Claims
- 1. A color printer, for use with color image data generating means which sequentially generates color image data corresponding to different colors of a multi-color image, for printing the multi-color image on a recording medium, said color printer comprising:
- a photo-sensitive body adapted to circulate in response to a print request signal from the color image data generating means;
- electrostatic latent image forming means for forming on said circulating photo-sensitive body an electrostatic latent image of color image data received from the color image data generating means and corresponding to a respective color of the multi-color image;
- developing means for developing the electrostatic latent image formed on said photo-sensitive body to form thereon a one-color toner image of the received color image data;
- conveying means for circulating a recording medium in synchronism with the circulating photo-sensitive body for transfer to the recording medium of the one-color toner image on said circulating photo-sensitive body; and
- image data request signal generation means for sequentially generating and applying image data request signals to the image data generating means, to request generation of color image data corresponding to a respective color of the multi-color image, said image data request signal generation means including:
- (a) image data request reference signal generating means responsive to the print request signal for generating an image data request reference signal;
- (b) clock means for generating a clock signal;
- (c) passage detecting means, responsive to each passage of a particular portion of said conveying means through a predetermined position during circulation of the recording medium, for generating passage detection signals;
- (d) first measuring means, response to the clock signal and to each passage detection signal, for measuring each respective circulation period of the recording medium on said conveying means between successive passage detection signals and for providing an output signal indicative thereof;
- (e) second measuring means, responsive to the clock signal and each output signal from said first measuring means, for controlling a synchronization interval for each respective image data request signal, each synchronization interval having a duration determined by the respective circulation period measured by said first measuring means, said second measuring means being responsive to termination of the synchronization interval for initiating a subsequent synchronization interval; and
- (f) means for generating a first image data request signal in response to the image data request reference signal and for generating a subsequent image data request signal in response to termination of the synchronization interval, so that the application to the image data generating means of each image data request signal subsequent to said first image data request signal occurs at a time synchronizing the circulation of said photo-sensitive body having the developed electrostatic image thereon with the circulation of the recording medium on said conveying means to cause sequential transfer of color toner images to the recording medium in registry to form a multi-color image on the recording medium.
- 2. A color printer according to claim 1, wherein said conveying means comprises two oppositely positioned rollers and an endless conveyer belt positioned around said rollers.
- 3. A color printer according to claim 2, wherein said position detecting means comprises light reflecting means disposed on said conveyer belt and a reflection type interrupter for projecting light to said light reflecting means and detecting reflected light.
- 4. A color printer according to claim 2, wherein said position detecting means comprises a slit formed in said conveyer belt and a transmission type interrupter disposed opposite said slit.
- 5. A color printer according to claim 1, wherein said photo-sensitive body comprises a photo-sensitive drum, and said conveying means comprises a transferring drum rotated in contact with said photo-sensitive drum.
- 6. A color printer according to claim 5, wherein said position detecting means comprises a reflection type interrupter disposed for detecting the front edge of the recording medium conveyed by said transferring drum.
- 7. A color printer, for use with color image data generating means which sequentially generates color image data corresponding to different colors of a multi-color image, for printing the multi-color image on a recording medium, said color printer comprising:
- a photo-sensitive body adapted to circulate in response to a print request signal from the color image data generating means;
- electrostatic latent image forming means for forming on said circulating photo-sensitive body an electrostatic latent image of color image data received from the color image data generating means and corresponding to one color of the multi-color image;
- developing means for developing the electrostatic latent image formed on said photo-sensitive body to form thereon a one-color toner image of the received color image data;
- conveying means for circulating a recording medium in synchronism with the circulating photo-sensitive body for transfer to the recording medium of the one-color toner image on said circulating photo-sensitive body; and
- image data request signal generation means for sequentially generating and applying image data request signals to the image data generating means, to request generation of color image data corresponding to a respective color of the multi-color image, said image data request signal generation means including:
- (a) image data request reference signal generating means responsive to the print request signal for generating an image data request reference signal;
- (b) clock means for generating a clock signal;
- (c) passage detecting means, responsive to each passage of a particular portion of said conveying means through a predetermined position during circulation of the recording medium, for generating passage detection signals;
- (d) first measuring means responsive to the clock signal and to each passage detection signal, for measuring each respective circulation period of the recording medium on said conveying means between successive passage detection signals;
- (e) second measuring means responsive to the clock signal for controlling a synchronization interval for the image data request signals, each synchronization interval having a duration determined by the circulation period measured by said first measuring means just prior to initiation of that synchronization interval, said second measuring means being responsive to termination of the synchronization interval for initiating a subsequent synchronization interval; and
- (f) means for generating a first image data request signal in response to the image data request reference signal and for generating a subsequent image data request signal in response to termination of the synchronization interval, so that the application to the image data generating means of each image data request signal subsequent to said first image data request signal occurs at a time synchronizing the circulation of said photo-sensitive body having the developed electrostatic image thereon with the circulation of the recording medium on said conveying means to cause sequential transfer of color toner images to the recording medium in registry to form a multi-color image on the recording medium.
- 8. A color printer according to claim 7, wherein:
- said first measuring means comprises a resettable up-counter for counting up the clock signals, delay means responsive to the passage detection signal for resetting said up-counter at a predetermined time after the passage detection signal, and latch means responsive to each passage detection signal for latching the count value of said up-counter as a measurement of the circulation period; and
- said second measuring means comprises a down-counter responsive to the clock signal for counting down to zero from the count value in said latch means at the termination of a synchronization interval, to terminate the synchronization interval.
- 9. A color printer according to claim 8, wherein said clock means generates the clock signal at a horizontal-sync frequency.
- 10. A color printer, for use with color image data generating means which sequentially generates color image data corresponding to different colors of a multi-color image, for printing the multi-color image on a recording medium, said color printer comprising:
- a photo-sensitive body adapted to circulate in response to a print request signal from the color image data generating means;
- electrostatic latent image forming means for forming on said circulating photo-sensitive body an electrostatic latent image of color image data received from the color image data generating means and corresponding to one color of the multi-color image;
- developing means for developing the electrostatic latent image formed on said photo-sensitive body to form thereon a one-color toner image of the received color image data;
- conveying means for circulating a recording medium in synchronism with the circulating photo-sensitive body for transfer to the recording medium of the one-color toner image on said circulating photo-sensitive body; and
- image data request signal generation means for sequentially generating and applying image data request signals to the image data generating means, to request generation of color image data corresponding to a respective color of the multi-color image, said image data request signal generation means including:
- (a) image data request reference signal generating means responsive to the print request signal for generating an image data request reference signal;
- (b) clock means for generating a clock signal;
- (c) passage detecting means, responsive to each passage of a particular portion of said conveying means through a predetermined position during circulation of the recording medium, for generating passage detecting signals;
- (d) first measuring means responsive to the clock signal and to each passage detection signal, for measuring each respective circulation period of the recording medium on said conveying means between successive passage detection signals;
- (e) second measuring means responsive to the clock signal for controlling a synchronization interval for the image data request signals, each synchronization interval having a duration determined by the circulation period being measured by said first measuring means when that synchronization interval is initiated, said second measuring means being responsive to termination of the synchronization interval for initiating a subsequent synchronization interval; and
- (f) means for generating a first image data request signal in response to the image data request reference signal and for generating a subsequent image data request signal in response to termination of the synchronization interval, so that the application to the image data generating means of each image data request signal subsequent to said first image data request signal occurs at a time synchronizing the circulation of said photo-sensitive body having the developed electrostatic image thereon with the circulation of the recording medium on said conveying means to cause sequential transfer of color toner images to the recording medium in registry to form a multi-color image on the recording medium.
- 11. A color printer according to claim 10 wherein:
- said first measuring means comprises a first resettable up-counter for counting up the clock signals, delay means responsive to the passage detection signal for resetting said first resettable up-counter at a predetermined time after the passage detection signal, and latch means responsive to each passage detection signal for latching the count value of said first resettable up-counter as a measurement of the circulation period; and
- said second measuring means comprises a second resettable up-counter for counting up the clock signals, means responsive to termination of a synchronization interval for resetting said second resettable up-counter, and a comparator for terminating the synchronization interval when the count value in said latch means is equal to or less than the count value in said second resettable up-counter.
- 12. A color printer according to claim 11, wherein said clock means generates the clock signal at a horizontal-sync frequency.
Priority Claims (1)
Number |
Date |
Country |
Kind |
1-287923 |
Nov 1989 |
JPX |
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Parent Case Info
This application is a continuation of application Ser. No. 07/608,470, filed Nov. 2, 1990, now abandoned.
US Referenced Citations (14)
Foreign Referenced Citations (3)
Number |
Date |
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62-195687 |
Aug 1987 |
JPX |
63-155147 |
Oct 1988 |
JPX |
0142678 |
Jun 1989 |
JPX |
Continuations (1)
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Number |
Date |
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Parent |
608470 |
Nov 1990 |
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