JP3107445B2 - Image recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

(Table of Contents) Industrial application field Conventional technology (FIG. 6) Problems to be solved by the invention Means for solving the problem (FIG. 1) Action Embodiment (a) Description of one embodiment (FIG. 2) To FIG. 5) (b) Description of Another Embodiment Effect of the Invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image recording apparatus for forming an electrostatic latent image on an image carrier such as a photosensitive drum, developing the image, transferring a toner image to a sheet, and separating the sheet.

[0003] In image recording apparatuses such as copiers, printers, and facsimile apparatuses, latent image forming recording apparatuses such as electrophotographic apparatuses have been used in response to requests for plain paper recording. In such an image recording apparatus, an operation of forming an electrostatic latent image, developing it, and transferring a toner image to a sheet is necessary, so that the sheet must be smoothly conveyed at the transfer position.

[0004]

2. Description of the Related Art FIG. 6 is an explanatory diagram of the prior art. For example, in an electrophotographic apparatus, as shown in FIG. 6A, a photosensitive drum 31 is charged by a charger 32, and a light image is exposed to form an electrostatic latent image corresponding to the image. , The toner image is transferred to a sheet conveyed by an abutment roller 35 by a transfer charger 36, the sheet is separated from the photosensitive drum 31 by a separation charger 37, and is conveyed to a fixing device by a conveyance roller 40. .

In such an electrophotographic apparatus, a guide roller 42 is arranged in the middle of the transport path immediately before the transfer charger 36 in order to facilitate transport of the sheet at the transfer section.

The guide roller 42 does not transmit a driving force to the guide roller 42 in order to simply improve the slip of the sheet, and the guide roller 42 rotates passively by frictional force with the sheet, and positively conveys the sheet. In some cases, a driving force is transmitted for this purpose.

In order to ensure the conveyance of the sheet, it is necessary to drive the guide roller 42 and to provide the position as close to the transfer charger 36 as possible. It is difficult to design the distance from the contact roller (standby) roller 35 to the transport roller 40 located downstream of the transfer charger 36 to be shorter than a small sheet of paper such as a postcard. Providing the guide roller 42 immediately before the transfer charger 36 is an effective solution.

[0008]

However, the prior art has the following problems. Since the guide roller 42 is provided at the leading end of the transfer charger 36, the guide roller 42 is charged by the discharge corona of the transfer charger 36, adsorbs flying matter from the developing device 34, and stains the back surface of the sheet.

In particular, in the duplex printing apparatus, since the sheet is reversed and printed again after the front side printing, both printing surfaces are dirty and serious, and the user is required to periodically clean and replace the guide roller 42. Is also limited and requires the intervention of maintenance personnel.

When the tip of the transfer charger 36 is bent as shown in FIG. 6 (B), the transfer efficiency is improved. However, when the guide roller 42 is provided, the bent portion 41a cannot be provided. Decrease.

Since the guide roller 42 is provided at the tip of the transfer charger 36, the distance between the guide roller 42 and the fixing device becomes longer for printing postcards and the like, and
0 is required separately.

Accordingly, the present invention provides a method for cleaning a guide roller.
An object of the present invention is to provide an image recording apparatus capable of preventing a decrease in transfer efficiency. Another object of the present invention is to provide an image recording apparatus which can easily apply a driving force while preventing contamination of a guide roller and a decrease in transfer efficiency.

[0013]

FIG. 1 is a diagram illustrating the principle of the present invention. According to the first aspect of the present invention, the electrostatic latent image is formed on the image carrier 31 by the latent image forming units 32 and 33, and the electrostatic latent image is developed into a toner image by the developing device 34. the toner image is transferred to a sheet PP by the transfer charger 36, in the image bearing member 31 by a separation charger 37 image recording apparatus for separating the sheet PP, the transfer charger 36 and the separation zone
The electric charger 37 is formed integrally with the chassis 41 and the transfer charger is formed.
36, and is subjected to static elimination by the separation charger 37.
The kicking position, clamping the sheet PP in the image carrier 31
In addition, a guide roller 42 for conveying is provided.

[0014]

[0015] Claim 2 of the present invention is based on claim 1 ,
The gap roller 45 and the guide roller 42 are integrally formed, and the image carrier 31 is
The driving force is transmitted to the guide roller 42 for driving.

[0016]

[0017]

According to a third aspect of the present invention, in the first or second aspect, a bent portion 41 a is formed by bending the chassis 41 inside the transfer charger 36 on the upstream side of the sheet conveying path of the chassis 41. It is characterized by the following.

[0019]

[0020]

[0021]

According to the first aspect of the present invention, the transfer charger is separated from the transfer charger.
The charger 37 is formed integrally with the chassis 41, and the transfer charging is performed.
Is charged by the charger 36, and is discharged by the separation charger 37.
A guide roller 42 for nipping and conveying the sheet PP with the image carrier 31 is provided at a position where
Although the guide roller 42 is charged by the transfer charger 36, the charge is removed by the separation charger 37. Therefore, the suction of scattered matter can be significantly reduced, and the sheet PP is not likely to be stained. Since it is open, a bent portion can be formed at the tip of the chassis 41, and the transfer efficiency is improved.
In addition, since the distance between the fixing device and the fixing device can be reduced, there is no need to separately provide a transport roller.

[0022]

According to the second aspect of the present invention, the gap roller 45 is provided.
And the guide roller 42 are integrally formed, and the driving force of the image carrier 31 is transmitted to the guide roller 42 via the gap roller 45 to be driven. It can be driven by driving force and can be easily realized.

[0024]

[0025]

According to the third aspect of the present invention, since the bent portion 41a of the chassis 41 bent inside the transfer charger 36 is provided on the upstream side of the sheet conveying path of the chassis 41, the transfer of the transfer charger 36 is performed. The sheet can be conveyed by the guide roller 42 with improved efficiency.

[0027]

[0028]

[0029]

【Example】

(a) Description of an embodiment FIG. 2 is a configuration diagram of an image recording apparatus according to an embodiment of the present invention.
1 shows an electrophotographic printer capable of duplex printing.

In FIG. 2, the image recording apparatus 1 includes a paper cassette 2, a printing mechanism 3, and a transport system 5, and the printing mechanism 3 includes an electrophotographic unit, and is configured to be capable of double-sided printing. Have been.

The printing mechanism 3 includes a transport path 30, a rotating photosensitive drum 31, and a charger 32 for charging the photosensitive drum 31.
And a (laser) optical unit 33 for writing a light image on the photosensitive drum 31 to form a latent image, a developing device 34 for developing the latent image on the photosensitive drum 31 with toner, and a standby roller for waiting for a sheet to be transferred 35, a transfer charger 36 for transferring the toner image on the photosensitive drum 31 to the paper fed by the standby roller 35, a separation charger 37 for separating the paper PP from the photosensitive drum 31, and a cleaning of the photosensitive drum 31 after the transfer. And a heat roller fixing device 39 for thermally fixing the toner image on the sheet.

The paper transport system 5 includes a pick roller 50 for picking up the paper in the paper cassette 2 and transport rollers 51, 52, 53 for transporting the big paper to the standby roller 35.
An impeller 54 for directing the rear end of the sheet from the heat roller fixing device 39 toward the reverse side printing conveyance path 59;
A switchback roller 55 that conveys the paper from the printer in the discharge direction and then sends the paper to the reverse printing conveyance path 59, a guide roller 56 for guiding the discharge of the paper, and a discharge roller 57.
And a discharge tray 58 for storing the discharged sheets, and a back path printing conveyance path 59 for feeding the sheet from the switchback roller 55 to the standby roller 35 by the conveyance rollers 59a and 59b for the back side printing.

The operation of the image recording apparatus 1 is as follows.
1, 52, and 53 to the standby roller 35, and the charger 32
And an optical image is written by the optical system unit 33,
The latent image is formed, and the toner image is synchronized with the toner image on the photosensitive drum 31 on which the toner image is formed by the developing device 34.

On the sheet fed by the standby roller 35, the toner image on the photosensitive drum 31 is transferred to the surface by a transfer charger 36, separated from the photosensitive drum 31 by a separation charger 37, and fixed by a heat roller fixing unit 39. And is sent in the direction of the switchback roller 55, where the switchback roller 55
The sheet is conveyed in the direction of the discharge tray 58.

When the trailing edge of the paper reaches the impeller 54,
When the switchback roller 55 stops the transport operation and stops the paper, the trailing edge of the paper is turned in the counterclockwise direction of the impeller 54 so that the trailing edge of the paper is directed to the transport path 59 for backside printing. The roller 55 sends the sheet to the back-side printing conveyance path 59, and the sheet is sent to the standby roller 35 by the conveyance rollers 59 a and 59 b of the back-side printing conveyance path 59.

Thereafter, similarly to the front side printing, the standby roller 35
The toner image of the photosensitive drum 31 is transferred to the back surface of the sheet by the transfer charger 36, separated from the photosensitive drum 31 by the separation charger 37, fixed by the heat roller fixing device 39, and fixed to the switchback roller 55. And is conveyed in the direction of the discharge tray 58 by the switchback roller 55,
The sheet is discharged to a discharge tray 58 by a discharge roller 57, and double-sided printing is performed.

In the case of one-sided printing, only the front side is printed and the sheet is discharged to the discharge tray 58. Such a printing apparatus 1 includes:
Since the paper cassette 2 is mounted from the front, housed in the apparatus, and discharged to the upper discharge tray 58, no space is required on both sides, space can be saved, and the discharge path is used for switchback. Therefore, the size of the apparatus can be reduced and double-sided printing can be performed.

FIG. 3 is a configuration diagram of an embodiment of the present invention, FIG. 4 is an enlarged view of a main portion of the embodiment of the present invention, and FIG. 5 is a configuration diagram of a main portion of the embodiment of the present invention. As shown in FIGS. 3 and 4, the transfer charger 36 having the transfer wire 36 a and the separation charger 37 having the separation wire 37 a are integrated by a chassis 41 and are separated by a partition plate 44.

The chassis 41 is configured to be detachable from the block 10 of the apparatus main body. The chassis 41 on the upstream side of the transfer charger 36 forms a bent portion 41a that is bent inward, and the tip thereof is
It is arranged so as to have an interval of 0.3 to 0.5 mm with respect to 1.
The inside of the bent portion 41a is covered with an insulating tape in order to prevent leakage from the corona wire 36a, and the chassis 41 and the partition plate 44 are made of a stainless plate.

The guide roller 42 has its axis center disposed directly above the partition plate 44 and has a diameter of 6 mm. Incidentally, 43
Is a gap roller for maintaining an interval between the chassis 41 and the photosensitive drum 31.

As shown in FIG. 5A, the guide roller 42 has a cylindrical shape that is uniform in the longitudinal direction.
A shaft 42a having a diameter of 2 mm was erected in the longitudinal direction at the center of the roller at both ends thereof, and an insulating resin was used as a material.

The gap rollers 45 are disposed at both ends of the guide roller 42, and a hole having a diameter of 2 mm is formed at the center thereof, and the shafts 42 a at both ends of the guide roller 42 are passed through the holes. It was fixed with an adhesive.

As shown in FIG. 5 (B), the guide roller 42 has resin housings 46 for fixing wires at both ends of the chassis 41,
A bearing integral with the housing 46 was arranged with resin, and the shaft 42a of the guide roller 42 was inserted into the bearing and fixed rotatably.

As shown in FIG. 3, a standby roller 35 and a heat fixing roller 39 are disposed on the paper transport path 30 before and after the transfer charger 36, and the standby roller 35 and the guide roller 4
2, and the path length from the guide roller 42 to the heat fixing roller 39 was set within 140 mm.

As shown in FIG. 5B, a grounded stainless steel plate (1 mm thick) is placed under the chassis 41 of the block 10 and the chassis 41 is grounded. The entire surface of the transfer charger 36 was pressed against the photosensitive drum 31 by the elasticity of the stainless steel plate.

With this configuration, the guide roller 42
Is provided directly above the partition plate 44 of the chassis 41, the guide roller 42 is charged by the transfer charger 36, but the charge is removed by the separation charger 37, so that adsorption of scattered matters such as toner is reduced. The paper PP can be conveyed while preventing the paper PP from being soiled.

Since the tip of the chassis 41 can be opened,
A bent portion 41a can be formed at the front end of the chassis, so that the transfer efficiency of the transfer charger 36 can be prevented from lowering, and the conveyance of the sheet PP and the transfer of toner can be further improved.

Since the guide roller 42 is close to the heat fixing roller 39, even if the paper is short such as a postcard, there is no need to separately provide a conveying roller, and the heat fixing roller 39 can also be used as the conveying roller, so that the configuration can be made inexpensively and simply.

Since the guide roller 42 is provided on the chassis 41, the replacement of the chassis 41
The guide roller 42 can be replaced, and the maintainability of the guide roller 42 against dirt can be improved.

Since the guide rollers 42 have gap rollers 45 at both ends, they can be maintained at a constant interval without contacting the photosensitive drum 31, and the gap rollers 45 are provided on the shaft 42a. Since the gap can be maintained and the gap roller 45 is fixed to the guide roller 42, the rotational force of the photosensitive drum 31 can be transmitted to the guide roller 42, and a conveying force can be applied to the guide roller 42.

Further, the chassis 41 is a leaf spring 11
Since the photosensitive drum 31 is pressed against the photosensitive drum 31,
Regardless of the eccentricity of the photosensitive drum 3
1 while maintaining a constant interval, and the rotational force of the photosensitive drum 31 causes the guide roller 42 to rotate.
Can be rotated.

Since the leaf spring 11 is conductive, the chassis 41 can be grounded. As described above, when applied to a double-sided printing image recording apparatus, the guide rollers 42 do not stain both printing surfaces of the paper PP,
, Clean double-sided printing is possible.

(B) Description of Other Embodiments In addition to the above-described embodiments, the present invention can be modified as follows. In the above-described embodiment, the printing mechanism 3 has been described as an electrophotographic mechanism. However, the printing mechanism 3 can also be used for a printing mechanism (for example, an electrostatic recording mechanism) for transferring a toner image.

The sheet PP is not limited to paper, and other media can be used. Although the image recording apparatus has been described as a printer, another image recording apparatus such as a copying machine or a facsimile may be used.

The present invention has been described with reference to the embodiments.
Various modifications are possible within the scope of the present invention, and these are not excluded from the scope of the present invention.

[0056]

As described above, according to the present invention,
The following effects are obtained. Charged by the transfer charger 36,
The image carrier 3 is located at a position where the charge is removed by the separation charger 37.
1 and a guide row for holding and conveying the sheet PP.
Since the roller 42 is provided, the transfer roller
Even if is charged, the charge is immediately removed by the separate charger.
Because it is received, the device by charging up the guide roller
Adhesion of scattered matter in the machine to the guide roller is greatly reduced.
There is no risk of soiling the sheet PP. Also, installation, Lee
No circuit is required to prevent
Absent. Furthermore, the opening of the transfer device can be enlarged,
Because the transfer area can be wide, stable transfer
This makes it possible to improve transfer efficiency.

Since the end of the chassis 41 is opened,
A bent portion can be formed at the tip of the chassis 41, and transfer efficiency can be improved. Since the distance to the fixing device can be reduced, there is no need to separately provide a transport roller.

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a configuration diagram of an image recording apparatus according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of one embodiment of the present invention.

FIG. 4 is an enlarged view of a main part of one embodiment of the present invention.

FIG. 5 is a configuration diagram of a main part of an embodiment of the present invention.

FIG. 6 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 image recording device 2 paper cassette 3 printing mechanism 5 transport mechanism 10 block 11 leaf spring 30 paper transport path 31 photosensitive drum (image carrier) 32 charger 33 optical unit 34 developing device 35 standby roller 36 transfer charger 37 separation charger 39 Heat roller fixing device 41 Chassis 41a Bending portion 42 Guide roller 44 Partition plate 45 Gap roller 46 Housing

Claims (3)

(57) [Claims] A latent image forming section provided on an image carrier;
33), an electrostatic latent image is formed by a developing device (34) to develop the electrostatic latent image into a toner image, and the toner image on the image carrier (31) is transferred to a sheet (PP) by a transfer charger (36). ) And the sheet (PP) is separated from the image bearing member (31) by the separation charger (37), the transfer charger (36) and the separation charger (37) are sheared.
The transfer charger (36) is formed integrally with the sheet (41) and is charged by the transfer charger (36).
The image carrier (3) is located at a position where static electricity is removed by (37).
1) An image recording apparatus comprising a guide roller (42) for nipping and conveying the sheet (PP). 2. A gap roller (45) and said guide row.
And the gap roller (4).
5) The driving force of the image carrier (31) is
2. An image recording apparatus according to claim 1, wherein said image recording apparatus is driven by transmitting to a roller . 3. A sheet conveying path of said chassis (41).
The transfer charging of the chassis (41) is performed on the upstream side of the road.
Bent part (41a) bent inside the container (36)
The image recording apparatus according to claim 1 , wherein the image recording apparatus is provided.