JPH0452201Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a recording paper conveying device in an image recording apparatus such as an electrostatographic copying machine or a facsimile machine.

[Conventional technology]

The recording paper conveyance device includes an endless conveyance belt provided with a large number of holes wound around a pair of rollers, and is equipped with a fan that sucks the recording paper onto the conveyance belt. Some devices are designed to be attracted to a conveyor belt and conveyed to a fixing device.

However, in the above-mentioned conveyance device, conveyance may not be carried out effectively depending on the properties and size of the recording paper to be conveyed.

In other words, if the recording paper is small in size, such as a postcard or business card, and the surface of the paper has been warped due to the transfer process, the recording paper will be in line contact with the conveyor belt, and the fan will not be able to record the paper. The suction power of the paper was extremely reduced, and the paper conveyance capacity was reduced, resulting in delays in conveyance or even failure to convey the paper.

Furthermore, the above-mentioned transport delay is based on, for example, the time required from paper feeding to paper ejection (for example, by counting the number of pulses), and there is a control form that detects the time that exceeds this time and considers it to be a paper jam. In the case of such a model, even though the recording paper will eventually be ejected, it will be detected as a paper jam and image recording will be stopped.

As a recording paper conveyance device capable of solving the above-mentioned situation, the present applicant has developed an endless conveyance belt 22 and a guide plate 23 that are arranged alternately in a direction perpendicular to the paper surface, as shown in FIG. It is proposed that an idler 26 that comes into contact with the upper surface of the paper a to assist the conveyance of the recording paper a is provided between the conveyor belt 22 and the guide plate 23 that serve to convey the smallest size recording paper a. (Utility Model Application Publication No. 154331/1983).

According to such a device, even if the recording paper a is small in size and is curled, the recording paper a can be moved to the free rolling member 26.
Since the recording paper a is pressed against the conveyor belt 22 side by the conveyor belt 22, the recording paper a can be conveyed reliably, and since the guide plate 23 is used as a part of the conveyor device A,
This has the advantage that the cost is lower than when the entire conveying device has a conveying belt structure.

[Problem that the invention attempts to solve]

However, in the above-mentioned conveyance device, the conveyance capacity tended to decrease in other aspects, and it was discovered that there was room for improvement.

That is, when the recording paper a is pressed against the conveyor belt 22 side by the idler body 26, the recording paper a is also pressed against the guide plate 23 side at the same time. In the case of the recording paper a having a strong hardness, the conveyor belt 22 becomes a little bent, and the recording paper a becomes sandwiched between the guide plate 23 and the idler 26, and the conveyance ability of the conveyor belt 22 decreases. hand,
Paper jams were sometimes detected due to transport delays. There were also cases where transport was impossible.

Furthermore, when the conveyor belt 22 stretches over time and the top surface of the belt loosens downward, the conveyance capacity is significantly reduced.

[Means for solving problems]

The purpose of the present invention is to solve the above-mentioned problem of reduced conveyance capacity through simple improvements.The present invention has an endless conveyor belt and a guide plate that are alternately arranged, and are in contact with the top surface of the recording paper to record the paper. In a recording paper conveyance device of an image recording apparatus in which an idler for assisting paper conveyance is provided between a conveyance belt and a guide plate for conveying at least the minimum size recording paper to be conveyed, at least the minimum size recording paper to be conveyed is provided. The top surface of the guide plate used for transporting the recording paper is
The guide is curved slightly downward from the upper surface of the conveyor belt in a range extending near the pair of rollers around which the conveyor belt is wound, and the guide is curved slightly below the upper surface of the conveyor belt, and the upper surface of the conveyor belt does not fall below the upper surface of the guide plate. The present invention is characterized in that the amount of indentation of the maximum curved portion of the plate into the upper surface of the conveyor belt is set to be larger than the amount of indentation into the upper surface of the conveyor belt at the guiding start end and the terminal end of the guide plate.

[Effect]

According to the above characteristic structure, even if the conveyor belt is bent due to the stiffness of the paper or loosened due to elongation of the conveyor belt, the upper surface of the guide plate is Since the conveyor belt is curved slightly downward from the upper surface of the conveyor belt to prevent the conveyor belt from going lower than the conveyor belt, a decrease in conveyance capacity can be suppressed.

Even if the upper surface of the guide plate is curved downward, recording paper such as tracing paper, which has a weak stiffness, can be effectively guided by the upper surface of the curved guide plate as the recording paper itself flexes.

〔Example〕

Hereinafter, an embodiment of the present invention will be described based on the drawings. FIG. 1 shows a recording paper conveyance device A, and FIG. 2 shows a center reference type ( This is an electrophotographic copying machine of the type in which the width center of the document is aligned with the front and rear width center of the contact glass. It is of a so-called clamshell type in which the upper unit 1 is connected to the lower unit 2 rotatably around a horizontal axis (not shown) on the upstream side in the paper feeding direction, and the upper unit 1 is connected to the lower unit 2 on the downstream side in the paper feeding direction. By releasing the fixing mechanism (not shown), the upper unit 1 can be swung open as shown by the imaginary line.

The upper unit 1 is provided with a document table 3 that reciprocates in the supply direction, a photoreceptor 4, a charging device 5, an exposure device 6, a developing device 7, a cleaning device 8, and the like. , storage section 10 of cassette case 9, manual feed section 11, paper feed roller 12, registration rollers 13, 14, transfer device 1
5. A fixing device 2 consisting of a recording paper separation device 16, a recording paper transport device A, and a pair of upper and lower rollers 18 and 19.
0, a tray 17, a paper ejection device 21, etc. are provided.

As shown in FIGS. 1 and 3, the recording paper conveyance device A that conveys the recording paper a after transfer to the fixing device 20 is arranged in a sorting shape based on the conveyance center P corresponding to the center of the front and rear width of the contact glass. In addition, narrow guide plates 23a and 23b made of metal (can be changed to ones made of synthetic resin, etc.) are arranged at predetermined intervals, and between the guide plates 23a and 23b and on the outside of both outer guide plates 23b. Endless narrow conveyor belts 22a and 22b are disposed on each of the upper unit 1, and a bracket 25 is removably attached to the partition plate 24 of the upper unit 1. A conveyor belt 22a at the center in the width direction and guides on both sides of the belt 22a serve to convey the recording sheet a of the smallest size to be conveyed, using star-toothed idlers 26, 26 that assist in conveying the recording sheet a. It is provided on the bracket 25 so as to be positioned between the plates 23a, 23a.

The partition plate 24 consists of a substantially vertical surface portion 24a and a substantially horizontal surface portion 24b, and the substantially horizontal surface portion 2
A locking hole c... is bored in 4b.

On the other hand, the bracket 25 includes substrates 25a and 25b whose surfaces are in contact with the substantially vertical surface portion 24a and the substantially horizontal surface portion 24b, and these substrates 25a and 25b.
A pair of leg plates 25c, 25c hanging from both ends of
and a flexibly deformable locking arm 25 extending upward from the outside of each of the leg plates 25c, 25c.
d, 25d, and the locking arms 25d, 25d
and a locking body d connected to both sides of the horizontal board 25b,
d, e, e, and the free rolling body 26,
An idling shaft 27 having a shaft 26 is connected to the leg plates 25c, 2
It is held in elongated holes f and f formed at the lower end of 5c so as to be able to move up and down.

Thus, the pair of locking arms 25d, 25d
Apply force to bend it, and connect the locking bodies d, d connected to it.
and the locking bodies e, e connected to the horizontal board 25b are inserted into the locking holes c, c from below, and the vertical board 25a is brought into surface contact with the vertical surface portion 24a of the partition plate 24. The bracket 25 is moved to lock the locking bodies e, e to the horizontal surface portion 24b, and the force applied to the locking arms 25d, 25d is released, so that the locking bodies d, d are held approximately horizontally. When the bracket 25 is attached and the recording paper a is not being conveyed, the tips of the lower teeth of the idlers 26, 26 are substantially flush with the upper surface S of the conveyor belt 22a. Alternatively, it is set to be located slightly below.

Guide plates 23a, 23 on both sides of the central conveyance belt 22a for conveying the minimum size recording paper a.
a has its upper surface curved slightly lower than the upper surface S of the central conveyor belt 22a.

Specifically, all the guide plates 23a and 23b are connected to the pair of rollers 2 around which the conveyor belts 22a and 22b are wound, at the guide start end and the guide end.
8 and 29, and the upper surfaces of the guide plates 23a and 23a on both sides are such that the upper surfaces of the conveyor belts 22a and 22b do not fall below the upper surfaces of the guide plates 23a and 23b. It is curved downward with a large radius of curvature in a range near the rollers 28 and 29, and the curved upper surface is set to be lower than the upper surface S of the central conveyor belt 22a.

Note that rib-shaped protrusions long in the conveyance direction are provided at intervals in the width direction on the upper surfaces of the guide plates 23a, 23a on both sides of the central conveyor belt 22a, or the guide plates 23a, 23a are It is also possible to form slits in the conveyance direction at intervals in the width direction to reduce the conveyance resistance against the recording paper a.

Therefore, even if the recording paper a to be conveyed is stiff and the center conveyor belt 22a bends downward when the idlers 26, 26 assist the conveyance, or the conveyor belt 22a stretches. Even if the central portion of the conveyor belt 22a is loosened, the upper surface of the conveyor belt 22a does not fall below the upper surfaces of the guide plates 23a, 23a, so that the recording paper a is kept between the idlers 26, 26 and the guide plates 23a, 23a. This prevents the paper from being strongly pinched by the paper, and effectively prevents a decline in conveyance capacity.

Incidentally, the distance between the shafts of the rollers 28 and 29 is 72 mm.
And, the diameter of the roller 28 on the upstream side in the conveyance direction is
18.5mm, the diameter of the roller 29 on the downstream side in the conveyance direction is 15.5mm
mm recording paper conveyance device A, the guide plate 2
3a, 23a from the top surface S of the belt at the guide start end side and the end side to approximately 0.85 _mm , and the amount of recess from the top surface of the belt at the maximum curved portion l ₂
It should be noted that when a postcard was conveyed as recording paper A with the paper set to approximately 2.85 mm, good conveyance was achieved with no conveyance delay or failure of conveyance.

In the recording paper conveyance device A, the width center of the conveyor belt 22a is made to coincide with the conveyance center P, but the configuration in which the width center of the guide plate 23a is made to coincide with the conveyance center P (that is, in FIG. (Configuration where the positional relationship between the conveyor belt and the guide plate is reversed)
In this case, at least the upper surface of the central guide plate 23a is curved as described above.

In addition, in the embodiment, the target is a so-called center reference type electrostatic photocopier, but the target is a so-called one end reference type electrophotographic copier in which two sides of a document are aligned with two adjacent sides of a contact glass. , the upper surface of the guide plate used for conveying the smallest size recording paper a on the document placement reference side may be curved downward.

Furthermore, although a star tooth-shaped free rotating body 26 is shown, it can be changed to a shape such as an abacus bead.

[Effect of idea]

As explained above, the present invention prevents the conveyor belt from bending downward when transporting stiff recording paper, or from stretching and loosening downward, by providing an idler. As this is unavoidable, even if such a situation occurs, the recording paper to be conveyed is devised so as not to be strongly pinched between the idler and the guide plate, and the upper surface of the guide plate is lowered from the upper surface of the conveyor belt. By making it slightly curved downward, it has become possible to prevent a decline in conveyance capacity due to paper pinching, and in turn, it has become possible to solve situations where recording paper cannot be conveyed or unnecessary paper jam detection. It is.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention,
FIG. 1 is a perspective view of essential parts of the recording paper conveyance device, FIG. 2 is a schematic sectional view of the entire electrostatographic copying machine, and FIG. 3 is a sectional view of the recording paper conveyance device. FIG. 4 is a sectional view of a conventionally proposed recording paper conveying device. 22a, 22b...conveyor belt, 23a, 23
b... Guide plate, 26... Idle body, 28, 29...
...Roller, a...Recording paper, S...Top surface of conveyor belt.

Claims (1)

[Scope of utility model registration request] Endless conveyance belts and guide plates are arranged alternately, and an idler body that comes into contact with the upper surface of the recording paper to assist the conveyance of the recording paper is used to convey at least the smallest size recording paper to be conveyed. In a recording paper conveyance device of an image recording apparatus provided between a conveyance belt and a guide plate, at least the upper surface of the guide plate used for conveying the minimum size recording paper extends near the pair of rollers around which the conveyance belt is wound. The maximum curved portion of the guide plate is curved slightly below the upper surface of the conveyor belt in the range, and the upper surface of the conveyor belt is not lower than the upper surface of the guide plate. A recording paper conveyance device in an image recording apparatus, wherein an amount of recess is set to be larger than an amount of recess into an upper surface of the conveyor belt at a guide start end side and a guide end side of the guide plate.