JPH0323963A - Printer - Google Patents

Abstract

PURPOSE:To ensure that an image is freely written or deleted on the surface of a sheet without damaging the image by printing the image on the rear of the sheet, if the sheet is transparent or translucent. CONSTITUTION:A paper type sensor 1 is a photointerrupter consisting of a combination of a light-emitting diode 27 and photosensor 28, and the sensor 1 is provided at a paper cassette mounting part of a device enclosure 31. A transparent or translucent sheet such as OHP sheet 29 is loaded in a paper cassette 30. Light enters the photosensor 28 from a light-emitting diode 27 after being transmitted through the sheet 29 and the type of paper is identified. If even a single translucent paper is present in the paper cassette 30, an image cannot be printed on the rear of the sheet as the light is prevented from reaching the photosensor 28. Therefore, the light-emitting diode 27 and photosensor 28 are provided at a halfway position between the paper cassette 30 and a printing part 32. The transparent or translucent sheet can be used as OHP sheet by printing an image with the right and left reversed on the rear of the sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printing device, and particularly to a transparent or translucent printing device that is designed to be illuminated and projected from the back side, such as an OHP sheet. It relates to an improved method for printing on media.

[Prior Art] Generally, printing devices print on opaque paper, but in some cases transparent IJ such as OHP stickers
J also sometimes prints on the almost semi-transparent body of JJ.

Further, conventional printing devices are not provided with a -f stage for detecting paper persimmons, and print in a graphical manner regardless of the type of paper.

E Problems to be Solved by the Invention j By the way, when printing on an OHP sheet or the like and actually projecting it with a projector or the like, writing may be written on sheets 1 and 7 with a pen. In this case, if you later try to erase the writing, since the printing and the writing are on the same surface, you may end up erasing or scratching the printed information as well.

In the present invention, when the sheet to be printed is transparent or translucent, by printing the image to be printed on the back side of the sheet, it is possible to freely write on the surface of the sheet and erase it without damaging the printed image. The purpose of the present invention is to capture and provide a printing device that uses the following methods.

[Means for Solving the Problems] The present invention provides a printing device capable of printing on a transparent or translucent sheet, including an identification means for identifying that printing paper is a transparent or translucent sheet, and a pattern to be printed on the sheet. A memory for temporarily storing information, and an address control means for incrementing or decrementing each line according to the paper type identified by the identification means when generating a video signal based on the pattern information from this memory. and bit 1 control means for transposing the transfer word block σ of the video signal from the most significant bit 1 to the lowest bin 1 when the address control means decrements each line. do.

[Function] In wooden inventions, for transparent or translucent sheets,
By printing the printing pattern as a mirror image on the back side of Sheet 1, it is possible to use this Sheet 1 as an OHP sheet, etc., without any problems, and without damaging the printed image on Sheet 1. , writing and erasing can be performed freely on the sheet surface.

[Example] FIG. 1 is a block diagram showing one embodiment of the present invention.

This embodiment device includes a paper type sensor 1, a buffer 3, a control section 5, a bitmap memory 6, a DMA controller 1/roller (DMAC) 10, a flip-flop 16, a counter 17, and a register 22. , a selector 23 , a shift 1 register 25 , an address bus 27 , and a data bus 28 .

The control unit 5 outputs a sense signal 4 for enabling the buffer 3, a chip select signal 7 for the bitmap memory 6, a write signal 8, and a read signal 9.

The control unit 5 also sends a hold acknowledge signal 12 and address increment 1 to the DMAC 10.
/signal l3 for setting decrement.

On the other hand, DMACIO outputs a hold signal l1 to the control unit 5. Further, the DMAC 10 supplies the register 22 with a clock 21 that causes the register 22 to latch the video transfer data.

In addition, a beam detect signal 14 is supplied from a printer engine section (not shown) to a flip-flop l6 via an inverter 2, and a video signal transfer clock (VDCK) is supplied to the flip-flop l6, counter l7, and shift register 25. )15 are supplied.

Counter l7 counts the number of VDCK clocks 15 and generates a carry signal 19 every time l6 clocks are counted. The flip-flop l6 outputs an enable signal l8 to the counter 17, and the DMAC10 outputs a terminal count signal 20 generated when the video signal for one scan is transferred to each clear terminal of the flip-flop l6 and the counter 17. supply

The selector 23 selects whether or not the order of the data in the register 22 from MSB (bit 15) to LSB (bit O) is to be changed or not.

The shift register 25 sends out the output of the selector 23 as a video signal 26 in synchronization with the video clock 15.

FIGS. 2(a) and 2(b) are schematic diagrams showing the printing method in the apparatus of this embodiment.

As shown in FIG. 2(a), when the dot pattern developed on the bitmap memory 6 is printed on the surface of paper, the dot pattern is sequentially video-transferred line by line starting from the one with the smallest relative address. However, when printing on the back side, it is necessary to decrement 1 from the larger address to the smaller address on one line, and to sequentially arrange the data bits 1 on the video transfer screen, as shown in Figure 2 (b). It is transferred in reverse.

As a result, the actual printing is reversed in the left-right direction from the leading edge of the paper, resulting in a mirror image compared to normal printing.

FIG. 3 is a timing chart explaining this printing operation. Note that the subscript of each signal indicates that it is a negative logic signal.

At T1 in the figure, the select signal (SEL) is set to "L" based on the input result of the paper type sensor 1. At this time, the control unit 5 decrements the address counter for DMAC 1 0 (that is, sets the U/D signal J= to “L”).
) has been set. At the rising edge of VDCK of T2, BD
．． When the signal is set to the flip-flop 16, the enable signal (HENB) 18 of the counter 17 is set to "TRU".
E”. Next rise of VDCK15 (T3)
starts transmitting video signals. At this time, at least T3
It goes without saying that the data to be sent previously has been set in the register 22.

After this, while transmitting the contents of the register 22 of l word (16 bits 1.), the carry signal (DREQ) 19 of the counter l7 becomes "TRUE" at the rising edge of the clock T4.
become. As a result, DMACIO sends a hold signal (HOLD) to the control unit 5, which is a request to open the bus.
11, and as soon as the control unit 5 is ready, it sets the hold acknowledge signal (HOLDA.) 12 to "' TRUE.
''' and open the bus to the DMAC 10 side.

When the bus is opened, DMACIO outputs the address of the bitmap, and latches the output data into the register 22 using the register launch signal (DACK) k: at T5. Then DREQ. Since the signal 19 becomes "FALSE", the HOLD◆ signal l1 from DMACIO becomes "FALSE", and therefore, the HOLD◆ signal l1 from DMACIO becomes "FALSE".
The OLDA signal 12 becomes "FALSE'". Also, it is clear that by then the DMAC 10 has put the address bus 27 and data path 28 into high interrupter dance. 16 latched in register 22 after T6
Bit 1. is output in synchronization with VDCK15, and each time these processes are repeated, one scan is sent to the printer engine.

Although not shown in FIG. 3, when the l-scan video signal is sent out, the terminal output un1. Clear.

This is done by using the carry signal 19 from the counter 17 after the DMAC 10 sets the number of words for l scan in advance.
This is because the terminal count signal 20 is output when the set number of words is reached by counting and comparing the number of times.

FIG. 4 is a schematic diagram showing details of the paper type sensor 1.

The paper type sensor 1 is a fat interrupter formed by a combination of a light emitting diode 27 and a photosensor 28, and is provided in a paper cassette mounting portion of the device housing 31. Transparent or translucent sheets 1 such as OHP sheets 29 are set in the paper cassette 1 30 .

Here, the light from the light emitting tie 127 passes through the sheet 1 29 and enters the photo 1 sensor 28, and the type of paper is determined.

FIG. 5 is a schematic diagram showing another embodiment of the present invention.

In the case of FIG. 4 above, if even one sheet of opaque paper is mixed in the paper cassette 30, the photo sensor 28 will not be exposed to light and printing will not be possible on the back side. Therefore, in order to avoid this, a light emitting diode 27 and a photosensor 28 are provided halfway between the paper cassette 1-30 and the printing section 32. Therefore, the type of paper on which printing is currently being attempted can be sensed, which is more effective.

Furthermore, it goes without saying that, instead of providing such a sensor, the same effect can be obtained by manually selecting the paper type from an operating section such as a panel.

[Effects of the Invention] q 10 According to the present invention, for a transparent or translucent sheet, by printing the printing pattern on the back side of the sheet with the print pattern reversed left and right, this sheet can be used as an OHP sheet, etc. without any problems. Moreover, it has the effect of allowing writing on the surface of the sheet and erasing it freely without damaging the printed image on the sheet.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. FIGS. 2(a) and 2(b) are schematic diagrams showing the printing method in the apparatus of the embodiment. FIG. 3 is a timing chart explaining the printing operation in the same embodiment. FIG. 4 is a schematic diagram showing details of the paper type sensor. FIG. 5 is a schematic diagram showing another embodiment of the present invention. 11 1...Paper type sensor, 5...Control unit, 6...Bitmap memory, IO...DMAC, 23...Selector, 25...Shift register, 27...Light emitting diode, 28...Photo sensor, 30...Paper strength set 1.

Claims (1)

[Scope of Claims] A printing device capable of printing on a transparent or translucent sheet, comprising: an identification means for identifying that the printing paper is a transparent or translucent sheet; and a means for temporarily storing pattern information to be printed on the sheet. an address control means for incrementing or decrementing for each line according to the paper type identified by the identification means when a video signal based on the pattern information is generated from the memory; A printing device comprising: bit control means for sequentially replacing the most significant bit to the least significant bit for each transfer word of a video signal when decrementing each line.