JP2001318541A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To clean the inner peripheral surface of a carrying belt by transmitting driving force in the vicinity of a more upstream side than a transfer device especially in an image forming device where the inner peripheral surface of the carrying belt can be cleaned. SOLUTION: A cleaner roll 36 is disposed on the lower surface of the carrying belt 25, and a scraper 34 is provided on the peripheral surface of the roll 36, so that toner or paper powder adhering to the lower surface of the belt 25 is removed by the roll 36, and the toner or the paper powder on the peripheral surface of the roll 36 is scraped by a scraper 34 and stored in a cleaner box 35. By such constitution, the toner or the paper powder adhering to the lower surface of the belt 25 is removed by the roll 36 and stored in the box 35 through the scraper 34, so that the soil of the lower surface of the belt 25 is removed without frequently exchanging a cleaner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus capable of cleaning an inner peripheral surface of a conveyor belt.

[0002]

2. Description of the Related Art As an image forming apparatus for performing color printing,
For example, a so-called tandem system is provided in which an image forming unit that performs printing of yellow (Y), magenta (M), cyan (C), and black (K) is provided, and printing of each color is sequentially performed to print on paper. Printer devices are known.

FIG. 14 is a sectional view schematically showing the configuration of such a printer. A printer device (main device) 1 shown in FIG. 1 is a printer device that can print a full-color image. The printer 1 has a paper feed cassette 2 detachably provided at the lower part of the main body, and a slide type paper feed tray unit 3 provided at the front face so as to be freely opened and closed. Also,
A transport unit 4 and four image forming units 5 are provided in the center of the main body. The four image forming units 5 include magenta (M), cyan (C),
They are arranged in the order of yellow (Y) and black (K).

The paper stored in the paper feed cassette 2 is fed by a paper feed roller 6 to a standby roller pair 7. The paper placed on the paper feed tray unit 3 is fed to the standby roller pair 7 by the paper feed roller 8. This sheet is fed onto the transport belt 9 of the transport unit 4 at the print timing, and the transport belt 9
As the driven roller 11 rotates, the paper circulates in the counterclockwise direction in the figure and conveys the sheet backward (to the left in the figure).

The conveyed paper is subjected to magenta (M), cyan (C), yellow (Y) and black (K) toner images by four image forming units 5 (5M, 5C, 5Y, 5K). Are sequentially transferred onto the paper surface, and the transferred and transferred toner image is fixed on the paper surface by the fixing device 12, inverted through the discharge path 13, and discharged onto the paper discharge tray 14 with the image surface facing downward. .

Here, the image forming units 5M, 5C, 5C
Y and 5K have the same configuration except for (the color of) the developer stored in the developing container. Therefore, the transfer of the toner image to the sheet will be described by taking the image forming unit 5Y for yellow (Y) as an example. The photosensitive unit is formed by a charger, a print head, a developing roll, and the like formed on the peripheral surface of the photosensitive drum 16. The toner image formed on the peripheral surface of the body drum 16 reaches the position of the transfer device 17 with the rotation of the photosensitive drum 16 in the direction of the arrow, and the transfer device 17 moves directly below the photosensitive drum 16. Is transferred to the paper.

The transfer device 17 is a contact type transfer device using a transfer sheet. In recent years, such a contact-type transfer device is mainly used in consideration of problems such as generation of ozone.
A belt cleaner 15 that cleans toner and paper dust attached to the outer peripheral surface of the transport belt 9 is provided on the outer periphery of the transport belt 9 below the transport unit 4.

FIG. 15 is a perspective view of the transport unit 4. As shown in the figure, the transport unit 4 is a transport unit of a belt transport type using a transport belt 9. In recent years, a transport system using such a belt transport system is generally used. Usually, the transport unit 4 is provided with a side frame 18 on a side portion thereof.

Therefore, for the reason that the inside of the transport unit 4 is covered by the side frame 18, for example,
Conventionally, there are few devices provided with a configuration for cleaning toner and paper dust attached to the inner peripheral surface of the transport belt, and the configuration is simple if any.

FIG. 16 is a side sectional view schematically showing an example of a cleaning mechanism for cleaning the inner peripheral surface of the transport belt. FIG. 2 shows only the configuration around the transport belt 9. As shown in the figure, a belt cleaner 18 is fixedly provided on the upstream side (the right side in the figure) of each transfer device 17 so as to be in contact with the inner peripheral surface of the transport belt 9. The belt cleaner 18 has the same length as the belt width of the transport belt 9 in the direction perpendicular to the paper transport direction. The belt cleaner 18 contacts the inner circumferential surface of the transport belt 9 that circulates by bringing a cleaning felt into contact with the transport belt. 9 to clean toner and paper dust attached to the inner peripheral surface.

FIG. 17 is a side sectional view schematically showing another example of a cleaning mechanism for cleaning the inner peripheral surface of the transport belt. still,
The transfer device shown in the figure is a contact type transfer device using a transfer roll 19. As shown in the drawing, a cleaner 20 is provided in contact with the outer peripheral surface of the transfer roll 19 of each transfer device. The cleaner 20 cleans toner and paper powder attached to the transfer roll using a scraper. That is, the toner and paper dust adhering to the inner peripheral surface of the conveyor belt 9 adhere to a transfer roll that comes into contact with the conveyor belt, and the toner or the like adhered to the transfer roller is cleaned by a scraper.
Is to clean the inner peripheral surface.

[0012]

As described above, when toner or paper dust adheres to the inner peripheral surface of the conveyor belt 9, the toner image formed on the photosensitive drum 16 is appropriately transferred onto the paper by the transfer unit. Cannot be transferred to the sheet, resulting in poor transfer.

In order to prevent such transfer failure, the belt cleaners 18 and 20 shown in FIGS. 16 and 17 have been developed. However, these cannot completely prevent transfer failure. . That is, since the belt cleaner 18 shown in FIG. 16 is in contact with the elastic transport belt 9, if the transport belt 9 is partially displaced (lifted), it adheres to this portion. Could not be cleaned. Further, when the cleaning felt itself became dirty, the cleaning effect was significantly reduced.

Further, since the belt cleaner 18 is fixedly provided and is configured to be covered by the conveyor belt 9 and the side frame 18, the cleaning felt cannot be easily replaced. Therefore, with the belt cleaner 18 shown in FIG. 16, the transfer failure could not be prevented yet.

Since the cleaner 20 shown in FIG. 17 does not directly clean the inner peripheral surface of the transport belt 9, it cannot clean the transport belt 9 before transfer. Therefore, even with the cleaner 20 shown in FIG. 17, transfer failure could not be prevented yet.

It is an object of the present invention to provide an image forming apparatus which prevents transfer failure by cleaning the inner peripheral surface of a conveyor belt in view of the above situation.

[0017]

According to the first aspect of the present invention,
An image carrier, toner image forming means for forming a toner image on the image carrier, and at least two of a driving roll and a driven roll
A transfer belt that is wrapped around three rolls and circulates so as to adsorb the transfer material on the outer peripheral surface and bring the transfer material into contact with the image carrier, and a transfer unit inside the transport belt corresponding to the image carrier. A contact-type transfer device that is pressed against the image carrier via the transport belt to transfer a toner image to the transfer material that is in contact with the image carrier, and the contact-type transfer device inside the transport belt. An image forming apparatus comprising: a belt cleaning unit that is located near the upstream side of the transfer device and that receives a driving force and contacts an inner surface of the transport belt to clean the inner surface.

As described above, the belt cleaning means includes:
Driving force is transmitted inside the conveyor belt and upstream of the contact-type transfer device, and the driving force is transmitted to contact the inner surface of the conveyor belt to clean the inner surface, whereby transfer failure can be prevented. According to a second aspect of the present invention, there is provided an image carrier, a toner image forming means for forming a toner image on the image carrier, and a transfer material wound around at least two of a driving roll and a driven roll. A transport belt that is circulated and moved to contact the transfer material with the image carrier by suction, and an image carrier via the transport belt to form a transfer unit corresponding to the image carrier inside the transport belt; A contact-type transfer device for transferring a toner image to the transfer material being in contact with the image carrier while being in contact with the image carrier; and An image forming apparatus comprising: a belt cleaning unit that contacts inner surfaces of both ends in the width direction of the belt to clean the inner surfaces.

As described above, the belt cleaning means
The transfer failure can be prevented by contacting the inner surfaces of both ends in the width direction of the conveyor belt near the upstream side of the contact type transfer device and inside the conveyor belt to clean the inner surfaces.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view schematically showing the cleaning mechanism according to the first embodiment. FIG. 2 shows the image forming unit, the transport belt 25, and the belt cleaner 26. The image forming unit includes a cleaner 28 and a charging unit 2 around the photosensitive drum 27 and around the photosensitive drum 27.
9, a transfer roll (transfer device) 33 provided via a print head 30, a development roll 31, and a transport belt 25.

The photosensitive drum 27 has its peripheral surface made of, for example, an organic photoconductive material, rotates in the direction of arrow b, and first charges the peripheral surface of the photosensitive drum 27 by applying a charge from the charger 29. Charge. Then, the photosensitive drum 27 is written by optical writing based on the print information from the print head 30.
An electrostatic latent image is formed on the peripheral surface of the developing roller 31, and a toner image is formed by a developing process using the developing roll 31. At this time, the toner image formed on the peripheral surface of the photosensitive drum 27 is based on the color toner stored in the developing container 32. The toner image formed on the peripheral surface of the photosensitive drum 27 in this manner is
With the rotation in the direction of the arrow, the transfer roller 33 reaches the position of the transfer roller 33, and the transfer roller 33 transfers the image to a sheet that moves immediately below the photosensitive drum 27 in the direction of the arrow a.

A belt cleaner 26 is provided upstream of the transfer roll 33 (on the right side in the figure), in the vicinity of the transfer roll 33. This belt cleaner 26
It is composed of a cleaner roll 36, a scraper 34, a cleaner box 35 and the like. The cleaner roll 36 is provided with a brush on the outer peripheral surface thereof, is pressed against the transfer roll 33, and is in contact with the transport belt 25.

Therefore, when the transfer roll 33 rotates in the direction of the arrow c, the cleaner roll 36 pressed against the transfer roller 33 rotates in the direction of the arrow d, and at the same time, the inner circumference of the transport belt 25 abutted against the cleaner roll 36. The toner, paper powder, and the like adhering to the surface are cleaned by a brush on the outer peripheral surface of the cleaner roll 36. Then, the toner and the like adhering to the brush are collected by the cleaning box 35 by the scraper 34.

FIG. 2 is a perspective view schematically showing the structure of the transfer roll 33 and the belt cleaner 26. As shown in the drawing, the cleaner rolls 36 of the belt cleaner 26 are configured to abut on both ends of the conveyor belt 25 with a predetermined width. This configuration is based on the fact that, based on various studies conducted in order to carry out the present invention, it was found that toner and the like adhered to the inner peripheral surface of the transport belt 25 adhered to both ends of the transport belt 25. It is.

As described above, according to the first embodiment, the toner adhered to the brush is collected in the cleaner box 35 by the scraper 34, so that the cleaning effect can be maintained without replacing the brush. it can. Further, since the traveling direction of the transport belt 25 and the rotation direction of the cleaner roll 36 are opposite to each other, the effect of cleaning the toner and the like attached to the transport belt 25 can be further enhanced.

In the first embodiment, it is desirable that the cleaning roll 36 is configured to abut at a predetermined width at each end of the conveyor belt 25, but the present invention is not particularly limited to this. For example, a configuration may be employed in which the transfer belt 25 comes into contact with the entire belt width. Next, a second embodiment will be described.

The transfer device shown in the second embodiment is constituted by a contact type transfer device using a transfer sheet. Therefore, there is no transfer roll for rotating the cleaner roll 36 as shown in the first embodiment. Therefore, in the present embodiment, the cleaner roll 36 is rotated by other means.

FIG. 3 is a perspective view schematically showing a cleaning mechanism according to the second embodiment. As shown in the figure, the transfer device is a contact type transfer device using a transfer sheet 40. The belt cleaner 26 includes a cleaner roll 36, a scraper 34, and a cleaner box 35 (not shown), similarly to the configuration shown in FIG. However, the cleaner roll 36 is inserted into the shaft 41, and this shaft 41
, A gear 42 is also inserted. The belt cleaner 26 having the above configuration is provided before each transfer unit.

A gear belt 45 is wound around each gear 42, and the driving force of the gear belt 45 is supplied from a belt driven roll 46. The rotation of the belt driven roll 46 is transmitted to the gear belt 45 via gears 47 and 48. Therefore, while the belt driven roller 46 rotates, the belt cleaner 26 is also driven via the gear belt 45 to remove toner and paper dust adhering to the inner surface of the transport belt 25. Next, a third embodiment will be described.

FIG. 4 is a diagram for explaining a third embodiment of the present invention. FIG. 5 is a sectional view of this example. In FIG. 4, a roll cleaner 50 is provided in front of the transfer sheet 40.
51 is provided, and each of the roll cleaners 50 and 51 is provided at a position for cleaning the side portion on the back surface of the sheet. For example, the roll cleaner 50 on the front side of the drawing shown in FIG. 1 includes a roll 53 provided with a worm gear 52 at one end, and a driven roll 54, and a cleaner 55 whose surface is planted between the rolls 53 and 54 is disposed. It is configured. on the other hand,
The other roll cleaner 51 has the same configuration, and includes a roll 57 provided with a worm gear 56 at one end, and a driven roll 58, and a cleaner 59 having a flocked surface disposed between the rolls 57 and 58. Have been.

The worm gears 52 and 56 receive driving force from the drive shaft 60, and the worm gear 60a provided on the drive shaft 60 meshes with the worm gear 52, and the worm gear 60b meshes with the worm gear 56. Therefore, when the drive shaft 60 rotates in the direction of the arrow, the worm gear 52 of the roll cleaner 50 rotates in the direction of the arrow e in the same figure, and moves the cleaner 50 in the same direction. Similarly, when the drive shaft 60 rotates in the direction indicated by the arrow, the worm gear 56 of the roll cleaner 51 rotates in the direction indicated by the arrow f in the figure, and moves the cleaner 59 in the same direction.

The roll cleaners 50 and 51 are disposed on the lower surface of the transfer belt 25 and on both sides thereof. Therefore, the cleaners 55 and 59 of the roll cleaners 50 and 51 move in the direction of the arrow in FIG.
The stain on the lower surface of 5 is removed to the side.

Therefore, the dirt on the lower surface of the sheet is eliminated on both sides by the roll cleaners 50 and 51. In particular, since the roll cleaners 50 and 51 are disposed immediately before the transfer sheet 40, the transfer is performed without being affected by the dirt. Processing can be performed. FIG. 6 is an enlarged view of the vicinity of the transfer sheet 40 shown in FIG. In the figure, a transfer sheet 40 is disposed on a transfer electrode 70, and a predetermined positive voltage is applied from a power supply 72 via the transfer electrode 70. Here, the leading end of the transfer sheet 40 is located on the right side (upstream in the sheet transport direction) of the position P ′ where the photosensitive drum and the sheet P (or the transfer belt 25) are in contact, and contacts the lower surface of the transport belt 25. Further, the contact width between the transfer sheet 40 and the conveyor belt is set to h. In addition, g shown in the figure is a nip width at which the photosensitive drum 27 and the conveyor belt 25 come into contact.

Further, the relationship between the nip width g and the contact width h satisfies the relationship g> h. With this configuration, it is possible to prevent reverse transfer in which toner adheres to the photosensitive drum downstream of the nip portion. On the other hand, FIG. 7 is a view showing an example of a transfer brush, and a transfer brush 75 is provided on the transfer electrode 74.
4 is supplied with a predetermined voltage from a power supply 76. Also in this case, the leading end of the transfer brush 75 is located on the right side (upstream side in the paper transport direction) of the position P ′ where the photosensitive drum and the paper P are in contact, and the contact width between the transfer brush 75 and the transfer belt is set to h. When the nip width g is configured to satisfy the relationship of g> h as described above, it is possible to prevent reverse transfer in which toner adheres to the photosensitive drum downstream of the nip portion. Next, a fourth embodiment of the present invention will be described.

FIG. 8 shows the overall structure of the image forming apparatus of the present embodiment. The same image forming apparatus is used in the first to third embodiments. In addition, since the configuration is basically the same as the configuration shown in FIG. 14, the description of the configuration is omitted. In this example, in particular, the manual sheet feeding section (MP
F) is for explaining the structure of 80, and as shown in FIG.

FIG. 9A is a diagram for explaining the overall configuration of the MPF 80. In the drawing, reference numeral 81 denotes a cover,
2 is a tray assembly, and 83 to 85 are three trays to be sequentially drawn. FIG. 3B is a side view showing a state where three trays 83 to 85 are pulled out. Further, FIG. 9C shows a state before the trays 83 to 85 are pulled out, and FIG. 9D is a side view thereof.
FIG. 7E is a front view of the MPF 80.

FIG. 10 shows a cover 81 and a tray assembly 82.
It is a perspective view explaining the specific structure of. Rail members 81a and 81b formed of grooves are formed on the cover 81, and each groove is formed in a direction facing each other. On the other hand, on both sides of the tray assembly 82, the projections 82a, 82b
The projection 82a fits into the groove (rail member 81a) of the rail member 81a, and the projection 82b fits into the groove (rail member 81b) of the rail member 81b.
Guide grooves 81c and 81d are formed on the upper surface of the cover 81, and linear protrusions (not shown) formed on the lower surface of the tray assembly 82 fit into the guide grooves 81c and 81d.

Further, a cam member 81a 'is formed at the upper end of the groove of the rail member 81a.
A cam member 81b 'is also formed at the upper end of the groove b. 11A shows a state in which the tray assembly 82 is stored in the cover 81, and FIG. 11B shows a state in which the tray assembly 82 is pulled out from the cover 81. This shows a state where the eye trays 83 to 85 are stored. At this time, the tray assembly 82 (the trays 83 to 85) is pulled out along the rail members 81a and 81b.

FIGS. 12A to 12C are diagrams for explaining the state at this time in detail. First, FIG. 7A shows a state in which the tray assembly 82 is housed in the cover 81. When the tray assembly 82 (tray 83) is pulled out from this state, as shown in FIG. The portion 82a slides in the direction of the arrow along the rail member 81a and is pulled out while being pressed upward by the cam member 81a '.

Thereafter, when the tray assembly 82 is pulled out to the end as shown in FIG.
The tray assembly 82 is pushed upward from the shape of a ′ (cam member 81b ′) and the shape of the convex portion 82a (convex portion 82b). Therefore, when the tray assemblies 82 are all pulled out, the tray assemblies 82 (the trays 83 to 83)
85) is inclined upward.

FIG. 13 is a side view of the MPF 80 showing this state. 7A to 7E shown in the drawing, the trays 83 to 85 are gradually extended as the tray assembly 82 is pulled out, and are inclined upward in a state where the trays 83 are completely pulled out. With this configuration, when the paper is placed, the trailing edge of the paper is eliminated, and the paper can be reliably supplied.

[0042]

As described in detail above, according to the present invention, the dirt on the lower surface of the transfer belt can be cleaned, and transfer failure can be prevented. Further, it is possible to prevent the toner from being reversely transferred to the photosensitive drum.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a cleaning mechanism according to a first embodiment.

FIG. 2 is a perspective view schematically showing a configuration of a transfer roll and a belt cleaner.

FIG. 3 is a perspective view schematically showing a cleaning mechanism according to a second embodiment.

FIG. 4 is a diagram illustrating a third embodiment.

FIG. 5 is a sectional view illustrating a third embodiment.

FIG. 6 is an enlarged view near a transfer sheet.

FIG. 7 is a diagram illustrating an example of a transfer brush.

FIG. 8 is a diagram illustrating an overall configuration of an image forming apparatus.

9A is a view for explaining the overall configuration of the MPF, FIG. 9B is a side view showing a state where three trays are pulled out, and FIG. 9C is a state before the trays are drawn out. (D) is a side view thereof, and (e) is a diagram showing M
It is a front view of PF.

FIG. 10 is a perspective view illustrating a specific configuration of a cover and a tray assembly.

11A is a perspective view illustrating a state in which a tray assembly is stored in a cover, and FIG. 11B is a perspective view illustrating a state in which the tray assembly is pulled out from the cover.

12A is a view showing a state in which the tray assembly is stored in a cover, FIG. 12B is a view showing a state in which a protrusion of the tray assembly slides in the direction of the arrow along the rail member, and FIG. FIG. 5 is a diagram showing a state where the tray assembly has been pulled out to the end.

FIGS. 13A to 13E are diagrams showing a state in which all trays are pulled out.

FIG. 14 is a cross-sectional view schematically illustrating a configuration of a conventional printer device.

FIG. 15 is a perspective view of a transport unit.

FIG. 16 is a side sectional view schematically showing an example of a cleaning mechanism for cleaning the inner peripheral surface of the transport belt.

FIG. 17 is a side sectional view schematically illustrating another example of a cleaning mechanism for cleaning the inner peripheral surface of the transport belt.

[Explanation of symbols]

 Reference Signs List 25 conveyor belt 26 belt cleaner 27 photoconductor drum 28 cleaner 29 charging unit 30 print head 31 developing roll 33 transfer roll (transfer unit) 34 scraper 35 cleaner box 36 cleaner roll 40 transfer sheet 41 shaft rod 42 gear 45 gear belt 46 belt driven roll 47, 48 Gear 50, 51 Roll cleaner 52 Worm gear 53 Roll 54 Follower roll 55 Cleaner 56 Worm gear 57 Roll 58 Follower roll 59 Cleaner 60 Drive shaft 60a, 60b Worm gear 70, 74 Transfer electrode 76 Electrode 80 MPF 81a, 81b Rail member 82 Tray Assy 83-85 Tray 82a, 82b Convex portion 81c, 81d Guide groove 81a ', 81b' Cam member

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masayoshi Kanasugi 2-229 Sakuragaoka, Higashiyamato-shi, Tokyo Casio Computer Co., Ltd. Tokyo Office (72) Inventor Satoshi Fujio 2-229 Sakuragaoka, Higashiyamato-shi, Tokyo Casio Computer Inside the Tokyo office (72) Inventor Hiroshi Ikemoto 2-229 Sakuragaoka, Higashiyamato-shi, Tokyo Casio Computer Co., Ltd. Tokyo office F-term (reference) 2H032 AA05 BA18 BA23 BA30

Claims (2)

[Claims] An image bearing member, a toner image forming means for forming a toner image on the image bearing member, and a transfer material wound on at least two of a driving roll and a driven roll to adsorb a transfer material on an outer peripheral surface thereof. A transport belt that circulates to bring the transfer material into contact with the image carrier, and is pressed against the image carrier via the transport belt to form a transfer unit corresponding to the image carrier inside the transport belt. A contact-type transfer device for transferring a toner image to the transfer material in contact with the image carrier, and a driving force transmitted near the upstream side of the contact-type transfer device inside the transport belt and near the contact-type transfer device A belt cleaning unit that contacts an inner surface of the transport belt to clean the inner surface. 2. An image bearing member, a toner image forming means for forming a toner image on the image bearing member, and at least two rolls of a driving roll and a driven roll, which are attached to a transfer material on an outer peripheral surface thereof by suction. A transport belt that circulates to bring the transfer material into contact with the image carrier, and is pressed against the image carrier via the transport belt to form a transfer unit corresponding to the image carrier inside the transport belt. A contact-type transfer device for transferring a toner image to the transfer material in contact with the image carrier, and a width of the conveyance belt near the upstream side of the contact-type transfer device inside the conveyance belt and near the contact-type transfer device An image forming apparatus, comprising: a belt cleaning unit that contacts inner surfaces of both ends in the direction to clean the inner surfaces.