JP2002167075A - Image forming device and method, control device and method, and paper feeding device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the occurrence of disorder of a printed image due to disorder in carrying paper. SOLUTION: One sheet of paper extracted by paper feeding rollers 11-2, 12-2 is carried by carrying rollers 13-2A, 13-2B to a position of timing rollers 14A, 14B. When the timing rollers 14A, 14B hold the paper and starts carrying toward a drum 15 and a press roller 16, the carrying roller 13-2B on the driven side is driven by a solenoid 55, and separated from the carrying roller 13-2A on the driving side. Therefore, braking force is prevented from acting on the paper carried by the timing rollers 14A, 14B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus and method, a control apparatus and method, and a paper feeding apparatus and method, and more particularly, to a disturbance of a printed image caused by a fluctuation in a sheet conveying speed during printing. TECHNICAL FIELD The present invention relates to an image forming apparatus and method, a control apparatus and method, and a sheet feeding apparatus and method for suppressing image forming.

[0002]

2. Description of the Related Art Recently, printing apparatuses have been reduced in size and speed, and large-scale printing can be performed at high speed with small apparatuses.

[0003]

However, when the size of the printing apparatus is reduced, the paper transport path becomes shorter. That is, the length of the paper transport path from the paper supply unit that supplies the paper to the image forming unit that forms an image on the paper is reduced. Therefore,
The image forming unit is easily affected by the transport load in the paper feed unit and the paper transport path. Therefore, it is difficult to smoothly convey the paper, and the conveyance speed becomes uneven, and as a result, a phenomenon such as distortion or blurring occurs in a print image printed on the paper.

[0004] The present invention has been made in view of such a situation, and it is an object of the present invention to suppress a disturbance of a printed image due to a disturbance in a sheet conveying speed.

[0005]

According to a first aspect of the present invention, there is provided a first image forming apparatus, comprising: rotating means for printing on a sheet while rotating; and first conveying means for conveying the sheet toward the rotating means at a predetermined timing. A second transport unit that transports the paper toward the first transport unit, and a release that releases the transport by the second transport unit when the paper is ready to be transported by the first transport unit. Means.

For example, the rotating means is a drum 15 shown in FIG.
The first transport means is constituted by a press roller 16,
The second transport means is constituted by the timing rollers 14A and 14B in FIG. 4, and the transport rollers 13-2A and 13-
2B, a transport roller motor 53, and a transport clutch 54, and the releasing means includes a solenoid 55, a link 62, a link 103, and a spring 106 in FIG.

The image forming apparatus is, for example, a printing apparatus 1 shown in FIG.
It consists of. Here, the image forming apparatus means an apparatus that forms an image by transferring or printing an image on paper,
It includes a copying device, a printer, and the like.

In this image forming apparatus, the paper is first
When it becomes possible to carry by the carrying means, the carrying by the second carrying means is released.

As a result, when printing is performed while the sheet is being conveyed by the first conveying means, a brake is applied to the conveyed sheet, the conveying speed of the sheet becomes slower than the original speed, and the printed image is disturbed. (Jitter is generated) is prevented. Further, it is possible to prevent the sheet from being transported obliquely (skew occurs) or the image forming position from being shifted (vertical upset).

The second transport means includes a driving roller for nipping and transporting the sheet, and a driven roller which rotates while being pressed against the driving roller, and the releasing means includes the driven roller of the driven roller. A release mechanism for releasing the pressure contact with the drive roller can be provided.

For example, the drive roller here is shown in FIG.
, And the driven roller is constituted by the conveyance roller 13-2B.

For example, the release mechanism includes a spring for urging the driven roller such that the driven roller is pressed against the driving roller, and releases the bias of the driven roller against the urging force of the spring. And a drive source that drives the drive. For example, the spring here is constituted by the spring 106 of FIG.
The drive source is constituted by a solenoid 55.

[0013] This makes it possible to easily and surely cancel the paper transport by the second transport means.

The release means can be arranged so as to be rotatable around a predetermined fulcrum (for example, the fulcrum 101 in FIG. 14) with respect to the second transport means. This facilitates the operation of removing the paper when the paper is jammed during the conveyance.

The image forming method according to the present invention is an image forming method for an image forming apparatus, comprising: a rotating unit for printing on a sheet while rotating; and a conveying unit for conveying the sheet at a predetermined timing toward the rotating unit. The method includes a transporting step of transporting the paper toward the transporting means, and a releasing step of releasing the transporting by the processing of the transporting step when the paper becomes transportable by the transporting means.

For example, the rotating means is a drum 15 shown in FIG.
The first transport means is constituted by a press roller 16,
It is constituted by the timing rollers 14A and 14B of FIG. Further, the transporting step is constituted by step S3 in FIG. 7, and the releasing step is constituted by step S8.

In this image forming method, when the sheet can be conveyed by the conveying means, the conveyance in the conveying step is canceled. As a result, the same effect as in the image forming apparatus can be obtained.

The second image forming apparatus of the present invention is provided below the image forming apparatus and has a paper feed tray for storing paper in advance, and separates the paper stored in the paper feed tray one by one from the paper feed tray. Separating means, and in the transport path for transporting the paper separated by the separating means toward the rotating means,
A second transport unit that transports the paper toward the first transport unit, and a release unit that releases the transport by the second transport unit when the paper is ready to be transported by the first transport unit. It is characterized by having.

For example, the rotating means is a drum 15 shown in FIG.
The first transport means is constituted by a press roller 16,
The paper feed tray is constituted by the timing rollers 14A and 14B in FIG. 4, and the paper feed trays 2-1 to 2-3 in FIG.
The separation means is constituted by the paper feed roller 11- in FIG.
1, 12-1 through 11-3, 12-3,
The transport path is configured by the paths 21 to 23 in FIG.
The second transporting means includes transport rollers 13-2A and 13-2 in FIG.
-2B, a transport roller motor 53, and a transport clutch 54, and the releasing means is comprised of a solenoid 55, a link 62, a link 103, and a spring 106 in FIG.

The release operation of the release means can be controlled based on the size and quality of the paper.

Thus, it is possible to accurately convey the sheet and form an image without being affected by the size and quality of the sheet.

A control device according to the present invention is a control device for controlling an image forming apparatus including a rotating means for printing on a sheet while rotating, and a first conveying means for conveying the sheet at a predetermined timing toward the rotating means. In the apparatus, the second transport unit that transports the paper toward the first transport unit, and when the paper is ready to be transported by the first transport unit, the transport by the second transport unit is released. Release means.

For example, the rotating means is a drum 15 shown in FIG.
The first transport means is constituted by a press roller 16,
The second transport means is constituted by the timing rollers 14A and 14B in FIG. 4, and the transport rollers 13-2A and 13-
2B, a transport roller motor 53, and a transport clutch 54, and the releasing means includes a solenoid 55, a link 62, a link 103, and a spring 106 in FIG.

In this control device, when the sheet is ready to be transported by the first transport unit, the transport by the second transport unit is released.

As a result, when printing is performed while the sheet is being conveyed by the first conveying means, a brake is applied to the conveyed sheet, the conveying speed of the sheet becomes slower than the original speed, and the printed image is disturbed. This is prevented.

This control device may be formed integrally with the image forming apparatus, or may be formed separately.

According to a control method of the present invention, there is provided a control method of an image forming apparatus, comprising: a rotating means for printing on a sheet while rotating; and a conveying means for conveying the sheet at a predetermined timing toward the rotating means. , And a release step of releasing the transport by the transporting step when the paper is ready to be transported by the transport unit.

For example, the rotating means is a drum 15 shown in FIG.
The conveying means is constituted by the timing rollers 14A and 14B of FIG. Further, the transporting step is constituted by step S3 in FIG. 7, and the releasing step is constituted by step S8.

In this control method, when the sheet can be conveyed by the conveying means, the conveyance in the conveying step is canceled. As a result, the same effect as in the case of the control device can be obtained.

The first paper feeder of the present invention is provided with an image forming apparatus including a rotating means for printing on a sheet while rotating, and a first conveying means for conveying the sheet at a predetermined timing toward the rotating means. A paper feeder for feeding paper to the first transport means, a second transport means for transporting the paper toward the first transport means,
When the sheet is ready to be conveyed by the first conveying means, a release means for releasing the conveyance by the second conveying means is provided.

This paper feeder is, for example, a unit 6 shown in FIG.
It is composed of parts other than 1.

For example, the rotating means is a drum 15 shown in FIG.
The first transport means is constituted by a press roller 16,
The second transport means is constituted by the timing rollers 14A and 14B of FIG. 4, and the transport rollers 13-2A and 13-
2B, a transport roller motor 53, and a transport clutch 54, and the releasing means includes a solenoid 55, a link 62, a link 103, and a spring 106 in FIG.

In this paper feeder, when the sheet can be transported by the first transport unit, the transport by the second transport unit is released.

As a result, when printing is performed while the sheet is being conveyed by the first conveying means, a brake is applied to the conveyed sheet, and the conveying speed of the sheet becomes lower than the original speed, and the printed image is disturbed. This is prevented.

According to the paper feeding method of the present invention, paper is fed to an image forming apparatus having a rotating means for printing on paper while rotating, and a conveying means for conveying the paper at a predetermined timing toward the rotating means. In the paper feeding method of the paper feeding device, a transporting step of transporting the paper toward the transporting means, and a release step of releasing transporting by the transporting step when the paper is ready to be transported by the transporting means. It is characterized by including.

For example, the rotating means is the drum 15 of FIG.
The conveying means is constituted by the timing rollers 14A and 14B of FIG. Further, the transporting step is constituted by step S3 in FIG. 7, and the releasing step is constituted by step S8.

In this paper feeding method, when the paper is ready to be transported by the transport means, the transport in the transport step is canceled. As a result, the same effect as in the paper feeding device can be obtained.

The second paper feeder of the present invention comprises an image forming apparatus having a rotating means for printing on a sheet while rotating, and a first conveying means for conveying the sheet at a predetermined timing toward the rotating means. A sheet feeder that is provided below the image forming apparatus, and stores a sheet in advance and a sheet stored in the sheet feed tray from the sheet feed tray. A separating unit that separates the sheets one by one, a second conveying unit that conveys the paper toward the first conveying unit in a conveying path that conveys the paper separated by the separating unit toward the rotating unit, and A release unit that releases the transport by the second transport unit when the transport by the first transport unit becomes possible.

The rotating means includes the drum 15, the press roller 1
6, the first conveying means is constituted by the timing rollers 14A and 14B of FIG. 4, the sheet feeding tray is constituted by the sheet feeding trays 2-1 to 2-3 of FIG. Paper feed rollers 11-1 and 12-1 in FIG.
11-3 and 12-3, and the transport route is
The second conveying means is constituted by conveying rollers 13-2A and 13-2B, a conveying roller motor 53 and a conveying clutch 54, and the releasing means is constituted by a solenoid 55 shown in FIG. , The link 62, the link 103 in FIG. 11, and the spring 106.

In this paper feeder, the release operation of the release means can be controlled based on the size and quality of the paper.

Thus, the paper can be fed accurately without being affected by the size and quality of the paper.

[0042]

FIG. 1 shows an example of the configuration of a printing apparatus to which the present invention is applied. The printing apparatus 1 is configured to supply the paper 4 from the supply trays 2-1 to 2-3.

The paper feed trays 2-1 to 2-3 may store all papers of the same size, or may store papers of different sizes for each paper feed tray.

More specifically, the sheets 4 in the lowermost sheet feeding tray 2-1 are separated one by one by sheet feeding rollers 11-1 and 12-1, and are conveyed via a path 21 to conveying rollers 13-1A, 13-1A.
13-1B, and are transported to the timing rollers 14A and 14B by the transport rollers 13-2A and 13-2B.

The paper 4 in the middle paper feed tray 2-2 is separated one by one by the paper feed rollers 11-2 and 12-2, and is separated by the transport rollers 13-2A and 13-2B via the path 22 at the timing. The sheet is transported to the rollers 14A and 14B.

Paper feed trays 2-1 and 2-2, transport roller 1
A sheet supply portion including 3-1A, 13-1B, 13-2A, 13-2B and paths 21 and 22 is provided at a lower portion of the printing apparatus 1 and is called a gantry sheet feeding apparatus.

The paper 4 in the upper paper feed tray 2-3 is separated one by one by paper feed rollers 11-3 and 12-3, and supplied to timing rollers 14A and 14B via a path 23.

The timing rollers 14A and 14B are pressed against each other at a predetermined timing and rotated at a predetermined timing from a state where they are separated from each other, and supply the supplied paper 4 to a joining point between the drum 15 and the press roller 16. The press roller 16
The sheet 4 pressed against the drum 15 as needed and supplied from the timing rollers 14A and 14B is pressed onto the rotating drum 15, and is conveyed while printing an image. The paper on which the image has been printed by the drum 15 is conveyed by the conveyance belt 19 applied to the conveyance rollers 17 and 18, and is discharged to the discharge tray 3.

FIG. 2 is an enlarged view showing the configuration of the main part when the paper 4 is supplied from the upper paper feed tray 2-3. A pad 34 made of rubber, resin, or the like is in contact with the paper feed roller 12-3. Thereby, the paper feed roller 1
By rotating 1-3, a plurality of sheets 4 separated from the sheet feed tray 2-3 are prevented from being simultaneously conveyed from between the sheet feed roller 12-3 and the pat 34.

The press roller 16 is supported by an arm 32 that rotates about a fulcrum 33.
When 2 rotates clockwise in the figure, it is pressed against the drum 15. A master 31 serving as a print original is mounted on the outer peripheral surface of the drum 15, and the ink in the drum 15 is extruded by pressing the paper 4 onto the master 31 of the rotating drum 15 by the press roller 16. Then, the ink corresponding to the document of the master 31 is printed on the paper 4.

FIG. 3 shows a path when the paper 4 is supplied from the paper feed tray 2-1 or 2-2.

FIG. 4 shows the configuration of a sheet feeding device for controlling the conveyance of the sheet 4 when the sheet 4 is conveyed. The transport roller 13-2A as a driving roller is rotated by the transport roller motor 53. The transport clutch 54 transmits the rotation of the transport roller motor 53 to the transport roller 13-2A or cancels the transmission. The transport roller 13-2B as a driven roller is pressed against the transport roller 13-2A as a drive roller, so that the transport roller 13-2B is pressed.
The rotation follows the rotation of A. The solenoid 55 is driven as necessary, and releases the pressure contact of the transport roller 13-2B with the transport roller 13-2A. Transport roller 13-
The transport sensor 51 disposed on the path 22 side of the paper 4 of 2A and 13-2B detects the presence or absence of the paper 4 similarly to the transport sensor 52 disposed downstream thereof.

FIG. 5 shows the printing apparatus 1 with paper 4
2 shows a configuration example of a control device 70 that controls the transport of the image data.
The CPU 71 controls each unit according to the program stored in the ROM 72 and controls the conveyance of the sheet 4. In the RAM 73, programs stored in the ROM 72 are expanded as necessary, and data and the like necessary for the CPU 71 to execute various processes are also stored as appropriate. Input unit 74
Is operated by the user and outputs a signal corresponding to the operation.
Input to CPU 71.

The interface 75 includes the transport sensor 5
1, 52, a transport roller motor 53, a transport clutch 54,
And the solenoid 55 are connected. Sensor 51,
The detection output of the CPU 52 is transmitted to the CPU 7 via the interface 75.
1 is supplied. The driving of the transport roller motor 53, the transport clutch 54, and the solenoid 55 is controlled by the CPU 71 via the interface 75.

FIG. 6 shows a state in which the solenoid 55 releases the pressing of the conveying roller 13-2B as a driven roller against the conveying roller 13-2A as a driving roller. As shown in FIG.
-2B is a transport roller 13- by a spring omitted here (a spring 106 in FIG. 14 described later).
2A is urged to be constantly pressed. The transport roller 13-2B is rotatably supported at one end of a link 62 that is rotatable about a fulcrum 61. A solenoid 55 is connected to the other end of the substantially L-shaped link 62. As a result, the solenoid 5
When 5 is urged, the link 62 rotates clockwise about the fulcrum 61, and the pressing of the transport roller 13-2B against the transport roller 13-2A is released. Instead of the spring 106 and the solenoid 55, a DC motor or a stepping motor may be rotated using a worm gear and a worm wheel to release the position of the driven roller.

Next, the operation of the printing apparatus 1 will be described with reference to the flowchart of FIG. 7 and the timing chart of FIG.

When the user instructs the start of printing, in step S1, a unit 6 having a drum 15, a press roller 16, and timing rollers 14A and 14B is provided.
A control device (not shown) that manages the operation of No. 1 (of course, the control device can also be the control device 70 shown in FIG. 5) rotates the drum 15 at a constant speed (FIG. 8C). 2), the arm 32 is rotated clockwise in FIG. 2 or FIG. 3 around the fulcrum 33, and the press roller 16 is pressed against the drum 15.

Further, the control device includes a timing roller 1
4A and 14B are rotated, and each time the drum 15 makes one rotation, the timing rollers 14A and 14B are brought into pressure contact with one rotation of the drum 15 at a predetermined timing (FIG. 8B). FIG. 8B shows the pressing and rotating operation of the timing rollers 14A and 14B in which such a drum 15 of the timing rollers 14A and 14B is performed once per rotation. In this example, at time t4, the timing rollers 14A and 14B start rotating and are pressed against each other. Drum 15 at this point
9B, the rotation angle θ of FIG.
224 ° (θ = 22) from the home position shown in FIG.
4 ()) (FIG. 8 (C)).

At time t5, the timing roller 14
The rotation speed of A, 14B reaches a certain speed, and the timing rollers 14A, 14B are rotated at that speed until time t6. Then, at time t6, the driving of the rotation of the timing rollers 14A and 14B is stopped, and at time t7, the rotation is completely stopped, and the timing rollers 14A and 14B are separated from each other by a timing roller release mechanism (not shown). .

When the timing rollers 14A and 14B
When the sheet 4 is pressed and rotated at the time, the sheet 4 whose leading end has been conveyed to the position of the timing rollers 14A and 14B at that time is pressed and held between the timing rollers 14A and 14B and conveyed. Then, at time t6, the sheet 4 is transported to a position where the leading end thereof contacts the drum 15 and the press roller 16.

The above processing is performed by the drum 15 and the press roller 1
6, and the unit 61 having the timing rollers 14A and 14B are repeatedly executed in synchronization with the rotation of the drum 15.

On the other hand, the control device 70 controls the conveyance of the sheet 4 as follows based on an instruction from the control device of the unit 61. In step S1, the drum 15 is controlled based on an instruction from the control device of the unit 61 as described above.
Rotates at a constant speed, and the press roller 16
, The sheet 4 is supplied to the timing rollers 14A and 14B of the unit 61.

That is, the CPU 71 determines in step S2 that the paper feed rollers 11-1 and 12-1
−2, 12-2, or paper feed rollers 11-3, 12-3
Is driven to separate one sheet from the paper feed tray 2-1, the paper feed tray 2-2, or the paper feed tray 2-3.

It is to be noted that which of the paper feed trays 2-1 to 2-3 is supplied with the paper 4 depends on the selection of the user. When the user instructs paper feeding from the lower paper feeding tray 2-1, one sheet is separated by the paper feeding rollers 11-1 and 12-1, and the conveyance roller 13 is separated from the path 21.
-1A and 13-1B, the transport rollers 13-2A,
13-2B. Middle paper tray 2-2
When a paper feed from the printer is instructed, the paper feed roller 11-
2, 12-2, one sheet is separated and the path 22
Are supplied to the transport rollers 13-2A and 13-2B. When a command to feed from the upper feed tray 2-3 is issued, one sheet is separated by the feed rollers 11-3 and 12-3, and the feed roller 13-2A,
13-2B.

In the following, it is assumed that the paper 4 is fed from the paper feed tray 2-2 for the sake of simplicity.

Then, in step S 3, the CPU 71 rotates the transport roller motor 53 to
4 is turned on. Thereby, the transport rollers 13-2A,
13-2B conveys the paper 4 supplied from the paper feed tray 2-2 at a speed of, for example, 1500 mm / s.

In step S4, the CPU 71 determines whether or not the leading end of the sheet 4 has been conveyed to a position where it can reach a position where it can be conveyed by the timing rollers 14A and 14B (a position where it can be pinched by the timing rollers 14A and 14B). I do. That is, since the sheet 4 is currently being conveyed, if the conveyance is continued as it is, it is determined whether or not the leading end of the sheet 4 can reach a position where it can be held between the timing rollers 14A and 14B. . The transport by the transport rollers 13-2A and 13-2B (the process of step S3) is continued until it is determined that the sheet 4 has reached a position where the sheet 4 can be nipped by the timing rollers 14A and 14B.

In step S4, when the leading end of the sheet 4 reaches a position where the sheet 4 can be conveyed by the timing rollers 14A and 14B, the CPU 71 determines that the conveying rollers 13-2A,
The conveyance of the sheet by 13-2B is stopped.

That is, the CPU 71 stops the driving of the transport roller motor 53 at time t1, whereby the rotation of the transport roller motor 53 is completely stopped at time t2 (FIG. 8E). Therefore, the rotation of the transport rollers 13-2A and 13-2B decreases from time t1, and stops at time t2 (FIG. 8A).

At this time, the time t is set so that the leading end of the sheet 4 reaches the position of the timing rollers 14A and 14B.
1 is set.

Thereafter, at time t3, the CPU 71
The transfer clutch 54 is turned off (FIG. 8F). The reason that the transport clutch 54 is turned off at the time t3 after the time t2 is that if the transport clutch 54 is turned off before the time t2, the rotation of the transport roller motor 53 is stopped.
At that time, the rotation of the transport rollers 13-2A and 13-2B is stopped, and the sheet 4 is not transferred to the transport rollers 13-2A and 13-2B.
This is because it is not possible to reliably transport the sheet to the positions A and 14B.

Further, the timing of the time t2 is controlled in the unit 61 so as to be surely before the time t4 of the rotation start of the timing rollers 14A and 14B which is periodically performed. . Time t
This is because if timing 2 is later than time t4, the timing rollers 14A and 14B will not be able to convey the paper 4.

Next, in step S5, the unit 6
The first control device determines whether or not the drum 15 has rotated to a predetermined position. If the drum 15 has not yet rotated to the predetermined position, the control device waits until the drum 15 rotates to the predetermined position. Drum 1
5 has determined that it has rotated to a predetermined position (a position at which the rotation angle θ from the home position is 224 °), the rotation of the timing rollers 14A and 14B is started in step S6 as described above. (FIG. 8
(B)). At this time, when the drum 15 has rotated to a predetermined position, the CPU 71 drives the solenoid 55 in step S7, and connects the link 62 to the fulcrum 6 in FIG.
1 is rotated clockwise. Thereby, the transport roller 13-2B is separated from the transport roller 13-2A (FIG. 8D).

Therefore, thereafter, the sheet 4 is conveyed by the timing rollers 14A and 14B. At this time, since the transport roller 13-2B is already separated from the transport roller 13-2A, it is possible to prevent the brake force acting on the sheet 4 in the transport direction. Therefore, the sheet 4 is transported to the position of the drum 15 and the press roller 16 based on the transport force by the timing rollers 14A and 14B.

Then, in step S8, a printing process is performed. That is, the press roller 16 and the drum 15
The paper 4 nipped by is moved along the drum 15 and printing is performed.

Thereafter, in step S9, the CPU 71
Stops driving of the solenoid 55 at time t8 when the drum 15 reaches a preset rotation angle. Accordingly, the transport roller 13-2B is moved by the transport roller 13 based on the urging force of the spring 106 (FIG. 14).
-2A again. As a result, the transport rollers 13-
The next sheet 4 can be conveyed by 2A and 13-2B. The timing of stopping the driving of the solenoid 55 at the time t8 (the rotation angle θ of the drum 15)
Is changed according to the size of the sheet 4.

FIG. 10 shows an example of the size (size) of the sheet 4 and the rotation angle θ of the drum 15 at the timing when the driving of the solenoid 55 is stopped. The table in FIG. 10 is stored in the control device 70 in advance. In this example, for example, when the size of the paper 4 is mm in Japan, θ = 90 ° when the size is A3, and θ = 50 ° when the size is B4. If it is A4, paper 4
Is vertical, θ = 15 °, and when horizontal, θ = 310 °. When the paper is B5, θ = 350 ° when it is in the vertical direction, and θ = 300 ° when it is in the horizontal direction.

In the case of overseas inch-size paper, if the size is LT, when it is in the vertical direction, θ = 15
、, and in the horizontal direction, θ = 310 °.
Further, when the size is LG, θ = 310 °, and
In the case of LDR, θ = 90 °.

The paper size is determined by a command from the control device for controlling the unit 61 (a destination code indicating whether the paper size is a domestic mm system or an overseas inch system, and paper width data representing the width of the paper) and a paper feed. The CPU 71 works on the result determined by the length sensor provided in the apparatus, and determines which size in FIG. 10 corresponds to the size based on the fetched data.

As described above, by changing the angle θ in accordance with the size of the sheet 4, it is possible to prevent the solenoid 55 from being driven for an unnecessarily long time and unnecessarily consuming power.

The timing at which the driving of the solenoid 55 is stopped is determined regardless of the rotation angle of the drum 15.
It is also possible to detect the rear end by the transport sensor 52 and control based on the detection timing.

Next, in step S10, the control device of the unit 61 determines whether or not printing of a predetermined number of sheets has been completed, and if not completed, returns to step S2. Repeat the subsequent processing. If it is determined in step S10 that printing of the predetermined number of sheets has been completed, the process proceeds to step S11, where the control device of the unit 61 stops the rotation of the drum 15 and ends the printing operation.

FIG. 11 shows another example of sheet transport control. Based on the table of FIG. 11, the timing at which the driving of the solenoid 55 is stopped is controlled with respect to the rotation angle θ of the drum 15 in accordance with the size (size) and the paper quality of the paper 4. In this case, paper quality data representing paper quality is added to the command from the control device for controlling the unit 61 in addition to the case of the example described with reference to FIG.

In this example, the paper quality is classified as follows.・ Standard paper: 64-80 (g / m ² ) ・ Thick paper: 80 (g / m ² ) or more ・ Thin paper: Thin paper such as reprint ・ Special: Set paper that is specially used for each user

Here, the special paper quality is set in advance according to the paper quality of the paper used by the user.

The paper feed timing may be controlled according to the paper quality. For example, there is a case where a sheet of the paper quality set as the special paper quality has a low coefficient of friction and easily slips with respect to the transport roller.

In such a case, step S in FIG.
The paper feed control corresponding to steps 2 to S4 is started earlier by a predetermined time. Therefore, the difference in the arrival time of the sheet 4 with respect to the timing rollers 14A and 14B caused by the slip due to the difference in the sheet quality is corrected.

Note that the transport rollers 13-
The separation between 2A and 13-2B may not be performed.
For example, in the case of a sheet of paper that easily slips, it is preferable that the transport rollers 13-2A and 13-2B are not separated from each other, and that auxiliary transport by the transport rollers 13-2A and 13-2B is added. . FIG. 12 shows an example of a timing chart of such sheet transport control, and FIG. 13 shows a flowchart thereof.

In this case, from time t9 to time t9 in FIG.
11, the rotation speed of the transport rollers 13-2A and 13-2B is such that the transport speed of the paper 4 by the transport rollers 13-2A and 13-2B is slightly higher than the transport speed of the paper 4 by the drum 15 and the press roller 16. It is desirable to set the rotation speed of the transport roller motor 53 so as to be (for example, 3% faster speed).

FIG. 14 shows a more specific configuration example of a mechanism for pressing the conveying roller 13-2B against the conveying roller 13-2A by the solenoid 55 and releasing the pressed state.

In this example, the plate 102 is held on the chassis of the image forming apparatus 1 so as to be rotatable about the fulcrum 101. A solenoid 55 is attached to the plate 102, and a link 103 (corresponding to the link 62 in FIG. 6) is supported rotatably about a fulcrum 104 (corresponding to the fulcrum 61 in FIG. 6). I have.

A transport roller 13-2B as a driven roller is rotatably attached to one end of the link 103, and a solenoid 5 is attached to the other end of the link 103.
The five movable parts 55A are connected via the connection part 105.

One end of a spring 106 is fixed to the link 103 near the connecting portion 105. The other end of the spring 106 is locked to an end of the plate 102.

On the left side of the timing rollers 14A and 14B, a plate 111 is supported by the chassis so as to be rotatable about a fulcrum 112. A bent portion 111 </ b> A is formed at an end of the plate 111. Plate 1
A guide portion 113 for guiding the conveyance of the sheet 4 is formed on the left side surface in FIG.

When the paper 4 is jammed in the middle of conveyance (when a jam occurs), the user
02 is rotated clockwise about the fulcrum 101. This allows the user to easily remove the jammed paper.

In normal use, the user operates the plate 102
Is rotated counterclockwise about the fulcrum 101. At this time, the projection 102A of the plate 102 comes into contact with and presses the bent portion 111A of the plate 111, and the plate 111 rotates clockwise about the fulcrum 112. The plate 102 is locked to the chassis by a mechanism (not shown). At this time, the transport rollers 13-2B are
Since it rotates counterclockwise around the fulcrum 104 based on the urging force of the spring 106, it is pressed against the transport roller 13-2A.

At this time, the guide unit 113 is arranged at a position where the transported paper 4 is guided by the transport rollers 13-2A and 13-2B.

When driven, the solenoid 55 sucks the movable portion 55A inside. As a result, since the connecting portion 105 is urged downward in FIG. 14 by the movable portion 55A, the link 103 rotates clockwise around the fulcrum 104 against the urging force of the spring 106. . As a result, the transport roller 13-2B is
Move away from 3-2A.

In the above, the transport rollers 13-2A,
13-2B has been described.
A and 13-2B have the same configuration and are controlled in the same manner.

Further, the configuration for separating the transport rollers can be applied to the timing rollers 14A and 14B. In this case, the timing rollers 14A, 1
4B is controlled so that the braking force does not act on the conveyance by the drum 15 and the press roller 16.

[0101]

As described above, according to the present invention, when the sheet is ready to be conveyed by the first conveying means, the second
Since the conveyance by the conveyance means is canceled, it is possible to suppress the occurrence of the disturbance of the image due to the fluctuation of the conveyance speed.

[Brief description of the drawings]

FIG. 1 is a side view illustrating a configuration example of a printing apparatus to which the present invention is applied.

FIG. 2 is a diagram illustrating a paper transport path in the printing apparatus of FIG.

FIG. 3 is a diagram illustrating another conveyance path of a sheet in the printing apparatus of FIG. 1;

FIG. 4 is a diagram illustrating a configuration for controlling paper transport in the printing apparatus of FIG. 1;

FIG. 5 is a block diagram illustrating a configuration example of a control device that controls paper transport of the printing apparatus in FIG. 1;

FIG. 6 is a diagram illustrating a configuration of a mechanism for releasing a pressed state of a conveyance roller in FIG. 4;

FIG. 7 is a flowchart illustrating a printing process of the printing apparatus in FIG. 1;

FIG. 8 is a timing chart illustrating a control operation of sheet conveyance of the printing apparatus in FIG. 1;

FIG. 9 is a diagram illustrating a rotational position of a drum of the printing apparatus in FIG. 1;

FIG. 10 is a diagram illustrating a correspondence between a sheet size and a rotation angle of a drum at a timing when a solenoid is driven.

FIG. 11 is a diagram for explaining the correspondence between the paper quality of the paper and the rotation angle of the drum at the timing of driving the solenoid.

FIG. 12 is a timing chart for explaining a sheet conveyance control operation of the printing apparatus in FIG. 1;

FIG. 13 is a flowchart illustrating a printing process of the printing apparatus in FIG. 1;

14 is a diagram illustrating a more specific example of a mechanism for releasing a pressed state of the transport roller in FIG. 4;

[Explanation of symbols]

DESCRIPTION OF REFERENCE NUMERALS 1 printing device 2-1 to 2-3 paper feed tray 3 discharge tray 11-1, 12-1 to 11-3, 12-3 paper feed roller 13-1A, 13-1B, 13-2A, 13-2B,
Conveying rollers 14A, 14B Timing roller 15 Drum 16 Press roller 55 Solenoid 61 Support point 62 Link

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Koji Matsuura, 46 Nogoshi, Nogoshi, Okumachi, Ichinomiya, Aichi Prefecture Inside Omron Ichinomiya Co., Ltd. Inside Ichinomiya Co., Ltd. (72) Inventor Masato Miyaki 2-20-15 Shimbashi, Minato-ku, Tokyo Ritsumeikan Kogyo Co., Ltd. (72) Inventor Hideshi Sekiguchi 2-20-15 Shimbashi, Minato-ku, Tokyo Riso Kagaku Kogyo Inside the company (72) Inventor Akira Yasuda 2-20-15 Shimbashi, Minato-ku, Tokyo Inside Riso Kagaku Kogyo Co., Ltd. (72) Inventor Atsushi Kubota 2-20-15 Shimbashi, Minato-ku Tokyo (72) Inventor Kazuyuki Yoshida 2-20-15 Shimbashi, Minato-ku, Tokyo F-term in Riso Kagaku Kogyo Co., Ltd. 3F049 AA01 AA02 CA32 DA12 EA21 LA01 LB03 3F102 AA01 AB01 BA02 CB01 DA08 EA03 FA08

Claims (14)

[Claims] A rotating unit that prints on a sheet while rotating; a first transporting unit that transports the sheet at a predetermined timing toward the rotating unit; Second paper transport
An image forming apparatus comprising: a conveying unit; and a release unit configured to release the conveyance by the second conveyance unit when the sheet can be conveyed by the first conveyance unit. 2. The driving device according to claim 2, wherein the second transporting unit includes a driving roller that sandwiches and transports the sheet, and a driven roller that rotates while being pressed against the driving roller. The image forming apparatus according to claim 1, further comprising a release mechanism configured to release the pressure contact with the driving roller. 3. The release mechanism includes: a spring for urging the driven roller so that the driven roller is pressed against the drive roller; and releasing the driven roller against the urging force of the spring. The image forming apparatus according to claim 2, further comprising: a driving source configured to perform driving. 4. An image forming method for an image forming apparatus, comprising: a rotating unit that prints on a sheet while rotating; and a conveying unit that conveys the sheet toward the rotating unit at a predetermined timing. Image forming comprising: a transporting step of transporting the paper toward the paper sheet; and a releasing step of releasing the transporting by the processing of the transporting step when the paper becomes transportable by the transporting means. Method. 5. An image forming apparatus comprising: a rotating unit that prints on a sheet while rotating; and a first transport unit that transports the sheet toward the rotating unit at a predetermined timing. A paper feed tray provided beforehand for storing the paper; separating means for separating the paper previously stored in the paper feed tray one by one from the paper feed tray; and A second transport unit that transports the paper toward the first transport unit in a transport path that transports the paper toward the rotating unit; and a state where the paper can be transported by the first transport unit. An image forming apparatus comprising: a release unit configured to release the conveyance by the second conveyance unit when the time has come. 6. The release operation of the release means is controlled based on a size of the sheet.
4. The image forming apparatus according to claim 1. 7. The image forming apparatus according to claim 5, wherein the release operation of the release unit is controlled based on the quality of the paper. 8. A control device for controlling an image forming apparatus, comprising: a rotating unit that performs printing on a sheet while rotating; and a first conveying unit that conveys the sheet toward the rotating unit at a predetermined timing. A second transporting the paper toward the first transporting means;
And a releasing means for releasing the transport by the second transport means when the sheet can be transported by the first transport means. 9. A method for controlling an image forming apparatus, comprising: a rotating unit that performs printing on a sheet while rotating; and a conveying unit that conveys the sheet toward the rotating unit at a predetermined timing. A transporting step of transporting the paper, and a releasing step of releasing the transport by the processing of the transporting step when the paper becomes transportable by the transporting means. 10. A sheet is fed to an image forming apparatus including a rotating unit that prints on a sheet while rotating, and a first conveying unit that conveys the sheet at a predetermined timing toward the rotating unit. In the paper feeding device, a second paper transporting the paper toward the first transporting means
And a release unit for releasing the transport by the second transport unit when the sheet can be transported by the first transport unit. 11. A sheet feeding device for feeding the sheet to an image forming apparatus, comprising: a rotating unit that prints on the sheet while rotating; and a conveying unit that conveys the sheet toward the rotating unit at a predetermined timing. A transporting step of transporting the paper toward the transporting means; and a releasing step of releasing transporting by the transporting step when the paper becomes transportable by the transporting means. And a paper feeding method comprising: 12. A supply unit for supplying the sheet to an image forming apparatus, comprising: a rotating unit that performs printing on the sheet while rotating; and a first conveying unit that conveys the sheet toward the rotating unit at a predetermined timing. A paper device, wherein the paper supply device is provided below the image forming apparatus, and a paper supply tray for storing the paper in advance; and the paper stored in the paper supply tray in advance from the paper supply tray. Separating means for separating the sheets one by one, and second conveying means for conveying the paper toward the first conveying means in a conveying path for conveying the paper separated by the separating means toward the rotating means. And a release unit that releases the transport by the second transport unit when the paper is ready to be transported by the first transport unit. 13. The sheet feeding device according to claim 12, wherein the release operation of the release unit is controlled based on a size of the sheet. 14. The method according to claim 1, wherein the releasing operation of the releasing means is controlled based on the quality of the paper.
14. The paper feeding device according to 2 or 13.