JP3249973B2 - Paper transport device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper transport device, and more particularly, to a printer, a facsimile machine, a copier, etc., which performs alignment between an image and paper at the time of picking the paper.
The present invention relates to a sheet transport device that corrects a delay in sheet transport in the middle of the process and accurately aligns an image with a sheet.

[0002]

2. Description of the Related Art Printers, facsimile machines, copiers, etc., in which the position of an image and a sheet must be considered at the time of picking the sheet rather than starting writing of an image after the sheet reaches a registration roller. In this type of conventional paper transport device, the transport of the paper is performed by using a frictional force between the pick roller and the transport roller and the paper,
When a slip phenomenon occurred between the pick roller and the transport roller and the paper, and the paper transport was delayed, the paper transport delay could be recovered within a certain time during which the paper was stopped by the registration roller. However, when the sheet is stopped by the registration roller for a predetermined time or more, there is a drawback that printing is performed in a state where the sheet and the image are misaligned.

[0003]

As described above, in the conventional paper transport apparatus, when a slip phenomenon occurs between the pick roller and the transport roller and the paper, and the transport of the paper is delayed, the paper is transported. However, there is a problem that printing is performed with a positional shift between the image and the image.

SUMMARY OF THE INVENTION It is an object of the present invention to correct a sheet conveyance speed so that even when a sheet conveyance delay occurs, the sheet can be corrected so that image and sheet alignment can be performed accurately. An object of the present invention is to provide a transport device.

[0005]

According to a first aspect of the present invention, there is provided a sheet conveying apparatus, comprising: a photosensitive belt on which an image is written; a charger for uniformly charging the surface of the photosensitive belt; A laser unit that writes an electrostatic latent image of each color, a developing device that develops the written electrostatic latent image of each color to form a toner image on the surface of the photoreceptor belt, and a transfer roller that transfers the developed image to paper And an eraser for removing charges remaining on the surface of the photoreceptor belt, a motor for driving the photoreceptor belt, a hopper for storing paper, and a plurality of transport rollers for transporting the paper from the hopper to a transfer roller on which an image is transferred. A registration roller for aligning the transferred paper with the image, a paper sensor provided on the plurality of conveyance roller units and the registration roller unit for detecting the presence or absence of paper, and a plurality of conveyance rollers. A motor for rotating the roller,
A pick roller for picking a sheet from a hopper, and a control device for controlling each of a photoreceptor belt, a developing device, and a mechanism for transporting the sheet, and a plurality of motors for rotating a plurality of transport rollers; Means for correcting the transport speed of
The means for correcting the paper conveyance speed has means for changing the conveyance speed of the conveyance roller located on the registration roller side among the plurality of conveyance rollers independently of the other conveyance rollers, and among the plurality of conveyance rollers, The paper sensor of the transport roller located on the registration roller side calculates the time from when the paper is picked up from the hopper at the time of detecting the ON signal of the transported paper until the paper sensor detects the ON signal, and the value is the theoretical value. In the case where the length is longer, a paper transport device that corrects the transport delay by increasing the transport speed of the transport roller positioned on the registration roller side
Means for correcting the paper transport speed,
The paper is picked from the hopper among a plurality of transport rollers.
Transport roller located on the pick roller side
Set the transport speed with the transport roller located on the registration roller side.
Means for changing, among the plurality of transport rollers,
Place the paper on the pick roller side to pick paper from the hopper.
Transported by the paper sensor of the transport roller
When the ON signal of the sheet is detected, the sheet is
The paper sensor detects an ON signal after picking from the paper
And if the value is longer than the theoretical value,
The transport speed of the transport roller located on the pick roller side
Speed up to compensate for transport delays, and
Conveying roller unit positioned on the registration straw la side in La
Of the paper conveyed by the paper sensor
Pick the paper from the hopper at the point
To determine the time until the paper sensor detects the ON signal,
If the value is longer than the theoretical value,
To increase the transport speed of the transport rollers located at
It is characterized by correction .

The means for correcting the paper transport speed is characterized in that the paper transported by the plurality of transport rollers from the hopper is temporarily stopped at the registration rollers, and the paper and the image are aligned. .

Means for correcting the paper transport speed is to adjust the timing for aligning the image and the paper by absorbing the fluctuation of the paper transport time from the time when the registration roller picks the paper with the pick roller to the time when the paper is transported to the registration roller. It is characterized in that printing is performed while rotating.

Means for correcting the paper transport speed is to correct the positional deviation between the paper and the image by increasing the paper transport speed when the paper does not reach the resist roller due to the timing of rotating the registration roller. It is characterized by.

[0009]

[0010]

[0011]

[0012]

[0013] The laser unit is characterized by comprising a yellow laser unit, a magenta laser unit, a cyan laser unit and a black laser unit.

The developing device comprises a yellow developing device, a magenta developing device, a cyan developing device and a black developing device.

[0015]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic structural view showing a sheet conveying device 50 of the present invention.

Referring to FIG. 1, a paper transport device 50 of the present invention connected to an information processing device 30 for processing an image and issuing a print request includes a photosensitive belt 1 on which an image is written and a surface of the photosensitive belt 1. Charger 11 for uniformly charging the surface of the photoreceptor belt 1, a yellow laser unit 3, a magenta laser unit 4, a cyan laser unit 5, and a black laser unit 6 for writing an electrostatic latent image of each color by exposing the surface of the photoreceptor belt 1; A yellow developing device 7, a magenta developing device 8, a cyan developing device 9 and a black developing device 10 for developing the written electrostatic latent images of the respective colors to form toner images on the surface of the photoreceptor belt 1; A transfer roller 2 for transferring to the paper 40, an eraser 12 for removing charges remaining on the surface of the photoconductor belt 1, a motor 28 for driving the photoconductor belt, and a paper 40 A hopper 29 to be stored, the paper 4
And a plurality of transport rollers 14, 15, 16, 17, 1 for transporting the image No. 0 from the hopper 29 to the transfer roller 2 on which the image is transferred.
8, a registration roller 13 for aligning the conveyed sheet 40 with the image, and a plurality of conveyance rollers 14, 1
Paper sensors 20, 21, provided at 5, 16, 17, 18 and the registration rollers 13 to detect the presence or absence of paper;
22, 23, 24, 19 and a plurality of transport rollers 15, 1
A motor 27 for rotating 6, 17, 18; a motor 26 for rotating the transport roller 14;
Roller 25 for picking up the photosensitive drum, photosensitive belt 1, yellow developing device 7, magenta developing device 8, cyan developing device 9
And a control device 31 for controlling each mechanism of the black developing device 10 and the conveyance of the paper 40.

Here, the transport roller 14 located on the registration roller 13 side has a transport speed independent of the transport rollers 15, 16, 17 and 18 located on the other pick roller 25 side. And the pick roller 25 can be changed.
The transport rollers 15, 16, 17, 18 located on the side have the same rotation speed, but are configured to be able to start and stop rotation independently.

Next, the operation of the paper transport apparatus 50 of the present invention configured as described above will be described.

FIGS. 2 and 3 are flow charts showing the operation of the paper conveying apparatus 50 according to the first embodiment of the present invention.

Referring to FIGS. 2, 3 and 1, first, when a print request is sent from the information processing device 30 to the control device 31 in the paper transport device 50 (step 1), the control device 31 The belt 1 is rotated to activate the yellow laser unit 3, magenta laser unit 4, cyan laser unit 5, and black laser unit 6, and the charger 11 and eraser 12 are turned on. When the activation of the yellow laser unit 3, the magenta laser unit 4, the cyan laser unit 5, and the black laser unit 6 is completed and the printer is ready for printing, the information processing device 30
Flows the image data of each color, and each laser unit 3,
4, 5 and 6 laser (not shown), photoreceptor belt 1
To start writing the image.

On the other hand, on the paper 40, the image written on the photosensitive belt 1 is transferred to the transfer roller 2, and
The transfer is started at the timing when the sheet 40 comes to the position of the transfer roller 2 when the sheet is transferred to the transfer roller 2. At this time, the size of the paper 40 to be picked is recognized (step 2).

Next, when the paper sensor 20 detects an ON signal on the picked paper 40 (step 3), the paper 4
The actual time from picking 0 to turning on the paper sensor 20 is compared with its theoretical value. If the actual transport time of the paper 40 is longer than the theoretical value, the paper 4
Shows that 0 conveyance of delayed, therefore, registration
The paper 40 of the transport roller 14 located on the side of the stroller 13
If the actual transfer time is shorter than the theoretical value, nothing is performed (steps 4 and 5). When increasing the transport speed of the paper 40, the registration rollers 13
It is determined whether or not it is possible to recover the transport delay of the paper 40 by the time the paper 40 reaches the registration roller 13 in consideration of the limit value of the speed of rotating the transport roller 14 located on the side (step 6). ), If not possible, paper 40
Is transported at the maximum transportable speed or is in a jam state (step 7).

If the delayed time can be recovered, the transport speed of the paper 40 of the transport roller 14 located on the side of the registration roller 13 is increased to a speed (step 8) determined by a predetermined formula, and the transport of the paper 40 is performed. Correct the delay.
At this time, of the transport rollers 15, 16, 17, and 18 located on the pick roller 25 side, the transport roller that is recognized as still transporting the paper 40 is the registration roller 1
Since the transport speed is different from that of the transport roller 14 located on the third side, the transport of the paper 40 is stopped and the paper 40 is caused to rotate (step 9).

Next, after the paper sensor 19 is turned on, it is determined that the paper 40 has reached the registration rollers 13 (step 10). After a predetermined time, the conveyance rollers 14, 15, 16, 17 before the registration rollers 13 are determined. , Out of 18,
The transport roller on which the paper 40 is applied is stopped (step 11).

The paper 40 reaches the registration roller 13,
At the timing when the position of the image written on the photoreceptor belt coincides with the position of one image (after a certain period of time after picking the sheet 40), the rotation of the registration roller 13 is started (step 12), and then the printing is completed (step 13). ).

Next, the operation of the paper transport apparatus according to the second embodiment of the present invention will be described with reference to the drawings.

FIGS. 4, 5 and 6 are flow charts showing the operation of the sheet conveying apparatus according to the second embodiment of the present invention.

The difference between the operation of the second embodiment of the paper transport apparatus of the present invention and the operation of the first embodiment is that the transport speed is corrected by the speed correction when the transport of the paper 40 is delayed. Is changed from one to two. The same components are denoted by the same reference numerals.

Referring to FIG. 4, FIG. 5, and FIG. 6, first, when there is a print request (step 101), the size of the paper 40 to be picked is recognized and the picking of the paper 40 is started. 1 is started to write an image (step 102). When the picked sheet 40 is conveyed and reaches the sheet sensor 24 (step 103), the theoretical value of the time from picking until the sheet sensor 24 is turned on and the time actually taken (step 104). (Step 105), if the time actually taken is longer, that is, if the transport of the paper 40 is delayed, it is determined whether or not the transport delay of the paper 40 can be recovered. (Step 106),
If not possible, the speed is set to the maximum speed at which the transport rollers 15, 16, 17, and 18 located on the pick roller 25 side can rotate (step 107).

If it is possible to recover the delay of the transport of the paper 40, the speed of the transport rollers 15, 16, 17, 18 located on the pick roller 25 side is changed to a speed determined by a predetermined formula (step 108). ).

Next, when the paper 40 has been transported to the paper sensor 20 (step 109), the paper 4
The theoretical value from picking 0 until the paper sensor 20 is turned on is compared with the actual value (step 110) (step 111). If the conveyance of the paper 40 is delayed, It is determined whether or not the conveyance delay can be recovered (step 112), and if not, the maximum speed at which the conveyance roller 14 located on the registration roller 13 side can rotate is set (step 113).

If it is possible to recover the delay of the transport of the paper 40, the speed of the transport roller 14 located on the side of the registration roller 13 is changed to a speed determined by a predetermined formula (step 114).

The operations in steps 115 to 119 shown in FIG. 6 are the same as those in steps 9 to 13 in FIG.

If the transport speed of the paper 40 cannot be freely changed steplessly, the speed is changed by two or three steps. If the transport of the paper 40 is delayed, the transport of the paper 40 is delayed. The speed of the paper 40 is adjusted by the registration roller 13
It is also possible to align the image with the paper 40 by lengthening the time that the image is stopped by the registration roller 13 in accordance with the speed that is faster than the prescribed time, which is included in the present invention. Needless to say.

[0036]

As described above, the paper transport apparatus of the present invention detects a delay in paper transport during paper transport, and if it is delayed, increases the speed of the transport roller to increase the delay. Is carried out until the image is transferred, so that there is an effect that the positional deviation between the image and the sheet due to the delay of the sheet conveyance can be eliminated.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a paper transport device of the present invention.

FIG. 2 is a flowchart illustrating an operation of the sheet transport device according to the first embodiment of the present invention.

FIG. 3 is a flowchart illustrating an operation of the paper transport apparatus according to the first embodiment of the present invention.

FIG. 4 is a flowchart illustrating an operation of the paper conveying apparatus according to a second exemplary embodiment of the present invention.

FIG. 5 is an operation flowchart illustrating a second embodiment of the paper conveying apparatus of the present invention.

FIG. 6 is an operation flowchart illustrating a second embodiment of the paper conveying apparatus of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor belt 2 transfer roller 3 yellow laser unit 4 magenta laser unit 5 cyan laser unit 6 black laser unit 7 yellow developing device 8 magenta developing device 9 cyan developing device 10 black developing device 11 charger 12 eraser 13 resist roller 14, 15 Conveying rollers 16 and 17 Conveying rollers 18 Conveying rollers 19 and 20 Paper sensors 21, 22 Paper sensors 23 and 24 Paper sensors 25 Pick rollers 26 and 27 Motor 28 Motor 29 Hopper 30 Information processing device 31 Control device 40 Paper 50 Paper conveying device

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 15/00 G03G 21/00-21/04 G03G 21/14 B65H 5/00-7/20 B65H 29 / 00-29/70 B65H 43/00-43/08

Claims (6)

(57) [Claims] 1. A photoreceptor belt on which an image is written, a charger for uniformly charging the surface of the photoreceptor belt, and a laser unit for exposing the surface of the photoreceptor belt to write an electrostatic latent image of each color. A developing device that develops the written electrostatic latent image of each color to form a toner image on the surface of the photoreceptor belt, and a transfer roller that transfers the developed image to paper.
An eraser for removing charges remaining on the surface of the photoreceptor belt, a motor for driving the photoreceptor belt, a hopper for storing the paper, and conveying the paper from the hopper to the transfer roller on which an image is transferred. A plurality of transport rollers, a registration roller for performing alignment between the transported paper and the image, a paper sensor provided in the plurality of transport roller units and the registration roller unit to detect the presence or absence of the paper, A motor that rotates a plurality of transport rollers, a pick roller that picks up the paper from the hopper, and a control device that controls each mechanism of the photoconductor belt, the developing device, and the transport of the paper. ,
A plurality of motors for rotating the plurality of transport rollers are provided, and a means for correcting the transport speed of the sheet is provided.The means for correcting the transport speed of the sheet is a portion of the plurality of transport rollers closer to the registration roller. Has a means to change the transport speed of the transport roller located in independently of the other transport rollers,
The paper sensor of the transport roller unit located on the registration roller side among the plurality of transport rollers picks up the paper from the hopper at the time of detecting the ON signal of the transported paper, and then the paper sensor determined the time until the oN signal detection, the sheet conveying apparatus to correct for conveying delay a faster transport speed of the transport rollers whose value is positioned at the registration roller side is longer than the theoretical value, corrects the transport speed of the paper Means for performing the plurality of transports
Picking the paper from the hopper with rollers
The conveying roller located on the pick roller side and the registration roller
Means to change the transfer speed with the transfer roller located on the roller side
And transports the sheet among the plurality of transport rollers to the
Conveying located on the pick roller side to pick from a hopper
The paper transported by the paper sensor of the roller section
When the paper ON signal is detected, the paper is picked from the hopper.
From when the paper sensor detects the ON signal
If the value is longer than the theoretical value, the pick
Transportable a faster transport speed of the transport rollers positioned on the low la side
Compensate for the feeding delay and set the front
The paper of the transport roller portion located on the registration roller side
ON signal detection of the transported paper by a sensor
At this point, pick the paper from the hopper and
The paper sensor calculates the time until the ON signal is detected.
If it is longer than the theoretical value, it is located on the registration roller side
A paper transport device wherein a transport speed of a transport roller is increased to correct a transport delay . 2. The method according to claim 1, wherein the means for correcting the sheet conveying speed includes:
2. The sheet conveying device according to claim 1, wherein the sheet conveyed from the hopper by the plurality of conveying rollers is temporarily stopped at the registration roller to perform alignment between the sheet and an image. . 3. The means for correcting the paper transport speed,
The registration roller absorbs fluctuations in the transport time of the paper from the pick roller to the paper after the pick roller picks up the paper to the registration roller, and performs printing by rotating at a timing for aligning the image and the paper. The sheet conveying device according to claim 1, wherein: 4. A means for correcting the paper transport speed,
2. The image forming apparatus according to claim 1, wherein when the sheet does not reach the registration roller at a timing when the registration roller is rotated, a conveyance speed of the sheet is increased to correct a positional shift between the sheet and an image. Paper transport device. 5. The sheet conveying apparatus according to claim 1, wherein said laser unit comprises a yellow laser unit, a magenta laser unit, a cyan laser unit, and a black laser unit. 6. The sheet conveying device according to claim 1, wherein said developing device comprises a yellow developing device, a magenta developing device, a cyan developing device and a black developing device.