JPH0411392B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Technical Field> The present invention relates to a control system for a page printer that performs printing operations on a page-by-page basis. More specifically, it relates to control in laser printers and LED printers that use electrophotography and use lasers or LEDs as light sources.

<Prior Art> Conventionally, in a laser printer using electrophotography, a photoconductive drum is irradiated with laser light. At this time, the laser light is controlled ON/OFF,
A potential contrast is formed on the drum photoreceptor, a coloring material called toner is attached to it, and this toner is then transferred to paper to perform printing, but due to the drum's characteristics and mechanical mechanism, continuous printing operation is not possible. is necessary.

On the other hand, in conventional serial printers, line printers, etc., once a predetermined character or line is printed, the printing operation is temporarily interrupted, and then printing is executed in response to the next print start signal, that is, printing → interruption → printing → interruption...Printing It is possible to print in a temporally discontinuous manner in printing within one page, such as → end.

Further, when the printer is caused to perform a printing operation from an external device (host computer, various data processing machines), etc., printing data is transferred to the printer side. At this time, data is transferred from the external device to the printer completely randomly in terms of time. That is, the printer cannot determine the time from the start of transfer of print data for one page to the end of transfer. Furthermore, data transferred from an external device to the printer side is transferred using a so-called "character code" in order to improve transfer efficiency. For dot printers, from this character code,
The dot pattern of the character generator (CG) prepared in advance on the printer side is accessed and converted into data in dot units.

FIG. 1 shows the configuration of the buffer memory inside the page printer and the flow of data from external equipment. Character codes are sequentially transferred from the external device 1 to the printer 2 side. This character code is sequentially stored (stored) in the character code buffer memory 3 of the printer 2. In this example, A, B...X, CR
(line feed code, 1, 2,...9, CR (line feed code),..., E, EF (code indicating the end of one page)
It will be transferred according to this procedure. code batshua 3
This character code is set in order. The control circuit inside the printer 2 refers to the CG memory 4 based on this character code, and sequentially performs writing processing to the image buffer memory 5 for storing data in units of dots. The dot data on the image buffer 5 is stored in exact one-to-one correspondence with the print screen shown in FIG. In FIG. 2, 6 indicates a printing paper, and 7 indicates a printing area.

The above are code buffer 3 and image buffer 5.
This is an explanation of the functions and data flow.

When the writing process of one page of data to the image buffer 5 is completed as described above, the printing operation of the printer 2 to obtain a hard copy is controlled from this point on. The time chart at that time is shown in Figure 3. Further, FIG. 4 is a diagram showing an outline of a printing section of a laser printer using an electrophotographic method. This printer rotates a drum-shaped photoreceptor 11 in the direction of the arrow, and after uniformly charging the surface of the photoreceptor 11 with a charger 12, ON/OFF control is performed according to data written to an image buffer 5. Laser light 13
is scanned onto the photoreceptor 11 to form a potential latent image on the photoreceptor 11 according to the data of the image buffer 5. Next, toner is attached to this image in a developing section (not shown), and the attached toner is applied to the printing position (transfer position) on the printing paper 6 that is sent via the synchronization conveyance roller 14 according to the potential image. ) is transferred by a transfer device 15 disposed opposite to each other. The paper 6 is stored in a paper feed cassette 16, and is fed one by one to the conveyance roller 14 by the action of a half-moon-shaped paper feed roller 17. The paper on which the transfer has been completed passes through the fixing section 18 while being discharged outside the machine along the conveyance path shown by the broken line.
The toner on the paper is fixed. On the other hand, the photoreceptor 11
For the next image formation, the surface of the photoreceptor is neutralized and residual toner is cleaned.

Conventional printing control in the above printer configuration will be described next. As shown in the time chart of FIG. 3, when character data is transferred to the printer 2 from the external device 1, this character data is sequentially stored in the code buffer 3 and the CG memory 4.
Writing of the character pattern to the image buffer 5 is started via the . Then, a transfer end signal b indicating that one page of character data has been transferred is sent from the external device, and the writing process to the image buffer 5 ends after _T3 hours from this point. Here, the period T1, which is the sum of the period _T2 from receiving the transfer start signal to receiving the transfer end signal and the above _{T3 ,} is the time required for data processing. Therefore, when the writing to the image buffer 5 is completed, the data processing has been completed, and if the operation of each mechanical system of the printing section of the printer 2 is started from this point, the entire printing operation will be executed normally. be done.

In other words, conventionally, the paper feed roller 1 is
7 is started, and a series of print operations are executed. Here, since the paper feeding roller 17 has insufficient feeding accuracy, in order to align the potential latent image on the photoreceptor 11 with the paper to be transported, the synchronizing transport roller 14 is inserted into the paper transport path to the transfer section. It is set up.
The conveyance path roller 14 is normally stopped, regulates the position of the leading edge of the sheet being fed, and is driven in synchronization with the rotation of the photoreceptor 11 and the like. In particular, if the formation of a latent image by irradiation of the laser beam 13 onto the photoconductor 11 and the driving of the conveyance roller 14 are performed at the same time, the distance l ₁ from the laser beam irradiation position to the photoconductor to the transfer position to the paper and the conveyance It can be seen that if the distance l ₂ from the roller 14 to the transfer position is the same, and the rotational peripheral speed of the photoreceptor 11 and the conveyance speed of the paper are the same, printing is performed sequentially from the leading edge of the paper. Therefore, the start of driving the conveyance roller 14 serves as a reference signal for starting the laser beam irradiation 13. Therefore, when the writing of the image buffer 5 is completed, the printer 2
When performing print control, the paper feed roller 17
The start of actual printing was delayed by a period T ₄ from the start of driving until the leading edge of the paper reaches the transport roller 17 and the start of driving of the transport roller 17 .
This naturally results in a reduction in printing speed.

<Purpose of the Invention> An object of the present invention is to provide a printer that prints on a page-by-page basis, which can improve the printing speed by starting actual printing from the moment data processing for one page is completed. It is said that

<Embodiment> As an example, the present invention describes the timing when the character code "A" in FIG. After the data is written, the last character "E" is developed and written in a dot pattern, and a signal indicating the end of one page is input, the data is written in the remaining storage area of the image buffer 5 on the print screen. The start control of the printing operation by the printer 2 is performed based on the timing when one page's worth of data is completely stored in the entire so-called image buffer 5 so that white is to be printed.

The present invention will be specifically explained below. The present invention will be explained using a laser printer as shown in FIG. 4 to control each mechanical system of the printing section. FIG. 5 is a time chart according to the present invention. However, the present invention is not limited to the laser printer shown in FIG. In particular, the control of the printer 2 of the present invention is such that the control circuit of the printer 2 controls the paper feed roller 17 at the timing when a signal a indicating the start of character code transfer is sent from the external device 1.
A signal e for rotationally driving the printer 2 is output, and the paper feeding operation of the printer 2 is started in advance. In this case, the conveyance roller 14 is in a stopped state, and the printing paper 6 fed by the paper feed roller 17 is in a state in which the leading edge of the printing paper 6 is sent to the contact portion of the conveyance roller 14 and accurate position regulation is performed. It is expected that

On the other hand, after the signal a indicating the start of transfer is input, the character data is sequentially transferred to the printer 2 side and sequentially stored in the character code buffer memory 3, and the dot data corresponding to the character code is sent via the CG memory 4. Pattern data is written into the image buffer memory 5. This is the same as before. When the printer 2 receives a signal b indicating the end of one page from the external device 1, after writing the final character data to the image buffer 5, post-processing, that is, the remaining part of the storage area of the image buffer 5 is performed. Processing for printing in white is executed. After this process is executed, a signal d indicating that writing for one page of the image buffer 5 has been completed.
is output. A signal f is sent to the puncher 2 to rotate the conveyance roller 14 at the timing of the signal at this time.
output from the control unit to start rotation. At the same time, irradiation of the photoreceptor 1 with the laser light 3 is started. In other words, compared to the time chart in FIG. 3, according to the present invention, the paper feeding time T ₄ by the paper feeding roller 17 for feeding the paper to the conveying roller 14 is unnecessary.
Immediately after the image buffer 5 finishes writing, actual printing is controlled. In this case, naturally the photoreceptor 11 from the laser beam irradiation position to the transfer position
If the movement distance l ₁ of the peripheral surface of the photoreceptor 11 is the same as the transport distance l ₂ of the paper from the transport roller 14 to the transfer position, and the peripheral speed of the photoreceptor 11 and the paper transport speed match, then The image is transferred from the image starting edge to the leading edge of the paper, and printing is attempted as shown in FIG.

Here, before the photoreceptor 11 is irradiated with the laser beam 13, the photoreceptor 11 is uniformly charged by a charger 12. Therefore, it is necessary to rotate the photoreceptor 11 and drive the charger 12 before starting the laser beam irradiation. As for the timing of this drive, the control circuit may drive the photoreceptor 11 and the like at the stage when the printer 2 receives the signal b indicating the end of one page's worth of character codes. In such a case, the period T ₃
Since the voltage is not constant, it is considered that the area where the photoreceptor 11 is unnecessarily charged is also not constant. However, if control is executed to discharge unnecessary charges on the photoreceptor 11 during the period from the start of rotation of the photoreceptor 11 until the start of laser light irradiation for printing character data, , photoreceptor 1 at the same time as the start of laser beam irradiation for printing character data.
1 charging area can be set.

For example, a light source that irradiates light is provided at the same position as the laser light irradiation, and the light source is driven in synchronization with the driving of the photoreceptor 11 and the charger 12, and when the laser light irradiation starts printing, the light source is activated. All you have to do is stop the drive. In this case, the light source may also be used as a laser beam for printing. In other words, without turning the laser ON/OFF using the character data written in the image buffer 5, the photoconductor 1
Laser light irradiation may be driven to discharge the charges on the charged photoreceptor 11 from the start of charging to 1 to the start of laser light irradiation according to character data. By controlling in this manner, it is possible to eliminate areas where the photoreceptor 11 is unnecessarily charged, and also to drive the photoreceptor 11 etc. in advance before starting irradiation with laser light driven according to character data. Printing can be performed normally even if the

Note that the present invention uses the image buffer 5 to perform the stamp starting operation (at the start of laser beam irradiation) by the printer 2.
This is the end point of writing character data to.
This is the time from the start to the end of character code transfer.
_T2 and the time _T3 from the end of character code transfer to the end of writing to the image buffer 5 are completely non-fixed lengths. Therefore, before the image buffer 5 finishes writing, the transport roller 1
When the drive and laser beam irradiation start in step 4 is executed, a situation occurs in which the data from the image buffer 5 must be transferred as laser drive data even though the dot data has only been written halfway into the image buffer 5. However, at this time, it becomes necessary to stop the rotation of the drum photoreceptor 11. If this happens, it is necessary to stop the paper conveyance, etc. at the same time, which makes it impossible to expect normal printing, resulting in an inconvenience. However, if the timing is controlled as in the present invention, the printing operation can be normally controlled without causing the above-mentioned problems.

<Effects of the Invention> According to the present invention, in a page printer that stores all sent data for one page and prints the data sequentially after the storage is completed, all the data for one page can be stored and processed. Since the actual printing operation of the stored data is started based on the timing when printing is performed, one page can be surely printed without any inconvenience occurring during the printing of one page.

In addition, in the paper feeding operation, before the actual printing operation starts, feeding to the specified position is executed in advance, and the printing operation is started based on the completion of storing one page. , printing speed can be improved.

Especially in printers using electrophotography,
It is possible to feed the paper to a designated position in advance and transport the paper at the designated position to the printing position (transfer position) at the same time as printing starts.

[Brief explanation of drawings]

Fig. 1 is a block diagram of data processing in the page printer according to the present invention, Fig. 2 is a diagram showing an example of printing by the page printer, Fig. 3 is a time chart showing the control timing of a conventional page printer, and Fig. 4 is a diagram showing a printing example by the page printer. FIG. 5 is a cross-sectional view showing an outline of the printing unit of the page printer of the present invention, and a time chart showing the control timing of the page printer of the present invention. 1: External device, 2: Page printer, 3: Character code buffer (memory), 4: Character generator (CG) memory, 5: Image buffer (memory), 6: Print paper, 11: Photoreceptor, 12:
Charger, 13: Laser light irradiation, 14: Conveyance roller, 15: Transfer device, 17: Paper feed roller.

Claims (1)

[Claims] 1. By storing print data for one page,
A page printer that starts printing operation, and when printing starts, the printing paper is fed to a specified position located in front of printing, and after it is temporarily stopped at that position, it is fed to the above specified position in synchronization with print control. In a page printer that prints the print data for the above-mentioned one page on the paper by transporting the paper stopped at a feeding means that feeds the printing paper to a specified position at a first timing of the time, and a printing operation that starts a printing operation at a second timing of storing the last print data for storing the print data of the one page. 1. A page printer comprising: a printing control means that performs the following operations; and a conveyance drive means that starts conveyance of the printing paper located at the specified position based on the timing at which the printing operation is started by the print control means. 2 The page printer uses an electrophotographic method, and when printing starts, the storage medium is irradiated with optical information driven according to print data to form an image, and the image is transferred to the print position to print the image. 2. The page printer according to claim 1, wherein the page printer transfers data onto paper. 3. The distance from the light irradiation position to the printing position is the same as the distance from the specified position to the printing position, and the transport driving means transports the printing paper in synchronization with the second timing. Page printer as described in section.