JP2001294337A - Paper feeding device and storage medium in which paper feeding control program is recorded - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeding device capable of correctly, easily detecting a movement of a paper sheet carried in a carrying passage within the device and stably feeding, and provide a storage medium in which a paper feeding control program is recorded. SOLUTION: This paper feeding device has a first paper feeding mechanism for taking out the paper sheet on a paper feeding stand and feeding to the carrying passage; a second paper feeding mechanism for feeding the paper sent from the first paper feeding mechanism to a printing part; and an encoder for producing a pulsed signal at a cycle linked with the movement of the paper, and the carrying speed of the paper in the first paper feeding mechanism and the carrying speed of the paper in the second sheet feeding mechanism are detected based on the pulsed signal produced with the encoder to detect the carrying state of the paper with each paper feeding mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeder used for an image forming apparatus for forming an image on a print sheet and a recording medium on which a sheet feed control program is recorded. The present invention relates to a sheet feeding device capable of accurately detecting a movement and a recording medium on which a sheet feeding control program is recorded.

[0002]

2. Description of the Related Art Generally, in a paper feeder used in an image forming apparatus such as a printing machine or a copying machine, the presence or absence of a sheet on a sheet transport path is detected by a sensor to detect a sheet transport state. are doing. That is, a sensor of a reflection type, a transmission type, or the like is installed on the paper conveyance path, and the sensor detects that the paper has been interrupted, thereby recognizing that the paper has passed that location. Thus, for example, when the sensor does not detect the passage of the sheet even after the predetermined time has elapsed, it recognizes that a failure such as a jam has occurred, and performs a process at the time of failure such as stopping the drive of the apparatus. Is going.

As means for measuring the paper transport speed, a plurality of sensors are installed at intervals on the transport path,
By measuring the time required for the paper to pass between the sensors, the conveyance speed of the paper is estimated, thereby controlling the apparatus.

[0004]

In such a conventional system, since the movement of the sheet is detected only at the location where the sensor is installed, the state of sheet conveyance such as the sheet conveyance speed is strictly detected. Can not do. Therefore, it has been difficult to accurately detect the position where a jam or the like has occurred.

Further, the printing paper is reliably taken out of the paper feeding table without being superposed one by one, and the taken out printing paper is fed to the printing drum at a high speed corresponding to the rotation speed of the printing drum rotating at high speed. In order to perform a stable printing process, for example, it is necessary to strictly control the paper conveyance.

Particularly, in an image forming apparatus in which the printing speed can be switched, it is necessary to control the paper feeding speed of the printing paper according to the printing speed, and strictly detect the paper transporting state such as the paper transporting speed. Is required.

[0007] Further, depending on the quality of the printing paper, the pickup roller of the paper feed mechanism may run idle, and the conveyance timing of the paper may be incorrect.

On the other hand, a method of increasing the number of sensors to be installed and increasing the number of measurement positions to improve the accuracy of detecting the state of transport of the sheet can be considered.

However, even with this method of increasing the number of measurement positions, the movement of the paper itself is not detected, so that it is difficult to accurately control the timing at which the paper is delivered to the printing unit in accordance with the printing speed. Met.

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation, and can accurately and easily detect the movement of a sheet conveyed along a conveying path in an apparatus, and stabilize the sheet. It is an object of the present invention to provide a paper feeding device capable of feeding paper by feeding and a recording medium recording a paper feeding control program.

[0011]

In order to solve the above-mentioned problems, a paper feeder according to the present invention includes a first paper feed mechanism for taking out paper from a paper feed table and feeding the paper to a conveyance path; A sheet feeding device having a second sheet feeding mechanism for sending the sheet sent from the sheet feeding mechanism to a printing unit, comprising: an encoder for generating a pulse signal in a cycle interlocked with the movement of the sheet; Detecting the transport speed of the paper in the first paper feed mechanism and the transport speed of the paper in the second paper feed mechanism from the pulse signal generated by the encoder,
It is characterized in that a state of conveyance of the sheet by each of the sheet feeding mechanisms is detected.

[0012] Further, when the paper transport speed detected from the pulse signal generated by the encoder is less than a predetermined speed, the paper feeding mechanism based on difference data between the moving speed and the predetermined speed. It is characterized in that the paper transport speed is controlled.

Further, the recording medium on which the sheet feeding control program according to the present invention is recorded is characterized in that a step of counting a pulse signal generated from the encoder for a predetermined period, and comparing the counted pulse number with the predetermined pulse number. Determining a difference data between the moving speed of the sheet and a predetermined moving speed, and controlling a conveyance pitch of the sheet by the sheet feeding mechanism based on the difference data. I do.

According to the present invention, since the encoder detects the transport speed of the paper from the pulse signal generated in a cycle corresponding to the movement of the printing paper, the transport operation is stopped due to a jam or the like, or the transport pitch is delayed. , Etc., it is possible to accurately detect the paper transport status. In addition, since the delay or excessive advance of the transport pitch of the printing paper can be corrected and delivered to the printing unit, stable printing processing can be performed.

[0015]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a simplified side view showing a sheet feeding unit of a sheet-fed printing apparatus as an image forming apparatus.

The plate cylinder 1 constituting the printing section has a porous structure that allows the passage of printing ink. A stencil sheet 2 made by heat-sensitive stencil is wound around the outer circumference of the plate cylinder 1, and as shown in FIG. It is driven to rotate counterclockwise. An ink application roller 14 is provided inside the plate cylinder 1, and a squeegee element 15 is provided as an ink amount control element at a predetermined gap from the outer peripheral surface of the ink application roller 14. Printing ink is supplied to the section 16 by an ink supply mechanism (not shown).

Below the plate cylinder 1, there is disposed a paper cylinder 3 which rotates in a direction opposite to and synchronously with the plate cylinder 1. The paper cylinder 3 has a sheet gripper 4 and has a function of holding printing paper P continuously supplied from a paper feeding mechanism described later. The sheet gripper 4 opens and closes at a predetermined timing by a drive mechanism (not shown), holds the leading end of the printing paper P supplied from the paper feeding mechanism, and conveys the printing paper P along with the rotation of the paper cylinder 3. Printing corresponding to the image of the stencil sheet 2 is performed.

The printing paper P is stacked on a paper feeding table 7 and has a pickup roller 5 a as a primary paper feeding mechanism 5.
The sheet is taken out one by one from the upper portion by the scraper roller 5b and sent out to the secondary sheet feeding mechanism 6.

An intermittently driven timing roller 6a as a secondary paper feeding mechanism 6 is provided between the paper cylinder 3 as a printing unit and a pickup roller 5a as a primary paper feeding mechanism 5. By the operation, the printing paper P is sent out to the sheet gripper 4 of the paper cylinder 3 at a predetermined timing synchronized with the rotation operation of the paper cylinder 3, and the intended printing operation is performed.

As described above, a two-stage paper feed mechanism is provided.
The primary paper feed mechanism 5 reliably removes the printing paper P from the paper feed table 7 without overlapping one by one, and the secondary paper feeding mechanism rotates the printing paper P at a high speed corresponding to the rotation speed of the paper cylinder 3. Paper is fed to the drum 3 at a speed. The printing speed can be switched stepwise from low speed to high speed.

FIG. 2 is a side view showing a specific example of the sheet feeding unit shown in FIG. 1, and FIG. 3 is a perspective view thereof.

Pickup roller 5 of primary paper feed mechanism 5
a is an intermittent drive, and after the printing paper P is taken out of the paper feeding table 7 by a predetermined driving force and delivered to the secondary paper feeding mechanism 6, the “paper rotation” interlocks with the movement of the printing paper P. I do. That is, the pick-up roller 5a obtains a predetermined driving force and drives by itself until it takes out the printing paper P from the paper feeding table 7 and delivers it to the secondary paper feeding mechanism 6.
Is transferred to the secondary paper feed mechanism 6 and rotates in conjunction with the transport operation of the printing paper P without obtaining a driving force.

Between the primary paper feed mechanism 5 and the secondary paper feed mechanism 6, there are provided rotating rollers 17a and 17b which rotate in synchronization with the movement of the printing paper P. The rotating rollers 17a and 17b are provided. Reference numeral 17b denotes a roller having no driving means of its own, that is, a roller which rotates in synchronization with only the movement of the printing paper P.

An encoder disk 9 is coaxially fixed to the rotating roller 17a by a shaft 10. The encoder disk 9 rotates in conjunction with the rotation of the rotating roller 17a.

The encoder disk 9 is provided with, for example, optical slits 13 at predetermined regular intervals. The displacement of the rotational motion of the encoder disk 9 is pulsed by an encoder sensor 11 of a reflection type or a transmission type. Measure as a waveform. That is, by measuring the displacement of the rotary motion of the encoder disk 9, the displacement of the rotary motion of the co-rotating roller 17a, that is, the displacement of the linear motion of the printing paper P can be detected.

Thus, for example, when a continuous pulse waveform is obtained from the encoder sensor 11 while the primary paper feed mechanism 5 takes out the print paper P from the paper feed table 7, the print paper P Printing paper P by primary paper feed mechanism 5
When the pulse waveform from the encoder sensor 11 is interrupted, it can be determined that the removal of the printing paper P has been interrupted due to the occurrence of a failure or the like.

Further, if a continuous pulse waveform is obtained from the encoder sensor 11 even after the printing paper P is delivered to the secondary paper feeding mechanism 6, the printing paper P is transferred to the secondary paper feeding mechanism 6. If the pulse waveform from the encoder sensor 11 is interrupted after the printing paper P has been delivered to the secondary paper feeding mechanism 6, it can be determined that the conveyance has been performed to the printing unit. It can be determined that the conveyance of the printing paper P has been interrupted by the occurrence of.

Next, an operation example of the sheet feeding process will be described with reference to FIGS. 4 to 6, using the sheet feeding device of the image forming apparatus shown in FIGS. 1 to 3 as a model. FIG. 4 is a block diagram showing an example of a functional configuration with a focus on a sheet feeding device portion of the image forming apparatus. In FIG. 4, the image forming apparatus includes a processing control unit 30 that controls processing of the entire image forming apparatus, an image processing unit 60 that performs plate making processing and the like, and a printing unit 50 that performs printing processing. The printing unit 50 and the image processing unit 60
The detailed description of the configuration is omitted.

The processing control section 30 has a memory section 32 for storing parameters used when processing a program, and an arithmetic control section 31 for executing the program. The paper feed control program described below performs arithmetic processing in the arithmetic control unit 31 based on the parameter values in the memory unit 32 and data from the various sensors 11, 22, 12, and the like, and the driver circuits 41, 43, 45 Drive systems 42, 44, 4 via
6 and 47 are controlled.

FIG. 5 is a flowchart showing an example of the processing procedure of the paper feed control program.

First, necessary parameters are read from the memory unit 32 (Step 01). The parameters used here are a parameter (P_KYU1) for the primary paper feed mechanism 5 and a parameter (P_KYU2) for the secondary paper feed mechanism 6. This parameter is the expected number of pulses (the number of pulses to be detected when the printing paper P is normally conveyed) in each paper feeding mechanism.

Next, the printing process is started (Step 10).

First, the printing paper P in the primary paper feed mechanism 5
Is detected (Step 11). Specifically, a period during which the primary paper feed mechanism 5 is transporting the printing paper P is obtained, and the number of pulses (k1) detected by the encoder sensor 11 is counted during that period. That is, the distance that the printing paper P moves per unit time, that is, the speed of the printing paper P is determined.

Here, how to determine the "period during which the primary paper feed mechanism 5 is transporting the printing paper P" will be described with reference to FIG. A drum encoder sensor 22 for detecting a rotation operation is installed on the plate cylinder 1, and the printing paper P
Is obtained. For example, using line L as a reference line and line Q
When the plate cylinder 1 is rotated to the position 1, the primary paper feed mechanism 5 starts conveying the printing paper P, and starts counting the number of pulses (k1) detected by the encoder sensor 11. When the plate cylinder 1 rotates to the position of the line Q2, it is determined that the primary paper feed mechanism 5 has finished conveying the printing paper P, and the counting of the number of pulses (k1) detected by the encoder sensor 11 ends. That is, the section from Q1 to Q2 is defined as "the period during which the primary paper feed mechanism 5 is transporting the printing paper P". Similarly,
The section from R1 to R2 is referred to as “a period during which the secondary paper feeding mechanism 6 is transporting the printing paper P”. Further, according to this method, it is possible to cope with the switching of the printing speed.

Returning to FIG. 5, when the period during which the primary paper feed mechanism 5 is transporting the printing paper P has expired, the counted number of pulses (k1) is compared with a predetermined number of pulses (P_KYU1) ( Step12). If the difference between the two is within 4%, it is determined that the printing paper P has been normally conveyed and the next processing (St
ep21). If the difference between the two exceeds 7% (Step 13), it is determined that a trouble such as a jam has occurred, and the operation of the image forming apparatus is stopped (Step 30). Specifically, the paper feed clutch is turned off via the paper feed driver circuit 45, and the main motor 42 is stopped via the main motor driver circuit 41.

On the other hand, the difference between the counted number of pulses (k1) and the predetermined number of pulses (P_KYU1) is -4% to -7%.
(Step 13), it is determined that the conveyance of the printing paper P is delayed for some reason, and the delay time (X1) is calculated from the detected number of pulses (Step 14). Then, the primary paper feed motor 46 is driven for X1 hours (Step 15). Thereby, the conveyance pitch of the printing paper P in the primary paper feeding mechanism 5 is corrected, and a stable paper feeding operation can be performed.

The same applies to the secondary paper feed mechanism 6.

First, the printing paper P in the secondary paper feed mechanism 6
Is detected (Step 21). When the period during which the secondary paper feeding mechanism 6 is transporting the printing paper P has expired, the counted number of pulses (k1) and a predetermined number of pulses (P_KY
U2) (Step 22). If the difference between the two is within 4%, it is determined that the printing paper P has been normally conveyed, and the process proceeds to the next processing (Step 40 and thereafter). If the difference between the two exceeds 7% (Step 23), it is determined that a failure such as a jam has occurred, and the operation of the image forming apparatus is stopped (Step 30).
On the other hand, if the difference between the counted number of pulses (k2) and the predetermined number of pulses (P_KYU2) is -4% to -7% (Step 23), the conveyance of the printing paper P is delayed for some reason. The time (X2) delayed from the detected number of pulses is calculated (Step 24), and the paper feed driver circuit 4
5 drive the secondary paper feed motor 47 for X2 hours (St.
ep25). Thereby, the printing paper P in the secondary paper feeding mechanism 6 is
Can be corrected, and a stable sheet feeding operation can be realized.

That is, if the conventional sensor attempts to detect the state of conveyance of the printing paper P in the primary paper feeding mechanism 5, the state of conveyance of the printing paper P in the secondary paper feeding mechanism 6 will be near the primary paper feeding mechanism 5. To detect the secondary paper feed mechanism 6
Have to be installed in the vicinity of the first sheet feeding mechanism, however, according to the method of the present invention, one encoder sensor 11 installed between the primary sheet feeding mechanism 5 and the secondary sheet feeding mechanism 6 is required.
Thus, it is possible to detect the transport state of the printing paper P not only in the primary paper feed mechanism 5 but also in the secondary paper feed mechanism 6.

As described above, according to the present invention, the amount of rotation of the encoder disk 9 that rotates in conjunction with the transport operation of the printing paper P is measured by the encoder sensor 11, so that the printing paper P
Can be detected with high accuracy. Moreover,
Since the movement of the printing paper P can be detected with high accuracy by a sensor installed at one place, it is not necessary to install several places to increase the accuracy unlike the conventional paper sensor.

Further, the encoder sensor 11 and the plate cylinder 1
The measurement position can be arbitrarily set by combining with the drum encoder sensor 22 that detects the rotation operation of the recording medium, and a correction process of the transport pitch according to the measurement position can be performed. Further, even when a failure such as a jam occurs, it is possible to detect where the failure has occurred.

Next, a description will be given of an example in which the difference in the transport amount due to the difference in the quality of the printing paper P is corrected. By using the reflection type paper sensor 12 that detects the passage of the printing paper P as described in the section of the related art, it is possible to correct a difference in the transport amount due to a difference in paper quality or the like.

Referring to FIG. 1, a reflection type paper sensor 12 for detecting the passage of the printing paper P is provided between the primary paper feeding mechanism 5 and the secondary paper feeding mechanism 6. This paper sensor 1
2 detects that the printing paper P has shut off the paper sensor 12, so that it can be recognized that the printing paper P has passed that location. Until the paper sensor 12 detects the arrival of the printing paper P, the primary paper feeding mechanism 5
The displacement of the rotational movement of the encoder disk 9 attached to the sensor is measured by the encoder sensor 11.

For example, when the printing paper P having a smooth surface is conveyed, the pickup roller 5a slips (runs idle), and the encoder sensor 11 detects the amount compared with the amount of the printing paper P actually conveyed. The number of pulses increases. The difference between the actually obtained pulse number and the predetermined pulse number is the amount by which the pickup roller 5a slips.

By taking measures such as advancing the drive start timing of the primary paper feed mechanism 5 according to the slip amount obtained here, it is possible to correct a difference in the transport amount due to a difference in paper quality or the like. By combining the conventional paper sensor in this way, finer detection is possible and a stable paper feeding operation can be performed.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments, and various improvements and modifications may be made without departing from the gist of the present invention. .

For example, in this embodiment, an example has been described in which the encoder and the encoder sensor are provided between the primary paper feed mechanism 5 and the secondary paper feed mechanism 6, but the installation location of the sensor is not limited to this. Absent. It may be installed anywhere as long as the movement of the printing paper being conveyed can be detected.

Therefore, the present invention should be limited only by the matters specifying the invention according to the claims that are reasonable from this disclosure.

[0050]

According to the present invention, since the encoder detects the moving speed of the paper from the pulse signal generated in a cycle corresponding to the movement of the printing paper, the paper movement is stopped or greatly reduced due to a jam or the like. It is possible to accurately detect the state of conveyance of the printing paper, such as when it is late. Moreover, since the movement of the printing paper P can be detected with high accuracy by a sensor installed at one place, it is not necessary to install several places to improve the accuracy unlike the conventional paper sensor.

Further, the printing paper can be transferred to the printing section after correcting the delay or excessive advance of the conveying pitch of the printing paper, so that a stable printing process can be performed.

Further, by combining with another sensor, the transport status can be detected with higher accuracy, and a fine correction process or the like can be performed. Further, even when a failure such as a jam occurs, it is possible to detect where the failure has occurred.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment in which a sheet feeding device according to the present invention is applied to an image processing apparatus.

FIG. 2 is a side view showing an embodiment of the sheet feeding device shown in FIG.

FIG. 3 is a perspective view showing an embodiment of the sheet feeding device shown in FIG. 1;

FIG. 4 is a block diagram illustrating a functional configuration example of an image forming apparatus including the sheet feeding device illustrated in FIG. 1;

FIG. 5 is a flowchart showing an example of a processing procedure of a sheet feeding control program according to the present invention.

FIG. 6 is an image diagram for explaining how to determine a period during which a primary paper feed mechanism or a secondary paper feed mechanism is transporting print paper.

[Explanation of symbols]

 1. Plate cylinder 2. Stencil paper 3. Paper cylinder 4. Sheet gripper 5. Primary paper feed mechanism 5a. Pickup roller 5b .. Scraper Roller 6 Secondary paper feed mechanism 6a Timing roller 7. Paper feed table 9. Encoder disk 10. Encoder shaft 11. Encoder sensor 12. ... Paper sensor 13 .... Slit 14 .... Ink applying roller 15 .... Squeegee element 16 .... Ink reservoir 17a, 17b ... Rotating roller

[Procedure amendment]

[Submission date] March 23, 2001 (2001.3.2)
3)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 4

[Correction method] Change

[Correction contents]

FIG. 4

Claims (3)

[Claims] A first paper feed mechanism for taking out paper from a paper feed table and feeding the paper on a conveyance path; and a second paper feed mechanism for feeding the paper sent from the first paper feed mechanism to a printing unit. A paper feed device having an encoder that generates a pulse signal in a cycle interlocked with the movement of the paper, wherein a transport speed of the paper in the first paper feed mechanism from the pulse signal generated by the encoder and A sheet feeding device, wherein the sheet feeding speed of the sheet in the second sheet feeding mechanism is detected, and the sheet feeding status of each sheet feeding mechanism is detected. 2. The method according to claim 2, wherein the sheet conveying speed detected from the pulse signal generated by the encoder is lower than a predetermined speed, and the sheet feeding mechanism operates based on difference data between the moving speed and the predetermined speed. The sheet feeding device according to claim 1, wherein the sheet feeding speed is controlled. 3. A recording medium on which a sheet feeding control program for controlling a sheet feeding device according to claim 1 is recorded, wherein a pulse signal generated from said encoder is counted for a predetermined period. And comparing the counted number of pulses with a predetermined number of pulses,
A step of obtaining difference data between the moving speed of the sheet and a predetermined moving speed; and a step of controlling a conveyance pitch of the sheet by the sheet feeding mechanism based on the difference data. A recording medium on which a paper control program is recorded.