JP2003171031A - Linear velocity difference absorbing mechanism, conveyance mechanism, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear velocity difference absorbing system capable of absorbing liner velocity difference between a pair of carrier rollers with a simple structure. <P>SOLUTION: For a sheet which is sandwiched by the pair of carrier rollers for conveyance, when conveyance speed (linear velocity), which is applied to the sheet by the pair of the carrier rollers, on a downstream side in the conveying direction is higher, tensional force works on a driving roller 112A on the upstream side in the conveying direction through the sheet based on the linear velocity difference. By action of the tensional force, the driving roller 112A rotates at a higher speed than the rotational speed (linear velocity) of a driving gear 120, and engagement protrusions 118A, 118B provided at the shaft end of a driving shaft 116 of the driving roller 112A separate from engagement protrusions 124A, 124B of the driving gear 120 which rotates in an arrow A direction (and moves in the arrow C direction). As a result, the driving roller 112A rotates at a speed corresponding to the conveyance speed (linear velocity) on the downstream side in the conveying direction. Thus, overload such as excessive extension of the sheet can be prevented from being applied to the sheet by absorbing the linear velocity difference. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear velocity difference absorption mechanism of a conveyance system for nipping and conveying a sheet-like conveyed material with a pair of conveyance rollers, and a conveyance mechanism and an image forming apparatus to which the linear velocity difference absorption mechanism is applied. Regarding

[0002]

2. Description of the Related Art A sheet-like conveyed product (hereinafter referred to as a sheet)
A conveyance system that nips and conveys a pair of conveyance rollers is widely used. In such a transport system, the sheet is basically transported at a constant speed, but the transport speed may change depending on a processing step for the sheet. In such a case, for example, when the conveyance speed (linear velocity) of the sheet nipped by the conveyance roller pair is higher on the downstream side in the conveyance direction than the conveyance roller pair (there is a difference in linear velocity), the sheet is overloaded. (Sheet may be stretched). Therefore, a one-way clutch is provided between a drive roller that constitutes a pair of conveyance rollers and a drive gear that transmits a driving force to the drive roller to prevent the sheet from being overloaded (for example, Patent Document 1). 1).

That is, even if the tensile force based on the difference in conveyance speed (difference in linear velocity) acts on the pair of conveyance rollers via the sheet,
A one-way clutch provided between the drive roller and the drive gear acts to rotate the drive roller at a linear velocity that follows the transport velocity (linear velocity) on the downstream side in the transport direction. As a result,
The sheet is prevented from being excessively stretched by absorbing the difference in linear velocity.

[0004]

[Patent Document 1] Japanese Unexamined Patent Application Publication No. 8-241010

[0005]

However, providing the one-way clutch between the drive roller and the drive gear in the conveying system (using the drive gear as the gear with the one-way clutch) in this way increases the cost. There was an inconvenience.

Also, the one-way clutch may be damaged over time due to wear or the like.

In order to solve the above-mentioned inconvenience, the present invention provides
It is an object of the present invention to provide a linear velocity difference absorbing mechanism, a transporting mechanism and an image forming apparatus capable of absorbing a linear velocity difference between a pair of conveying rollers with a simple structure.

[0008]

The invention according to claim 1 is
A linear velocity difference absorbing mechanism applied to a nipping and conveying member that nips and conveys a sheet-like conveyed object, which is provided in a radial direction on a rotary shaft or a ring body that transmits a driving force to the nipping and conveying member. An engaging portion, a rotating region in which the engaging portion can rotate, and an abutting portion in which the engaging portion can abut, are provided.
Drive force transmitting means for transmitting a drive force to the rotating shaft or the ring body by rotating the contact portion and pressing the engagement portion located in front of the contact portion in the rotation direction. Is characterized by.

The operation of the invention according to claim 1 will be described.

During normal conveyance, the driving force transmitting means is driven to rotate the abutment portion and press the engagement portion forward in the rotational direction to integrally rotate the engagement portion and the abutment portion. To do. As a result, the sandwiching / conveying member is driven based on the driving force transmitted from the driving force transmitting means to the rotary shaft or the ring body, and the conveyed object sandwiched by the sandwiching / conveying member is conveyed at a predetermined speed.

On the other hand, when the conveyed object is conveyed at a conveying speed (linear velocity) higher than the conveying speed (linear velocity) of the nipping and conveying member on the downstream side of the nipping and conveying member which nips the conveyed object in the conveying direction, The tensile force due to the difference in linear velocity acts on the sandwiching / conveying member via the conveyed object. As a result, due to the action of the force, the rotational speed (linear velocity) transmitted from the sandwiching / conveying member to the rotary shaft or the ring body is greater than the rotational speed (linear velocity) transmitted from the driving force transmission means to the rotary shaft or the ring body. Is also increased, and the rotating shaft or the engaging portion of the ring body rotates in the direction in which the engaging portion of the driving force transmitting means separates from the abutting portion. That is, the rotating shaft or the engaging portion of the ring body freely rotates (idles) the rotating region to absorb (the action of force based on) the linear velocity difference. In this way, it is possible to prevent an excessive force from being applied to the conveyed object nipped by the nip conveying member due to the difference in the conveying speed (difference in linear velocity).

The nipping and conveying member is a pair of conveying rollers,
It is not particularly limited as long as it sandwiches and conveys a sheet-like conveyed product, such as a pair of belts arranged to face each other, a rotating drum and a belt mechanism for pressing the conveyed product against this.

Further, the rotary shaft or the ring body provided between the sandwiching / conveying member and the drive source has only to be provided on the path through which the driving force is transmitted. It is not limited to the ring body that rotates integrally.

According to a second aspect of the present invention, in an image forming apparatus for forming an image on a recording material, an image forming means for forming an image on the recording material, and a conveyance direction rather than an image forming position of the image forming means. A first conveying roller pair which is arranged on the downstream side and which nips and conveys the recording material, and a first conveying roller which is arranged on the upstream side in the conveying direction with respect to the image forming position of the image forming means and at least during image formation. A second conveying roller pair that nips and conveys the recording material sandwiched in a pair, wherein the first conveying roller pair is the second
The linear velocity difference absorbing mechanism according to claim 1 is arranged between the second transport roller pair and a drive source of the second transport roller pair while being driven at a linear velocity higher than that of the transport roller pair. It is characterized by

The operation of the invention according to claim 2 will be described.

The driving speed (linear velocity) of the first conveying roller pair arranged downstream in the conveying direction with respect to the image forming position of the image forming means is set to the driving speed of the second conveying roller pair arranged upstream in the conveying direction. By making it higher than the driving speed (linear velocity),
A predetermined tension is applied to the recording material at the time of image formation to ensure the flatness, so that the image can be favorably formed on the recording material. At this time, tension acts on the second conveying roller pair through the recording material from the first conveying roller pair, and the linear velocity difference absorbing mechanism according to claim 1 is provided between the second conveying roller pair and its driving source. Therefore, the second conveying roller pair can follow and rotate based on the linear velocity difference between the first and second conveying roller pairs (the linear velocity difference can be absorbed). Therefore, it is possible to prevent the recording material from slipping on the second conveying roller pair, and it is possible to perform better image recording.

According to a third aspect of the present invention, in an image forming apparatus that liquid-processes a recording material on which an image has been recorded, it is provided upstream of the liquid processing position in the transport direction, and the liquid processing is performed by sandwiching the recording material. And a main drive roller pair that is provided downstream of the liquid processing position in the transport direction and that holds the recording material and draws it from the liquid processing position. The linear velocity difference absorbing mechanism according to claim 1, wherein the pair is driven at a higher linear velocity than the sub driving roller pair, and the linear velocity difference absorbing mechanism according to claim 1 is provided between the sub driving roller pair and a driving source of the sub driving roller pair. It is characterized by that.

The operation of the invention according to claim 3 will be described.

Various liquid treatments are performed in the image forming apparatus. For example, in an image forming apparatus that performs thermal development transfer, liquid coating is performed on a photosensitive material (recording material) on which a latent image is formed at a liquid coating section (liquid processing position), and the liquid coated photosensitive material and the image receiving material are superposed. Thermal development transfer is performed by heating together.

In the liquid applying section of such an image forming apparatus, the recording material (photosensitive material) conveyed by the sub-driving roller pair is inserted between the guide member and the liquid applying tray, and immersed in the liquid to apply the liquid. After that, it is conveyed downstream by the main drive roller pair. At this time, the linear velocity (rotational speed) of the main drive roller pair disposed on the downstream side of the liquid application section in the transport direction is set higher than the linear velocity (rotational speed) of the sub drive roller pair to set a predetermined recording material. So that the tension works
The recording material is prevented from sagging and the emulsion surface of the recording material slidingly contacting the liquid coating dish to prevent the emulsion surface from being damaged.

However, if this tension (linear velocity difference) becomes excessive, the recording material may come into strong contact with the guide surface of the guide member and break, or the recording material may slip with respect to the sub-driving roller pair. is there. However,
Since the sub-driving roller pair is provided with the linear velocity difference absorbing mechanism according to claim 1 between the sub-driving roller pair and the driving source, the linear velocity difference between the sub-driving roller pair and the main driving roller pair can be absorbed, and the above-mentioned inconvenience occurs. Can be prevented.

According to a fourth aspect of the present invention, there is provided a transport mechanism for sandwiching and transporting a sheet-like conveyed product, which comprises a first sandwiching / conveying member for sandwiching and conveying the sheet-like conveyed product, and a conveying direction relative to the first sandwiching / conveying member. A second nipping and conveying member, which is disposed on the upstream side, nipping and conveying the conveyed object at least until the first nipping and conveying member nips the sheet-like conveyed object, the second nipping and conveying member, and the second nipping and conveying means. The linear velocity difference absorbing mechanism according to claim 1 provided between a driving source for driving the member, wherein the first nipping and conveying member is driven at a higher linear velocity than the second nipping and conveying member. It is characterized by being done.

The operation of the invention of claim 4 will be described.

The sheet-like conveyed material is sandwiched between the first nipping and conveying member and the second.
In the transport mechanism for sandwiching and transporting by the sandwiching and transporting member, the transporting speed (linear velocity V1) of the first sandwiching and transporting member on the downstream side in the transporting direction.
Is higher than the transport speed (linear velocity V2) of the second sandwiching / conveying member, it is provided between the second sandwiching / conveying member and the drive source of the second sandwiching / conveying member based on the linear velocity difference (V1-V2). The engaging portion provided on the rotary shaft or the ring body of the linear velocity difference absorbing mechanism separates from the abutting portion of the driving force transmitting means to rotate (idle) the rotating region to absorb the linear velocity difference.

The second sandwiching / conveying member is not limited to a single member, but may be a plurality of members. In this case as well, the linear velocity difference is absorbed by the linear velocity difference absorbing mechanism provided in the plurality of second holding and conveying members.

According to a fifth aspect of the present invention, in the invention according to the fourth aspect, when the sandwiching and conveying member is a pair of conveying rollers, the first sandwiching and conveying member satisfies the formula (1). It is characterized in that the conveying speed of the conveying roller pair and the second conveying roller pair which is the second sandwiching conveying member is controlled.

ΠD / [n (V1-V2)]> Lmax / V2 (1) Here, the diameter of the conveying roller of the second pair of conveying rollers provided with the linear velocity difference absorbing mechanism: D In the mechanism, the number of abutting portions arranged at equal intervals in the circumferential direction: n Transport speed (linear velocity) of the first transport roller pair: V1 Transport speed (linear velocity) of the second transport roller pair: V2 Sheet-shaped transport Maximum length in the conveying direction of the object: Lmax.

The operation of the invention of claim 5 will be described.

The sheet-like conveyed material is transferred to the first conveying roller pair and the second conveying roller pair.
In the transport mechanism for sandwiching and transporting by the transport roller pair, the transport speed (linear velocity V1) of the first transport roller pair on the downstream side in the transport direction.
Is higher than the transport speed (linear velocity V2) of the second transport roller pair, it is provided between the second transport roller pair and the drive source of the second transport roller pair based on the linear velocity difference (V1-V2). The engaging portion provided on the rotary shaft or the ring body of the linear velocity difference absorbing mechanism separates from the abutting portion of the driving force transmitting means to rotate (idle) the rotating region to absorb the linear velocity difference.

Here, the conveying speed (linear velocity) of the conveying roller pair is controlled so as to satisfy the above expression (1). The left side of Expression (1) means the maximum idling time of the engaging portion based on the linear velocity difference (maximum rotation angle of the engaging portion / rotational angular velocity based on the linear velocity difference). That is, the maximum rotation angle of the engaging portion is 2π / n due to the n contact portions arranged at equal intervals in the circumferential direction.
And the rotational angular velocity based on the linear velocity difference is (V1-V2)
/ (D / 2). Therefore, the maximum idling time during which the engaging portion can idle in the rotation region is obtained by dividing the maximum rotation angle by the rotation angular velocity, and (2π / n) / [(V1-V2) / (D / 2)] = It is the left side of equation (1).

On the other hand, the right side of the equation (1) means the maximum passage time for the sheet-like conveyed product to pass through the second conveying roller pair. That is, the conveyance direction length Lmax of the sheet-like conveyed product having the maximum conveyance direction length is defined by the linear velocity V of the second conveyance roller pair.
It is calculated by dividing by two.

Therefore, if the condition of equation (1) is satisfied,
When there is a linear velocity difference (V1-V2) between the transport speeds of the first transport roller pair and the second transport roller pair, no matter what size sheet-shaped transport object is transported, the second transport roller pair is The engaging portion that is rotating (idling) in the rotation region based on the difference in linear velocity until it passes does not come into contact with the abutting portion. That is, while the sheet-like conveyed product passes through the second conveying roller pair, the engaging portion comes into contact with the abutting portion, and the linear velocity difference cannot be absorbed.
It is possible to reliably prevent excessive tension from acting on the sheet-shaped conveyed product, slipping of the conveyed product on the second conveying roller, and the like.

The invention according to claim 6 is the invention according to claim 4 or 5.
In the invention described above, when the nipping and conveying member is a conveying roller pair, the second conveying roller pair which is the second nipping and conveying member is configured to satisfy the expression (2).

ΠD / n <G (2) Here, of the second pair of conveying rollers, the diameter of the conveying roller provided with the linear velocity difference absorbing mechanism: D In the linear velocity difference absorbing mechanism, at equal intervals in the circumferential direction. The number of arranged abutting portions: n The minimum distance between the sheet-like conveyed products: G 1. .

The operation of the invention of claim 6 will be described.

The sheet-like conveyed material is transferred to the first conveying roller pair and the second conveying roller pair.
In the transport mechanism for sandwiching and transporting by the transport roller pair, the transport speed (linear velocity V1) of the first transport roller pair on the downstream side in the transport direction.
Is higher than the transport speed (linear velocity V2) of the second transport roller pair, it is provided between the second transport roller pair and the drive source of the second transport roller pair based on the linear velocity difference (V1-V2). The engaging portion provided on the rotary shaft or the ring body of the linear velocity difference absorbing mechanism separates from the abutting portion of the driving force transmitting means to rotate (idle) the rotating region to absorb the linear velocity difference.

At this time, if the configuration of the second conveying roller pair satisfies the expression (2), the engaging portion is separated from the abutting portion by the passage of the preceding sheet-like conveyed material to rotate the rotation region (idle rotation). Even after the above), it is possible to return to a state (hereinafter, referred to as an initial state) in which the contact portion can press the engaging portion before the succeeding sheet-shaped conveyed material is nipped by the second conveying roller pair.

Here, the left side of the equation (2) is required for the contact portion and the engagement portion to come into contact with each other again to return to the initial state, and in fact, for the contact portion to rotate to the position of the engagement portion. It means the maximum recovery time. This is because the maximum rotation angle at which the engaging portion and the abutting portion are separated most by idling is 2π / n by the n abutting portions arranged at equal intervals in the circumferential direction, and the maximum rotation angle is driven to the second conveying roller pair. The rotational angular velocity of the contact portion that transmits force is V2 / (D /
2). On the other hand, when the abutting portion and the engaging portion are separated from each other, there is no rotational force that acts on the engaging portion from the second conveying roller pair unless the sheet-shaped conveyed object is sandwiched (the engaging portion does not rotate). . Therefore, the return time required for the contact portion to come into contact with the separated engagement portion (to return to the initial state) is obtained by dividing the maximum rotation angle by the rotation angular velocity of the contact portion, (D / 2) × (2π / n) / V2 = πD / (n × V2).

On the other hand, the right side of the equation (2) means the minimum time from when one sheet-shaped conveyed product passes through the second conveying roller pair to when the succeeding sheet-shaped conveyed product is pinched. To do. Here, it is assumed that the upstream transport speed of the second transport roller pair is substantially the same as that of the second transport roller pair.

That is, it is G / V2 obtained by dividing the minimum distance G between the trailing end of the preceding conveyed product and the leading end of the succeeding conveyed product by the linear velocity V2 of the second conveying roller pair.

Therefore, if the roller diameter of the second conveying roller pair is configured so as to satisfy the expression (2), from the passage of the preceding sheet-like conveyed object to the sandwiching of the succeeding sheet-like conveyed object. It is possible to surely return to the initial state in which the contact portion contacts the engagement portion. That is, it is possible to always exhibit a predetermined linear velocity absorbing ability regardless of the transportation interval of the transported objects.

[0042]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) A transport mechanism including a linear velocity difference absorbing mechanism for a transport system according to a first embodiment of the present invention will be described below based on a preferred embodiment shown in the accompanying drawings.
The details will be described.

The transport system to which the linear velocity difference absorption mechanism is applied is
As shown in FIG. 1, the transport roller pair 11 on the upstream side in the transport direction.
2 and a transport roller pair 114 on the downstream side in the transport direction,
The pair of transport rollers 112 and 114 are used to transport a sheet-like product (hereinafter,
A conveyance system or the like that may simultaneously sandwich sheets 115).

The conveying roller pairs 112 and 114 are provided with upper rubber driving rollers 112A and 114A and lower rubber driven rollers 112B and 114B, respectively. The driven rollers 112B and 114B are driving rollers 112A and 1A, respectively.
The drive rollers 112A and 114 by the nip with 14A.
It is configured to rotate following A.

Drive shaft 1 with drive roller 112A mounted
As shown in FIG. 2, 16 is provided with a fitting member 119 having a pair of engaging projections 118A and 118B protruding in the radial direction at the shaft end. Engaging projection 118A,
As shown in FIG. 3, 118B is formed at a position opposite to the axis of the drive shaft 116 by 180 degrees.

On the other hand, the drive gear 120 for transmitting the drive force from the drive source (not shown) to the drive shaft 116 has teeth 122 for meshing with the other gear for transmitting the drive force from the drive source on the outer peripheral surface. And a pair of engaging projections 1 on the inner peripheral surface.
24A and 124B are formed to project in the radial direction. As shown in FIG. 3, the engagement protrusions 124A and 124B are formed at positions facing each other by 180 degrees about the rotation center of the drive gear 120 (the axis of the drive shaft 116).

The roller diameter (diameter) of the driving roller 112A is D (mm), the conveying speed (linear velocity) of the conveying roller pair 114 is V1 (mm / s), and the conveying speed (linear velocity) of the conveying roller pair 112. Is V2 (mm / s), and the maximum length of the conveyed sheet in the conveying direction is Lmax (mm), the rollers are set so as to satisfy πD / [2 (V1-V2)]> Lmax / V2 (1) The diameter is configured and the transport speed is controlled.

Further, the minimum distance between sheets (the distance between the trailing edge of the preceding sheet and the leading edge of the succeeding sheet in the conveying direction) is G (mm).
Then, the drive roller 112A is configured so as to satisfy πD / n <G (2).

The transport mechanism (linear velocity difference absorbing mechanism) thus constructed operates as follows.

First, in normal times, the pair of conveying rollers 112, 11
4 is rotated at the same rotation speed (conveying roller pair 1
12 and 114 are sending the sheet 115 at the same linear velocity). In this case, the drive gear 120 rotates in the direction of arrow A by the rotational force transmitted from the drive source (not shown) via the tooth flank 122, and the drive gear 12
The engaging protrusions 124A, 124B provided on the inner peripheral surface of the drive shaft 0 are the engaging protrusions 118A, 1A provided on the end of the drive shaft 116.
18B (see the position of the implementation line in FIG. 3) is pressed. As a result, the drive gear 120 and the drive shaft 116 rotate integrally.

The sheet 115 is nipped and conveyed at a predetermined speed by the driving roller 112A (conveying roller pair 112) mounted on the driving shaft 116 to which the rotational force is transmitted in this manner. In this case, the drive rollers 112A, 1
Sheet 1 by 14A (conveying roller pair 112, 114)
The transport velocities of 15 (linear velocities V2 and V1) are equal. That is, the linear velocity difference (V1
Since −V2) is 0, the sheet 115 is conveyed without being excessively stretched.

On the other hand, when the conveying speeds (linear velocities) of the conveying roller pairs 112 and 114 are different, for example, the conveying roller pair 112 by the driving force transmitted from the driving gear 120.
The conveying speed (linear velocity V2) of the sheet 115 by the (driving roller 112A) is equal to that of the conveying roller pair 114 (driving roller 11A).
4A) is lower than the transport speed (linear velocity V1) of the sheet 115, the linear velocity difference (V1-V2) is applied to the transport roller pair 112 via the sheet 115 sandwiched by the transport roller pair 114. Tensile force acts.

Due to the action of this force, the rotational speed (linear velocity) of the drive roller 112A becomes faster than the rotational speed (linear velocity V2) of the drive gear 120. As a result, the engagement protrusions 118A and 118B formed at the end of the drive shaft 116 on which the drive roller 112A is mounted have the linear velocity difference (V1) in the rotation region B of the drive gear 120 that is rotating at the linear velocity V2.
The distance from the engaging protrusions 124A and 124B is increased in the direction of arrow C at a speed based on −V2). That is, the drive shaft 116
Of the engaging protrusions 118A and 118B of the linear velocity difference (V1-V
Based on 2), by freely rotating (idling) without abutting on the engaging protrusions 124A and 124B, it is possible to absorb the action of force due to this linear velocity difference (V1-V2).

By absorbing the linear velocity difference in this way, the engaging projections 118A and 118B and the engaging projection 124 are
Although the A and 124B are separated from each other, the engagement protrusions 124A and 124B are caused to continue by driving the drive source of the drive roller 112A even after the sheet 115 has passed.
It is possible to return to the state of contacting 8B.

As described above, in the linear velocity difference absorbing mechanism according to the present embodiment, the pair of engaging projections 11 is provided at the end of the drive shaft 116.
8A and 118B, a pair of engagement protrusions 124A and 124B are provided on the inner peripheral surface of the drive gear 120, and the engagement protrusions 118A and 118B are provided between the engagement protrusions 124A and 124B.
By providing the rotation region B in which the sheet can rotate by approximately 180 degrees, the pair of conveyance rollers 112 and 11 that sandwich the sheet 115 are provided.
4 when there is a difference in linear velocity between the engaging projections 118A, 11A
By freely rotating 8B within the rotation region B, the linear velocity difference (V1-V
It absorbs 2).

As described above, since the linear velocity difference can be absorbed with a simple structure, the manufacturing cost of the linear velocity difference absorbing mechanism can be reduced as compared with the one-way clutch or the like. Further, unlike the one-way clutch, the engagement protrusion 118 provided at the end of the rotary shaft 16
Since A and 118B have a simple structure in which the engaging protrusions 124A and 124B provided on the inner peripheral surface of the drive gear 120 are simply brought into contact with each other, the possibility of breakage with time is extremely low.

In the present embodiment, the operation has been described only in one direction, but the same operation can be achieved when the material is conveyed (rotated) in the opposite direction. Also, one of the pair of transport rollers 112
Although the linear velocity difference absorbing mechanism is provided only in the above, the linear velocity difference absorbing mechanism may be provided in the other conveying roller pair 114.

Further, in the present embodiment, the driving source side is the ring body (driving gear 120) and the driven side is the driving shaft 116. That is, the same operational effect can be obtained even if the drive source side is the drive shaft, the driven source side is the ring body, and the transport roller is provided on the ring body side.

Furthermore, in the present embodiment, a pair of engaging protrusions is provided, but the number may be one. In this case, the rotation region B can be set to be close to 360 °, and the range in which the linear velocity difference can be absorbed becomes large.

The roller diameter (diameter) D (mm) of the driving roller 112A, the conveying speeds V2 (mm / s) and V1 (mm / s) of the pair of conveying rollers 112 and 114, and the maximum conveyance of the conveyed sheets. The direction length Lmax (mm) is calculated by the formula (1).
By configuring and controlling so as to satisfy the requirement, it is possible to reliably absorb the transport speed difference (linear velocity difference) no matter what size sheet 115 is transported.

This is the maximum rotation time (πD /) during which the engagement protrusion 118 can rotate (idle) in the rotation region B, rather than the maximum passage time (Lmax / V2) during which the sheet-like conveyed product passes through the conveyance roller pair 112. 2) / (V1−V2) is increased, so that the rotation (idling) of the engagement protrusion 118 caused by the difference in transport speed when the sheet passes is within the range of the rotation region B.

That is, the engaging protrusions 118A and 118B rotating in the rotation region B based on the difference in linear velocity collide with the engaging protrusions 124B and 124A in the direction of arrow C (FIG. 3, FIG. 3).
By referring to the position indicated by the chain double-dashed line), it becomes possible to reliably prevent the conveyance speed difference from being absorbed, and it is possible to reliably prevent the sheet 115 from being excessively tensioned and the conveyance roller pair 112 and 114 from slipping the sheet 115.

Further, when the minimum distance between the trailing edge of the preceding sheet 115 and the leading edge of the succeeding sheet 115 is G (mm), the driving and conveying roller 112A is configured so as to satisfy the equation (2). The engaging protrusions 118A separated from the engaging protrusions 124A and 124B during the conveyance of one sheet,
118B, the succeeding sheet is the conveyance roller pair 112.
It is possible to return to the contact state (hereinafter referred to as the initial state (FIG. 3, solid line position)) in which the engaging protrusions 124A and 124B can be pressed before being nipped. Conversely, when the pair of conveying rollers 114 nip the sheet 115 while the engaging protrusions 118A and 118B are returning to the initial state, the engaging protrusions 124A and 124B are separated from the engaging protrusions 118A and 118B. Transport roller pair 112 until both contact
Although A may not be driven and the sheet 115 may be folded or slipped, this is surely prevented.

In this embodiment, the drive roller 112 is used.
Although the transport speed absorbing mechanism is provided on the rotating shaft 116 of A, it may be provided anywhere as long as the driving force is transmitted from the driving source to the driving roller 112A. For example, as shown in FIG. 8, between the driven gear 150 provided at the end of the rotary shaft 116 of the drive roller 112A and the drive gear 156 provided at the end of the drive shaft 154 of the motor 152 that is the drive source. The speed difference absorbing gear 158 may be provided in the. The speed difference absorbing gear 158, as shown in FIGS. 8 and 9, has a large-diameter portion 160 that meshes with the drive gear 156 to transmit the rotational force.
The idle gear 16 that is rotatably attached to the rotary shaft 162 of the large diameter portion 160 and transmits the rotational force to the driven gear 150.
4 and. That is, when there is no difference in transport speed, when the engagement protrusions 166A and 166B of the large diameter portion 160 press the engagement portions 168A and 168B of the idle gear 164 to transmit the rotational force and absorb the difference in linear velocity. Engaging projection 1
The engaging portions 168A and 168B can be separated from the 66A and 166B.

In this embodiment, there are two pairs of conveying rollers.
Although two cases have been described, the present invention can be applied to three or more pairs of conveying rollers that simultaneously hold the sheet 115. For example,
As shown in FIG. 10, a transport roller pair 180 is provided further upstream in the transport direction than the transport roller pair 112, and the transport velocities V3, V of the three transport roller pairs 180, 112, 114 are provided.
It is applicable as long as the relationship between 2 and V1 is V1>V2> V3.

Further, in the present embodiment, the case of the pair of conveying rollers has been described, but as long as it is a mechanism for transmitting the driving force via the rotating shaft, the conveying mechanism to which the linear velocity difference absorbing mechanism is applied (the sandwiching conveying member). ) Is not particularly limited. For example, the present invention may be applied to a mechanism for sandwiching and conveying a sheet by a pair of belts arranged opposite to each other, or may be applied to a mechanism for winding and conveying a sheet around a drum. (Second Embodiment) An image forming apparatus to which a conveyance mechanism (linear velocity difference absorption mechanism) according to a second embodiment of the present invention is applied will be described. The description of the transport mechanism (linear velocity difference absorption mechanism) described in the first embodiment is omitted. First, a schematic description of the image forming apparatus will be given. <Schematic Description of Entire Image Forming Apparatus> As shown in FIG. 4, the image forming apparatus 10 includes a photosensitive material magazine 12 containing a photosensitive material A, a receiving material magazine 14 containing an image receiving material B, and a photosensitive material A. An exposure section 16 for exposing to form a latent image, and a water application section 18 for applying water to the photosensitive material A on which the latent image is formed.
And a heat-development transfer section 20 for transferring the latent image formed on the photosensitive material A to the image-receiving material to develop by laminating the water-coated photosensitive material A and the image-receiving material B and heating, and peeling after the thermal development. A storage tray 22 for storing the exposed photosensitive material A,
It is basically configured by a drying unit 24 for drying the peeled image receiving material B and a storage tray 26 for storing the dried image receiving material B.

A specific image forming operation will be described below.
First, the photosensitive material A is extracted from the photosensitive material magazine 12 by the extraction roller 32, cut into a sheet by the cutter 34 into a predetermined length, and formed into a sheet, and then a predetermined latent image is formed by the optical scanning of the optical scanning device 36 in the exposure unit 16. Is formed. Further, the photosensitive material A coated with water in the water coating section 18 has a squeeze roller pair 4
The excess water is removed by 8 and supplied to the thermal development transfer section 20.

On the other hand, the image receiving material B drawn out from the image receiving magazine 14 by the drawing roller 50 and cut into a sheet by the cutter 52 into a predetermined length is supplied to the heat development transfer section 20.

The photosensitive material A and the image receiving material B thus supplied to the heat development transfer section 20 are sent from the squeeze roller pair 48 and the guide member 53 to the space between the heat drum 54 and the nip roller 56 for bonding. The photosensitive material A and the image receiving material B are bonded to each other by the pressing roller 56 pressing the photosensitive material A and the image receiving material B against the heat drum 54 with a relatively strong pressure.

The photosensitive material A and the image receiving material B thus bonded by the bonding roller 56 move in the direction of arrow D as the heat drum 54 rotates, and the endless belt 62 of the belt support mechanism 58 and the heat drum 54. Is sandwiched between and. Since the endless belt 62 operates without being displaced from each other due to frictional resistance between the endless belt 62 and the heat drum 54, the photosensitive material A and the image receiving material B sandwiched between the endless belt 62 and the heat drum 54 are relatively positioned. The sheet is conveyed in the direction of arrow D in synchronism with the rotating operation of the heat drum 54 without being misaligned.

In this way, the heat drum 54 from the leading end to the trailing end of the light-sensitive material A and the image-receiving material B which are overlapped with each other.
When it reaches a state where it is wound around and is held and held by the belt support mechanism 58, the rotation of the heat drum 54 is stopped, and the heater inside the heat drum 54 raises the temperature of the outer peripheral surface portion of the heat drum 54 to a predetermined level. Heated to the temperature of
This stopped and heated state is maintained for a predetermined processing time until the end of the heat development transfer processing.

During this heat development transfer process, the photosensitive material A was
The movable dye is released by the heating by the heat drum 54, and at the same time, this dye is transferred to the dye fixing layer of the image receiving material B, and an image is obtained on the image receiving material B.

After the light-sensitive material A and the image-receiving material B, which are overlapped with each other, are wound around the heat drum 54 until reaching the end,
The bonding roller 56 is switched by an operating means (not shown) so as to be pressed against the heat drum 54 with a relatively weak pressure for peeling.

The movement operating member 64 rotates and moves to the retracted position in synchronization with the switching of the pressing force of the bonding roller 56 (see FIGS. 4 to 5). As a result, the attachment member 76 supported by the movement operation member 64 rotates and the peeling claw 7 moves.
4 is dropped on the outer peripheral surface of the heat drum 54. Further, the peeling claw 72 located at the position shown in FIG. 4 advances to a predetermined use position near the heat drum 54 shown in FIG.

In this state, the photosensitive drum A and the image receiving material B, which are overlapped with each other, are sandwiched by the laminating roller 56 again by continuously rotating the heat drum 54. Since the bonding roller 56 is pressed against the heat drum 54 with a relatively weak pressure force for peeling, the photosensitive material A is peeled from the image receiving material B, and the guide member 94 is peeled off by the peeling claw 72.
Be guided to the side. As a result, the photosensitive material A is stored in the storage tray 22 via the guide member 94 and the guide roller 96.

Further, the image receiving material B attached to the heat drum 54 and further fed from the position of the peeling claw 72 in the direction of the arrow D is peeled off from the outer peripheral surface of the heat drum 54 by the peeling claw 74, and the guide member 80 and the comb. It is inserted between the rollers 82. While passing between the guide member 80 and the comb roller 82, the outside air is blown from the fan 86 and is quickly dried. Further, the image receiving material B is a guide roller 98,
The sheet is conveyed through the guide member 100 and the paper discharge roller 102 and stored in the storage tray 26. <Exposure Unit 16> Next, the case of the exposure unit 16 to which the linear velocity difference absorbing mechanism is applied in the image forming apparatus 10 will be described.

As shown in FIG. 6, the exposure unit 16 includes a conveying roller pair 38 on the upstream side in the conveying direction and a conveying roller pair 40 on the downstream side in the conveying direction with respect to the optical scanning position of the optical scanning device 36. These conveying roller pairs 38 and 40 are the upper driving rollers 38A and 40A and the lower driven roller 3 respectively.
8B and 40B, and a pair of conveying rollers 384
The photosensitive material A is optically scanned while being sandwiched between the two.

The drive rollers 38A and 40A are respectively provided.
Is driven at a predetermined speed by each drive source (not shown),
It is configured to rotate together with the driven rollers 38B and 40B nipped by the drive rollers 38A and 40A. Further, the linear velocity difference absorbing mechanism described in the first embodiment is provided between the drive roller 38A and its drive source.

The operation of the exposure unit 16 thus configured will be described.

The driving rotation speed (linear velocity) of the transport roller pair 40 on the downstream side in the transport direction with respect to the optical scanning position is higher than that of the transport roller pair 38 on the upstream side. In this way, by causing a linear velocity difference between the pair of conveying rollers 38 and 40 that sandwich the photosensitive material A at the optical scanning position, a predetermined tension is applied to the photosensitive material A and the photosensitive material A at the optical scanning position. To ensure the flatness of. As a result, good image recording can be performed.

Further, the force based on the linear velocity difference is transmitted from the conveying roller pair 40 to the conveying roller pair 38 through the photosensitive material A, but the line arranged between the conveying roller pair 38 and its driving source. By the action of the speed difference absorbing mechanism, the conveying roller pair
It is possible to prevent the photosensitive material A from slipping on the conveying roller pair 38 due to the linear velocity difference by rotating following the linear velocity difference. Therefore, better image recording can be performed.

In the present embodiment, the exposure section 16 of the image forming apparatus 10 for carrying out the heat development transfer process is explained, but the flatness of the image recording material such as the writing position of the ink jet printer and the developing section of the wet electrophotographic apparatus. Applicable if required. (Third Embodiment) An image forming apparatus to which a linear velocity difference absorbing mechanism according to a third embodiment of the present invention is applied will be described.
The description of the linear velocity difference absorbing mechanism described in the first embodiment is omitted. The same components as those in the second embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. Here, since the configuration of the image forming apparatus is the same as that of the second embodiment, description thereof will be omitted, and only the water application unit 18 to which the linear velocity difference absorption mechanism, which is a main part, is applied will be described.

As shown in FIG. 7, the water application section 18 has a conveyance path formed between the bottom surface 44A of the water application tray 44 and the bottom surface 45A of the guide member 45, and the auxiliary drive roller pair 46.
The light-sensitive material A is dipped in water stored in the water-coating tray 44 with the emulsion surface fed downward by the feeding path by the main drive roller pair. Excess water is removed by a certain squeeze roller pair 48, and the squeeze roller pair 48 conveys the water to the heat drum 54.

Since the emulsion surface of the light-sensitive material A is on the lower side (bottom surface 44A of the water coating dish 44), the roller pair 46,
If the tension acting on the light-sensitive material A is insufficient between 48 and it is loosened, the emulsion surface is damaged by the sliding between the emulsion surface and the bottom surface 44A and the formed image quality is deteriorated. Therefore, in the water application unit 18, the linear velocity (rotational speed) of the squeeze roller 48 is set higher than the linear velocity (rotational speed) of the sub-driving roller pair 46, and a predetermined tensile force is applied to the photosensitive material A. Bottom 44A
It avoids sliding with and prevents damage to the emulsion surface.

However, when the tensile force becomes excessive, the photosensitive material A slips on the sub-driving roller pair 46 or the photosensitive material A strongly contacts the bottom surface 45A of the guide member 45, causing the photosensitive material A to break. Photosensitive material A has bottom surface 4
There is a possibility that the guide member 45 may be lifted by pushing up 5A.

However, by providing the linear velocity difference absorbing mechanism according to the first embodiment between the sub-driving roller pair 46 and its driving source, the linear velocity difference between the driving roller pairs 46 and 48 is absorbed, and the water application is performed. Excessive tension is prevented from acting on the photosensitive material A in the portion 18, and the above-mentioned inconvenience (slip of the photosensitive material A, bending of the photosensitive material A, etc.) can be reliably prevented, and high-quality image formation can be achieved. Can be achieved.

In the present embodiment, the water coating section 18 of the image forming apparatus 10 for carrying out the heat development transfer processing has been described, but any application can be applied as long as the recording material is impregnated with a liquid and the development processing is carried out.

[0088]

The linear velocity difference absorbing mechanism according to the present invention can reliably absorb the linear velocity difference with a simple structure. Further, with the transport mechanism according to the present invention, slipping or the like based on the transport speed can be reliably avoided. Further, in the image forming apparatus to which the linear velocity difference absorbing mechanism is applied, good image formation can be performed.

[Brief description of drawings]

FIG. 1 is a side view showing a transport mechanism according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a linear velocity difference absorbing mechanism according to the first embodiment of the present invention.

FIG. 3 is a side view of essential parts of the linear velocity difference absorbing mechanism according to the first embodiment of the present invention.

FIG. 4 is an overall schematic diagram of an image forming apparatus to which a linear velocity difference absorbing mechanism according to a second embodiment of the present invention is applied.

FIG. 5 is an operation state explanatory diagram of the image forming apparatus according to the second embodiment of the present invention.

FIG. 6 is a main part explanatory view of an exposure unit of the image forming apparatus according to the second embodiment of the present invention.

FIG. 7 is an explanatory view of a main part of a water application light section of an image forming apparatus according to a third embodiment of the present invention.

FIG. 8 is a perspective view showing another example of the linear velocity difference absorbing mechanism according to the first embodiment of the present invention.

FIG. 9 is an exploded perspective view showing a linear velocity difference absorbing gear according to the first embodiment of the present invention.

FIG. 10 is a side view showing another example of the transport mechanism according to the first embodiment of the present invention.

[Explanation of symbols]

10 ... Image forming apparatus 15 ... Sheet (conveyed object) 18A, 18B ... Engaging protrusion (engaging portion) 22 ... Drive gear (driving force transmission means) 24A, 24B ... Engaging projections (abutting parts) 36 ... Optical scanning device (exposure means) 38 ... Conveying roller pair (second conveying roller pair) 40 ... Conveying roller pair (first conveying roller pair) 46 ... Sub drive roller 48 ... Squeeze roller (main drive roller) 112 ... Conveying roller pair (sandwiching conveying member)

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Claims (6)

[Claims] 1. A linear velocity difference absorbing mechanism applied to a nipping and conveying member that nips and conveys a sheet-like conveyed object, the radial direction being on a rotary shaft or a ring body that transmits a driving force to the nipping and conveying member. An engaging portion that is provided so as to project in the direction of rotation, a rotation region in which the engaging portion can rotate, and an abutting portion in which the engaging portion can abut, are provided, and the abutting portion rotates and abuts. A linear velocity difference absorbing mechanism, comprising: a driving force transmitting unit that transmits a driving force to the rotating shaft or the ring body by pressing the engaging portion located in front of the rotational direction of the portion. 2. An image forming apparatus for forming an image on a recording material, wherein the image forming means forms an image on the recording material, and the image forming means is arranged downstream of the image forming position of the image forming means in the transport direction. A first conveying roller pair for nipping and conveying the recording material; and a first conveying roller pair arranged upstream of the image forming position of the image forming means in the conveying direction, and nipped by the first conveying roller pair at least during image formation. Second for nipping and conveying the recording material
A pair of transport rollers, wherein the first transport roller pair is driven at a linear velocity higher than that of the second transport roller pair, and the second transport roller pair and a drive source for the second transport roller pair. An image forming apparatus, wherein the linear velocity difference absorbing mechanism according to claim 1 is provided between the image forming apparatus and the image forming apparatus. 3. An image forming apparatus for liquid-processing an image-recorded recording material, which is provided upstream of the liquid processing position in the transport direction, and which holds the recording material and transports it to the liquid processing position. A pair of rollers, and a main drive roller pair that is provided on the downstream side in the transport direction with respect to the liquid processing position and that holds the recording material and draws the recording material from the liquid processing position. It is driven at a linear velocity higher than that of the drive roller pair, and the linear velocity difference absorbing mechanism according to claim 1 is provided between the sub drive roller pair and a drive source of the sub drive roller pair. Image forming apparatus. 4. A transport mechanism for sandwiching and transporting a sheet-like conveyed product, comprising: a first sandwiching / conveying member for sandwiching and conveying the sheet-like conveyed product; and an upstream side of the first sandwiching / conveying member in the conveying direction. A second nipping and conveying member that nips and conveys the conveyed object at least until the first nipping and conveying member nips the sheet-like conveyed object, and a drive source that drives the second nipping and conveying member and the second nipping and conveying member. The linear velocity difference absorbing mechanism according to claim 1, which is provided between the first pinching and conveying member and the second pinching and conveying member, the linear velocity difference absorbing mechanism being driven at a higher linear velocity than the second pinching and conveying member. A transport mechanism that does. 5. When the nipping and conveying member is a conveying roller pair, a first conveying roller pair which is the first nipping and conveying member and a second nipping and conveying member which is the first nipping and conveying member so as to satisfy the expression (1). The transport mechanism according to claim 4, wherein the transport speed of the transport roller pair is controlled. πD / [n (V1-V2)]> Lmax / V2 (1) Here, the diameter of the transport roller of the second transport roller pair provided with the linear velocity difference absorbing mechanism: D in the linear velocity difference absorbing mechanism, Number of abutting portions arranged at equal intervals in the circumferential direction: n Transport speed (linear velocity) of the first transport roller pair: V1 Transport speed (linear velocity) of the second transport roller pair: V2 Maximum of sheet-shaped transported object Length in transport direction: Lmax. 6. The second conveying roller pair, which is the second sandwiching and conveying member, is configured to satisfy the expression (2) when the sandwiching and conveying member is a conveying roller pair. Alternatively, the transport mechanism according to item 5. πD / n <G (2) Here, of the second pair of conveying rollers, the diameter of the conveying roller provided with the linear velocity difference absorbing mechanism: D In the linear velocity difference absorbing mechanism, they are arranged at equal intervals in the circumferential direction. The number of abutting portions: n The minimum distance between the sheet-like conveyed products is G.