JPH05219320A - Scanner and printer - Google Patents

Abstract

PURPOSE:To obtain the scanner and printer in which a simple copy function is added to a laser printer. CONSTITUTION:A close contact nonmagnification sensor 24 reads a picture of an original with a write synchronization clock signal WCLK and outputs the result as picture data. A multi-value/binary conversion circuit 31 converts the multi-value picture data into binary picture data by using the write synchronization clock signal WCLK. The binarized picture data are fetched by a 2-line buffer 32 by using the write synchronization clock signal WCLK and stored tentatively by an input line buffer 32a and the data are given to an output line buffer 32b with a toggle signal T being a main scanning direction synchronizing signal, inverse of LSYNC, and the picture data are outputted to a laser printer as write data by using the write synchronization clock signal WCLK from the output line buffer 32b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanner printer device in which a copy function and a scanner function are easily added to a laser printer without impairing its structure and function.

[0002]

2. Description of the Related Art A conventional multi-function digital copying machine has a function as a laser printer in addition to a copy function.
Data sent from a higher-level device such as a computer or a word processor can be printed out by a laser scanning method.

[0003]

However, since the above-mentioned digital copying machine is mainly a copying machine, it is required to have a high level of image quality and editing functions. Therefore, at least one page of images can be obtained. A memory with a capacity that can be fully taken in is required, and its peripheral circuits must be controlled at independent timings, which makes the control complicated. The present invention has been made in view of the above problems, and an object thereof is to provide a laser printer with a simple copy function.

[0004]

In order to achieve the above object, the present invention provides a laser printer with a contact image sensor for reading an image of a document, converting it into a signal, and outputting the image data as image data. A data conversion circuit for binarizing image data from multiple values, an input line buffer for temporarily storing the binarized image data by the circuit, and an output for writing the image data in the buffer as write data. (EN) A scanner-printer device in which a two-line buffer consisting of an output line buffer is added and each of the above-mentioned added parts is operated in synchronization with the operation of a laser printer.

When the laser printer is a laser printer which does not modulate the frequency of the write synchronization clock signal, the contact image sensor is activated by the main scanning direction synchronizing signal of the laser printer for each line in the main scanning direction. It suffices to drive each of the added units in synchronization with the write synchronization clock signal for each pixel.

If the laser printer is a laser printer that modulates the frequency of the write synchronization clock signal, the contact image sensor is activated by the main scanning direction synchronization signal of the laser printer for each line in the main scanning direction. The contact image sensor, the data conversion circuit, and the input line buffer side of the two-line buffer are clock signals without frequency fluctuations synchronized with the write synchronization clock signal, and the output line buffer side of the two-line buffer is the write synchronization clock signal. 1
It suffices to drive each pixel in synchronization.

Further, a delay circuit for delaying the sub-scanning direction write permission signal of the laser printer by one line and the output of the output line buffer of the two-line buffer are logically ANDed with the output of the delay circuit. An AND circuit for outputting as write data may be provided.

[0008]

In the scanner printer device of the present invention, each part of the added contact image sensor, data conversion circuit, and two-line buffer is operated in synchronization with the operation of the laser printer.

As a result, the contact image sensor reads the image of the original and outputs it as image data, and the data conversion circuit binarizes the image data from multiple values. The 2-line buffer takes in the binarized image data,
After temporarily storing it in the input line buffer, it is passed to the output line buffer, the image data is output from the output line buffer as write data to the laser printer, and thereafter, the capture and the output are alternately performed to display one page of the image. Is printed out.

When the laser printer is a laser printer which does not modulate the frequency of the write synchronization clock signal, the contact type image sensor is activated by the main scanning direction synchronizing signal of the laser printer for each line in the main scanning direction. By driving each of the added units in synchronization with the write synchronization clock signal for each pixel, a very inexpensive scanner printer device can be provided without requiring a special timing circuit.

When the laser printer is a laser printer which modulates the frequency of the write synchronization clock signal, the contact image sensor is activated by the main scanning direction synchronization signal of the laser printer for each line in the main scanning direction. The contact image sensor, the data conversion circuit, and the input line buffer side of the two-line buffer are clock signals without frequency fluctuations synchronized with the write synchronization clock signal, and the output line buffer side of the two-line buffer is the write synchronization clock signal. 1
By driving in synchronization with each pixel, stable image data can be captured.

Further, the subscanning direction write enable signal of the laser printer is delayed by one line, and the write data is obtained by taking the logical product of the image data output from the output line buffer side of the two line buffer and the delayed signal. It is very effective to output as.

Since the scanner printer uses a two-line buffer, invalid data is contained in the output line buffer of the two-line buffer at the start of reading the original (reading the first line), and the last of the original is read. The line data is taken into the input line buffer and then transferred to the output line buffer at the next timing.

That is, since one line of timing is required to transfer the image data from the input line buffer to the output line buffer, invalid data is output from the output line buffer as the first line of image data as it is, and the final data is output. Writing may end with the image data of the line left. Therefore, as described above, by logically ANDing the image data output from the output line buffer side of the two-line buffer and the delayed signal and outputting the logical product as the write data, the above problems can be reliably prevented. it can.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be specifically described below with reference to the drawings. FIG. 2 is a schematic configuration diagram showing the internal mechanism of the scanner / printer apparatus embodying the present invention. The scanner printer device includes a laser printer body 1 and a scanner unit 20.

The laser printer body 1 is composed of an upper structure 1a and a lower structure 1b, and the upper structure 1a is attached to the lower structure 1b by a shaft 2 so as to be openable and closable. Further, in the figure of the upper structure 1a, the paper feed cassette 3 is detachably provided on the right side and the paper discharge tray 4 is provided on the left side. As the paper feed cassette 3, various paper feed cassettes containing various transfer papers (papers) of different sizes can be used.

A belt-shaped photosensitive member 5 is provided substantially in the center of the printer body 1, and a charging charger 6, a developing unit 7, a transfer charger 8 and a cleaning device are arranged around the photosensitive member 5 in the order indicated by the arrow (rotating direction). The electrophotographic process equipment excluding the laser writing unit of the unit 9 is arranged, the laser writing unit 10 is below them and the heater 11 is above.
Fixing units 11 each including a heat roller (fixing roller) 11a having a built-in c and a pressure roller 11b are provided.

Further, in the printer body 1, a paper feed section including a paper feed roller 12 and a registration roller pair 13 is provided.
Transport guide plate 14, paper discharge roller 15, and paper discharge guide plate 1
6 and a paper discharge unit composed of 6. Scanner unit 2
Reference numeral 0 includes a document tray 21, a document feeding roller 22, a platen roller 23, a contact type equal-magnification sensor (contact type image sensor) 24, a document discharging roller 25, and a stepping motor 26.

When a print sequence is started by a command from a host system such as a word processor or a computer, the paper feed roller 12 causes the paper feed cassette 3 to start.
The transfer paper is started to be fed from, and then the transfer paper is conveyed to the upper side of the photoconductor 5 by the registration roller pair 13 at a timing. The photoconductor 5 rotates in the direction of the arrow, and at that time, the surface uniformly charged by the charging charger 6 is exposed to laser light modulated by the laser writing unit 10 according to the image information signal (writing data). Irradiation is performed while performing main scanning in the body width direction to form an electrostatic latent image. At this time, the sub-scan is performed by the rotation of the photoconductor 3.

When the toner passes through the developing unit 7, it is visualized by adhering toner, and after being transferred by the transfer charger 8 to the lower surface of the transfer paper conveyed to the upper side of the photoconductor 5, it is guided to the conveyance guide plate 14. Then, the toner image is fed between the heat roller 11a and the pressure roller 11b in the fixing unit 11, and the toner image is fixed there by the heat of the heater 11c. Then, the transfer paper that has exited the fixing unit 11 is discharged by the paper discharge roller 15, whereby the paper discharge guide plate 16
And is stacked on the discharge tray 4.

On the other hand, when a document for image reading is placed on the document tray 21 and a copy start command is given by a switch or the like, the stepping motor 26 is turned on, and the document feeding roller 22, the platen roller 23, and The paper discharge roller 25 is driven to rotate. As a result, the document on the document tray 21 is fed into the scanner section 20 by the document feeding roller 22, and the fed document is conveyed while being pressed against the surface of the contact type equal-magnification sensor 24 by the platen roller 23. It

At this time, the contact type equal-magnification sensor 24 reads the original image (image information) line by line, converts it into a digital multivalued signal, and outputs it as image data to the printer body 1. The document whose image has been read by the contact-type equal-magnification sensor 24 is discharged to the outside by the document discharge roller 25. The stepping motor 26 is used for the document tray 2
So that the original placed on the first sheet is conveyed at the same speed as the transfer sheet conveying the printer body 1.
2. The platen roller 23 and the document discharge roller 25 are driven.

The printer body 1 is equipped with a control board including a conventional printer control circuit for controlling the above-mentioned operations and a scanner control circuit described later. Of which
The printer control circuit has a sub-scanning direction write enable signal / FGATE ("/" indicates negative logic), a main scanning direction synchronizing signal / LSYNC, and a writing synchronizing clock signal WCLK as signals used during a printing operation. The timing relationship is as shown in FIG.

That is, the printing operation on the transfer sheet is permitted while the sub-scanning direction write enable signal / FGATE is at the low level "L", and the printing operation in each main scanning direction is performed by the main scanning direction synchronizing signal / LSYNC. It is performed in synchronization with the write synchronization clock signal WCLK from the time of becoming "L" until the time of becoming "L" again next time. Therefore, the binary data / WDATA that is the write data is
The signal is transmitted between the circuits in the control unit in synchronization with the write synchronization clock signal WCLK from the time when the main scanning direction synchronization signal / LSYNC becomes "L" until the time when it again becomes "L".

The multi-valued signal image data output from the contact-type unity-magnification sensor 24 in the scanner unit 20 is
Binary data / WDAT via the scanner control circuit described later
It is transferred to the printer control circuit as A. The printer control circuit prints out the delivered binary data / WDATA on the transfer paper by the above-mentioned printing operation. In this embodiment, the operations of feeding, reading, and discharging a document by the scanner unit 20 are performed in synchronization with the feeding, printing, and discharging of the transfer sheet of the laser printer body 1 to read and transfer the original image. Printing on paper is performed in real time. The details will be described below.

FIG. 1 is a block diagram of the main part of this scanner control circuit. In this scanner control circuit, when the start signal S1 is input to the contact type equal-magnification sensor 24 (when the main scanning direction synchronization signal / LSYNC becomes "L"), the synchronization clock signal SCLK (write synchronization clock signal W
The image information is converted into a digital multilevel signal (multilevel data) in synchronization with CLK) and transferred to the multilevel / binary conversion circuit 31.

The multi-value / binary conversion circuit 31 converts the multi-valued data from the contact-type unity-magnification sensor 24 into the synchronization clock signal SCLK.
In synchronism with the above, it is compared with a preset threshold value and converted into a digital binary signal (binary data). Reference numeral 32 is a two-line buffer, which outputs an input line buffer 32a for temporarily storing the binary data converted by the multi-value / binary conversion circuit 31 and the binary data in the buffer as write data. For output line buffer 32b.

An input clock signal INCLK (write synchronization clock signal WCLK) and an output clock signal OUTCLK (write synchronization clock signal WC) are input to the input line buffer 32a and output from the output line buffer 32b, respectively.
LK). Also, from the input line buffer 32a to the output line buffer 32b
The internal switching of the data to (1) is performed by a toggle signal T (main scanning direction synchronizing signal / LSYNC). That is, the two captured in the input line buffer 32a
The value data is transferred to the output line buffer 32b by the toggle signal T, and the output clock signal O
The timing is adjusted again by UTCLK and the data is output.

A signal selection circuit 33 selects and outputs either the binary data / WDATA from the printer control circuit or the binary data from the output line buffer 32b. That is, the binary data / WDATA from the printer control circuit is selected and output during the normal printing operation and returned to the printer control circuit as it is, but the binary data from the output line buffer 32b is selected and output during the copy operation. , Binary data in printer control circuit
Output as WDATA.

As described above, according to this embodiment, the contact type magnification sensor 24 is activated by the start signal S1 which is the main scanning direction synchronizing signal / LSYNC for each line in the main scanning direction, and the write synchronizing clock signal WCLK is generated. The image of the original is read by the synchronous clock signal SCLK, which is output as image data, and the image data is multivalued / 2.
The value conversion circuit 31 binarizes the multivalued image data by the synchronous clock signal SCLK, and the two-line buffer 32 captures the binary image data by the input clock signal INCLK which is the write synchronous clock signal WCLK and temporarily stores it in the input line buffer 32a. The image data is stored and passed to the output line buffer 32b by the toggle signal T which is the main scanning direction synchronization signal / LSYNC, and the image data is output from the output line buffer 32b as the write data by the output clock signal OUTCLK which is the write synchronization clock signal WCLK. An image for one page can be printed out by outputting the image to the printer control circuit of the printer and then alternately taking in and outputting the image. Therefore, in this embodiment, a special timing circuit is unnecessary, and a very inexpensive scanner / printer device can be provided.

FIG. 4 is a block diagram of a main part of a scanner control circuit according to another embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals. This scanner control circuit is used in a scanner printer device using a laser printer in which the frequency of the write synchronization clock signal WCLK is modulated. In this scanner control circuit, a clock circuit 34 outputs a clock signal having no frequency fluctuation.

Reference numeral 35 is a timing circuit, which applies the clock signal from the clock circuit 34 to the main scanning direction synchronizing signal / LS.
The clock signal ICLK is output in synchronization with the write synchronization clock signal WCLK at the YNC timing. That is, as shown in FIG. 3, the change of the main scanning direction synchronization signal / LSYNC is caused by the write synchronization clock signal WCL.
Since it is performed in synchronization with the fall of K, the synchronization clock signal WCLK and the clock signal from the clock circuit 34 can be synchronized with each other by using the main scanning direction synchronization signal / LSYNC as a trigger.

When a laser printer with frequency modulation is used, the frequency of the write synchronization clock signal WCLK in each line changes, so that the synchronization clock signal WCLK is used as it is for image input timing as in the above-described embodiment. Then, the image data may become unstable. Further, in order to input and output images in real time, it is necessary to synchronize the asynchronous synchronous clock signal WCLK and the clock signal from the clock circuit 34 with the beginning of each line. From that time to the beginning of the next line, each timing may be unique.

Therefore, in this embodiment, the main scanning direction synchronizing signal / LSYNC from the printer control circuit is used for the start signal S1 and the toggle signal T, and the synchronizing clock signal SCLK and the input clock signal IN are used.
A stable clock signal ICLK that is synchronized with the write synchronization clock signal WCLK at the beginning of each line by the main scanning direction synchronization signal / LSYNC is used for CLK, and a write synchronization clock signal WCLK is used for the output clock signal OUTCLK. Therefore, stable image data can be captured.

FIG. 5 is a block diagram of a main part of a scanner control circuit according to still another embodiment of the present invention. The same parts as those in FIG. 4 are designated by the same reference numerals. Reference numeral 36 denotes a timing circuit, which has the same function as the timing circuit 35 shown in FIG.
It has a function of outputting a signal / VGATE which is obtained by delaying ATE by one main scanning direction synchronization signal / LSYNC.

Here, in the scanner / printer apparatus of each of the above-described embodiments, the 2-line buffer 32 is used without adopting a means of collectively fetching one page of image data into a memory and editing it to fetch only valid data. Since the image data is input / output in real time, invalid data is stored in the output line buffer 32b when the first line of the original image is read, and the data of the final line is captured in the input line buffer 32a. Then, the main scanning direction synchronization signal / LSYNC is transferred to the output line buffer 32b at the timing when it becomes "L" next, so that invalid data is output from the output line buffer 32b as the image data of the first line, and Scan direction write enable signal / FG
There is a possibility that the image data of the final line may remain in the output line buffer 32b when ATE becomes "H".

Therefore, in this embodiment, the subscanning direction write enable signal / FGATE sent from the printer control circuit by the timing circuit 36 is delayed by one main scanning direction synchronizing signal / LSYNC / VGATE.
And the image data from the output line buffer 32b are input to the AND gate 37, and the AND operation is performed there and output, thereby deleting the first invalid data and validating the final image data.

Further, the signal / VGATE and the subscanning direction write enable signal / FG sent from the printer control circuit.
By inputting ATE and OR gate 38 to the negative logic OR gate 38 and taking the logical sum, the signal / VGATE becomes "H" after the sub-scanning direction write enable signal / FGATE becomes "L" as shown in FIG. The output of the OR gate 38 becomes "L" until it becomes, and it is sent back to the printer control circuit as the sub-scanning direction write enable signal / FGATE, so that the image data of the final line is validated and the print output can be performed. To do so.

The subscanning direction write enable signal / FGATE output from the OR gate 38 is applied to the OR gate 3
8 sub-scanning direction write enable signal / FGAT
Although it becomes "L" from the time when E becomes "L", since the first invalid data is gated by the AND gate 37, it is not output as the binary data / WDATA for writing (white data is printed. Not output).

[0040]

As described above, according to the scanner printer device of the present invention, the internal timing of the laser printer is used as it is without damaging the control circuit of the conventional laser printer, and a simple two-line buffer is used. As a result, since the copy function is added to the conventional laser printer, the conventional laser printer can be easily converted into a scanner printer at low cost. Moreover, in this apparatus, copying can be performed without going through a host computer.

Further, according to the scanner printer device of the second aspect, the timing from the reading of the image data to the passing of the write data to the printer control circuit is performed by the timing signals of the main scanning direction synchronizing signal and the writing synchronizing clock signal. Copying can be realized with a simple additional circuit configuration.

Further, according to the scanner printer device of the third aspect, the process from the reading of the image data to the input to the input line buffer side of the 2-line buffer is performed by the newly generated clock signal having no frequency fluctuation,
Output of 2 line buffer Data is transferred from the output of the line buffer to the printer control circuit by the write synchronization clock signal, so stable image data can be input and stable write data can be input even in a write frequency modulation type laser printer. Can be output.

Further, according to the scanner printer device of the fourth aspect, the writing data is delivered with a delay of one line from the start of reading the image data to the output of the output line buffer of the two-line buffer from the end of the reading. Since the permission is permitted, it is possible to delete the invalid data of the first line at the start of writing, validate the image data of the last line at the end of writing, and copy the set valid image area.

[Brief description of drawings]

FIG. 1 is a block diagram of a main part of a scanner control circuit of the scanner printer apparatus of FIG.

FIG. 2 is a schematic configuration diagram showing an internal mechanism of a scanner / printer device according to an embodiment of the present invention.

FIG. 3 is a timing chart showing the relationship of each signal existing in the printer control circuit of the scanner printer apparatus of FIG. 2 according to the present invention.

FIG. 4 is a block diagram of a main part of a scanner control circuit according to another embodiment of the present invention.

FIG. 5 is a block diagram of a main part of a scanner control circuit according to still another embodiment of the present invention.

FIG. 6 is a timing chart for explaining the operation of the scanner control circuit of FIG.

[Explanation of symbols]

20 Scanner Part 21 Document Tray 22 Document Feeding Roller 23 Platen Roller 24 Contact Type Equal Size Sensor 25 Document Ejection Roller 26 Stepping Motor 31 Multi-value / Binary Conversion Circuit 32 2 Line Buffer 32a Input Line Buffer 32b Outline Buffer 33 Signal Selection Circuit 34 Clock circuit 35, 36 Timing circuit 37 AND gate 38 Negative logic OR
Gate

Claims (4)

[Claims] 1. A laser printer, a contact type image sensor for reading an image of an original, converting it into a signal and outputting it as image data, and a data conversion circuit for binarizing the image data output from the sensor from multi-valued to binary. An input line buffer for temporarily storing the image data binarized by the circuit and a two-line buffer including an output line buffer for outputting the image data in the buffer as write data are added, and the laser is added. A scanner-printer device, wherein each of the added units is operated in synchronization with the operation of the printer. 2. The scanner printer apparatus according to claim 1, wherein the laser printer is a laser printer that does not modulate the frequency of a write synchronization clock signal, and the contact-type image sensor is provided for each line in the main scanning direction. A laser printer characterized in that the laser printer is activated by a main scanning direction synchronization signal and is driven in synchronization with the write synchronization clock signal on a pixel-by-pixel basis. 3. The scanner printer device according to claim 1, wherein the laser printer is a laser printer that modulates a frequency of a write synchronization clock signal, and the contact image sensor is provided for each line in the main scanning direction. The 2-line buffer is activated by a main scanning direction synchronization signal, and the contact type image sensor, the data conversion circuit, and the input line buffer side of the 2-line buffer are synchronized with the write synchronization clock signal to a clock signal having no frequency fluctuation. Output line buffer side of the write synchronization clock signal,
A scanner printer device characterized in that each pixel is driven in synchronization. 4. The scanner printer apparatus according to claim 1, wherein a delay circuit delays the subscanning direction write enable signal of the laser printer by one line, and an output line buffer of the two line buffer. A scanner-printer device, comprising: a logical product circuit for taking a logical product of the image data output from the side and the output of the delay circuit and outputting the logical product as write data.