JPH0573654U - Color copier - Google Patents

Abstract

(57) [Abstract] [Purpose] In a color copying machine, it is possible to prevent color misregistration only by a hardware circuit without providing a complicated control circuit. [Structure] One of the axes for driving each of a scanner, a photosensitive drum, and a transfer drum constituting a color copying machine is a reference axis, and one of the other two axes is a synchronized axis. First,
The reference axis is driven in response to the copy instruction. Then, when the reference axis is in a predetermined driving state, the sensor outputs a detection signal. Upon reception of this detection signal, the time counting means starts time counting, and when a predetermined time has elapsed, the synchronized axis drive means drives the synchronized axis.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a color copying machine.

[0002]

[Prior Art]

 FIG. 3 is a basic schematic configuration diagram of a color copying machine. In this figure, 1 is a scanner, which is moved in the direction of arrow a at a constant speed by the drive of the scanner drive motor M1. Here, when the scanner 1 has passed a predetermined position on the movement path, a detection signal is output by a scanner sensor (not shown). Reference numeral 2 denotes a photosensitive drum, which is rotated at a constant speed in the arrow B direction by driving a photosensitive drum drive motor (not shown). Further, 3 is a transfer drum, which is rotated at a constant speed in the arrow C direction by the drive of the transfer drum drive motor. Further, a transfer drum sensor (not shown) for detecting a mark printed on the outer peripheral surface of the transfer drum 3 is installed. Reference numeral 4 denotes a paper feeding unit, and the transfer paper stored in the paper feeding unit 4 is conveyed in the direction of arrow d. A toner developing unit 5 supplies toner onto the outer peripheral surface of the photosensitive drum 2. Further, a timing means (not shown) for controlling the drive timing of the scanner 1, the photosensitive drum 2 and the transfer drum 3 is provided.

FIGS. 4A and 4B are timing charts showing the operations of the scanner 1 and the transfer drum 3 in the conventional color copying machine. FIG. 5 is a timing chart in which the driving states of the clock, the sensor for the scanner, and the sensor for the transfer drum are added to the partially enlarged view between time T0 and time T4 shown in FIG. The operation of the conventional color copying machine will now be described with reference to FIGS. 4 (a), 4 (b) and 5. When a document is set at a predetermined reference position on a document table (not shown) and the copy start button is pressed at time T0, the first color is copied as described below. First, the rotation of the transfer drum 3 and the photosensitive drum 2 is started. After that, the transfer drum 3 and the photosensitive drum 2 are controlled to rotate in association with each other. Then, the mark for the transfer drum 3 is detected by the transfer drum sensor, and at the time when the detection pulse P1 is output, the time counting means starts the time counting.

Next, when a predetermined time t elapses from the time when the transfer drum sensor detects the mark, the scanner drive motor M1 is activated, and the scanner 1 is reset from the home position at time T1. Moves in the direction, scans the document on the document table, and outputs the reflected light from the document. At time T3 during the movement of the scanner 1, the above-mentioned scanner sensor outputs the detection signal P2 indicating that the scanner 1 has passed the scanning start position. The time Ta from the time when the mark on the transfer drum 3 is detected to the time T3 when the sensor for the scanner outputs is read from the time measuring means. (Hereinafter, this time Ta will be referred to as an actual value.) Then, the time Tc from the mark detection of the transfer drum 3 (photosensitive drum 2) to the scanner sensor output, which is theoretically obtained from the actual value and the calculation, The difference Δt from the specified theoretical value is obtained as the deviation time. This shift time Δt is caused by manufacturing errors that cannot be prevented in the manufacturing process of each element that constitutes the copying machine.

Then, the document is scanned by the scanner 1, and the output light from the scanner 1 is applied to the outer peripheral surface of the photosensitive drum 2 through the color filter corresponding to the first color. As a result, an electrostatic latent image corresponding to the first color is formed on the outer peripheral surface of the photosensitive drum 2. To the electrostatic latent image on the outer periphery of the photosensitive drum 2 formed in this way, toner having a complementary color relationship with the first color of black, yellow, magenta, and cyan is supplied by the toner developing unit 5 to electrostatically The latent image is visualized as a toner image. Then, the transfer paper is conveyed from the paper supply unit 4. Here, the transfer paper is conveyed at a timing such that the front end position of the transfer paper and the front end portion of the toner image on the photosensitive drum 2 coincide with each other. Then, the toner image formed on the photosensitive drum 2 reaches the transfer portion where the photosensitive drum 2 and the transfer drum 3 are closest to each other. At the same time, the leading edge of the transfer paper is supplied to the transfer section. As a result, the toner image of the first color formed on the photosensitive drum 2 is transferred onto the transfer paper. In order to perform color printing without causing color misregistration, the scanner 1 always starts scanning at the scanning start position at the time T2 when a time corresponding to the theoretical value Tc has elapsed from the time when the marker on the transfer drum 3 was detected. Need to go through. However, as described above, the scanner 1 may pass the scanning start position at time T3, which is deviated from the ideal timing by Δt. Therefore, at time T4 (the period when there is no transfer sheet) before the detection of the next transfer drum sensor, the rotational speed of the transfer drum 3 is accelerated / decelerated to correct the deviation time Δt. Then, the same operation as in the case of printing the first color is performed, and the second color and the third color are superimposed and transferred. A color copying machine of this type is disclosed in, for example, Japanese Patent Laid-Open No. 162367/1990.

[0006]

[Problems to be solved by the device]

 As described above, in the conventional color copying machine, it is necessary to correct the deviation during driving due to the manufacturing error of each axis. Therefore, the complicated control circuit for performing the correction operation is required, The problem was that the machine became expensive. Further, in order to obtain the correction amount for the deviation, it is necessary to perform the correction calculation by using the CPU, and in particular, in the color copying machine, there is a problem that the proper processing cannot be performed only by the hardware circuit. The present invention has been made under such a background, and an object thereof is to provide a color copying machine in which color misregistration is prevented without providing a complicated control circuit.

[0007]

[Means for Solving the Problems]

 A color copying machine according to the first aspect of the present invention includes: a scanner that emits light onto a document while moving, and a scanner that outputs reflected light from the document; and a scanner that rotates in conjunction with the movement of the scanner to move from the scanner. A photosensitive drum on the outer peripheral surface of which an electrostatic latent image corresponding to the optical image of the output light is formed, developing means for visualizing the electrostatic latent image as a toner image, and a transfer paper wrapped around the outer peripheral surface. A transfer drum that rotates in conjunction with the photosensitive drum and transfers the toner image on the outer peripheral surface of the photosensitive drum to the transfer paper; and a transfer paper supply unit that supplies the transfer paper to the transfer drum, In a color copier that performs color copying on the transfer paper by repeatedly driving the scanner, the photosensitive drum, and the transfer drum, the axis for driving the photosensitive drum is used as a reference axis, and A transfer drum is a synchronized shaft, and a sensor that outputs a detection signal when the photosensitive drum driven by the reference shaft is in a predetermined driving state, and a predetermined time is counted by inputting the detection signal. Timing means, reference axis drive means for driving the reference axis in response to a copying instruction, and synchronized axis drive means for driving the synchronized axis when the timing of the predetermined time is completed by the timing means. It is characterized by having. A color copying machine according to the invention as claimed in claim 2 projects a light beam onto a document while moving, and a scanner that outputs reflected light from the document, and rotates in conjunction with the movement of the scanner. A photosensitive drum on the outer peripheral surface of which an electrostatic latent image corresponding to the optical image of the output light is formed, developing means for visualizing the electrostatic latent image as a toner image, and a transfer paper wrapped around the outer peripheral surface. A transfer drum that rotates in conjunction with the photosensitive drum and transfers the toner image on the outer peripheral surface of the photosensitive drum to the transfer paper; and a transfer paper supply unit that supplies the transfer paper to the transfer drum, In a color copier that performs color copying on the transfer paper by repeatedly driving the scanner, the photosensitive drum, and the transfer drum, the axis for driving the scanner is used as a reference axis and A sensor that outputs a detection signal when the scanner driven by the reference axis is in a predetermined driving state, with the image pickup drum as a synchronized axis, and a timekeeping that measures a predetermined time by inputting the detection signal Means, a reference axis driving means for driving the reference axis in response to a copying instruction, and a synchronized axis driving means for driving the synchronized axis at the time when the timing of the predetermined time is completed by the timing means. It is characterized by having. A color copying machine according to the invention as claimed in claim 3 projects a light beam onto an original document while moving, and a scanner that outputs reflected light from the original document, and rotates in conjunction with the movement of the scanner. A photosensitive drum on the outer peripheral surface of which an electrostatic latent image corresponding to the optical image of the output light is formed, developing means for visualizing the electrostatic latent image as a toner image, and a transfer paper wrapped around the outer peripheral surface. A transfer drum that rotates in conjunction with the photosensitive drum and transfers the toner image on the outer peripheral surface of the photosensitive drum to the transfer paper; and a transfer paper supply unit that supplies the transfer paper to the transfer drum, In a color copier that performs color copying on the transfer paper by repeatedly driving the scanner, the photosensitive drum, and the transfer drum, the axis for driving the transfer drum is used as a reference axis, and A sensor that outputs a detection signal when the transfer drum driven by the reference axis is in a predetermined drive state, with a scanner as a synchronized axis, and a clock that measures a predetermined time by inputting the detection signal Means, a reference axis driving means for driving the reference axis in response to a copying instruction, and a synchronized axis driving means for driving the synchronized axis at the time when the timing of the predetermined time is completed by the timing means. It is characterized by having.

[0008]

[Action]

 According to the first aspect of the invention, the photosensitive drum is first driven by the reference axis drive means in response to a copying instruction. Then, when the photosensitive drum is in a predetermined driving state, the sensor outputs a detection signal. Upon receiving this detection signal, the time counting means starts time counting. When a predetermined time has elapsed until the synchronized shaft is driven, the transfer drum is driven by the synchronized shaft driving means. Further, the scanner is driven in association with the rotation of the photosensitive drum. Then, the document is scanned by the scanner, and an electrostatic latent image corresponding to the optical image of the output light from the scanner is formed on the outer peripheral surface of the photosensitive drum. The electrostatic latent image described above is visualized by the developing means and becomes a toner image. Then, the transfer drum is rotated in conjunction with the photosensitive drum in a state where the transfer paper supplied from the transfer paper supply means is wound around the outer peripheral surface, and the toner image on the outer peripheral surface of the photosensitive drum is transferred to the transfer paper. When the processing is performed as described above and the first color is printed, the transfer drum is once stopped. On the other hand, the photosensitive drum continues to rotate at a constant speed due to the rotation of the reference shaft. Then, when it is detected by the sensor that the photosensitive drum is in a predetermined driving state, thereafter, the temporarily stopped synchronized shaft is repeatedly driven. In each of the inventions described in claims 2 and 3, the same operation as the invention described in claim 1 can be obtained.

[0009]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. The color copying machine according to the present invention is different from the conventional one in that the control circuit shown in FIG. 1 is provided. In the copying machine according to the present invention, one of the three drive shafts for driving the scanner 1, the photosensitive drum 2 and the transfer drum 3 is used as the reference axis A, and one of the other two drive shafts is used as the reference axis A. The asynchronous shaft B is driven along with the rotation. Here, the reference axis A and the synchronized axis B are driven so as to be synchronized with each other. In FIG. 1, M2 is a drive motor for the synchronized shaft B that drives the synchronized shaft B, and M3 is a drive motor for the reference shaft A that drives the reference shaft A. SE is a sensor that detects that the object driven by the reference axis A has reached a predetermined driving state. The details of the combination of the drive shafts set for the reference shaft A and the synchronized shaft B will be described later. CT is a counter, which counts up a clock generated at regular intervals. The comparator CP 1 is a comparator, which compares the counter CT with the predetermined data DT. Here, as the data DT, the delay time required after the sensor SE for the reference axis A detects that the reference axis A has been activated until the asynchronous axis B is activated is converted into a clock count value. The specified value is set. MD is a motor driver, which controls the drive current for the drive motor M2 of the synchronized shaft B.

The control circuit realized by the combination of the reference axis A and the synchronized axis B in this embodiment will be described below. First, a first embodiment in which the photosensitive drum 2 is set to the reference axis A and the transfer drum 3 is set to the synchronized axis B as shown in FIG. 2A will be described. When the user presses the copy start button, a CPU (not shown) outputs a trigger signal. Upon receiving this trigger signal, the drive motor M3 for the reference axis A is activated, and the photosensitive drum 2 starts to rotate. When the sensor SE detects a mark printed on the outer peripheral surface of the photosensitive drum 2, a Z signal (zero marker) is output. Upon receiving the Z signal, the counter CT in the initial value state starts counting up the clock. Then, the comparator CP compares the data DT with the value of the counter CT, and when the value of the counter CT is equal to or larger than the data DT, a coincidence signal is output to the motor driver MD. Upon receiving the coincidence signal, the motor driver MD sends a drive current to the drive motor M2 for the synchronized shaft B. As described above, the drive of the transfer drum 3 is started when the time corresponding to the data DT elapses from the time when the photosensitive drum 2 is started to be driven. By performing such control, the leading edge of the transfer sheet is conveyed so as to match the leading edge of the toner image formed on the outer peripheral surface of the photosensitive drum 2, and the transfer is started. At the transfer portion where the photosensitive drum 2 and the transfer drum 3 are close to each other, when both drums rotate at the same peripheral speed to finish printing the first color, the transfer drum 3, which is the synchronized shaft, is temporarily stopped. Let Then, the counter CT is reset. When the sensor SE detects a mark printed on the outer peripheral surface of the photosensitive drum 2, a Z signal (zero marker) is output. At this point, the counter CT starts counting up again. After that, the second color and the third color are repeatedly processed in the same manner as the processing of the first color described above, and a plurality of colors are transferred to one transfer sheet to complete a color copy.

Next, a second embodiment in which the scanner 1 is set to the reference axis A and the transfer drum 3 is set to the synchronized axis B will be described. When the user presses the copy button, the drive motor M3 for the reference axis A starts to be driven and the scanning of the scanner 1 is started. When the driving start of the scanner 1 is detected, a signal is output from the sensor SE and the counter CT starts counting up the clock. Then, after a lapse of time corresponding to the data DT, a coincidence signal is output to the motor driver MD. In response to this, a drive current is sent from the motor driver MD to the drive motor M2 for the synchronized shaft B, and the transfer of the first color is started.

Next, a third embodiment in which the transfer drum 3 is set to the reference axis A and the scanner 1 is set to the synchronized axis B will be described. When the user presses the copy button, the drive motor M3 for the reference axis A is activated and the transfer drum 3 starts rotating at a constant speed. When the front end of the transfer paper wrapped around the outer circumference of the transfer drum 3 is detected, a signal is output from the sensor SE and the counter CT starts counting up the clock. At the time when the time corresponding to the data DT has elapsed from the start of driving the transfer drum 3, a drive current is sent from the motor driver MD to the drive motor M2 for the synchronized shaft B, and the transfer of the first color is started. It In the above embodiment, the case where the CPU controls the drive of the reference axis A has been described, but the control may be performed by hardware other than the CPU.

[0013]

[Effect of the device]

 As described above, according to the present invention, since the scanner 1, the photosensitive drum 2, and the transfer drum 3 are synchronously controlled by the hard circuit, a circuit for correction calculation is unnecessary even when copying a plurality of colors. Therefore, there is an effect that a low-cost color copying machine can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a control circuit of a color copying machine according to an embodiment of the present invention.

FIG. 2 is a correspondence table showing a setting example of reference axes and synchronized axes in the same embodiment.

FIG. 3 is a block diagram showing a general schematic configuration example of a color copying machine.

FIG. 4 is a waveform diagram showing an operation of a conventional color copying machine.

FIG. 5 is a waveform diagram showing an operation of a conventional color copying machine.

[Explanation of symbols]

 1 Scanner 2 Photosensitive Drum 3 Transfer Drum M2 Drive Motor for Synchronized Axis B MD Motor Driver M3 Drive Motor for Reference Axis A SE Sensor DT Data CT Counter CP Comparator

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location H04N 1/29 G 9186-5C

Claims (3)

[Scope of utility model registration request] 1. A scanner that projects light on a document while moving and outputs reflected light from the document; and a scanner that rotates in conjunction with the movement of the scanner and corresponds to an optical image of the output light from the scanner. A photosensitive drum on which an electrostatic latent image is formed on the outer peripheral surface, developing means for visualizing the electrostatic latent image as a toner image, and a transfer paper wound around the outer peripheral surface and rotated in conjunction with the photosensitive drum. A transfer drum configured to transfer the toner image on the outer peripheral surface of the photosensitive drum onto the transfer paper, and a transfer paper supply unit configured to supply the transfer paper to the transfer drum, the scanner, the photosensitive drum, and the transfer In a color copier that performs color copying on the transfer paper by repeatedly driving a drum, a shaft for driving the photosensitive drum serves as a reference shaft, and the transfer drum serves as a synchronized shaft. A sensor that outputs a detection signal when the photosensitive drum driven by the reference shaft is in a predetermined driving state, a timing unit that counts a predetermined time by inputting the detection signal, and a response to a copying instruction. And a reference axis drive means for driving the reference axis, and a synchronized axis drive means for driving the synchronized axis at the time when the time counting means finishes measuring the predetermined time. Machine. 2. A scanner that projects light onto a document while moving and outputs reflected light from the document, and a scanner that rotates in conjunction with the movement of the scanner and that corresponds to an optical image of the output light from the scanner. A photosensitive drum on which an electrostatic latent image is formed on the outer peripheral surface, developing means for visualizing the electrostatic latent image as a toner image, and a transfer paper wound around the outer peripheral surface and rotated in conjunction with the photosensitive drum. A transfer drum configured to transfer the toner image on the outer peripheral surface of the photosensitive drum onto the transfer paper, and a transfer paper supply unit configured to supply the transfer paper to the transfer drum, the scanner, the photosensitive drum, and the transfer In a color copier that performs color copying on the transfer paper by repeatedly driving a drum, a shaft that drives the scanner is a reference shaft, and the transfer drum is a synchronized shaft, A sensor that outputs a detection signal when the scanner driven by the quasi-axis is in a predetermined driving state, a time measuring unit that measures a predetermined time by receiving the detection signal, and a sensor that responds to a copying instruction. A copying machine comprising: a reference shaft driving means for driving the reference shaft; and a synchronized shaft driving means for driving the synchronized shaft at a time point when the time measuring means finishes measuring the predetermined time. . 3. A scanner that projects light onto a document while moving and outputs reflected light from the document, and a scanner that rotates in conjunction with the movement of the scanner and that corresponds to an optical image of the output light from the scanner. A photosensitive drum on which an electrostatic latent image is formed on the outer peripheral surface, developing means for visualizing the electrostatic latent image as a toner image, and a transfer paper wound around the outer peripheral surface and rotated in conjunction with the photosensitive drum. A transfer drum configured to transfer the toner image on the outer peripheral surface of the photosensitive drum onto the transfer paper, and a transfer paper supply unit configured to supply the transfer paper to the transfer drum, the scanner, the photosensitive drum, and the transfer In a color copying machine that performs color copying on the transfer paper by repeatedly driving a drum, the axis that drives the transfer drum is a reference axis, and the scanner is a synchronized axis. A sensor that outputs a detection signal when the transfer drum driven by the quasi shaft is in a predetermined drive state, a time measuring unit that measures a predetermined time by receiving the detection signal, and responds to a copying instruction. And a reference axis drive means for driving the reference axis, and a synchronized axis drive means for driving the synchronized axis at the time when the time counting means finishes measuring the predetermined time. Machine.