Patent Description:
In a binding process, a sheet conveyance apparatus is used so that sheets discharged from an upstream sheet processing apparatus (a printing machine or the like) are conveyed to a downstream sheet processing apparatus (a binding apparatus or the like), which improves productivity. The sheet conveyance apparatus is connected to the upstream sheet processing apparatus and the downstream sheet processing apparatus.

In such a case, the sheet conveyance apparatus supplies sheets such that the upstream sheet processing apparatus and the downstream sheet processing apparatus have a synchronized processing timing.

The processing speed of the upstream sheet processing apparatus and the processing speed of the downstream sheet processing apparatus are not the same in general. For example, when the processing speed of the upstream sheet processing apparatus is higher than the processing speed of the downstream sheet processing apparatus, the sheet conveyance apparatus is required to temporarily accumulate sheets and then convey the accumulated sheets to the downstream so as to synchronize the conveying timing with the processing timing of the downstream sheet processing apparatus.

A conventional sheet conveyance apparatus is disclosed in PTL <NUM>, for example. As illustrated in Fig. <NUM> of PTL <NUM>, the sheet conveyance apparatus has a conveying belt <NUM> having a plurality of airflow holes and a suction box <NUM>. The sheet conveyance apparatus temporarily accumulates sheets <NUM> on the conveying belt <NUM> in a sheet accumulation area. The sheet conveyance apparatus then produces a negative pressure in the suction box <NUM> to cause the sheets <NUM> to be sucked on the conveying belt <NUM> by the airflow holes, and rotates the conveying belt <NUM> to convey the sheets <NUM> one by one.

In such an apparatus, if all the sheets accumulated in the sheet accumulation area have been conveyed out and there is no sheet on the conveying belt, and then if a next sheet enters the sheet accumulation area, the next sheet may be caught on the conveying belt, and may be fold or jammed (sheet jam).

The object to be achieved by the present invention is to provide a sheet conveyance apparatus and a control method of a sheet conveyance apparatus that enable a sheet to enter a sheet accumulation area without being caught on a conveying belt and to provide a control program for the sheet conveyance apparatus.

The sheet conveyance apparatus according to the first aspect of the present invention is a sheet conveyance apparatus that conveys a sheet fed out of an upstream sheet processing apparatus to a downstream sheet processing apparatus, the sheet conveyance apparatus comprising: a conveying unit configured to convey the sheet; a conveying unit drive mechanism configured to drive the conveying unit; a sheet accumulation area in which the sheet fed out of the upstream sheet processing apparatus is accumulated on the conveying unit; and a control unit configured to control conveyance of the sheet performed by the conveying unit.

The control unit includes a counter unit configured to count the number of sheets accumulated in the sheet accumulation area, and when a conveyance instruction signal for conveying the sheet from the sheet accumulation area is received and the number of the sheets currently accumulated in the sheet accumulation area is counted to be one by the counter unit, the control unit stops conveyance of the one sheet without conveying the one sheet from the sheet accumulation area until a next sheet is guided onto the one sheet.

In the sheet conveyance apparatus described above, the control unit may include a sheet number determination unit (named "first determination unit") that may determine, based on a count of the sheets by the counter unit, whether the number of the sheets currently accumulated in the sheet accumulation area is two or greater, or one. When it is determined by the first determination unit that the number of the sheets currently accumulated in the sheet accumulation area is two or greater, the control unit may convey the sheet from the sheet accumulation area.

In the sheet conveyance apparatus described above, the control unit may include a final sheet determination unit (named "second determination unit") that may determine whether or not the sheet currently accumulated in the sheet accumulation area is a final sheet to be processed. When it is determined by the second determination unit that the sheet currently accumulated in the sheet accumulation area is the final sheet to be processed, the control unit may perform control to convey the sheet from the sheet accumulation area.

In the sheet conveyance apparatus described above, in response to receiving information on the number of the sheets to be processed from the upstream sheet processing apparatus, the second determination unit may determine, based on the count of the sheets by the counter unit, whether or not the sheet accumulated in the sheet accumulation area is the final sheet to be processed.

In the sheet conveyance apparatus described above, an airflow hole may be formed in the conveying unit, and the sheet conveyance apparatus may include a suction switch mechanism configured to switch whether or not to suck the sheet on the conveying unit through the airflow hole.

The control method of a sheet conveyance apparatus according to the second aspect of the present invention is a control method of a sheet conveyance apparatus that conveys a sheet fed out of an upstream sheet processing apparatus to a downstream sheet processing apparatus, the sheet conveyance apparatus comprises: a conveying unit that conveys the sheet, a conveying unit drive mechanism that drives the conveying unit, and a sheet accumulation area in which the sheet fed out of the upstream sheet processing apparatus is accumulated on the conveying unit, and the control method comprising: when a conveyance instruction signal for conveying the sheet from the sheet accumulation area is received and the number of sheets currently accumulated in the sheet accumulation area is counted to be one, stopping conveyance of the one sheet without conveying the one sheet from the sheet accumulation area until a next sheet is guided onto the one sheet.

The third aspect of the present invention is a non-transitory computer readable storage medium storing a control program that causes the control unit comprised in the sheet conveyance apparatus of the first aspect to control said sheet conveyance apparatus.

The sheet conveyance apparatus according to the present invention enables a sheet to enter the sheet accumulation area without being caught on the conveying unit.

Embodiments of a sheet conveyance apparatus according to the present invention will be described below with reference to the drawings.

The configuration of a sheet conveyance apparatus <NUM> will be described with reference to <FIG>.

As illustrated in <FIG>, the sheet conveyance apparatus <NUM> is connected to an upstream sheet processing apparatus (a printing machine or the like) <NUM> and a downstream sheet processing apparatus (a binding apparatus or the like) <NUM>. The sheet conveyance apparatus <NUM> conveys sheets S, which have been discharged from the upstream sheet processing apparatus <NUM>, to the downstream sheet processing apparatus <NUM> such that the upstream sheet processing apparatus <NUM> and the downstream sheet processing apparatus <NUM> have a synchronized processing timing.

As illustrated in <FIG>, the sheet conveyance apparatus <NUM> has a drive roller <NUM> and an idle roller <NUM> extending parallel to each other and horizontally, four endless conveying belts (a conveying unit) <NUM> extended between the drive roller <NUM> and the idle roller <NUM>, and a belt drive mechanism <NUM> that rotates the drive roller <NUM>.

The drive roller <NUM> has a horizontal rotary shaft 1a and four first pulleys 1b arranged spaced apart from each other in the axial direction of the rotary shaft 1a. The first pulleys 1b are integrally attached to the rotary shaft 1a in a rotatable manner.

The idle roller <NUM> has a shaft 2a parallel to the rotary shaft 1a of the drive roller <NUM> and four second pulleys 2b rotatable about the shaft 2a. The second pulleys 2b are each arranged facing the four first pulleys 1b.

Each conveying belt <NUM> is extended between the first pulley 1b of the drive roller <NUM> and the second pulley 2b of the idle roller <NUM>. Each conveying belt <NUM> has a plurality of airflow holes 3a at predetermined intervals over the entire length.

The belt drive mechanism <NUM> has a pulley 4a fixed to one end of the rotary shaft 1a of the drive roller <NUM>, a motor 4b having a drive shaft parallel to the drive roller <NUM>, a pulley 4c fixed to the drive shaft of the motor 4b, and an endless belt 4d extended between the pulley 4a and the pulley 4c.

In the sheet conveyance apparatus <NUM>, the four conveying belts <NUM> rotate at a constant speed in response to rotation of the drive roller <NUM> driven by the motor 4b, and the sheets S placed on a conveying face 3b of the four conveying belts <NUM> are conveyed from the idle roller <NUM> (upstream) toward the drive roller <NUM> (downstream). Thus, the conveying belt <NUM> is formed of a material having a large friction coefficient (for example, a natural resin, a synthetic resin) in order to prevent sliding of the sheet S.

The sheet conveyance apparatus <NUM> has a suction switch mechanism <NUM> (<FIG>) configured to switch whether or not to suck the sheet S on the conveying belts <NUM> via the airflow holes 3a of the conveying belts <NUM>. The suction switch mechanism <NUM> has a suction box <NUM> arranged between an upper section 3c and a lower section 3d of the four conveying belts <NUM> and a suction fan (an intake source) <NUM> directly connected to the suction box <NUM>. The suction fan (intake source) <NUM> is configured to generate a negative pressure in the suction box <NUM>.

The suction box <NUM> has four intake holes 11a in the upper face. Each intake hole 11a is arranged facing the upper section 3c of each conveying belt <NUM>. The suction box <NUM> further has a shutter 11b that opens and closes the intake holes 11a.

The suction switch mechanism <NUM> has a shutter drive mechanism that drives the shutter 11b. For example, the shutter drive mechanism has a lift mechanism (not illustrated) attached to the shutter 11b and a motor (not illustrated) attached to the lift mechanism. During the operation of the sheet conveyance apparatus <NUM>, while a suction fan <NUM> is continuously operated, the shutter 11b is moved vertically by the lift mechanism, and the shutter 11b opens and closes at predetermined timings to switch suction through the intake holes 11a.

As illustrated in <FIG>, the sheet conveyance apparatus <NUM> has a feed-in roller <NUM> on the upstream. The feed-in roller <NUM> is provided above the upstream end u of the conveying face 3b of the conveying belts <NUM> and takes in and conveys the sheet S onto the conveying face 3b. The sheet conveyance apparatus <NUM> further has a stopper plate <NUM> extending upward from the conveying face 3b.

In this embodiment, the stopper plate <NUM> is divided into four portions in the width direction orthogonal to the longitudinal direction of the conveying belt <NUM>, and the portions of the stopper plate <NUM> correspond to respective conveying belts <NUM>. Note that the stopper plate <NUM> may be a single plate extending across the whole conveying face 3b of the four conveying belts <NUM>.

A lower end 14a of the stopper plate <NUM> faces the suction box <NUM> and is arranged spaced apart from the conveying face 3b by a predetermined spacing.

The sheet conveyance apparatus <NUM> has a sheet accumulation area <NUM> that is a region from the stopper plate <NUM> above the conveying face 3b to the upstream end u of the conveying face 3b.

The sheet conveyance apparatus <NUM> has a feed-out roller <NUM> on the downstream. The feed-out roller <NUM> receives the sheet S from the downstream end w of the conveying face 3b and discharges the received sheet S to the outside of the sheet conveyance apparatus <NUM>.

During the operation of the sheet conveyance apparatus <NUM>, the sheets S are taken in from the upstream sheet processing apparatus <NUM> by the feed-in roller <NUM>. The front end of the sheet S collides with the stopper plate <NUM>, and the sheet S is sequentially accumulated in the sheet accumulation area <NUM>. The lowermost sheet S out of the accumulated sheets S is then sequentially adsorbed on the conveying face 3b of the conveying belts <NUM> by the suction box <NUM> and separated from the remaining sheets S. The lowermost sheet S is then conveyed through the gap between the conveying face 3b and the stopper plate <NUM> to the downstream end w of the conveying face 3b by the conveying belts <NUM> and supplied to the downstream sheet processing apparatus <NUM> by the feed-out roller <NUM>.

In such a way, even when the processing speed of the upstream sheet processing apparatus <NUM> and the processing speed of the downstream sheet processing apparatus <NUM> are different, the sheet conveyance apparatus <NUM> can temporarily accumulate the sheets S sequentially discharged from the upstream sheet processing apparatus <NUM> in the sheet accumulation area <NUM>. Then, the sheet conveyance apparatus <NUM> can supply the lowermost sheet S out of the accumulated sheets S from the sheet accumulation area <NUM> to the downstream sheet processing apparatus <NUM> one by one at timings synchronized with the processing speed of the downstream sheet processing apparatus <NUM>. Therefore, the sheet conveyance apparatus <NUM> can smoothly hand over the sheet S from the upstream processing apparatus <NUM> to the downstream sheet processing apparatus <NUM>.

As illustrated in <FIG> and <FIG>, the sheet conveyance apparatus <NUM> has a feed-in sensor <NUM> provided downstream of the feed-in roller <NUM>. The feed-in sensor <NUM> is configured to detect the sheet S fed into the sheet accumulation area <NUM>. The sheet conveyance apparatus <NUM> further has a feed-out sensor <NUM> provided downstream of the stopper plate <NUM>. The feed-out sensor <NUM> is configured to detect the sheet S fed out of the sheet accumulation area <NUM>.

As illustrated in <FIG>, the sheet conveyance apparatus <NUM> has a control unit <NUM> connected to the feed-in sensor <NUM>, the feed-out sensor <NUM>, the belt drive mechanism <NUM>, and the suction switch mechanism <NUM>. The control unit <NUM> is formed of, for example, a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), a computer readable storage medium, and the like. Further, a series of processes to implement respective functions is stored in a storage medium or the like in a form of a program, as an example. The CPU reads such a program into the RAM or the like and executes a process of edition and operation of information, so that various functions are implemented. Note that a program may be installed in advance in a ROM or other storage mediums, a program may be provided in a state of being stored in a computer readable storage medium, or a program may be delivered via a wired or wireless communication unit. The computer readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.

The control unit <NUM> is further connected to a conveyance instruction unit <NUM>. The conveyance instruction unit <NUM> is programed in a control unit (not illustrated) of the sheet processing apparatuses <NUM> and <NUM>, for example. The conveyance instruction unit <NUM> transmits, to the control unit <NUM> of the sheet conveyance apparatus <NUM>, an accumulation instruction signal AS for accumulating the sheet S without conveying the sheet S from the sheet accumulation area <NUM> and a conveyance instruction signal CS for conveying the sheet S from the sheet accumulation area <NUM>.

The control unit <NUM> includes a counter unit <NUM>, a first determination unit <NUM>, a second determination unit <NUM>, and a conveyance control unit <NUM>. The counter unit <NUM>, the first determination unit <NUM>, the second determination unit <NUM>, and the conveyance control unit <NUM> are controlled by a control program stored in the control unit <NUM>.

The counter unit <NUM> is configured to count the sheets S fed into the sheet accumulation area <NUM> by using the feed-in sensor <NUM>, and count the sheets S fed out of the sheet accumulation area <NUM> by the feed-out sensor <NUM>. Then, based on the difference between the counts, the counter unit <NUM> is configured to count the number of sheets S currently accumulated in the sheet accumulation area <NUM>.

The first determination unit <NUM> is configured to determine, based on the count of the sheets S by the counter unit <NUM>, whether the number of sheets S currently accumulated in the sheet accumulation area <NUM> is two or greater, or one.

The second determination unit <NUM> determines, in response to receiving a signal indicating the end of process from the conveyance instruction unit <NUM>, that the sheet S accumulated in the sheet accumulation area <NUM> is the final sheet FS to be processed. Further, in response to receiving information on the number of sheets S to be processed from the conveyance instruction unit <NUM>, the second determination unit <NUM> determines, based on the count of sheets S received from the counter unit <NUM>, whether or not the sheet S accumulated in the sheet accumulation area <NUM> is the final sheet FS to be processed. For example, when the number of sheets S to be processed is <NUM>, the tenth sheet S conveyed from the sheet accumulation area <NUM> is determined to be the final sheet FS.

The conveyance control unit <NUM> is configured to control driving of the belt drive mechanism <NUM> and the suction switch mechanism <NUM>. When conveying the sheet S from the sheet accumulation area <NUM>, the conveyance control unit <NUM> controls the shutter 11b to open to adsorb the sheet S on the conveying face 3b of the conveying belts <NUM> and controls the conveying belts <NUM> to rotate. On the other hand, when accumulating the sheet S in the sheet accumulation area <NUM>, the conveyance control unit <NUM> controls the shutter 11b to close and controls the conveying belts <NUM> not to rotate.

The operation of the sheet conveyance apparatus <NUM> will be described with reference to <FIG> and <FIG>.

The sheet conveyance apparatus <NUM> receives the accumulation instruction AS and the conveyance instruction CS from the conveyance instruction unit <NUM> (step S1). In response to receiving the accumulation instruction AS from the conveyance instruction unit <NUM>, the sheet conveyance apparatus <NUM> accumulates the sheet S from the feed-in roller <NUM> in the sheet accumulation area <NUM> and does not convey the sheet S from the sheet accumulation area <NUM> (step S2).

In response to receiving the conveyance instruction CS from the conveyance instruction unit <NUM>, the sheet conveyance apparatus <NUM> determines by the first determination unit <NUM> whether or not the number of sheets S currently accumulated in the sheet accumulation area <NUM> is two or greater, or one (step S3).

If the number of sheets S currently accumulated in the sheet accumulation area <NUM> is two or greater, the sheet conveyance apparatus <NUM> conveys the sheet S from the sheet accumulation area <NUM> as illustrated in <FIG> (step S4).

If the number of sheets S currently accumulated in the sheet accumulation area <NUM> is one, the sheet conveyance apparatus <NUM> determines by the second determination unit <NUM> whether or not the sheet S accumulated in the sheet accumulation area <NUM> is the final sheet FS to be processed (step S5).

If the one sheet S accumulated in the sheet accumulation area <NUM> is not the final sheet FS to be processed even when the conveyance instruction CS is received from the conveyance instruction unit <NUM>, the sheet conveyance apparatus <NUM> leaves the one sheet S in the sheet accumulation area <NUM> without conveying the sheet S from the sheet accumulation area <NUM> (step S6).

As illustrated in <FIG>, the one sheet S left in the sheet accumulation area <NUM> is used as a skid sheet KS, the sheet S fed in from the feed-in roller <NUM> slides on the one left sheet S (a skid sheet KS) and is accumulated in the sheet accumulation area <NUM>. Since the friction coefficient of the sheet S (skid sheet KS) is not higher than the conveying belts <NUM>, the next sheet S can smoothly enter the sheet accumulation area <NUM> without being caught by the conveying belts <NUM>.

After two sheets S are accumulated in the sheet accumulation area <NUM>, the first determination unit determines that the number of sheets S currently accumulated in the sheet accumulation area <NUM> is two or greater (step S3). Then, as illustrated in <FIG>, the sheet conveyance apparatus <NUM> conveys the sheet S used as the skid sheet KS from the sheet accumulation area <NUM> (step S4).

If it is determined by the first determination unit <NUM> that the number of sheets S currently accumulated in the sheet accumulation area <NUM> is one (step S3) and it is determined by the second determination unit <NUM> that the one sheet S accumulated in the sheet accumulation area <NUM> is the final sheet FS to be processed, the sheet conveyance apparatus <NUM> conveys the sheet S from the sheet accumulation area <NUM> (step S7). This is because no next sheet S is fed into the sheet accumulation area <NUM> and it is thus not necessary to leave the one sheet S in the sheet accumulation area <NUM> as the skid sheet KS.

The advantageous effects of the present embodiment will be described.

If the sheet S accumulated in the sheet accumulation area <NUM> is not the final sheet FS to be processed even when the conveyance instruction CS is received from the conveyance instruction unit <NUM>, the sheet conveyance apparatus <NUM> leaves one sheet S in the sheet accumulation area <NUM> without conveying the sheet S from the sheet accumulation area <NUM>.

The one sheet S left in the sheet accumulation area <NUM> is used as the skid sheet KS, and the next sheet S fed in from the feed-in roller <NUM> slides on the one left sheet S (skid sheet KS) and is accumulated in the sheet accumulation area <NUM>. As a result, the sheet S can enter the sheet accumulation area <NUM> without being caught by the conveying belts <NUM>.

Although the preferred embodiment of the present invention has been described above, the configuration of the present invention is not limited to this embodiment.

For example, the suction switch mechanism <NUM> may have a path connected between the suction box <NUM> and the suction fan <NUM>, and a closure mechanism that opens and closes the path. The path may be opened or closed by the closure mechanism to switch whether or not to suck the sheet S on the conveying belts <NUM> through the airflow holes 3a in the conveying belts <NUM>. Further, with respect to the suction switch mechanism <NUM>, no suction box <NUM> may be provided, and the suction fan <NUM> and the airflow holes 3a of the endless conveying belts <NUM> may be directly connected via a path.

Claim 1:
A sheet conveyance apparatus (<NUM>) that conveys a sheet fed out of an upstream sheet processing apparatus (<NUM>) to a downstream sheet processing apparatus (<NUM>), the sheet conveyance apparatus (<NUM>) comprising:
a conveying unit (<NUM>) configured to convey the sheet (S);
a conveying unit drive mechanism (<NUM>) configured to drive the conveying unit (<NUM>);
a sheet accumulation area (<NUM>) in which the sheet (S) fed out of the upstream sheet processing apparatus (<NUM>) is accumulated on the conveying unit (<NUM>); and
a control unit (<NUM>) configured to control conveyance of the sheet (S) performed by the conveying unit (<NUM>),
wherein the control unit (<NUM>) includes a counter unit (<NUM>) configured to count a number of sheets (S) accumulated in the sheet accumulation area (<NUM>),
characterised in that
when a conveyance instruction signal for conveying the sheet (S) from the sheet accumulation area (<NUM>) is received and the number of the sheets currently accumulated in the sheet accumulation area (<NUM>) is counted to be one by the counter unit (<NUM>), the control unit (<NUM>) stops conveyance of the one sheet (S) without conveying the one sheet (S) from the sheet accumulation area (<NUM>) until a next sheet is guided onto the one sheet (S).