JP2006256720A - Sheet conveying device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably eliminate static electricity of a recording sheet, while restricting increase of the number of parts items. <P>SOLUTION: A sheet conveying device has a static electricity eliminating part 6c for eliminating static electricity of a charged recording sheet S, and this sheet conveying device is provided with a resist roll Rr for conveying the recording sheet S to an image recording area Q3 for recording images. With this structure, this sheet conveying device can eliminate static electricity, while restricting increase of the number of parts items. Since static electricity is eliminated by the resist roll Rr having large force (nip pressure) for pinching the recording sheet S, static electricity of the recording sheet S can be stably eliminated. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sheet conveying apparatus that conveys a recording sheet on which an image is recorded, and an image forming apparatus such as a printer, a FAX, a copying machine including the sheet conveying apparatus, and a multifunction peripheral having these functions. The present invention relates to a sheet conveying apparatus and an image forming apparatus having a configuration capable of discharging a recording sheet that is frictionally charged during conveyance.

In a conventional image forming apparatus, when a recording sheet on which an image is recorded is conveyed, the recording sheet may be charged by contact between the recording sheet and a conveyance roll or friction. In particular, when the paper is fed, the friction between the paper feed roll and the recording sheet is large, so that it is easily charged.
When the recording sheets are charged, there is a problem that the recording sheets are adsorbed by static electricity on the paper discharge tray, resulting in poor alignment. Also, in an electrophotographic image forming apparatus in which toner is transferred onto a recording sheet by a transfer device, if the recording sheet is conveyed to a transfer area in a charged state, the toner is not properly transferred to the recording sheet, and toner scattering, etc. There is a problem that the image failure occurs and the image quality deteriorates.

In order to solve such a problem, it is necessary to neutralize the charged recording sheet.
The following prior arts (J01) and (J02) are well known as techniques for neutralizing a charged recording sheet.
(J01) Techniques described in Patent Document 1 (Japanese Patent Laid-Open No. 5-132175), Patent Document 2 (Japanese Patent Laid-Open No. 5-213470) and Patent Document 3 (Japanese Patent Laid-Open No. 6-124791) Describes a technique for discharging a recording sheet by disposing a discharging member on a sheet conveying path through which the recording sheet is conveyed. In particular, Patent Documents 1 and 2 describe a static eliminating member that performs static elimination by making contact with a recording sheet, and Patent Documents 2 and 3 are arranged in proximity to the recording sheet and eliminate static electricity without contacting the recording sheet. A static elimination member that performs the above is described.

(J02) Technology described in Patent Document 4 (Japanese Patent Application Laid-Open No. 6-20791) In Patent Document 4, an alternating high voltage is applied between a pair of conductive members that elastically sandwich both front and back surfaces of a dielectric. Thus, a technique for discharging the dielectric is described. In particular, FIG. 8 of Patent Document 4 describes a technique for discharging a dielectric by applying an alternating high voltage to a pair of conductive rubber rolls.

JP-A-5-132175 (paragraph numbers “0030” to “0042”, FIG. 1, FIG. 2, FIG. 4) JP-A-5-213470 ("0092" to "0100", FIG. 4, FIG. 21 to FIG. 27) JP-A-6-124791 ("0013" to "0022", FIG. 1) JP-A-6-20791 ("0014" to "0021", "0032" to "0042", Fig. 1, Fig. 6 to Fig. 10)

However, in the prior art (J01), since it is necessary to separately arrange a static eliminating member for static elimination, there is a problem that the number of parts increases and the cost increases.
In the structure of the static eliminating member of the prior art (J02), since the elastic member extending in the longitudinal direction (sheet width direction) is used for performing static elimination on the entire surface of the dielectric, the dielectric and the elastic member are disposed in the entire longitudinal direction. It is difficult to make a stable contact. In other words, the conventional technique (J02) has a problem that it is difficult to stably remove a dielectric such as a recording sheet.

In view of the above circumstances, the present invention has the following description (O01) as a technical problem.
(O01) To stably remove static electricity from the recording sheet while suppressing an increase in the number of parts.

(Invention)
Next, the present invention that has solved the above problems will be described. In order to facilitate the correspondence between the elements of the present invention and elements of specific examples (examples) of the embodiments described later, Add the code enclosed in parentheses. The reason why the present invention is described in correspondence with the reference numerals of the embodiments described later is to facilitate understanding of the present invention, and not to limit the scope of the present invention to the embodiments.

(First invention)
In order to solve the technical problem, a sheet conveying apparatus according to a first aspect of the present invention comprises the following structural requirement (A01):
(A01) A registration roll having a charge eliminating portion (6c, 6c ″, 16c) for discharging the charged recording sheet (S) and conveying the recording sheet (S) to an image recording area (Q3) where an image is recorded (Rr).

(Operation of the first invention)
In the sheet conveying apparatus according to the first aspect of the present invention having the structural requirement (A01), the registration roll (Rr) conveys the recording sheet (S) to an image recording area (Q3) where an image is recorded. The charge removal units (6c, 6c ″, 16c) of the registration roll (Rr) perform charge removal on the charged recording sheet (S).
Therefore, in the sheet conveying apparatus according to the first aspect of the invention, the recording sheet (S) is neutralized by the neutralization units (6c, 6c ″, 16c) provided on the registration roll (Rr), so that an increase in the number of parts can be suppressed. Further, since the charge removal is performed by the registration roll (Rr) having the characteristic of stably transporting the recording sheet (S), the recording sheet (S) and the charge removal portions (6c, 6c ″, 16c) are stably contacted. Or the space (clearance) between the recording sheet (S) and the charge removal portions (6c, 6c ″, 16c) can be secured stably. Therefore, the recording sheet (S) can be stably discharged. Can do.

(First Embodiment 1)
A sheet conveying apparatus according to a first aspect of the present invention is characterized in that, in the first aspect, the following structural requirements (A02) and (A03) are provided.
(A02) A paper feed roll (Rp) that rotates and feeds paper while being in contact with a part of the sheet width direction perpendicular to the sheet conveyance direction of the recording sheet (S),
(A03) With respect to the sheet width direction perpendicular to the sheet conveying direction, the static elimination units (6c, 6c ″, provided at positions corresponding to the contact positions of the sheet feeding roll (Rp) and the recording sheet (S). 16c).

(Operation of Form 1 of the First Invention)
In the sheet conveying apparatus according to the first aspect of the first invention having the structural requirements (A02) and (A03), the sheet feeding roll (Rp) is one in the sheet width direction perpendicular to the sheet conveying direction of the recording sheet (S). The paper is rotated while being in contact with the section. The charge removal units (6c, 6c ″, 16c) are provided at positions corresponding to the contact position between the sheet feeding roll (Rp) and the recording sheet (S) in the sheet width direction perpendicular to the sheet conveying direction. Therefore, in the sheet conveying apparatus according to the first aspect of the present invention, the contact position of the recording sheet (S) charged by the contact with the paper feed roll (Rp) is set to the charge eliminating section (6c, 6c ″, 16c). The charge can be removed by the above.

(First Embodiment 2)
A sheet conveying apparatus according to a second aspect of the present invention is characterized in that, in the first aspect of the first aspect of the present invention, the following structural requirement (A04) is provided.
(A04) The charge eliminating portion (6c, 6c ″, 16c) provided facing the same surface as the surface with which the sheet feeding roll (Rp) contacts the recording sheet (S).
(Operation of the second aspect of the first invention)
In the sheet conveying apparatus according to the second aspect of the first invention having the structural requirement (A04), the charge removal units (6c, 6c ″, 16c) are in contact with the sheet feeding roll (Rp) of the recording sheet (S). Therefore, in the sheet conveying apparatus according to the second aspect of the first invention, the charged contact position can be discharged efficiently.

(Embodiment 3 of the first invention)
A sheet conveying apparatus according to a third aspect of the first invention is characterized in that, in any one of the first invention and the first and second aspects of the first invention, the following structural requirement (A05) is provided.
(A05) The neutralization section (6c, 6c ″, 16c) that neutralizes the recording sheet (S) in contact with or in proximity to the recording sheet (S) passing through the registration roll (Rr).
(Operation of the third aspect of the first invention)
In the sheet conveying apparatus according to the third aspect of the first invention having the structural element (A05), the static eliminating portions (6c, 6c ″, 16c) are in contact with or close to the recording sheet (S) passing through the registration roll. The recording sheet (S) can be neutralized.

(First aspect 4)
A sheet conveying apparatus according to a fourth aspect of the first invention is characterized in that in any one of the first invention and the first to third aspects of the first invention, the following structural requirement (A06) is provided.
(A06) The static eliminating portion (6c, 6c ″, 16c) made of conductive fiber.
(Operation of the fourth aspect of the first invention)
In the sheet conveying apparatus according to the fourth aspect of the first invention having the structural requirement (A06), the recording sheet (S) is neutralized by the neutralization sections (6c, 6c ″, 16c) composed of conductive fibers.

(First embodiment 5)
A sheet conveying apparatus according to a fifth aspect of the first invention is characterized in that, in any one of the first invention and the first to fourth aspects of the first invention, the following structural requirement (A07) is provided.
(A07) The static eliminator (6c ″) constituted by the fur brush (6c ″).
(Operation of the fifth aspect of the first invention)
In the sheet conveying apparatus according to the fifth aspect of the first invention having the structural requirement (A07), the recording sheet (S) is neutralized by the neutralizing section (6c ″) configured by a fur brush (6c ″).

(First embodiment 6)
A sheet conveying apparatus according to a sixth aspect of the first invention is characterized in that, in any of the first invention and the first to fourth aspects of the first invention, the following structural requirement (A08) is provided.
(A08) The static eliminating portion (6c) formed of the nonwoven fabric (6c).
(Operation of the sixth aspect of the first invention)
In the sheet conveying apparatus according to the sixth aspect of the first invention having the structural requirement (A08), the charge removal is performed by the charge removal portion (6c) formed of the nonwoven fabric (6c).

(First embodiment 7)
A sheet conveying apparatus according to a seventh aspect of the first invention is characterized in that, in any of the first invention and the first to sixth aspects of the first invention, the following structural requirement (A09) is provided.
(A09) The static eliminating section (6c, 6c ″, 16c) connected to the ground.
(Operation of the first aspect 7)
In the sheet conveying apparatus according to the seventh aspect of the first invention having the structural requirement (A09), neutralization is performed by the neutralization units (6c, 6c ″, 16c) connected to the ground.

(Second invention)
In order to solve the technical problem, an image forming apparatus according to a second aspect of the invention includes the sheet conveying apparatus according to any one of the first aspect and the first to seventh aspects of the invention.
(Operation of the second invention)
Since the image forming apparatus according to the second aspect of the present invention having the above-described constituent elements includes the sheet conveying device according to any one of the first aspect and the first to seventh aspects of the present invention, the charge eliminating provided on the registration roll (Rr). Since the recording sheet (S) is neutralized by the sections (6c, 6c ″, 16c), an increase in the number of components can be suppressed. Also, a registration roll having a characteristic of stably conveying the recording sheet (S). Since the static elimination is performed by (Rr), the recording sheet (S) and the static eliminator (6c, 6c ″, 16c) are stably brought into contact, or the recording sheet (S) and the static eliminator (6c, 6c ″, 16c) Thus, the recording sheet (S) can be stably discharged.

The above-described present invention has the following effect (E01).
(E01) It is possible to stably neutralize the recording sheet while suppressing an increase in the number of parts.

Next, specific examples (examples) of the embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following examples.
In order to facilitate understanding of the following description, in the drawings, the front-rear direction is the X-axis direction, the left-right direction is the Y-axis direction, the up-down direction is the Z-axis direction, and arrows X, -X, Y, -Y, The direction indicated by Z and -Z or the indicated side is defined as the front side, the rear side, the right side, the left side, the upper side, the lower side, or the front side, the rear side, the right side, the left side, the upper side, and the lower side, respectively.
In the figure, “•” in “○” means an arrow heading from the back of the page to the front, and “×” in “○” is the front of the page. It means an arrow pointing from the back to the back.

FIG. 1 is a longitudinal sectional view of an image forming apparatus (digital copying machine) according to the present invention.
In FIG. 1, an image forming apparatus (digital copying machine) U according to the first embodiment includes an image forming apparatus main body (printer unit) U1 as an IOT (image output terminal, that is, an image recording unit), and IIT (image input terminal, that is, an image recording unit). A scanner unit U2 as an image reading unit) and an automatic document feeder (ADF: auto document feeder) U3.
The automatic document feeder U3 is supported on the platen glass PG on the top surface of the IIT.
A sheet discharge tray TRh is provided between the upper surface of the IOT and the upper IIT.

In FIG. 1, the automatic document feeder U3 has a document feed tray TG1 on which a plurality of documents Gi to be copied are stacked. Each of the plurality of documents Gi placed on the document feed tray TG1 is sequentially discharged by the document transport roller Rg to the document discharge tray TG2 through the copy position on the platen glass PG. . The automatic document feeder U2 is rotatable with respect to the upper surface of the platen glass PG by a hinge shaft (not shown) provided in the rear end portion (-X end portion) extending in the left-right direction (Y-axis direction). When the operator places the document Gi on the platen glass PG by hand, the document Gi is rotated upward.
The image forming apparatus body U1 has a control panel UI (user interface) on which a user inputs an operation command signal such as a copy start.

An exposure optical system A for reading a document image is disposed below the transparent platen glass PG.
Reflected light from a document transported to the upper surface of the platen glass PG by the automatic document transport device U3 or a document (not shown) manually placed on the platen glass PG is passed through the exposure optical system A to a CCD ( It is converted into an electrical signal by a solid-state imaging device).
An IPS (image processing system, image processing unit) converts RGB electrical signals input from the CCD into image data and temporarily stores them, and the image data is used as image data for forming a latent image at a predetermined timing. Output to the laser drive circuit DL.
The laser drive circuit DL outputs a laser drive signal to the ROS (latent image forming apparatus) according to the input image data. The system controller C controls operations of the UI (user interface), the IPS and laser drive signal output device DL, and a power supply circuit E for applying a bias voltage to a developing roll Ga and a transfer roll T described later.

In FIG. 1, a toner image carrier PR constituted by a photosensitive drum rotates in the direction of an arrow integrally with its axis PRa, and the surface of the toner image carrier PR is uniformly charged by a charging roll CR and then a latent image. At the writing position, exposure scanning is performed with a laser beam L of the ROS (latent image forming apparatus) to form an electrostatic latent image.
The surface of the toner image carrier PR on which the electrostatic latent image is formed rotates and moves sequentially through the developing area facing the developing roll Ga and the transfer area Q3 facing the transfer roll T.
The developing unit G includes a developing container V that rotatably supports the developing roll Ga and the developer stirring members Gb, Gc, and Gd and that stores the developer, and the toner image carrier PR that passes through the developing region. The upper electrostatic latent image is developed into a toner image.
The toner image carrier PR, the charging roll CR, the latent image forming device ROS, and the developing device G constitute a toner image forming device (PR + CR + ROS + G).

A plurality of paper feed trays TR1 to TR4 for storing recording sheets to be conveyed to the transfer area Q3 are a pair of rails arranged along the front-rear direction (the direction perpendicular to the paper surface in FIG. 1) on the left and right sides thereof. It is supported so as to be movable along RL1 and RL1.
The recording sheets S taken out from each of the paper feed trays TR1 to TR4 by a pick-up roll (paper feed roll) Rp are separated one by one by a separating roll Rs having a retard roll and a feed roll, and are fed to the sheet transport path SH. The sheet is transported by a plurality of sheet transporting rolls Ra arranged along, and is transported to the transfer region Q3 by a registration roll (registration roll) Rr at a predetermined timing.
Further, the recording sheet S fed from the manual feed tray TR0 (not shown in FIG. 1) is also transported to the transfer region Q3 by the sheet transport roll Ra and the registration roll Rr arranged along the sheet transport path SH.

A transfer roll (transfer device) T to which a transfer bias is applied is disposed in the transfer region Q3. The transfer roll T is in pressure contact with the toner image carrier PR in the transfer region Q3, and transfers the toner image on the toner image carrier PR to the recording sheet S passing through the transfer region Q3.
After the toner image on the surface of the toner image carrier PR is transferred to the recording sheet S in the transfer region Q3, the toner image carrier PR collects residual toner attached to the surface by the cleaner CL. The toner image carrier PR from which the residual toner adhering to the surface is collected by the cleaner CL is charged by the charging roll CR.

  The recording sheet S on which the unfixed toner image is transferred in the transfer area Q3 is conveyed to the fixing area Q4 with the toner image unfixed, and the toner image is fixed by the fixing device F disposed in the fixing area Q4. The The fixing device F includes a heating roll (heating rotary member) Fh that rotates while being pressed against each other, and a pressure roll (pressure rotating member) Fp, and a pressure contact region between the heating roll Fh and the pressure roll Fp. As a result, the fixing region Q4 is formed. A heater H extending in the rotation axis direction (X-axis direction perpendicular to the paper surface of FIG. 1) is disposed inside the heating roll Fh. A fixing rotation member (Fh + Fp) is constituted by the heating roll Fh and the pressure roll Fp. A fixing device F is constituted by the fixing rotating member (Fh + Fp), the heater H, and the like.

The recording sheet S on which the fixing toner image is formed is then guided by a sheet guide and conveyed to a paper discharge roll (standard discharge roll) R1, and is discharged to the sheet discharge tray TRh by the paper discharge roll R1. The paper discharge roll (standard discharge roll) R1 has an upper paper discharge drive roll R1a and a lower paper discharge driven roll R1b.
In FIG. 1, on the left side of the paper discharge roll R1, there are two sheet reverse discharge guide SG and optional discharge roll R2 mounted in the image forming apparatus main body U1 when the optional apparatus (sheet reverse apparatus) U4 is mounted. It is shown with a dashed-dotted line (virtual line). The option discharge roll R2 has a lower option discharge drive roll R2a and an upper option discharge driven roll R2b.

When image recording is performed on both sides of the recording sheet, the recording sheet on which single-side recording has been performed is retransmitted from the optional discharge roll R2 to the transfer area Q3 through the sheet reversing device U3 while being reversed.
The sheet reversal discharge guide SG and the optional discharge roll R2 are members (option discharge members) that are used only when the sheet reversing device U4, which is an optional device, is mounted on the image forming apparatus main body U1, and the sheet reversing device U4. Are mounted in the image forming apparatus main body U1 together with an optional driving force transmission member (not shown) for driving the optional discharge roll R2. In addition, in place of the optional sheet reversing device U4, a finisher for aligning the recording sheets S on which images have been recorded in order of pages (folding or collating) or stapling (punch hole creation or stapling) ( It is also possible to attach a post-processing device.
The pickup roll Rp, the separation roll Rs, the transport roll Ra, the registration roll Rr, the paper discharge rolls R1, R2, and the like constitute a sheet transport device (Ra to Rs).

(Description of cash register roll)
FIG. 2 is an explanatory diagram of a sheet conveyance path on which a recording sheet is conveyed and main conveyance members arranged on the sheet conveyance path.
FIG. 3 is an explanatory diagram viewed from the direction of arrow III in FIG.
FIG. 4 is an explanatory view of a registration roll, FIG. 4A is a cross-sectional view taken along line IVA-IVA in FIG. 3, and FIG. 4B is a cross-sectional view taken along line IVB-IVB in FIG.
2 to 4, in the image forming apparatus U according to the first embodiment, the pickup roll Rp has two roll portions 1 (see FIG. 3) disposed at positions separated in the roll axis direction. 1 is rotated in a state where it contacts the upper surface (contact surface) of the recording sheet S, and the recording sheet S is fed.

The registration roll Rr includes a rubber roll 6 disposed on the contact surface side of the recording sheet S with which the roll unit 1 contacts, and a metal roll 7 disposed opposite to the rubber roll 6. In FIG. 4, the rubber roll 6 has a roll shaft 6a and an insulating elastic rubber layer 6b coated around the roll shaft 6a.
In FIG. 3, in the central portion of the rubber roll 6 in the roll axis direction, a conductive static elimination layer (static elimination part) having the same width as the roll part 1 is provided at positions (two places) corresponding to the roll part 1 of the pickup roll Rp. 6c is provided. The charge removal layer 6c is made of a nonwoven fabric containing conductive fibers, and the nonwoven fabric is covered with an elastic rubber layer 6b. In the registration roll Rr of Example 1, the elastic rubber layer 6b of the portion covered with the charge removal layer 6c is coated with the charge removal layer 6c so that the outer diameter of the registration roll Rr is the same along the roll axial direction 6a. It is formed to have a smaller diameter than the part that is not.
In FIG. 3, the surface of the charge removal layer 6 c of the rubber roll 6 is in contact with a conductive contact roll 8 at a position opposite to the position facing the metal roll 7, and the contact roll 8 is grounded ( Grounded).

(Operation of Example 1)
FIG. 5 is a diagram for explaining the operation of the first embodiment, and is a diagram for explaining a case where static elimination is not sufficient in the prior art.
In the image forming apparatus U according to the first embodiment having the above-described configuration, since the roll unit 1 of the pickup roll Rp is relatively strongly in frictional contact with the surface of the recording sheet S at the start of paper feeding, the recording sheet S and the roll unit 1 are in contact with each other. The contact position may be charged. The charged recording sheet S is conveyed to the transfer area (image recording area) Q3 by the registration roll Rr. At this time, the charge recording sheet S is brought into contact with the roll section 1 by the charge removal layer 6c disposed at a position corresponding to the roll section 1. The charge at the position is removed. On the other hand, in FIG. 5, when the charge removal layer 6c is not provided, since the transfer and fixing are performed in a state where the contact position between the recording sheet S and the roll unit 1 is not discharged, a belt-like image failure S1 may occur.

Therefore, in the image forming apparatus U according to the first exemplary embodiment, the recording sheet S that has been neutralized by the neutralization layer 6c is conveyed to the transfer region Q3 in a state of being uniformly neutralized in the paper width direction. As a result, the toner image on the surface of the photoconductor PR is faithfully transferred to the recording sheet S, and it is possible to prevent the image quality deterioration such as toner scattering. In addition, since it is not necessary to separately provide a charge eliminating member for discharging the recording sheet S on the sheet conveyance path SH, an increase in the number of parts can be suppressed, and costs can be reduced.
In the image forming apparatus U according to the first exemplary embodiment, the charge removal layer 6c is provided on the registration roll Rr. In order to correct the inclination (skew) of the recording sheet S that has been conveyed and accurately convey it to the transfer region Q3, the registration roll Rr has a contact pressure (nip pressure) between the rubber roll 6 and the metal roll 7 to It is set higher than the sheet conveying roll Ra or the like. Therefore, the recording sheet S passing between the rubber roll 6 and the metal roll 7 is surely in contact with the charge removal layer 6c and is discharged. As a result, in the image forming apparatus U according to the first exemplary embodiment, it is possible to stably and reliably remove the charge on the recording sheet S.

6A and 6B are explanatory views of the registration roll of Example 2, FIG. 6A is a plan view, and FIG. 6B is a sectional view taken along the line VIB-VIB in FIG. 6A.
In the description of the second embodiment, components corresponding to those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
The second embodiment is different from the first embodiment in the following points, but is configured in the same manner as the first embodiment in other points.
In FIG. 6, the rubber roll 6 ′ of the registration roll Rr of Example 2 is formed so that the outer diameter of the elastic rubber layer 6 b ′ covered with the static elimination layer (static elimination part) 6 c is smaller than that in the case of Example 1. (In FIG. 6B, refer to the alternate long and short dash line indicating the outer diameter of the rubber roll 6 ′ other than the static eliminating portion). Therefore, the static elimination layer 6c and the metal roll 7 are separated. The interval (clearance) between the charge removal layer 6c and the metal roll 7 is set to such an interval that the charge on the surface of the adjacent recording sheet S can be removed, and the recording sheet is interposed between the rubber roll 6 and the metal roll 7. When S passes, the static elimination layer 6c and the recording sheet S are close to each other, and the static elimination is performed without contact.

(Operation of Example 2)
In the image forming apparatus U according to the second embodiment having the above-described configuration, the static elimination layer 6c does not come into contact with the recording sheet S and can be reliably eliminated, so that wear of the static elimination layer 6c can be reduced. As a result, it is possible to prevent a reduction in static elimination performance due to wear of the static elimination layer 6c. In addition, the image forming apparatus U including the registration roll Rr according to the second embodiment has the same effects as the image forming apparatus U according to the first embodiment. In Example 2, since the charge can be removed by non-contact discharge, the width of the charge removal layer 6c in the roll axis direction can be set according to the dischargeable range, and can be set narrower than the width of the pickup roll Rp. It is.

FIG. 7 is an explanatory view of a registration roll of Example 3, FIG. 7A is a plan view, and FIG. 7B is a sectional view taken along the line VIIB-VIIB in FIG. 7A.
In the description of the third embodiment, components corresponding to those of the first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. The third embodiment is different from the first and second embodiments in the following points, but is configured in the same manner as the first and second embodiments in other points.
In FIG. 7, in the registration roll Rr of Example 3, the charge removal portion is configured by a fur brush 6 c ″ in which conductive brush hairs are implanted.
(Operation of Example 3)
The image forming apparatus U according to the third embodiment having the above configuration has the same effects as the image forming apparatus U according to the first embodiment.

FIG. 8 is a diagram for explaining the positional relationship between the registration roll and the paper feed roll in the fourth embodiment, and corresponds to FIG. 3 in the first embodiment.
In the description of the fourth embodiment, components corresponding to the components of the first to third embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. The fourth embodiment is different from the first to third embodiments in the following points, but is configured in the same manner as the first to third embodiments in other points.
In FIG. 8, in the registration roll Rr of Example 4, the width in the roll axis direction of the static elimination layer (static elimination part) 16 is set wider than the width of the contact area between the two roll parts 1 of the pickup roll Rp and the recording sheet S. Has been.

(Operation of Example 4)
In the image forming apparatus U according to the fourth embodiment having the above-described configuration, since the width of the charge removal layer 16 is wider than the width of the contact area of the roll unit 1, the charged charges in the contact area can be stably and reliably discharged. . In addition, the image forming apparatus U according to the fourth embodiment has the same effects as the image forming apparatus U according to the first embodiment.

FIG. 9 is an explanatory diagram of the registration roll of the fifth embodiment and corresponds to FIG. 4B of the first embodiment.
In the description of the fifth embodiment, components corresponding to those of the first to fourth embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. The fifth embodiment is different from the first to fourth embodiments in the following points, but is configured in the same manner as the first to fourth embodiments in other points.
In FIG. 9, the rubber roll 6 of the registration roll Rr of Example 5 is configured by a conductive rubber layer 6d only in a portion where the charge removal layer (charge removal portion) 6c is covered, instead of the insulating elastic rubber layer 6b. . In the registration roll Rr of the fifth embodiment, the contact roll 8 of the first to fourth embodiments is omitted, and the roll shaft 6a is grounded.

(Operation of Example 5)
In the image forming apparatus U of Example 5 having the above-described configuration, the charge removal layer 6c is connected to the ground via the conductive rubber layer 6d and the roll shaft 6a. Therefore, the image forming apparatus U according to the fifth embodiment also has the same effects as the first embodiment.

(Change example)
As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the said Example, A various change is performed within the range of the summary of this invention described in the claim. It is possible. Modification examples (H01) to (H08) of the present invention are exemplified below.
(H01) The present invention is not limited to a copying machine, but can be applied to an image forming apparatus such as a printer, a FAX, or a multifunction peripheral having a plurality of functions. Further, the present invention is not limited to a monochrome image forming apparatus, and can be applied to a full-color image forming apparatus.

(H02) In Examples 1 to 4, the grounded contact roll 8 that contacts the surface of the charge removal layer 6c is used. However, the contact roll can be omitted and the metal roll 7 can be grounded. In this case, in the configurations of Examples 1 and 3, the static elimination unit is electrically connected to the ground. However, in the configuration of Example 2, the static elimination unit (static elimination layer 6c) is not electrically connected to the ground (non-conductive). In each of the above embodiments, a self-discharge type nonwoven fabric can be used. In this case, the contact roll 8 can be omitted.
(H03) In each of the above embodiments, the static eliminator is connected to the ground. However, in order to neutralize the charged charge, it can be connected to a DC power source or an AC power source having a polarity opposite to the charged polarity, or a DC / AC superimposed power source. It is. In addition, since the transfer roll T to which a high voltage is applied is disposed near the registration roll Rr and there is a risk of leakage occurring through the recording sheet, it is desirable to take countermeasures against leakage.

(H04) In each of the above embodiments, the number and width of the roll portions 1 of the pickup roll Rp can be appropriately changed according to the design. Further, the thickness (wall thickness), width, etc. of the elastic rubber layers 6b, 6b ′, 6d and the charge removal layers 6c, 6c ″, 16c can be appropriately changed.
(H05) In each of the above embodiments, a rubber roll can be used instead of the metal roll 7. Moreover, the metal roll 7 is not limited to electroconductivity, An insulating and semiconductive thing can be used. It is also possible to constitute a registration roll with a pair of rubber rolls 6 and 6 having the same configuration.
(H06) In each of the above embodiments, the static eliminator is composed of a non-woven fabric or fur brush containing conductive fibers, but the material and shape are not limited to these, and any configuration that can be neutralized (for example, conductive metal Or resin containing a conductive agent, rubber, or the like).

(H07) In each of the above embodiments, the elastic rubber layers 6b, 6b 'and 6d may be omitted, and the static eliminating layers 6c, 6c "and 16c may be provided directly on the conductive roll shaft 6a.
(H08) In Examples 1 and 5, the thickness of the static elimination layer 6c and the elastic rubber layer 6b was adjusted so that the diameters of the registration rolls Rr in the roll axis direction were the same, but the functions of the registration rolls Rr should not be hindered. For example, it is possible to make the outer diameter of the portion of the static elimination layer larger than the other portion.

FIG. 1 is a longitudinal sectional view of an image forming apparatus (digital copying machine) according to the present invention. FIG. 2 is an explanatory diagram of a sheet conveyance path on which a recording sheet is conveyed and main conveyance members arranged on the sheet conveyance path. FIG. 3 is an explanatory diagram viewed from the direction of arrow III in FIG. FIG. 4 is an explanatory view of a registration roll, FIG. 4A is a cross-sectional view taken along line IVA-IVA in FIG. 3, and FIG. 4B is a cross-sectional view taken along line IVB-IVB in FIG. FIG. 5 is a diagram for explaining the operation of the first embodiment, and is a diagram for explaining a case where static elimination is not sufficient in the prior art. 6A and 6B are explanatory views of the registration roll of Example 2, FIG. 6A is a plan view, and FIG. 6B is a sectional view taken along the line VIB-VIB in FIG. 6A. FIG. 7 is an explanatory view of a registration roll of Example 3, FIG. 7A is a plan view, and FIG. 7B is a sectional view taken along the line VIIB-VIIB in FIG. 7A. FIG. 8 is a diagram for explaining the positional relationship between the registration roll and the paper feed roll in the fourth embodiment, and corresponds to FIG. 3 in the first embodiment. FIG. 9 is an explanatory diagram of the registration roll of the fifth embodiment and corresponds to FIG. 4B of the first embodiment.

Explanation of symbols

6c ... non-woven fabric,
6c, 6c ″, 16c.
6c ″… fur brush,
Q3 ... Image recording area,
Rr ... Regiroll,
Rp: paper feed roll,
S: Recording sheet.

Claims (9)

A sheet conveying apparatus comprising the following configuration requirements (A01):
(A01) A registration roll that has a charge eliminating unit that removes charge from a charged recording sheet and conveys the recording sheet to an image recording area where an image is recorded. The sheet conveying apparatus according to claim 1, further comprising the following structural requirements (A02) and (A03):
(A02) a paper feed roll that rotates and feeds paper while being in contact with a part of the sheet width direction perpendicular to the sheet conveyance direction of the recording sheet;
(A03) The static eliminator provided at a position corresponding to a contact position between the sheet feeding roll and the recording sheet with respect to a sheet width direction perpendicular to the sheet conveying direction. The sheet conveying apparatus according to claim 2, comprising the following configuration requirements (A04):
(A04) The charge eliminating portion provided to face the same surface as the surface with which the sheet feeding roll contacts the recording sheet. The sheet conveying device according to any one of claims 1 to 3, further comprising the following constituent (A05):
(A05) The charge removal unit that performs charge removal on the recording sheet in contact with or in proximity to the recording sheet passing through the registration roll. The sheet conveying apparatus according to any one of claims 1 to 4, further comprising the following configuration requirement (A06):
(A06) The static eliminating portion made of conductive fibers. The sheet conveying apparatus according to any one of claims 1 to 5, further comprising the following constituent (A07):
(A07) The static eliminator configured by a fur brush. The sheet conveying apparatus according to any one of claims 1 to 5, further comprising the following constituent (A08):
(A08) The above-mentioned static elimination part comprised with the nonwoven fabric. The sheet conveying device according to any one of claims 1 to 7, further comprising the following constituent (A09):
(A09) The static eliminator connected to ground. An image forming apparatus comprising the sheet conveying device according to claim 1.

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