion can be further transported by a transport means (not shown) so as to pass through the pressure contact portions of the pair of fixing rolls 72, and can finally be discharged out of the image forming apparatus.

  Next, an image forming method using the image forming apparatus of FIG. 8 will be described. The toner image is formed for each developing unit. After uniformly charging the surface of the photoreceptor 79 rotating counterclockwise by the charging roll 83, the photoreceptor 79 charged by the laser generator 78 (exposure apparatus) is charged. A latent image was formed on the surface, and then this latent image was developed with a developer supplied from a developing device 85 to form a toner image, which was conveyed to the pressure contact portion between the primary transfer roll 80 and the photoreceptor 79. The toner image is transferred to the outer peripheral surface of the intermediate transfer belt 86 that rotates in the direction of arrow C. The photosensitive member 79 after the toner image has been transferred is cleaned of toner, dust and the like adhering to the surface thereof by a photosensitive member cleaner 84 to prepare for the formation of the next toner image.

  The toner images developed for each color development unit are sequentially superimposed on the outer peripheral surface of the intermediate transfer belt 86 so as to correspond to the image information, and are conveyed to the secondary transfer unit by the secondary transfer roll 75. The image is transferred from the sheet tray 77 to the surface of the recording sheet conveyed via the sheet path 76. The recording paper on which the toner image has been transferred is further fixed by being heated by pressure when passing through the pressure contact portion of a pair of fixing rolls 72 constituting the fixing portion, and after the image is formed on the surface of the recording medium. Then, it is discharged out of the image forming apparatus.

(Example 1)
<Production of belt>
(Preparation of belt body)
Solvent-soluble polyamideimide resin (manufactured by Toyobo Co., Ltd .: Viromax HR16NN (solid content 18% by weight, solvent: N-methyl-2-pyrrolidone)) as a polyamideimide resin, carbon black (Degussa as a conductive agent) Special Black 4: Co., Ltd. (pH 3.0, volatile content: 14% by weight) is added in an amount of 25 parts by weight per 100 parts by weight of the resin component, and the pressure is set to 150 MPa using a high-pressure collision disperser (PY made by Genus Co., Ltd.). Then, while passing through an orifice with a diameter of 0.1 mm, the slurry divided into two parts was collided five times to perform dispersion to obtain a polyamide-imide resin solution containing carbon black for a substrate.
This liquid is applied to the outer surface of an aluminum pipe having an outer diameter of 168 mm by a dispenser, spin-dried at 150 ° C. for 30 minutes, heated at 250 ° C. for 1 hour, and polyamide having an inner diameter of 168 mm, a width of 368 mm, and a thickness of 0.08 mm. An imide resin belt (belt body 2) was obtained. The surface resistivity of this belt body was 1.1 × 10 ¹² Ω / □.

(Guide member)
After the guide member is cut into a strip shape from a thermosetting polyurethane sheet (Tigers Polymer Co., Ltd. typelen TR-100-70) having a JIS hardness of 70 degrees, a notch is mechanically provided in FIG. A guide member having a notch having a concave cross section as shown in FIG. The cross-sectional shape before providing the notch is 2.0 mm in thickness and 3.0 mm in width, the maximum depth of the notch is ½ of the maximum thickness of the guide member, and the maximum width of the notch is A guide member that is 1/3 of the maximum width of the guide member was manufactured.

(Adhesion of guide member to belt body)
Super-XNo8008 mainly composed of acrylic modified silicone polymer manufactured by Cemedine Co., Ltd. as an elastic adhesive is applied to the guide member in a thickness of 20 μm, and then applied to the inner surface of the belt on one side of the polyamideimide resin belt. The belt including the guide member having a rectangular notch as shown in FIG. 3A was manufactured by arranging and pressurizing with a pressure of 0.03 Mpa.

<Belt life test>
As shown in FIGS. 4A and 4B, the guide member was guided by a guide groove provided in a pulley that freely rotates at one end of the roll, and the image forming apparatus was run. 100,000 test prints were made using a pulley having a slope angle of 45 ° on both sides of the guide groove. There was no breakage of the belt body, and no color misregistration was observed in the color image.

(Example 2)
As a guide member, the cross-sectional shape of the notch in Example 1 is changed to a shape that is an isosceles triangle as shown in FIG. 3B instead of the rectangle as shown in FIG. Made a belt with a triangular notch guide in exactly the same way.
100,000 test prints were made using pulleys with slopes of 45 ° provided on both sides of the guide groove. There was no breakage of the belt body, and no color misregistration was observed in the color image.

(Example 3)
As a guide member, the cross-sectional shape of the notch in Example 1 is changed to a trapezoidal shape as shown in FIG. 3C instead of the rectangular shape as shown in FIG. In exactly the same way, a belt with a triangular notched guide was produced.
Using a pulley having an inclination angle of 45 °, 100,000 test prints were made. There was no breakage of the belt body, and no color misregistration was observed in the color image.

Example 4
As a guide member, the cross-sectional shape of the notch in Example 1 was changed to a shape that is two continuous triangles as shown in FIG. 3D instead of a rectangle as shown in FIG. Except for the above, a belt with a triangular notch guide was manufactured in the same manner.
Using a pulley having an inclination angle of 45 °, 100,000 test prints were made. There was no breakage of the belt body, and no color misregistration was observed in the color image.

(Example 5)
100,000 test prints were made in exactly the same manner as in Example 1, except that pulleys having slopes of 20 ° on both sides of the guide groove were used. There was no breakage of the belt body, and no color misregistration was observed in the color image.

(Example 6)
100,000 test prints were made in exactly the same manner as in Example 1, except that pulleys having slopes of 50 ° provided on both sides of the guide groove were used. There was no breakage of the belt body, and no color misregistration was observed in the color image.

(Example 7)
100,000 test prints were made in exactly the same manner as in Example 1, except that pulleys having slopes of 0 ° provided on both sides of the guide groove were used. Although there was no breakage of the belt main body, a color shift of the color image was recognized, but it was in a range where there was no practical problem.

(Example 8)
100,000 test prints were made in exactly the same manner as in Example 1 except that pulleys having slopes of 15 ° provided on both sides of the guide groove were used. Although there was no breakage of the belt main body, a color shift of the color image was recognized, but it was in a range where there was no practical problem.

Example 9
100,000 test prints were made in exactly the same manner as in Example 1 except that pulleys having slopes of 55 ° provided on both sides of the guide groove were used. Although there was no breakage of the belt main body, a color shift of the color image was recognized, but it was in a range where there was no practical problem.

(Comparative Example 1)
A belt provided with a guide not having a notch was manufactured in the same manner as in Example 1 except that the guide member was not provided with a notch.
In FIGS. 4 (a) and 4 (b), a test print was performed using a pulley having an inclination angle of 0 ° (vertical) on both side surfaces of the guide groove. The belt body broke after 1,000 prints. In addition, a color shift of the color image was recognized.

(Comparative Example 2)
A test print was produced in the same manner as in Comparative Example 1 except that a belt provided with a guide member having no notch produced in Comparative Example 1 was used with pulleys having inclination angles of 15 ° on both sides of the guide groove. Went. The belt body broke after 3,000 prints. In addition, a color shift of the color image was recognized.

(Comparative Example 3)
A test print was produced in the same manner as in Comparative Example 1 except that the belt provided with the guide member having no notch produced in Comparative Example 1 was used with a pulley having an inclination angle of 45 ° on both sides of the guide groove. Went. The belt body broke after 20,000 prints. In addition, a color shift of the color image was recognized.

(Comparative Example 4)
A test print was produced in the same manner as in Comparative Example 1 except that a belt provided with a guide member having no notch produced in Comparative Example 1 was used with a pulley having an inclination angle of 75 ° on both sides of the guide groove. Went. The evaluation machine stopped due to the 50-print print.

  From the above results, the belt of the present invention provides an image forming apparatus that prevents a deviation run or meandering and produces a print with no color misregistration over a long period of time without causing a reduction in the life of the belt. Can do.

1 is a perspective view illustrating an example of a schematic configuration of a belt for an image forming apparatus of the present invention. It is sectional drawing which shows an example of the adhesion part of a belt main body and a guide member. It is sectional drawing which shows several examples of the cross-sectional shape of the notch of a guide member. It is a fragmentary perspective view or fragmentary sectional view for demonstrating the guide groove of the guide member provided in the roll. It is a fragmentary sectional view which shows the aspect which regulates a guide member with the inclination part of the both ends of a roll. 1 is a schematic configuration diagram of an example of an image forming apparatus provided with a belt for an image forming apparatus of the present invention as an intermediate transfer belt. 1 is a schematic configuration diagram of an example of an image forming apparatus including a belt for an image forming apparatus according to the present invention as a paper conveying belt. 1 is a schematic configuration diagram of an example of a tandem type image forming apparatus provided with a belt for an image forming apparatus of the present invention as an intermediate transfer belt.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Belt for image forming apparatus 2 Belt main body 3 Guide member 4 Adhesion part 20 Guide groove 21 Roll 22 Pulley 86,102 Intermediate transfer belt 206 Paper conveyance belt

Claims (7)

A belt body;
A guide member bonded to the belt body along a side edge of at least one side of the belt body;
A belt for an image forming apparatus, comprising: a notch provided on a surface of the guide member along a circumferential direction of the belt main body.   The image according to claim 1, wherein the entire cross-section of the guide member is a polygon, and the cross-sectional shape of the notch is one type selected from the group consisting of a rectangle, a triangle, and a trapezoid, or a combination thereof. Belt for forming equipment.   The belt for an image forming apparatus according to claim 1, wherein a maximum depth of the notch in the cross-sectional shape of the notch is not more than two-thirds of a maximum thickness of the guide member.   The belt for an image forming apparatus according to claim 1, wherein a maximum width of the notch in the cross-sectional shape of the notch is equal to or less than half of a maximum width of the guide member.   A belt tension comprising: the belt for an image forming apparatus according to claim 1; and a plurality of rolls that support the belt for the image forming apparatus by stretching the belt from the inside. Mounting device.   The guide member provided on the inner surface side of the belt for the image forming apparatus is guided by guide grooves provided on the outer periphery of the roll, and the inclination provided on the side surfaces on both sides of the guide groove is 20 ° to 50 °. The belt stretcher according to claim 5.   An image forming apparatus comprising the belt for an image forming apparatus according to claim 1 or the belt stretching apparatus according to claim 5 or 6.

Images